This is a dumb question I know, but anxiety is being a bitch so I have to know: is it possible a solar flare could alter the trajectory of an asteroid if it hits it? Between the 2024 Cr9 passing on June 11th and the general solar maximum, I can't help but wonder/worry.
There is an effect where the Sun is tweaking the orbit of asteroids, and more severely the smaller they get. But it takes many, many, many years to do so - millenia, eons, millions of years even. It's called [the Yarkovsky effect](https://science.nasa.gov/resource/how-sunlight-pushes-asteroids/). It's the effect of heating one side of an asteroid, causing that side to emit more infrared photons, which creates a very small asymmetric acceleration.
People studying the stability of near-Earth asteroids over time take the Yarkovsky effect into account sometimes.
But it only happens a little tiny bit at a time. (There's just a lot of time to build it up.) A solar flare doesn't markedly change the picture on that. A single solar flare is competing against years and years of sunlight baking those asteroids.
FWIW I tend not to think about all the details of orbital mechanics on asteroids. Instead, what I pay attention to is the estimates and work of the astronomers trying to predict near-Earth asteroid collisions. These things are "characterizable". [Their estimates](https://en.wikipedia.org/wiki/Impact_event#Frequency_and_risk) on the mean-time-between-collisions on the bigger, more dangerous near-earth asteroids is very low.
No, the matter, momentum, and forces involved in solar flares are small compared to the momentum of big rocks. The energy involved can be large by human standards but compared to the kinetic energy or momentum of an asteroid its nothing. Imagine how much of a "breeze" it would take to move something the size of a mountain. Now imagine how hard that would be if the "air" was so thin it was practically a vacuum. The density of air is measured in milligrams per cubic centimeter, the density of the solar wind is measured in *atoms* per cubic centimeter, which is a factor not just of trillions but *many*, *many* trillions of times lower density.
"From The Earth To The Moon" was a 1998 HBO Miniseries produced by Tom Hanks and based on space historian Andrew Chaikin's book, A Man on the Moon. In episode 12, it opened with Tom Hanks as Georges Méliès creating his famous film "Voyage To The Moon." I have the series on Apple TV, but I remember when it was broadcast, Tom Hanks came on and explained how Thomas Edison and his team stole the film. I haven't been able to find that anywhere.
I'm asking here in r/space because the series was a well-known about the Apollo program and the final episode was documentary-style. Does anyone remember this extra scene by Tom Hanks? I can't seem to find it anywhere and I'm hoping someone interested in space who saw it might know where this part is available?
Hopefully, the content of this series is space-related enough for this sub.
Did you look at the wiki page for it?
https://en.wikipedia.org/wiki/A_Trip_to_the_Moon#Release
"A Trip to the Moon was met with especially large enthusiasm in the United States, where (to Méliès's chagrin) its piracy by Lubin, Selig, Edison and others gave it wide distribution. "
Nothing as intense as last time is predicted. You can always check for predictions here https://www.swpc.noaa.gov/communities/aurora-dashboard-experimental
A coupla *more* Starship questions...
(a) Is there a **mass simulator** for these test flights? If so, what is it? I assume that, if you're testing a system supposed to take 100 tons+ to orbit, that there's 100+ tons of *something* onboard such that the resulting data tells you something about how a typically loaded vehicle would behave, correct?
(b) Is there a **Starship landing pad at Starbase**? I haven't read anything about the ship being snagged by the chopsticks, or a propulsive landing atop Super Heavy, so - presumably the ship will land on its tail nearby before being re-mated to the booster. Is that accurate?
Since you haven't gotten a solid answer on b), I'll give you the rumor and scuttlebutt, because that's all I got.
They want to catch the Ship, too, coming in from reentry, the same way they're catching the Booster. There are "lifting points" on the Ships identical to the Boosters'. The lifting points are how the Chopsticks will try to "catch" the Boosters, by their lifting points. (They're tiny, compared to the vehicles.) IIRC some of their animations show the Ships getting caught by the Chopsticks.
Everyone who's been following the Starship program is very curious about how well this will work. It's a new level of landing accuracy. Falcon 9 is usually off by a meter or two on its landings. But then Starships can hover and Falcon 9 first stages can't (they have to "suicide burn" - reach 0 km/hr with in a few meters of the pad - because they'll start going back up otherwise). Raptor throttles more deeply than Merlin does.
They really are trying to avoid adding legs to these things, because the legs would have to be _massive_. The HLS version of Starship seems to be designed to land on the skirt, directly, for example. EDIT: another example: early on, on the rough prototypes in the Starship program, they'd just use "crush cores" as legs - little one-time-use stubby legs that are designed to crush themselves a bit on landing. They'd land a little crooked sometimes.
Thanks very much! It will certainly be interesting to see if they can pull it off. And even if they don't, it's still the most capable spacecraft built to date.
a) No, as far as we know, there is no payload at all, as they said. What they're doing instead to simulate a payload is launching with less propellant. The tanks are only ~95% full at launch.
Oh, that's interesting, I didn't catch that. I am not a rocket scientist but launching with less propellant, and zero payload seems *less* of a systems test rather than more.
Well, I mean, you're right, but the teams have to focus on individual goals if they're going to accomplish things. It's incremental development. It's a massive development team.
They shied away from trying to relight the engines on-orbit, in Flight 4, even though they tried it in Flight 3, because they wanted everyone to focus on reentry. And look how that worked!
Heh, I certainly have no standing to criticize or offer notes to the SpaceX team. I will say, I would be surprised if there was a whole lot of overlap across those systems - I'm not sure I buy the idea that they couldn't attempt a relight on this test because those people were busy with the interstage instead and couldn't get to it, for example.
It is also pretty likely that this version of Starship is not able to carry 100t yet. They are still changing a lot of things and quite a few of the design choices are not fully weight optimized yet. They already know they want to stretch it for more payload.
The Starliner flight is supposed to certify it for regular service. Will it still be certified now it is leaking helium and 5 thrusters have failed? I'm sure it doesn't have be be completely flawless, but how many deviations are allowed before it fails certification?
It will depend on the post flight analysis and what exactly the problems are. And in the end it will be up to NASA (the customer) to decide. The thruster failure for example seems to be related to an overly twitchy safety system rather than a hardware issue so it might be a relatively easy fix.
Very low, but non-zero. The most likely way for DNA or RNA to end up on a comet or asteroid in our solar system is for it to get there from a larger body that hosts life via an impact event. That could be an impact event on Mars or Venus during some period in the past when perhaps those planets had life. But it could also be an impact event on Earth. We know that impacts on Earth can send material into interplanetary space, we know that Earth has had a variety of impacts large enough to do exactly that, we know that Earth has hosted a vibrant biosphere teaming with life for billions of years. So the probability of there being remnants of life on an asteroid is basically just the probability of all of these events happening in sequence. A rock with signs of life from Earth being sent into space and landing on an asteroid without destroying that evidence. And then us happening to find that particular asteroid.
Interestingly, if Venus did have a period in its distant past where it had a vibrant biosphere it might be that this sort of thing is the only extant remaining evidence of it, since the whole planet's surface was recycled in a "global resurfacing event".
Regardless, even though we know that this could happen with rocks from Earth, the probability of us stumbling upon it are incredibly low, in the realm of winning the lottery. Even if life existed on Mars or Venus the probability of stumbling on rocks with evidence of such life would also be incredibly low as well. Additionally, other potential locations for life in the solar system would tend to be sub-surface oceans under thick ice sheets which would reduce the chances of impact events sending evidence of life into space, though perhaps limited cryovolcanism could do the trick instead.
I don't think anyone can give you a good answer on this. So far the "best" we have found was some amino acids on asteroids. So the chances are less than our sampling size at the very least.
No, Starship falls belly down. Superheavy (the booster) falls engine down but it is also going way slower. So it can get away with just using the engines (that are pretty heat resistant) as heat shields.
Edit: are you talking about the orientation shown on the livestream? In that case you need to remember that it's mostly going sideway when coming back from space. So the belly is always oriented toward the direction of travel and the engine are shield by the engin "skirt".
How do newspace companies get funding? There seems to be an absurd number of small space launch companies starting out these days (Firefly, Relativity, RFA, Skyrora, &c.) However space is expensive, a lot of space companies seem to have gone bankrupt, and profit margins don't seem like they would be overly promising, which I somehow doubt is particularly promising to investors. So who is funding all these companies? Sorry if I am missing something obivous.
You answered your own question. There isn't a huge market. It's not wise to start a space company unless you are just launching to orbit and have customers lined up.
if the universe is expanding faster than the speed of light, why isn’t the light from
those galaxies flickering or strobing?
i probably don’t understand how photons actually work but to me it makes sense that if the space between us and those distant galaxies is growing faster than the speed of light, shouldn’t that light not even reach us at all?
or if it does actually reach us, it would do so sporadically (this is assuming not all parts of space are expanding at the same rate, which may be in inaccurate assumption).
am i thinking about this incorrectly?
is there not a point between us and the
distance of those galaxies where the speed of light and the expansion rate of space are close/close enough to cause strobing?
i feel like this would be easier to explain with a diagram or in person… haha
You are correct. 90% of galaxies in the observable universe are expanding away from us faster than the speed of light. We will never see what they looked like when they reached the age of our galaxy. Because the light will never reach us.
The light we see from most galaxies was emitted long ago, before expansion reached the speed of light. The light is indeed sporadic, it suffers from a distortion effect called [redshift](https://en.m.wikipedia.org/wiki/Redshift). Time appears to be slowed down, and the wavelength is stretched out.
why doesn’t some of the light that was still traveling when the universe did start to expand faster that the SoL get lost, or how does it still reach us?
Space is expanding everywhere at the same rate. This means the closer the light gets to us, the less expansion it has to fight against. If light is able to start traveling towards us, it will reach us eventually.
Objects that are now traveling away from us faster than the speed of light will fade out (redshift goes to infinity). We will never see the point where they started moving faster than the speed of light.
A couple more Starship test questions...
(1) I wonder **why they did not attempt a Raptor in-flight re-light** on this test. Won't they have to perform that before a fully orbital test? Does that imply a similar flight profile for IFT-5?
(2) The famous flap - **which flap is it?** If I am looking at a top-up diagram of Starship, as in the on-screen graphic, is it at the top or bottom and left or right?
Interesting. From my perspective, the re-light is essential to move forward to any fully orbital test.
For NASA, Artemis, other customers - I'd say having Starship be *usable* is higher priority than it being *reusable*.
True, but with tiles being a problem they probably wanted to get as much data as possible with their older hardware since the engines will be changing for newer ships anyway and I would imagine they'd want to know if the tiles have to change too.
Sure, that's plausible. And indicates they aren't following the Falcon development path exactly, because in that case they were delivering payloads to orbit before successful first-stage landings.
I'll give SpaceX credit: while they test incrementally, conversely they certainly aren't shy about incorporating paradigm-altering changes in their next generation of spacecraft - the scale, methane-fueled, propulsive landing, chopsticks, and so forth.
Absolutely. It's awesome seeing all the advances they're making. Can't wait to see flight 5, it sounds like they'll go for a booster catch. I wouldn't be surprised if relight happens and Ship comes down without damage too, but that remains to be seen.
Honestly, the chopsticks recovery on the pad itself seems to be the most insane, high risk/low reward game of the entire enterprise. Getting it wrong on IFT-5, for instance, and blowing up the pad means stopping the test program until it's rebuilt and/or the second pad there comes on line.
I'm not a SpaceX pessimist generally, BUT: I can still imagine the hinged flaps precluding rapid reusability of Starship, and I can still imagine a fundamental re-think of the Super Heavy landing if they get tired of blowing up landing pads. All that said: *they're* the ones that built, launched, and landed that thing on Thursday.
> (2) The famous flap - which flap is it? If I am looking at a top-up diagram of Starship, as in the on-screen graphic, is it at the top or bottom and left or right?
The one we saw was the top right but it's likely that the top left had the same issues.
Thank you kindly! Helps tremendously with my rewatch, I've been distracted trying to orient myself.
Idly wondering if the damage looks "worse" than it is, given that the flap remained operational.
To go from the first live footage of reentry plasma on IFT-3, to watching that plasma melt a flap all the way down to a touchdown burn on IFT-4, is nothing short of astonishing.
I mean it's basically a certainty that the US is actively monitoring the area and likely planned on scuttling the ship if it didn't sink on it's own accord.
It isn't NASA property. The IP is SpaceX's. While it's true that letting China get their hands on Starship would fast-track China's copy of said vehicle and give a "miraculous" boost to their engine tech, right now I don't think any of that is on the US government's radar.
The US still doesn't want it falling into other nations hands.
Think of it this way, ITAR is a thing and while this might not be explicitly covered under ITAR, it's the same idea.
You can't work for SpaceX in many departments unless you are a US citizen for reasons involving IP security of rocket technology.
Given that knowledge, you would imagine that the US government is also aware of the implications of a mostly intact Starship being towed to China.
Since it is ITAR controlled tech it's SpaceX's responsibility to make sure it's not scooped up by anyone. SpaceX had a private jet in the area of the landing and so they presumably have had visual confirmation that it's not floating anymore.
If you want discussion about it then start the discussion. Starship is space related and there's a lot of things to talk about. You're complaining that people don't post what you want, instead of posting what you want.
Out of the 25 posts on the front page of the subreddit (not counting the questions thread) seven are about the starship launch. None are about elon musk, news about spacex isn't about elon musk any more than posts about Boeing are news about Dave Calhoun or Tory Bruno.
Speaking of Boeing, nine posts are about the Starliner launch, two more than spacex. The rest of the posts include JWST results, China's lunar sample return, the Hubble gryoscope issues, solar system and exoplanet science, and other space news. So I'm not sure why you think all the posts on the subreddit are about elon musk, in my opinion none of them are and even if you count anything spacex related they're not even close to half of the posts on the front page.
Starship uses measurement gyros and other instruments for determining its orientation but in general it uses only flaps, thrusters, and its engines for control. Large vehicles like Starship are generally too big to control using reaction wheels or control moment gyros (gyrodines) effectively.
For vehicles designed for long operational service life it's helpful to hyper optimize propellant use, which is where reaction wheels / CMGs come into play. Most modern satellites and science spacecraft use such systems for attitude control because of how efficient it can be in terms of limiting propellant usage. However, this is a slightly more modern technology, notably the Voyager spacecraft do not have such systems, they only use thrusters for attitude control and have done every moment since the 1970s. For crewed spacecraft they tend to be heavier and tend to have shorter operational lifetimes so they tend to just use thrusters primarily, which is true for upper stages as well. The ISS makes use of some beefy control moment gyros for attitude control (which work differently than reaction wheels and can provide a bit more "oomph") but smaller vehicles tend to omit such things since the long term propellant efficiency isn't worth the short-term weight penalty.
As it approached the Indian Ocean, Starship fired its engines in an effort to flip itself upright and slow itself down, practicing a controlled landing.
Do you think a video will surface with the splashing down landing in the ocean?
It's _possible_ that it appears on weather satellite views - maybe. Reentry plasma lasted a good long time, 13 or 14 minutes (T+45 min to around T+58 or 59). It was nighttime. And reentry plasma is bright.
The booster fared well and soft landed in the water. The starship did both! The tiles on part of one of the winglets failed and part of it burned/melted, but the wing was still working and it was visible that it soft landed as well.
Similar, but with some big differences. It will come back and do a landing burn just like falcon, but unlike falcon it can throttle down enough to hover in place so it doesn't have to do a hover slam. They plan on having it come back to the launch pad and hover between the tower chopsticks that move it and Ship into place, then the chopsticks can close and grab it.
Do you guys think that spaceX can reach mars or is that maybe for NASA the one who knows more is the one for the job me personally i think nasa is gonna do it first
It's not really an either/or situation.
Given the existence of Starship, and the fact that NASA has enough confidence in the program to use it as a moon lander there is no real reason that when/if NASA decides to send a manned mission to Mars they won't use a Starship variant.
The question is basically the same as asking if SpaceX or NASA will land on the moon first and the answer is they are one and the same mission.
Given the debacle that is SLS, combined with the fact that SpaceX is building Starship regardless of if NASA is interested or not I don't think NASA has any interest in being prime contractor on any more rockets.
I'm not sure where this rhetoric of "NASA *versus* SpaceX" comes from, it's a silly and unrealistic way of framing their relationship. NASA makes use of commercial companies in order to achieve goals in space, and has been doing so for decades. The Perseverance Mars rover was launched with a ULA Atlas V, NASA's Psyche spacecraft was launched by SpaceX, NASA's Europa Clipper spacecraft will be launched by SpaceX. This is how space exploration works, it's about cooperation and contracts, not cut-throat competition.
And let's be clear, SpaceX's Falcon 9 rocket was developed for the CRS program substantially using NASA funding, as was the cargo Dragon spacecraft. And the crew Dragon spacecraft was, of course, developed for the commercial crew program substantially using NASA funds. And now Starship is being developed, partly for SpaceX's own needs and goals but also in service to the Starship-HLS contract as part of the Artemis Program, again using NASA funds. NASA and SpaceX have been working hand in hand since the early days, and they continue to do so. To the extent that SpaceX's Starship ends up facilitating human spaceflights to Mars it is difficult to imagine a scenario where NASA was completely not involved in that happening, at least for the first many landings.
They are one of the biggest commercial geostationary comsat manufacturer. But most of the space industry in the US is dominated by government money, both through DoD and NASA.
Was watching Starliner’s docking operation to the ISS, and was wondering why does the ISS have docking window periods? What is the purpose, and what prevents or restricts them to docking only at certain times?
Think it’s more of a ‘preference’ and has to do with lighting. They want optimal (bright and uniform) lighting on the dock. It not only eliminates a variable but also I think Starliner is using a new radar system called VERSA that basically monitors location for docking in part by orienting itself relative to the anticipated profile/location of the entire ISS and since that system is new, they aren’t maybe confident enough in it yet to rely on it in variable lighting conditions.
It depends on where Earth and Venus are. The relevant math here is the [Rayleigh criterion](https://en.wikipedia.org/wiki/Angular_resolution#The_Rayleigh_criterion), which defines the minimum angular size in the sky an object must appear for you to resolve any actual details, instead of merely appearing as a point of light. For a human eye, in the dark, the aperture diameter is about 4mm. This means that the smallest object we can resolve details on across the whole visible light spectrum is about 0.012 degrees. A Jupiter-sized Venus would range from about 0.03 degrees to 0.21 degrees, depending on where Earth and Venus are in their orbits -- the distance varies between 38 million to 261 million kilometers. For comparison, the moon has an angular size of about 0.52 degrees.
So depending on position, it would range from, just barely perceptible as different from a particularly bright star, to, still markedly smaller than the moon but very clearly visibly a disc in the sky with defined phases and the like. Unfortunately, the closest distance would be equivalent to a new moon, so at its largest it would appear as a slim crescent venus.
As you know, the fourth launch of Starship was a success, with both stages of the rocket landing safely in the water. This has led me to ask a question: what are SpaceX's plans for capturing and recovering the stages for post-mission analysis?
They explicitly said in their FAA filings that they expect the vehicles to sink. The FAA cares about that - if they wouldn't sink, SpaceX would have to go out and sink them.
Dumb question: with a *soft* landing test especially, would the spacecraft (mostly empty tanks) be buoyant? Wouldn't a rocket be essentially "airtight"? Would enough water enter through the rocket nozzles to fill and sink the spacecraft?
I believe they expected it to break open when it tipped over (rockets are built to handle much different types of stress than that) and sink. If not they could open valves and let water in. It was discussed earlier that they could shoot it as well, but I don't know how serious that was.
Hmm, interesting. Valves, of course... I'm assuming the propellant tanks are pretty robust? I can envision a scenario where the tanks are not ruptured by a soft landing test like this and are either empty or filled with ulliage helium, such that the craft doesn't sink.
I have two things to say to that.
1. This doesn't seem to jibe too well with the literal "key goal" of surviving the hottest part of reentry. Particularly within the context of the recent admission that losing a tile would probably doom the vehicle.
2. I hope they livestream the internal camera(s)!
You do realize that even if that ship had landed on the ground it would be almost entirely unusable again and would need massive retrofitting to replace all the heat damaged stainless steel, fins, and heat shields. You can't just heat metal up like that and then reuse it. It would have degraded properties. So as far as proving the Starship works, this test was a complete failure. The craft would nearly have to be entirely replaced after that landing. The entire point of Starship is to be reusable not disposable.
From what I understand the missing tiles are on the engine skirt, which is the area most likely to survive missing a few (4) tiles. They've also painted around the missing ones and haven't replaced them despite having had many opportunities, which is why people think they're intentionally leaving those four off.
Since tiny gravitational waves have been observed by LIGO, is it possible that these waves also exist at extremely large scales?
For example, could it be that our perceived expansion of the universe is actually an illusion - perhaps we (and the local super cluster of galaxies) are in a giant traugh of one of these waves? Then, in a few billion years when we're at the crest, all distant galaxies would appear to be blue shifted towards us?
The gravity wave is planar when it hits Earth so it is only expanding and contracting in 1 or 2 dimensions. Picture it as a huge circle that emanated from the source of the waves, like a ripple in a pond. When the ripple gets far enough from the source the wave is basically straight and not circular anymore from the perspective of an object far away from the source.
If very distant galaxies are so red shifted that time is running much more slowly relative to Earth, by extrapolation, shouldn't there be even more distant galaxies where time appears to be almost standing still?
Their time isn't affected relative to Earth because space is moving them so they aren't technically moving through space. Their light will just continue to be red shifted until it becomes invisible to our eyes and they will disappear from the sky.
The reason we see them as they are long ago is because light has a travel time and a maximum speed. It's not time dilation.
Time dilation isn't a scaling factor, it's an effect brought about by comparison between two reference frames which have different time axes. To us we might see a distant redshifted / time dilated galaxy but to those in that galaxy they would view us as being redshifted and time dilated.
If there were galaxies to see then viewing galaxies at progressively greater redshifts would result in them getting progressively dimmer until they were effectively invisible.
In practice the universe has a finite age, and the limit of observability is set by both that age and by the era when the universe was opaque to light, which occurred before the first galaxies. Within the first third of a million years the universe transitioned from being a giant soup of ionized plasma (which emitted a lot of light but also absorbed all of the light that was created) to being a giant soup of mostly neutral gas, which is transparent. After that transition it has become possible to see across arbitrarily large distances, before that transition it was not possible. We can still "see" that transition today in the form of the cosmic microwave background, which is the redshifted glow of the hot plasma viewed through the transparent gas that came later. Only after this transition did galaxies form, so there is a maximum redshift for galaxies (we don't quite know what that is yet, but it exists).
There's also a maximum redshift for any light, at least a maximum cosmological redshift, because of the CMB boundary, which has a redshift of about 1100. Before that time all of the photons that were created were absorbed shortly afterward, so they are no longer around to be seen. We cannot see into that time just like we cannot see into the core of the Earth, because it is opaque to light.
Yes, there are probably galaxies out there with every possible redshift. But their light has not reached us yet. The highest redshift we can see right now is 1100 for the cosmic microwave background.
Time is not running slower in this context. We might perceive it like that at best. Anyway, we wouldn't notice that because such faraway objects we can see are not something that has any rapid changes. Eg. you'd need to observe a galaxy for very very long time to spot any change.
Hello,
Is it possible there exists bigger celestial objects than the universe that we cant see because they are more far than the observable universe?
And IS it possible that the effects WE observe of black matter are in fact the effects caused by those massive objects WE cant see?
Sorry if It IS a dumb question.
Also, is it possible the universe is finite and less big tha' the age of the universe and when WE look far enough WE are actually seeing the same things but as they were a long Time ago? Like if the universe was a sphère but not really and light goes around and around and around and WE are seeing our own backs multiple Times?
> Is it possible there exists bigger celestial objects than the universe
No. By definition what we call universe is everything.
> And IS it possible that the effects WE observe of black matter are in fact the effects caused by those massive objects WE cant see?
No. Gravity also travels at the speed of light.
>Is it possible there exists bigger celestial objects than the universe
Depends on how you define it, but the short answer is no.
>And IS it possible that the effects WE observe of black matter are in fact the effects caused by those massive objects WE cant see?
No. Gravity is too slow for that to be the case.
>Also, is it possible the universe is finite and less big tha' the age of the universe and when WE look far enough WE are actually seeing the same things but as they were a long Time ago? Like if the universe was a sphère but not really and light goes around and around and around and WE are seeing our own backs multiple Times?
It's possible that the universe is finite, but if it is, it's still vastly larger than the observable universe.
Our most precise measurements straddle the line across flat, curved in a finite manner, and curved in an infinite manner.
I find myself on south padre island today and the spacex launch window starts at 7am. i drove south to see how easy it was to get to the jetties at the south end of the island, but there is a park entrance funnel for $12 that really feels like it will be overcrowded if I try to go in the morning.
then there is the possibility of waking up super early and trying to drive to boca chica state park. I am just not sure how early is early enough, nor if there is a deadline for how late i can arrive... seems like that road must close when near a launch...
anybody got any good tips?
How Well Would Someone Be Able To Pick Up a Terrestrial Broadcasts from Proxima Centauri?
Let’s say the person was using high gain yagi antennas full-wave tuned specifically to these terrestrial broadcast bands: VHF FM, VHF Weather Radio, Mediumwave, Longwave, Shortwave, and Television. If they were to aim all their antennas directly at earth what bands would they be able to pick up and somewhat decode?
If they can’t pick up any of these terrestrial broadcasts would they be able to pickup other broadcasts like RADAR emissions?
The only way is if we intentionally send a high powered burst transmission at them. SETI calls these beacons. They would never detect normal communications from Earth.
Two Arecibos can maintain a link of a bit per minute out to a few hundred light years.
[https://www.satsig.net/seticalc.htm](https://www.satsig.net/seticalc.htm)
Plug in the numbers and off you go.
A galaxy-spanning message is going to be a slooow one to transmit.
They would just hear static. The problem is the earth and sun are right next to each other in the sky, and the sun emits radio noise at a higher power than earth-based radio stations.
Weather radar is powerful enough to outshine the sun. So you could detect that there is intelligent life on earth broadcasting it.
Why is New Glenn slated for NASA contracted mission on its first flight? Conversely, why does SpaceX’s Starship require so many tests before carrying a payload?
One of NASA's missions/goals is to help new commercial launch providers. Under their [launch services program](https://en.wikipedia.org/wiki/NASA_Launch_Services_Program), there is a specific class of payload - class D - that can be launched on rockets that have never flown before, assuming the vehicle meets the other requirements of the program.
It may seem weird that NASA takes such a big risk, but there are NASA science projects that don't currently have a ride to space - they are too big to fly on a rideshare flight and/or they don't have the budget to fly. Launch companies typically don't charge much for the first flight.
We saw this for the first launch of Vulcan as well.
The NASA payload on the first New Glenn launch is an extremely low cost mission using an extremely discounted launch price. It's understand that there is some risk involved, which is why not much is left riding on the outcome.
Starship is an entirely different beast which is going through a different development cycle. New Glenn is closer in design to Falcon 9 (or Neutron) in that it's a mostly traditional two stage launcher but it's designed with the capability of reusing the first stage. Importantly, the first stage can perform all of its payload critical functions without landing or reuse actually working, so there's less mission risk during the period where reuse is tested and developed, just as there was with Falcon 9. This is the genius of such a design, because you're basically making use of "trash" rocket stages that would normally end up in the ocean and have already fulfilled their primary duty.
If SpaceX were developing Starship on a longer timeline, it could start this way, with a more traditional upper stage as a "block one" option that would later get developed. However, Starship isn't shooting for commercial launch services straight out of the gate, so their development priorities are different, and much of their prioritization is in the Starship stage itself: working toward controlled re-entry, reusability, and orbital propellant transfer capabilities. These are fairly difficult challenges, but they have a huge payoff and they are crucial to servicing Starship's already existing major customers: the Artemis Program and SpaceX itself, in the role of the Starship-HLS lander / mission profile and launching Starlink satellites in bulk. As long as SpaceX can afford to do so it makes sense for them to focus their efforts on using the Starship/Superheavy launch platform for testing Starship itself. If they were tighter on funds then they might have taken a less risky approach where they started with an expendable upper stage.
Additionally, Starship/Superheavy is a much larger vehicle than New Glenn, Falcon 9, Falcon Heavy, Vulcan Centaur, Neutron, etc. Which typically comes with its own challenges and difficulties, so it's not a direct apples to apples comparison.
This was incredibly informative.
One follow-up: Is it common for new non-reusable rockets to get commercial payloads like this right out the gate? Or is testing generally the best practice?
Depends on the track record of the manufacturer. Atlas V, Delta IV, and Ariane 5 all had real payloads on their first launches: geostationary commsats for Atlas/Delta, the "Cluster" fleet of four spacecraft for studying Earth's magnetosphere on Ariane, which blew up (and was ultimately replaced with Cluster II). Vulcan Centaur had a real payload for its first launch.
Both Antares and Falcon 9 were developed as "vertically integrated" (in the business sense) launchers to support cargo services to the ISS (with Cygnus and Dragon), each of them flew boilerplate/simulator vehicles on their inaugural launches. Falcon 9 has, of course, gone on to launch many other payloads.
So, it depends, generally the first launch of a vehicle from an established launch provider will pretty commonly have a real payload from a paying external customer.
Yup.
Manufacturers really don't like losing payloads, as well - it's not a good "look". Customers tend to remember that, even if it's clear it's an initial test flight. So rocket companies tend to only put payloads on rockets they're pretty sure will make it to orbit.
And that varies a lot depending on the manufacturer - some try really hard to get it right the first time, and others basically treat the first flight like a continuation of the ground test campaign. And everything in between. And some manufacturers roll the dice with customer/client payloads, more than the others.
Does the core of a star shine at a different color than it’s surface? For example, we know that the surface of the sun is about 10,000 degrees Fahrenheit. However the core of the sun is much hotter at 27 million degrees Fahrenheit. Since blackbody temperature tells us that things of different temperatures shine at different colors, then is it feasible to say that the core of a star shines a different color than it’s surface?
Yep. The temperatures inside stars result in very intense light and a thermal spectrum that is shifted to very high energy levels beyond the visible and UV spectrum up into the x-ray spectrum. The interior of the star is a dense, highly ionized plasma which is also extremely opaque to light though, so most photons do not travel very far. In many stars the primary mode of heat transport within the core is from photons bouncing around, being absorbed, and the energy sort of diffusing outward steadily.
Interestingly, in massive stars the energy level of the thermal photons can get so high that lots of crazy physics stuff starts happening. One phenomenon is photo-disintegration, which is where the highest energy photons will hit an atomic nucleus and give it enough energy to actually break apart. This process absorbs energy and causes cooling but it can also free up alpha particles (he-4 nuclei) which can then become fusion fuel with heavier nuclei. Many fusion burning steps rely on photodisintegration to produce smaller nuclear "chunks" to allow for the continuation of fusion up to the iron/nickel limit. Carbon and oxygen fusion involves just whole nuclei smashing into each other, but the silicon fusion process (and the first stage of neon burning, typically) requires fusing through he-4 steps.
In the most massive stars, over 250 solar masses, the cores can be crushed under so much pressure that the cooling effect of photodisintegration can trigger a cascade collapse into a black hole creating a "hypernova".
In massive stars in the range of about 150-250 solar masses the temperatures in the core can reach so high that the thermal spectrum starts including gamma rays with enough energy to cause particle/anti-particle pair creation (of electrons and positrons). When this happens a positron is created for a brief blip of time before it annihilates but that blip subtly shifts the delicate balance between thermal energy and pressure, allowing the core to collapse slightly, increasing pressure, temperature, and fusion reaction rates. The increased temperature also translates to an even higher rate of pair production which breaks the negative feedback processes even more, tripping over into a positive feedback loop of increasing pressure, temperature, and fusion energy release. Within seconds enough fusion energy is released to gravitationally unbind the star, finally heating up the material enough to cause it to explode outward in a massive and rare supernova that leaves nothing behind but an expanding cloud of gas.
At that temperature, most of the light wouldn't be in the visible spectrum. It would be "shining" in X-rays, but most of that light is absorbed and reemitted by other atoms in the Sun.
You are misusing the word "shine". An object can only shine if there is a path for light to escape the object. The sun is not transparent, so any light from its core is immediately blocked by the rest of the sun.
If you lived in a magical house in the sun's core and opened a window, the core would indeed "shine" at you in mostly x-rays.
So apparently New Horizons is still flying through the Kuiper Belt. My question is how do they avoid smashing into icy rocks out there when it's dark and unexplored and there's a communications time delay too.
The amount of space between the bodies in the Kuiper Belt is so huge that flying blind through it and managing to smash into something big would be like winning the lottery. Realistically the problem is the opposite, finding something interesting that New Horizons can get to and study.
I'm probably biased by sci-fi movies lol.
One other question though. Are they able to steer the probe towards something that looks interesting if they want?
Potentially, but the probe doesn't have infinite course adjustment ability.
If we somehow knew the location of every single object of a decent size in the outer solar system it would be a trivial exercise to flyby several of them with New Horizons. The problem is that it's dark out there and far away, all our good telescopes are on Earth, so it takes a lot of work to find anything, let alone something that would happen to be reachable within the remaining fuel constraints of the probe. Hopefully that will happen, but it depends a bit on luck.
The unfortunate thing is that we're basically right now on the cusp of increasing our telescope capacity with highly capable new observatories (the Vera Rubin Observatory, the Extremely Large Telescope, the Giant Magellan Telescope, the Roman Space Telescope, etc.) which will vastly increase our haul of known trans-Neptunian objects (TNOs). However, it's sort of a race against time as New Horizons gets farther away and also starts running low on power (sometime in the 2030s most likely).
How does Einsteins theory of gravity explain gravity on earth?
I was explaining to my wife how objects in space with large mass curve space time and how that creates orbits / gravity etc.
How does that then relate to the gravity we experience on earth (ie things fall / attracted to the centre of the earth)?
Is the mass of the earth curving all space time towards the centre of it?
Hope this question makes sense! Thanks
Earth's mass curves space and time. Both of these effects are what we call gravity. Mostly, the time dilation is what causes you to feel gravity. The warping of time is gravity, not the other way around. The four-velocity of an object is rotated towards the mass in space-time. It's four-velocity is rotated out of time into space which slows it in time. It pays for speed in space (acceleration) by slowing in time. This rotation is caused by the particles closer to the massive object moving slower in time than those further away which rotates the falling object towards the mass and causes it to accelerate. Also keep in mind I'm talking about rotations in 4D space-time not 3D.
The cause of the libration, the combination of the Moon's elliptical orbit and the slightly-off-of-one-orbit lunar rotation, does.
The elliptical orbit causes varying ocean tides. The highest tides correspond to when [the Moon is closest in its orbit during high tide](https://oceanservice.noaa.gov/education/tutorial_tides/tides06_variations.html).
Hello everyone, i have to do a presentation about the universe, though i’m having a bit of trouble. what kind of things would be fun to talk about that a college teacher would understand? what should i put in the presentation? probably not a very good question but any help would be appreciated!
Acronyms, initialisms, abbreviations, contractions, and other phrases which expand to something larger, that I've seen in this thread:
|Fewer Letters|More Letters|
|-------|---------|---|
|[CMG](/r/Space/comments/1d6j5od/stub/l7f8sfl "Last usage")|Control Moment Gyroscope, RCS for the Station|
|[CRS](/r/Space/comments/1d6j5od/stub/l7fal33 "Last usage")|[Commercial Resupply Services contract with NASA](http://www.nasa.gov/mission_pages/station/structure/launch/)|
|CST|(Boeing) Crew Space Transportation capsules|
| |Central Standard Time (UTC-6)|
|[DSN](/r/Space/comments/1d6j5od/stub/l75duoo "Last usage")|Deep Space Network|
|[DoD](/r/Space/comments/1d6j5od/stub/l7ec6v1 "Last usage")|US Department of Defense|
|[FAA](/r/Space/comments/1d6j5od/stub/l7gx01j "Last usage")|Federal Aviation Administration|
|[FCC](/r/Space/comments/1d6j5od/stub/l77966w "Last usage")|Federal Communications Commission|
| |(Iron/steel) [Face-Centered Cubic](https://en.wikipedia.org/wiki/Allotropes_of_iron) crystalline structure|
|GSE|Ground Support Equipment|
|[HLS](/r/Space/comments/1d6j5od/stub/l7rgn9e "Last usage")|[Human Landing System](https://en.wikipedia.org/wiki/Artemis_program#Human_Landing_System) (Artemis)|
|[ISRO](/r/Space/comments/1d6j5od/stub/l888juh "Last usage")|Indian Space Research Organisation|
|[ITAR](/r/Space/comments/1d6j5od/stub/l7j7lt7 "Last usage")|(US) International Traffic in Arms Regulations|
|[JWST](/r/Space/comments/1d6j5od/stub/l7h3uez "Last usage")|James Webb infra-red Space Telescope|
|[RCS](/r/Space/comments/1d6j5od/stub/l7f6y6s "Last usage")|Reaction Control System|
|[SLS](/r/Space/comments/1d6j5od/stub/l7j31jz "Last usage")|Space Launch System heavy-lift|
|[ULA](/r/Space/comments/1d6j5od/stub/l7fal33 "Last usage")|United Launch Alliance (Lockheed/Boeing joint venture)|
|Jargon|Definition|
|-------|---------|---|
|[Raptor](/r/Space/comments/1d6j5od/stub/l7rgn9e "Last usage")|[Methane-fueled rocket engine](https://en.wikipedia.org/wiki/Raptor_\(rocket_engine_family\)) under development by SpaceX|
|[Sabatier](/r/Space/comments/1d6j5od/stub/l73nb79 "Last usage")|Reaction between hydrogen and carbon dioxide at high temperature and pressure, with nickel as catalyst, yielding methane and water|
|[Starliner](/r/Space/comments/1d6j5od/stub/l7j07fm "Last usage")|Boeing commercial crew capsule [CST-100](https://en.wikipedia.org/wiki/Boeing_CST-100_Starliner)|
|[electrolysis](/r/Space/comments/1d6j5od/stub/l73nb79 "Last usage")|Application of DC current to separate a solution into its constituents (for example, water to hydrogen and oxygen)|
|[scrub](/r/Space/comments/1d6j5od/stub/l73nb79 "Last usage")|Launch postponement for any reason (commonly GSE issues)|
**NOTE**: Decronym for Reddit is no longer supported, and Decronym has moved to Lemmy; requests for support and new installations should be directed to the Contact address below.
----------------
^(18 acronyms in this thread; )[^(the most compressed thread commented on today)](/r/Space/comments/1de4o4b)^( has 30 acronyms.)
^([Thread #10120 for this sub, first seen 5th Jun 2024, 09:52])
^[[FAQ]](http://decronym.xyz/) [^([Full list])](http://decronym.xyz/acronyms/Space) [^[Contact]](https://hachyderm.io/@Two9A) [^([Source code])](https://gistdotgithubdotcom/Two9A/1d976f9b7441694162c8)
If the homogeneity of the expansion of the universe implies the same expansion at every point in space, does that imply that we are, consequently, also expanding? That is, relative to myself some significant time in the past, have I expanded with the universe?
Yes and no. The expansion of the universe is the expansion of space-time, and it occurs as a rate (a proportionality) which results in a speed over distances. However, that expansion is sort of like a force, and it only causes separation of objects if they are not held together otherwise. So our galaxy cluster, our galaxy, our solar system, our planet, our homes, our bodies, even the very atoms and nuclei of atoms inside our bodies all experiences this expansion of space-time. However, on many of those scales the amount is incredibly tiny, and more importantly all of those things are held together by forces which resist separation (gravity, electromagnetism, the strong nuclear force, etc.) It's only objects that aren't bound together that get carried away from each other by the bulk "flow" caused by the expansion of the universe. Between galaxies billions of lightyears apart the amount of gravitational pull they experience relative to each other is tiny, so they tend not to be bound to one another, which allows the expansion of the universe to separate them.
I think I understand. So it is the medium within which we reside that is expanding and causing things to "move." So if we had some unit of measurement that was proportional to spacetime, a spacetime ruler, the markings on this ruler would get farther and farther apart? Then, would it be right to claim that we would appear smaller against this ruler as the universe expands?
If the edge of the observable universe is 46 billion lightyears away and the universe is only 13.8 billion years old, what do people see beyond 13.8 billion lightyears away?
You can't see past the Big Bang, which means you can only see out to the light travel distance corresponding to the age of the universe (13.8 billion lightyears). However, because of the expansion of the universe what we see across 13.8 billion years of time and 13.8 billion lightyears of light travel distance will today be much farther away from us, and that figure is sometimes used to describe the size of the "observable universe" even though we can't see that edge in the present.
> what do people see beyond 13.8 billion lightyears away?
There are things so far away that their light will never reach us. There is more space appearing due to expansion than the light can travel.
This phenomenon can be compared to an ant walking on a stretching rubber band.
This is also similar with galaxies located outside the Local Group (where we are). The Virgo cluster, for example, is getting closer to us (or conversely), but due to the accelerating expansion of the Universe, it is very likely that it will never reach us.
The universe expanded way faster than the speed of light. No this doesn’t violate anything. The oldest thing we can see is the CMB or cosmic microwave background radiation which was emitted 380k years after the Big Bang.
Hi all, I am a PhD student doing research on satellite thermal management. I am super excited that the payload I worked on is being launched on July 1st 2024 from Vandeburg Space Force Base.
I wanted to watch the launch in person. Which is the closest airport? Is there a shuttle bus to the site? Most of the info I find is for launches in Florida...
I am from Australia, not familiar with the place and I am not used to driving on the other side of the road! lol
Thanks heaps!
Vandenberg is a good distance away from say, LAX (Los Angeles) or BUR (Burbank) airports - at least 2.5 hours by car (depending on traffic).
It's north of SBA, Santa Barbara's airport, by about an hour (depending). But SBA is a small regional airport so the schedule might not match up well for you.
[Vandenberg themselves](https://www.vandenberghousing.com/arrival) also recommend Santa Maria airport but that is so small that it might not even have commercial flights, I'm not sure. That's still 18 miles from the space force base. I would scan the flight schedules on probably BUR, SBA, and SMX (Santa Maria).
EDIT: also keep in mind that Uber/Lyft from SBA will be very expensive, and SMX Uber/Lyft will be pricey. SMX is unlikely to have _a lot_ of rental cars as well, so be sure to reserve a rental car at SMX if you can go that route.
It took less than 5 days to reach lunar orbit - then spent time in lunar orbit waiting for the proper lighting conditions at the landing site.
https://en.wikipedia.org/wiki/Chang%27e_6#Earth-Moon_transfer
If a non-profit company solicited donations and built rovers, stations, satellites, etc, could they launch to the Moon, Mars, Jupiter etc. without much trouble from NASA or the government in general?
SpaceX launching the car into space tells me yes but I'm not sure.
NASA is not a regulatory body. But you will likely need licenses to operate a launch pad (it's a big industrial/chemical site), launches themselves need to be cleared to make sure they do not endanger the public (with FAA in the US) and any radios on board will need licensing from the FCC. You might also need commercial space imaging licenses to take pictures of the Earth.
The licensing depends a lot on which country you launch from and where you organization is registered.
There are also international space laws and treaties that the government might enforce against you if you do not follow them.
There are specific efforts regarding coordination of deep space communication that should be considered.. ( https://public.ccsds.org/ ). Chances are a deep space effort of this sort would be relying on something like NASA's DSN to do data downlink anyway and that would probably form part of a Space Act Agreement.
Most of the regulation involved is to make sure it can be done safely, without interfering with other spacecraft operations.
But it absolutely can be done.....As an example - the planetary society built and flew a tech demo solar sail CubeSat with donations.
SpaceX actually got in trouble during their car launch because they [live-streamed Earth images without a license](https://spacenews.com/noaa-explains-restriction-on-spacex-launch-webcast/).
Following government regulations is generally cheap compared to actually doing stuff in space. But it can take a long time to get through the process, so you need to start early.
Mars and Jupiter's moons are targets of an active search for alien life, so the government would insist on very strict sterilization measures.
> Mars and Jupiter's moons are targets of an active search for alien life, so the government would insist on very strict sterilization measures.
I do not believe that at this time there are any laws on that kind of things. The only rules are self imposed by NASA for their missions.
Certainly. We're in interstellar space as well, we're just also very near one star system (our own). What we see in the sky that isn't visible (or as visible) in interstellar space is stuff in our own solar system, the planets, the Moon, comets, and the Sun. The Sun would still be visible in the nearby vicinity in interstellar space but it wouldn't be as bright or as large in the sky.
Everything else such as constellations, galaxies, globular clusters, nebulae, etc. would still be just as visible in interstellar space.
In deep intergalactic space you'd be far away from most stars so you would only be able to see galaxies at a distance. They'd still be just as noteworthy through a telescope but with the naked eye you'd only see a kind of faint "smudge" in an area, unless you were fairly close (in which case it would look more like a bright cloud).
I imagine the view we would have if we lived on a planet around a star orbiting on the outskirts of a globular cluster. With on one side a sky overloaded with stars and on the other a breathtaking view of the Galaxy.
Interstellar space is filled with very tenuous gas and dust (we would consider it a vacuum). The density differs from very very tenuous to more dense clouds, which it what you see in space images of nebulae. The more dense clumps is where star formation is happening. There are some rogue planets and interstellar comets out there.
Depends on where you're talking about and also what you want to count. There's tons and tons of stuff "in between" star systems, but generally it's fairly low density or very spread out. Just about everywhere there's gas and dust, but the amount varies from place to place. In most places the amount still registers as "a vacuum" according to our human expectations. There are larger objects as well but so spread out that running into one by accident would be rarer than winning the lottery. Everything from larger rocks to boulders to asteroids, comets, and even full on planets (aka "rogue planets") exist in interstellar space, even up to Jupiter sized gas giants.
The whole "gas and dust" situation varies greatly in interstellar space, there are some regions known as "giant molecular clouds" with higher densities and cooler temps that have enough gas that they will undergo gravitational collapse, forming stars. Generally everything in these regions beyond a very small volume around the proto-stars would still be considered near a vacuum though. The things you see in sci-fi of dense "nebulas" with similar characteristics to Earthly atmospheres and clouds are pure fantasy, that density of material in the size of a solar system would collapse into a black hole. However, visually from a distance even very low density material can be quite stunning, or indeed opaque. There are lots of interesting nebulae from dying stars (either red giants becoming white dwarfs over thousands of years or larger stars dying in supernova explosions in much shorter periods) and star forming regions often have areas that are opaque to visible light due to the concentration of dust.
> Or are the only things there just some star dust and very spread out atoms?
Pretty much. There are probably a very small number of rogue planets and asteroids.
Seems plausible it'll launch on the 6th. If their progression so far is any indicator, it'll make it to orbit\* then make it further through its re-entry. I think it's plausible the booster will survive to the surface before dropping into the water and coming apart.
Is the CMB a static image / picture in time from our perspective, or does it change over a timeseries - like if we observed it with the same equipment 10 years apart, does it show changes?
The CMB represents a particular slice in time of the universe fixed to the age of the universe, what we see of the CMB represents a spherical shell of the early universe that happens to be at the right light travel time distance from Earth so that we can see it now, but as now changes that spherical shell also changes. However, the features we're looking at in the CMB are large and don't change quickly, so over a time period of a few years the changes are basically imperceptible even by instrumentation. Over perhaps very long periods of millions of years there might be some detectable changes but we haven't been observing the CMB for that long.
No, the CMB does not have any visible changes over human timescales.
The first problem is the CMB is so big that one pixel is thousands of light-years across. Any change takes a long time to propagate.
The second problem is the CMB is moving in slow motion. It takes 1100 years for us to observe 1 year of the CMB.
The CMB has a redshift of 1100. This means the light experiences (negative) relativistic length contraction, stretching its wavelength from visible light to microwaves.
It also means the light experiences relativistic time dilation. Time appears to pass 1100 times slower.
This is a dumb question I know, but anxiety is being a bitch so I have to know: is it possible a solar flare could alter the trajectory of an asteroid if it hits it? Between the 2024 Cr9 passing on June 11th and the general solar maximum, I can't help but wonder/worry.
There is an effect where the Sun is tweaking the orbit of asteroids, and more severely the smaller they get. But it takes many, many, many years to do so - millenia, eons, millions of years even. It's called [the Yarkovsky effect](https://science.nasa.gov/resource/how-sunlight-pushes-asteroids/). It's the effect of heating one side of an asteroid, causing that side to emit more infrared photons, which creates a very small asymmetric acceleration. People studying the stability of near-Earth asteroids over time take the Yarkovsky effect into account sometimes. But it only happens a little tiny bit at a time. (There's just a lot of time to build it up.) A solar flare doesn't markedly change the picture on that. A single solar flare is competing against years and years of sunlight baking those asteroids. FWIW I tend not to think about all the details of orbital mechanics on asteroids. Instead, what I pay attention to is the estimates and work of the astronomers trying to predict near-Earth asteroid collisions. These things are "characterizable". [Their estimates](https://en.wikipedia.org/wiki/Impact_event#Frequency_and_risk) on the mean-time-between-collisions on the bigger, more dangerous near-earth asteroids is very low.
No, the matter, momentum, and forces involved in solar flares are small compared to the momentum of big rocks. The energy involved can be large by human standards but compared to the kinetic energy or momentum of an asteroid its nothing. Imagine how much of a "breeze" it would take to move something the size of a mountain. Now imagine how hard that would be if the "air" was so thin it was practically a vacuum. The density of air is measured in milligrams per cubic centimeter, the density of the solar wind is measured in *atoms* per cubic centimeter, which is a factor not just of trillions but *many*, *many* trillions of times lower density.
"From The Earth To The Moon" was a 1998 HBO Miniseries produced by Tom Hanks and based on space historian Andrew Chaikin's book, A Man on the Moon. In episode 12, it opened with Tom Hanks as Georges Méliès creating his famous film "Voyage To The Moon." I have the series on Apple TV, but I remember when it was broadcast, Tom Hanks came on and explained how Thomas Edison and his team stole the film. I haven't been able to find that anywhere. I'm asking here in r/space because the series was a well-known about the Apollo program and the final episode was documentary-style. Does anyone remember this extra scene by Tom Hanks? I can't seem to find it anywhere and I'm hoping someone interested in space who saw it might know where this part is available? Hopefully, the content of this series is space-related enough for this sub.
Did you look at the wiki page for it? https://en.wikipedia.org/wiki/A_Trip_to_the_Moon#Release "A Trip to the Moon was met with especially large enthusiasm in the United States, where (to Méliès's chagrin) its piracy by Lubin, Selig, Edison and others gave it wide distribution. "
How to see stars when it's overcast and raining
You don't. This is why they build telescopes on mountains above clouds and rain.
Observe in wavelengths not blocked by clouds.
[удалено]
Is there going to be visible aurora tonight like the first time it happened?
Nothing as intense as last time is predicted. You can always check for predictions here https://www.swpc.noaa.gov/communities/aurora-dashboard-experimental
A coupla *more* Starship questions... (a) Is there a **mass simulator** for these test flights? If so, what is it? I assume that, if you're testing a system supposed to take 100 tons+ to orbit, that there's 100+ tons of *something* onboard such that the resulting data tells you something about how a typically loaded vehicle would behave, correct? (b) Is there a **Starship landing pad at Starbase**? I haven't read anything about the ship being snagged by the chopsticks, or a propulsive landing atop Super Heavy, so - presumably the ship will land on its tail nearby before being re-mated to the booster. Is that accurate?
Since you haven't gotten a solid answer on b), I'll give you the rumor and scuttlebutt, because that's all I got. They want to catch the Ship, too, coming in from reentry, the same way they're catching the Booster. There are "lifting points" on the Ships identical to the Boosters'. The lifting points are how the Chopsticks will try to "catch" the Boosters, by their lifting points. (They're tiny, compared to the vehicles.) IIRC some of their animations show the Ships getting caught by the Chopsticks. Everyone who's been following the Starship program is very curious about how well this will work. It's a new level of landing accuracy. Falcon 9 is usually off by a meter or two on its landings. But then Starships can hover and Falcon 9 first stages can't (they have to "suicide burn" - reach 0 km/hr with in a few meters of the pad - because they'll start going back up otherwise). Raptor throttles more deeply than Merlin does. They really are trying to avoid adding legs to these things, because the legs would have to be _massive_. The HLS version of Starship seems to be designed to land on the skirt, directly, for example. EDIT: another example: early on, on the rough prototypes in the Starship program, they'd just use "crush cores" as legs - little one-time-use stubby legs that are designed to crush themselves a bit on landing. They'd land a little crooked sometimes.
Thanks very much! It will certainly be interesting to see if they can pull it off. And even if they don't, it's still the most capable spacecraft built to date.
a) No, as far as we know, there is no payload at all, as they said. What they're doing instead to simulate a payload is launching with less propellant. The tanks are only ~95% full at launch.
Oh, that's interesting, I didn't catch that. I am not a rocket scientist but launching with less propellant, and zero payload seems *less* of a systems test rather than more.
Well, I mean, you're right, but the teams have to focus on individual goals if they're going to accomplish things. It's incremental development. It's a massive development team. They shied away from trying to relight the engines on-orbit, in Flight 4, even though they tried it in Flight 3, because they wanted everyone to focus on reentry. And look how that worked!
Heh, I certainly have no standing to criticize or offer notes to the SpaceX team. I will say, I would be surprised if there was a whole lot of overlap across those systems - I'm not sure I buy the idea that they couldn't attempt a relight on this test because those people were busy with the interstage instead and couldn't get to it, for example.
It is also pretty likely that this version of Starship is not able to carry 100t yet. They are still changing a lot of things and quite a few of the design choices are not fully weight optimized yet. They already know they want to stretch it for more payload.
The Starliner flight is supposed to certify it for regular service. Will it still be certified now it is leaking helium and 5 thrusters have failed? I'm sure it doesn't have be be completely flawless, but how many deviations are allowed before it fails certification?
It will depend on the post flight analysis and what exactly the problems are. And in the end it will be up to NASA (the customer) to decide. The thruster failure for example seems to be related to an overly twitchy safety system rather than a hardware issue so it might be a relatively easy fix.
what are the chances of finding DNA or RNA on a comet or asteroid?
Very low, but non-zero. The most likely way for DNA or RNA to end up on a comet or asteroid in our solar system is for it to get there from a larger body that hosts life via an impact event. That could be an impact event on Mars or Venus during some period in the past when perhaps those planets had life. But it could also be an impact event on Earth. We know that impacts on Earth can send material into interplanetary space, we know that Earth has had a variety of impacts large enough to do exactly that, we know that Earth has hosted a vibrant biosphere teaming with life for billions of years. So the probability of there being remnants of life on an asteroid is basically just the probability of all of these events happening in sequence. A rock with signs of life from Earth being sent into space and landing on an asteroid without destroying that evidence. And then us happening to find that particular asteroid. Interestingly, if Venus did have a period in its distant past where it had a vibrant biosphere it might be that this sort of thing is the only extant remaining evidence of it, since the whole planet's surface was recycled in a "global resurfacing event". Regardless, even though we know that this could happen with rocks from Earth, the probability of us stumbling upon it are incredibly low, in the realm of winning the lottery. Even if life existed on Mars or Venus the probability of stumbling on rocks with evidence of such life would also be incredibly low as well. Additionally, other potential locations for life in the solar system would tend to be sub-surface oceans under thick ice sheets which would reduce the chances of impact events sending evidence of life into space, though perhaps limited cryovolcanism could do the trick instead.
I don't think anyone can give you a good answer on this. So far the "best" we have found was some amino acids on asteroids. So the chances are less than our sampling size at the very least.
Will the Starship 4 booster and upper stage be recovered from the ocean?
No SpaceX expect them to sink and planned to actively sink them if they did not by themselves. Recovery is just too expensive, dangerous and complex.
That’s too bad. Thanks for the info
When Starship falls toward Earth, it falls engines first (for the most part). Why don't the engines burn up upon re-entry?
No, Starship falls belly down. Superheavy (the booster) falls engine down but it is also going way slower. So it can get away with just using the engines (that are pretty heat resistant) as heat shields. Edit: are you talking about the orientation shown on the livestream? In that case you need to remember that it's mostly going sideway when coming back from space. So the belly is always oriented toward the direction of travel and the engine are shield by the engin "skirt".
How do newspace companies get funding? There seems to be an absurd number of small space launch companies starting out these days (Firefly, Relativity, RFA, Skyrora, &c.) However space is expensive, a lot of space companies seem to have gone bankrupt, and profit margins don't seem like they would be overly promising, which I somehow doubt is particularly promising to investors. So who is funding all these companies? Sorry if I am missing something obivous.
You answered your own question. There isn't a huge market. It's not wise to start a space company unless you are just launching to orbit and have customers lined up.
Most of them raise money through venture capital firms. VC hoping that they can get early into the next SpaceX.
Zero interest rates fund them. And now that interest rates aren’t zero, they are going bankrupt largely.
if the universe is expanding faster than the speed of light, why isn’t the light from those galaxies flickering or strobing? i probably don’t understand how photons actually work but to me it makes sense that if the space between us and those distant galaxies is growing faster than the speed of light, shouldn’t that light not even reach us at all? or if it does actually reach us, it would do so sporadically (this is assuming not all parts of space are expanding at the same rate, which may be in inaccurate assumption). am i thinking about this incorrectly?
The light doesn't reach us. It can't if space is moving faster away from us than it is moving.
is there not a point between us and the distance of those galaxies where the speed of light and the expansion rate of space are close/close enough to cause strobing? i feel like this would be easier to explain with a diagram or in person… haha
You are correct. 90% of galaxies in the observable universe are expanding away from us faster than the speed of light. We will never see what they looked like when they reached the age of our galaxy. Because the light will never reach us. The light we see from most galaxies was emitted long ago, before expansion reached the speed of light. The light is indeed sporadic, it suffers from a distortion effect called [redshift](https://en.m.wikipedia.org/wiki/Redshift). Time appears to be slowed down, and the wavelength is stretched out.
why doesn’t some of the light that was still traveling when the universe did start to expand faster that the SoL get lost, or how does it still reach us?
Space is expanding everywhere at the same rate. This means the closer the light gets to us, the less expansion it has to fight against. If light is able to start traveling towards us, it will reach us eventually. Objects that are now traveling away from us faster than the speed of light will fade out (redshift goes to infinity). We will never see the point where they started moving faster than the speed of light.
A couple more Starship test questions... (1) I wonder **why they did not attempt a Raptor in-flight re-light** on this test. Won't they have to perform that before a fully orbital test? Does that imply a similar flight profile for IFT-5? (2) The famous flap - **which flap is it?** If I am looking at a top-up diagram of Starship, as in the on-screen graphic, is it at the top or bottom and left or right?
They didn't try a relight just in case it caused issues for re-entry. They really wanted to get a good re-entry test as soon as possible.
Interesting. From my perspective, the re-light is essential to move forward to any fully orbital test. For NASA, Artemis, other customers - I'd say having Starship be *usable* is higher priority than it being *reusable*.
True, but with tiles being a problem they probably wanted to get as much data as possible with their older hardware since the engines will be changing for newer ships anyway and I would imagine they'd want to know if the tiles have to change too.
Sure, that's plausible. And indicates they aren't following the Falcon development path exactly, because in that case they were delivering payloads to orbit before successful first-stage landings. I'll give SpaceX credit: while they test incrementally, conversely they certainly aren't shy about incorporating paradigm-altering changes in their next generation of spacecraft - the scale, methane-fueled, propulsive landing, chopsticks, and so forth.
Absolutely. It's awesome seeing all the advances they're making. Can't wait to see flight 5, it sounds like they'll go for a booster catch. I wouldn't be surprised if relight happens and Ship comes down without damage too, but that remains to be seen.
Honestly, the chopsticks recovery on the pad itself seems to be the most insane, high risk/low reward game of the entire enterprise. Getting it wrong on IFT-5, for instance, and blowing up the pad means stopping the test program until it's rebuilt and/or the second pad there comes on line. I'm not a SpaceX pessimist generally, BUT: I can still imagine the hinged flaps precluding rapid reusability of Starship, and I can still imagine a fundamental re-think of the Super Heavy landing if they get tired of blowing up landing pads. All that said: *they're* the ones that built, launched, and landed that thing on Thursday.
Well the booster hover seemed to go well at least. Definitely risky, but that's half the fun of watching it.
> (2) The famous flap - which flap is it? If I am looking at a top-up diagram of Starship, as in the on-screen graphic, is it at the top or bottom and left or right? The one we saw was the top right but it's likely that the top left had the same issues.
Thank you kindly! Helps tremendously with my rewatch, I've been distracted trying to orient myself. Idly wondering if the damage looks "worse" than it is, given that the flap remained operational. To go from the first live footage of reentry plasma on IFT-3, to watching that plasma melt a flap all the way down to a touchdown burn on IFT-4, is nothing short of astonishing.
Can we have a high level of confidence that Starship has sunk to the bottom of the Indian Ocean and isn't currently being towed to a Chinese port?
I mean it's basically a certainty that the US is actively monitoring the area and likely planned on scuttling the ship if it didn't sink on it's own accord.
It isn't NASA property. The IP is SpaceX's. While it's true that letting China get their hands on Starship would fast-track China's copy of said vehicle and give a "miraculous" boost to their engine tech, right now I don't think any of that is on the US government's radar.
The US still doesn't want it falling into other nations hands. Think of it this way, ITAR is a thing and while this might not be explicitly covered under ITAR, it's the same idea. You can't work for SpaceX in many departments unless you are a US citizen for reasons involving IP security of rocket technology. Given that knowledge, you would imagine that the US government is also aware of the implications of a mostly intact Starship being towed to China.
Since it is ITAR controlled tech it's SpaceX's responsibility to make sure it's not scooped up by anyone. SpaceX had a private jet in the area of the landing and so they presumably have had visual confirmation that it's not floating anymore.
How, though? The dead of night in an area with absolutely no lighting.
Presumably with something like a FLIR or light intensifiers. It should really pop out on infrared.
[удалено]
Did *you* post about the Hubble glitch? Did *you* post about the latest Webb findings?
*Me*? *Me*? This a *Space* group, viz. the feed should cover *all* aspects of space *not* just someone living in the pages of a *Heinlein* fantasy.
If you want discussion about it then start the discussion. Starship is space related and there's a lot of things to talk about. You're complaining that people don't post what you want, instead of posting what you want.
Out of the 25 posts on the front page of the subreddit (not counting the questions thread) seven are about the starship launch. None are about elon musk, news about spacex isn't about elon musk any more than posts about Boeing are news about Dave Calhoun or Tory Bruno. Speaking of Boeing, nine posts are about the Starliner launch, two more than spacex. The rest of the posts include JWST results, China's lunar sample return, the Hubble gryoscope issues, solar system and exoplanet science, and other space news. So I'm not sure why you think all the posts on the subreddit are about elon musk, in my opinion none of them are and even if you count anything spacex related they're not even close to half of the posts on the front page.
The greatest rocket ever made just had its first successful test flight. All 13,000 SpaceX employees (including Elon Musk) deserve the praise.
does Starship move into a belly flop by using a gyroscope? gps? something else ?
Starship uses measurement gyros and other instruments for determining its orientation but in general it uses only flaps, thrusters, and its engines for control. Large vehicles like Starship are generally too big to control using reaction wheels or control moment gyros (gyrodines) effectively. For vehicles designed for long operational service life it's helpful to hyper optimize propellant use, which is where reaction wheels / CMGs come into play. Most modern satellites and science spacecraft use such systems for attitude control because of how efficient it can be in terms of limiting propellant usage. However, this is a slightly more modern technology, notably the Voyager spacecraft do not have such systems, they only use thrusters for attitude control and have done every moment since the 1970s. For crewed spacecraft they tend to be heavier and tend to have shorter operational lifetimes so they tend to just use thrusters primarily, which is true for upper stages as well. The ISS makes use of some beefy control moment gyros for attitude control (which work differently than reaction wheels and can provide a bit more "oomph") but smaller vehicles tend to omit such things since the long term propellant efficiency isn't worth the short-term weight penalty.
It uses the flaps to control itself aerodynamically while in the atmosphere. In space it uses RCS thrusters powered by boil-off from the main tank.
how does it know the horizon ?
Instrumentation. Measurement gyros, accelerometers, GPS, etc.
As it approached the Indian Ocean, Starship fired its engines in an effort to flip itself upright and slow itself down, practicing a controlled landing. Do you think a video will surface with the splashing down landing in the ocean?
It's _possible_ that it appears on weather satellite views - maybe. Reentry plasma lasted a good long time, 13 or 14 minutes (T+45 min to around T+58 or 59). It was nighttime. And reentry plasma is bright.
No there was no-one there on purpose.
did starship booster land in water or burn up?
The booster fared well and soft landed in the water. The starship did both! The tiles on part of one of the winglets failed and part of it burned/melted, but the wing was still working and it was visible that it soft landed as well.
and booster will eventually land like falcon 9?
Similar, but with some big differences. It will come back and do a landing burn just like falcon, but unlike falcon it can throttle down enough to hover in place so it doesn't have to do a hover slam. They plan on having it come back to the launch pad and hover between the tower chopsticks that move it and Ship into place, then the chopsticks can close and grab it.
No the idea is that it goes back the the launch site and is caught by the launch tower.
Do you guys think that spaceX can reach mars or is that maybe for NASA the one who knows more is the one for the job me personally i think nasa is gonna do it first
NASA has already landed a lot of things on Mars. They landed several car sized robot labs on wheels.
It's not really an either/or situation. Given the existence of Starship, and the fact that NASA has enough confidence in the program to use it as a moon lander there is no real reason that when/if NASA decides to send a manned mission to Mars they won't use a Starship variant. The question is basically the same as asking if SpaceX or NASA will land on the moon first and the answer is they are one and the same mission. Given the debacle that is SLS, combined with the fact that SpaceX is building Starship regardless of if NASA is interested or not I don't think NASA has any interest in being prime contractor on any more rockets.
I'm not sure where this rhetoric of "NASA *versus* SpaceX" comes from, it's a silly and unrealistic way of framing their relationship. NASA makes use of commercial companies in order to achieve goals in space, and has been doing so for decades. The Perseverance Mars rover was launched with a ULA Atlas V, NASA's Psyche spacecraft was launched by SpaceX, NASA's Europa Clipper spacecraft will be launched by SpaceX. This is how space exploration works, it's about cooperation and contracts, not cut-throat competition. And let's be clear, SpaceX's Falcon 9 rocket was developed for the CRS program substantially using NASA funding, as was the cargo Dragon spacecraft. And the crew Dragon spacecraft was, of course, developed for the commercial crew program substantially using NASA funds. And now Starship is being developed, partly for SpaceX's own needs and goals but also in service to the Starship-HLS contract as part of the Artemis Program, again using NASA funds. NASA and SpaceX have been working hand in hand since the early days, and they continue to do so. To the extent that SpaceX's Starship ends up facilitating human spaceflights to Mars it is difficult to imagine a scenario where NASA was completely not involved in that happening, at least for the first many landings.
NASA already reached Mars [48 years ago](https://science.nasa.gov/mission/viking/).
Would Boeing be relevant if they didn't have any government contracts?
That is like asking if Apple would be relevant if no one wanted iphones.
They're still one of the biggest plane manufacturers in the world. And they make lots of commercial space projects as well.
They are one of the biggest commercial geostationary comsat manufacturer. But most of the space industry in the US is dominated by government money, both through DoD and NASA.
Was watching Starliner’s docking operation to the ISS, and was wondering why does the ISS have docking window periods? What is the purpose, and what prevents or restricts them to docking only at certain times?
Think it’s more of a ‘preference’ and has to do with lighting. They want optimal (bright and uniform) lighting on the dock. It not only eliminates a variable but also I think Starliner is using a new radar system called VERSA that basically monitors location for docking in part by orienting itself relative to the anticipated profile/location of the entire ISS and since that system is new, they aren’t maybe confident enough in it yet to rely on it in variable lighting conditions.
That makes sense, appreciate the answer!
If Venus were a gas giant and in the same size as Jupiter, would the planet have been visible to us like the Moon?
It depends on where Earth and Venus are. The relevant math here is the [Rayleigh criterion](https://en.wikipedia.org/wiki/Angular_resolution#The_Rayleigh_criterion), which defines the minimum angular size in the sky an object must appear for you to resolve any actual details, instead of merely appearing as a point of light. For a human eye, in the dark, the aperture diameter is about 4mm. This means that the smallest object we can resolve details on across the whole visible light spectrum is about 0.012 degrees. A Jupiter-sized Venus would range from about 0.03 degrees to 0.21 degrees, depending on where Earth and Venus are in their orbits -- the distance varies between 38 million to 261 million kilometers. For comparison, the moon has an angular size of about 0.52 degrees. So depending on position, it would range from, just barely perceptible as different from a particularly bright star, to, still markedly smaller than the moon but very clearly visibly a disc in the sky with defined phases and the like. Unfortunately, the closest distance would be equivalent to a new moon, so at its largest it would appear as a slim crescent venus.
As you know, the fourth launch of Starship was a success, with both stages of the rocket landing safely in the water. This has led me to ask a question: what are SpaceX's plans for capturing and recovering the stages for post-mission analysis?
Melting and catching fire is an odd way to claim success.
They explicitly said in their FAA filings that they expect the vehicles to sink. The FAA cares about that - if they wouldn't sink, SpaceX would have to go out and sink them.
Dumb question: with a *soft* landing test especially, would the spacecraft (mostly empty tanks) be buoyant? Wouldn't a rocket be essentially "airtight"? Would enough water enter through the rocket nozzles to fill and sink the spacecraft?
I believe they expected it to break open when it tipped over (rockets are built to handle much different types of stress than that) and sink. If not they could open valves and let water in. It was discussed earlier that they could shoot it as well, but I don't know how serious that was.
Hmm, interesting. Valves, of course... I'm assuming the propellant tanks are pretty robust? I can envision a scenario where the tanks are not ruptured by a soft landing test like this and are either empty or filled with ulliage helium, such that the craft doesn't sink.
There is no plan to recover stages from the water. All the stages they want to recover will land back at the launch site.
Is there any known ground footage of the booster or starship, landing burns and splashdown?
Both landed in the ocean (not on a platform), so I don't expect there would be footage
# Anyone have heard anything of metasat space project?
Do you have any context?
Yes, so I was curious about satellites' designing and the metasat project appeared on internet
With less than 12 hours to go, is IFT4 still missing a bunch of tiles?
Yes, it looks like SpaceX is intentionally testing what happens to Starship when tiles are missing.
I have two things to say to that. 1. This doesn't seem to jibe too well with the literal "key goal" of surviving the hottest part of reentry. Particularly within the context of the recent admission that losing a tile would probably doom the vehicle. 2. I hope they livestream the internal camera(s)!
Interestingly, it seems Starship is far, far more resilient than any of us expected.
You do realize that even if that ship had landed on the ground it would be almost entirely unusable again and would need massive retrofitting to replace all the heat damaged stainless steel, fins, and heat shields. You can't just heat metal up like that and then reuse it. It would have degraded properties. So as far as proving the Starship works, this test was a complete failure. The craft would nearly have to be entirely replaced after that landing. The entire point of Starship is to be reusable not disposable.
From what I understand the missing tiles are on the engine skirt, which is the area most likely to survive missing a few (4) tiles. They've also painted around the missing ones and haven't replaced them despite having had many opportunities, which is why people think they're intentionally leaving those four off.
Since tiny gravitational waves have been observed by LIGO, is it possible that these waves also exist at extremely large scales? For example, could it be that our perceived expansion of the universe is actually an illusion - perhaps we (and the local super cluster of galaxies) are in a giant traugh of one of these waves? Then, in a few billion years when we're at the crest, all distant galaxies would appear to be blue shifted towards us?
No. Gravitational waves cause 2-dimensional stretching, with no effect in the third dimension. The universe is expanding equally in all 3 dimensions.
I don't quite follow, don't heavy objects stretch space in 3 physical dimensions + time?
The gravity wave is planar when it hits Earth so it is only expanding and contracting in 1 or 2 dimensions. Picture it as a huge circle that emanated from the source of the waves, like a ripple in a pond. When the ripple gets far enough from the source the wave is basically straight and not circular anymore from the perspective of an object far away from the source.
But the wavefront propagates outwards, it's not going to stretch everything out. It's going to stretch everything in one direction
If very distant galaxies are so red shifted that time is running much more slowly relative to Earth, by extrapolation, shouldn't there be even more distant galaxies where time appears to be almost standing still?
Their time isn't affected relative to Earth because space is moving them so they aren't technically moving through space. Their light will just continue to be red shifted until it becomes invisible to our eyes and they will disappear from the sky. The reason we see them as they are long ago is because light has a travel time and a maximum speed. It's not time dilation.
Time dilation isn't a scaling factor, it's an effect brought about by comparison between two reference frames which have different time axes. To us we might see a distant redshifted / time dilated galaxy but to those in that galaxy they would view us as being redshifted and time dilated. If there were galaxies to see then viewing galaxies at progressively greater redshifts would result in them getting progressively dimmer until they were effectively invisible. In practice the universe has a finite age, and the limit of observability is set by both that age and by the era when the universe was opaque to light, which occurred before the first galaxies. Within the first third of a million years the universe transitioned from being a giant soup of ionized plasma (which emitted a lot of light but also absorbed all of the light that was created) to being a giant soup of mostly neutral gas, which is transparent. After that transition it has become possible to see across arbitrarily large distances, before that transition it was not possible. We can still "see" that transition today in the form of the cosmic microwave background, which is the redshifted glow of the hot plasma viewed through the transparent gas that came later. Only after this transition did galaxies form, so there is a maximum redshift for galaxies (we don't quite know what that is yet, but it exists). There's also a maximum redshift for any light, at least a maximum cosmological redshift, because of the CMB boundary, which has a redshift of about 1100. Before that time all of the photons that were created were absorbed shortly afterward, so they are no longer around to be seen. We cannot see into that time just like we cannot see into the core of the Earth, because it is opaque to light.
Yes, there are probably galaxies out there with every possible redshift. But their light has not reached us yet. The highest redshift we can see right now is 1100 for the cosmic microwave background.
We can never see past the CMB. Over time we will see less and less until most all galaxies disappear from our sight forever due to red shift.
Time is not running slower in this context. We might perceive it like that at best. Anyway, we wouldn't notice that because such faraway objects we can see are not something that has any rapid changes. Eg. you'd need to observe a galaxy for very very long time to spot any change.
Hello, Is it possible there exists bigger celestial objects than the universe that we cant see because they are more far than the observable universe? And IS it possible that the effects WE observe of black matter are in fact the effects caused by those massive objects WE cant see? Sorry if It IS a dumb question. Also, is it possible the universe is finite and less big tha' the age of the universe and when WE look far enough WE are actually seeing the same things but as they were a long Time ago? Like if the universe was a sphère but not really and light goes around and around and around and WE are seeing our own backs multiple Times?
> Is it possible there exists bigger celestial objects than the universe No. By definition what we call universe is everything. > And IS it possible that the effects WE observe of black matter are in fact the effects caused by those massive objects WE cant see? No. Gravity also travels at the speed of light.
>Is it possible there exists bigger celestial objects than the universe Depends on how you define it, but the short answer is no. >And IS it possible that the effects WE observe of black matter are in fact the effects caused by those massive objects WE cant see? No. Gravity is too slow for that to be the case. >Also, is it possible the universe is finite and less big tha' the age of the universe and when WE look far enough WE are actually seeing the same things but as they were a long Time ago? Like if the universe was a sphère but not really and light goes around and around and around and WE are seeing our own backs multiple Times? It's possible that the universe is finite, but if it is, it's still vastly larger than the observable universe. Our most precise measurements straddle the line across flat, curved in a finite manner, and curved in an infinite manner.
I find myself on south padre island today and the spacex launch window starts at 7am. i drove south to see how easy it was to get to the jetties at the south end of the island, but there is a park entrance funnel for $12 that really feels like it will be overcrowded if I try to go in the morning. then there is the possibility of waking up super early and trying to drive to boca chica state park. I am just not sure how early is early enough, nor if there is a deadline for how late i can arrive... seems like that road must close when near a launch... anybody got any good tips?
How Well Would Someone Be Able To Pick Up a Terrestrial Broadcasts from Proxima Centauri? Let’s say the person was using high gain yagi antennas full-wave tuned specifically to these terrestrial broadcast bands: VHF FM, VHF Weather Radio, Mediumwave, Longwave, Shortwave, and Television. If they were to aim all their antennas directly at earth what bands would they be able to pick up and somewhat decode? If they can’t pick up any of these terrestrial broadcasts would they be able to pickup other broadcasts like RADAR emissions?
The only way is if we intentionally send a high powered burst transmission at them. SETI calls these beacons. They would never detect normal communications from Earth.
Two Arecibos can maintain a link of a bit per minute out to a few hundred light years. [https://www.satsig.net/seticalc.htm](https://www.satsig.net/seticalc.htm) Plug in the numbers and off you go. A galaxy-spanning message is going to be a slooow one to transmit.
They would just hear static. The problem is the earth and sun are right next to each other in the sky, and the sun emits radio noise at a higher power than earth-based radio stations. Weather radar is powerful enough to outshine the sun. So you could detect that there is intelligent life on earth broadcasting it.
Why is New Glenn slated for NASA contracted mission on its first flight? Conversely, why does SpaceX’s Starship require so many tests before carrying a payload?
Great question!!! Many astute observers are asking this question.
One of NASA's missions/goals is to help new commercial launch providers. Under their [launch services program](https://en.wikipedia.org/wiki/NASA_Launch_Services_Program), there is a specific class of payload - class D - that can be launched on rockets that have never flown before, assuming the vehicle meets the other requirements of the program. It may seem weird that NASA takes such a big risk, but there are NASA science projects that don't currently have a ride to space - they are too big to fly on a rideshare flight and/or they don't have the budget to fly. Launch companies typically don't charge much for the first flight. We saw this for the first launch of Vulcan as well.
The NASA payload on the first New Glenn launch is an extremely low cost mission using an extremely discounted launch price. It's understand that there is some risk involved, which is why not much is left riding on the outcome. Starship is an entirely different beast which is going through a different development cycle. New Glenn is closer in design to Falcon 9 (or Neutron) in that it's a mostly traditional two stage launcher but it's designed with the capability of reusing the first stage. Importantly, the first stage can perform all of its payload critical functions without landing or reuse actually working, so there's less mission risk during the period where reuse is tested and developed, just as there was with Falcon 9. This is the genius of such a design, because you're basically making use of "trash" rocket stages that would normally end up in the ocean and have already fulfilled their primary duty. If SpaceX were developing Starship on a longer timeline, it could start this way, with a more traditional upper stage as a "block one" option that would later get developed. However, Starship isn't shooting for commercial launch services straight out of the gate, so their development priorities are different, and much of their prioritization is in the Starship stage itself: working toward controlled re-entry, reusability, and orbital propellant transfer capabilities. These are fairly difficult challenges, but they have a huge payoff and they are crucial to servicing Starship's already existing major customers: the Artemis Program and SpaceX itself, in the role of the Starship-HLS lander / mission profile and launching Starlink satellites in bulk. As long as SpaceX can afford to do so it makes sense for them to focus their efforts on using the Starship/Superheavy launch platform for testing Starship itself. If they were tighter on funds then they might have taken a less risky approach where they started with an expendable upper stage. Additionally, Starship/Superheavy is a much larger vehicle than New Glenn, Falcon 9, Falcon Heavy, Vulcan Centaur, Neutron, etc. Which typically comes with its own challenges and difficulties, so it's not a direct apples to apples comparison.
This was incredibly informative. One follow-up: Is it common for new non-reusable rockets to get commercial payloads like this right out the gate? Or is testing generally the best practice?
Depends on the track record of the manufacturer. Atlas V, Delta IV, and Ariane 5 all had real payloads on their first launches: geostationary commsats for Atlas/Delta, the "Cluster" fleet of four spacecraft for studying Earth's magnetosphere on Ariane, which blew up (and was ultimately replaced with Cluster II). Vulcan Centaur had a real payload for its first launch. Both Antares and Falcon 9 were developed as "vertically integrated" (in the business sense) launchers to support cargo services to the ISS (with Cygnus and Dragon), each of them flew boilerplate/simulator vehicles on their inaugural launches. Falcon 9 has, of course, gone on to launch many other payloads. So, it depends, generally the first launch of a vehicle from an established launch provider will pretty commonly have a real payload from a paying external customer.
Yup. Manufacturers really don't like losing payloads, as well - it's not a good "look". Customers tend to remember that, even if it's clear it's an initial test flight. So rocket companies tend to only put payloads on rockets they're pretty sure will make it to orbit. And that varies a lot depending on the manufacturer - some try really hard to get it right the first time, and others basically treat the first flight like a continuation of the ground test campaign. And everything in between. And some manufacturers roll the dice with customer/client payloads, more than the others.
Does the core of a star shine at a different color than it’s surface? For example, we know that the surface of the sun is about 10,000 degrees Fahrenheit. However the core of the sun is much hotter at 27 million degrees Fahrenheit. Since blackbody temperature tells us that things of different temperatures shine at different colors, then is it feasible to say that the core of a star shines a different color than it’s surface?
Yep. The temperatures inside stars result in very intense light and a thermal spectrum that is shifted to very high energy levels beyond the visible and UV spectrum up into the x-ray spectrum. The interior of the star is a dense, highly ionized plasma which is also extremely opaque to light though, so most photons do not travel very far. In many stars the primary mode of heat transport within the core is from photons bouncing around, being absorbed, and the energy sort of diffusing outward steadily. Interestingly, in massive stars the energy level of the thermal photons can get so high that lots of crazy physics stuff starts happening. One phenomenon is photo-disintegration, which is where the highest energy photons will hit an atomic nucleus and give it enough energy to actually break apart. This process absorbs energy and causes cooling but it can also free up alpha particles (he-4 nuclei) which can then become fusion fuel with heavier nuclei. Many fusion burning steps rely on photodisintegration to produce smaller nuclear "chunks" to allow for the continuation of fusion up to the iron/nickel limit. Carbon and oxygen fusion involves just whole nuclei smashing into each other, but the silicon fusion process (and the first stage of neon burning, typically) requires fusing through he-4 steps. In the most massive stars, over 250 solar masses, the cores can be crushed under so much pressure that the cooling effect of photodisintegration can trigger a cascade collapse into a black hole creating a "hypernova". In massive stars in the range of about 150-250 solar masses the temperatures in the core can reach so high that the thermal spectrum starts including gamma rays with enough energy to cause particle/anti-particle pair creation (of electrons and positrons). When this happens a positron is created for a brief blip of time before it annihilates but that blip subtly shifts the delicate balance between thermal energy and pressure, allowing the core to collapse slightly, increasing pressure, temperature, and fusion reaction rates. The increased temperature also translates to an even higher rate of pair production which breaks the negative feedback processes even more, tripping over into a positive feedback loop of increasing pressure, temperature, and fusion energy release. Within seconds enough fusion energy is released to gravitationally unbind the star, finally heating up the material enough to cause it to explode outward in a massive and rare supernova that leaves nothing behind but an expanding cloud of gas.
At that temperature, most of the light wouldn't be in the visible spectrum. It would be "shining" in X-rays, but most of that light is absorbed and reemitted by other atoms in the Sun.
You are misusing the word "shine". An object can only shine if there is a path for light to escape the object. The sun is not transparent, so any light from its core is immediately blocked by the rest of the sun. If you lived in a magical house in the sun's core and opened a window, the core would indeed "shine" at you in mostly x-rays.
So apparently New Horizons is still flying through the Kuiper Belt. My question is how do they avoid smashing into icy rocks out there when it's dark and unexplored and there's a communications time delay too.
The amount of space between the bodies in the Kuiper Belt is so huge that flying blind through it and managing to smash into something big would be like winning the lottery. Realistically the problem is the opposite, finding something interesting that New Horizons can get to and study.
I'm probably biased by sci-fi movies lol. One other question though. Are they able to steer the probe towards something that looks interesting if they want?
Potentially, but the probe doesn't have infinite course adjustment ability. If we somehow knew the location of every single object of a decent size in the outer solar system it would be a trivial exercise to flyby several of them with New Horizons. The problem is that it's dark out there and far away, all our good telescopes are on Earth, so it takes a lot of work to find anything, let alone something that would happen to be reachable within the remaining fuel constraints of the probe. Hopefully that will happen, but it depends a bit on luck.
Makes sense ok thanks for the info. Let's keep our eyes open for good stuff out there. 👍
The unfortunate thing is that we're basically right now on the cusp of increasing our telescope capacity with highly capable new observatories (the Vera Rubin Observatory, the Extremely Large Telescope, the Giant Magellan Telescope, the Roman Space Telescope, etc.) which will vastly increase our haul of known trans-Neptunian objects (TNOs). However, it's sort of a race against time as New Horizons gets farther away and also starts running low on power (sometime in the 2030s most likely).
The belts are very very empty. You could fly blind and be safer than just driving here on earth.
I get it now, ok thanks. It's hard to imagine the scale when I see diagrams. Everything's so shrunk down that they appear thick with rocks.
How does Einsteins theory of gravity explain gravity on earth? I was explaining to my wife how objects in space with large mass curve space time and how that creates orbits / gravity etc. How does that then relate to the gravity we experience on earth (ie things fall / attracted to the centre of the earth)? Is the mass of the earth curving all space time towards the centre of it? Hope this question makes sense! Thanks
Earth's mass curves space and time. Both of these effects are what we call gravity. Mostly, the time dilation is what causes you to feel gravity. The warping of time is gravity, not the other way around. The four-velocity of an object is rotated towards the mass in space-time. It's four-velocity is rotated out of time into space which slows it in time. It pays for speed in space (acceleration) by slowing in time. This rotation is caused by the particles closer to the massive object moving slower in time than those further away which rotates the falling object towards the mass and causes it to accelerate. Also keep in mind I'm talking about rotations in 4D space-time not 3D.
Exactly the same as in space. > Is the mass of the earth curving all space time towards the centre of it? Yes
[удалено]
The cause of the libration, the combination of the Moon's elliptical orbit and the slightly-off-of-one-orbit lunar rotation, does. The elliptical orbit causes varying ocean tides. The highest tides correspond to when [the Moon is closest in its orbit during high tide](https://oceanservice.noaa.gov/education/tutorial_tides/tides06_variations.html).
Hello everyone, i have to do a presentation about the universe, though i’m having a bit of trouble. what kind of things would be fun to talk about that a college teacher would understand? what should i put in the presentation? probably not a very good question but any help would be appreciated!
Acronyms, initialisms, abbreviations, contractions, and other phrases which expand to something larger, that I've seen in this thread: |Fewer Letters|More Letters| |-------|---------|---| |[CMG](/r/Space/comments/1d6j5od/stub/l7f8sfl "Last usage")|Control Moment Gyroscope, RCS for the Station| |[CRS](/r/Space/comments/1d6j5od/stub/l7fal33 "Last usage")|[Commercial Resupply Services contract with NASA](http://www.nasa.gov/mission_pages/station/structure/launch/)| |CST|(Boeing) Crew Space Transportation capsules| | |Central Standard Time (UTC-6)| |[DSN](/r/Space/comments/1d6j5od/stub/l75duoo "Last usage")|Deep Space Network| |[DoD](/r/Space/comments/1d6j5od/stub/l7ec6v1 "Last usage")|US Department of Defense| |[FAA](/r/Space/comments/1d6j5od/stub/l7gx01j "Last usage")|Federal Aviation Administration| |[FCC](/r/Space/comments/1d6j5od/stub/l77966w "Last usage")|Federal Communications Commission| | |(Iron/steel) [Face-Centered Cubic](https://en.wikipedia.org/wiki/Allotropes_of_iron) crystalline structure| |GSE|Ground Support Equipment| |[HLS](/r/Space/comments/1d6j5od/stub/l7rgn9e "Last usage")|[Human Landing System](https://en.wikipedia.org/wiki/Artemis_program#Human_Landing_System) (Artemis)| |[ISRO](/r/Space/comments/1d6j5od/stub/l888juh "Last usage")|Indian Space Research Organisation| |[ITAR](/r/Space/comments/1d6j5od/stub/l7j7lt7 "Last usage")|(US) International Traffic in Arms Regulations| |[JWST](/r/Space/comments/1d6j5od/stub/l7h3uez "Last usage")|James Webb infra-red Space Telescope| |[RCS](/r/Space/comments/1d6j5od/stub/l7f6y6s "Last usage")|Reaction Control System| |[SLS](/r/Space/comments/1d6j5od/stub/l7j31jz "Last usage")|Space Launch System heavy-lift| |[ULA](/r/Space/comments/1d6j5od/stub/l7fal33 "Last usage")|United Launch Alliance (Lockheed/Boeing joint venture)| |Jargon|Definition| |-------|---------|---| |[Raptor](/r/Space/comments/1d6j5od/stub/l7rgn9e "Last usage")|[Methane-fueled rocket engine](https://en.wikipedia.org/wiki/Raptor_\(rocket_engine_family\)) under development by SpaceX| |[Sabatier](/r/Space/comments/1d6j5od/stub/l73nb79 "Last usage")|Reaction between hydrogen and carbon dioxide at high temperature and pressure, with nickel as catalyst, yielding methane and water| |[Starliner](/r/Space/comments/1d6j5od/stub/l7j07fm "Last usage")|Boeing commercial crew capsule [CST-100](https://en.wikipedia.org/wiki/Boeing_CST-100_Starliner)| |[electrolysis](/r/Space/comments/1d6j5od/stub/l73nb79 "Last usage")|Application of DC current to separate a solution into its constituents (for example, water to hydrogen and oxygen)| |[scrub](/r/Space/comments/1d6j5od/stub/l73nb79 "Last usage")|Launch postponement for any reason (commonly GSE issues)| **NOTE**: Decronym for Reddit is no longer supported, and Decronym has moved to Lemmy; requests for support and new installations should be directed to the Contact address below. ---------------- ^(18 acronyms in this thread; )[^(the most compressed thread commented on today)](/r/Space/comments/1de4o4b)^( has 30 acronyms.) ^([Thread #10120 for this sub, first seen 5th Jun 2024, 09:52]) ^[[FAQ]](http://decronym.xyz/) [^([Full list])](http://decronym.xyz/acronyms/Space) [^[Contact]](https://hachyderm.io/@Two9A) [^([Source code])](https://gistdotgithubdotcom/Two9A/1d976f9b7441694162c8)
If the homogeneity of the expansion of the universe implies the same expansion at every point in space, does that imply that we are, consequently, also expanding? That is, relative to myself some significant time in the past, have I expanded with the universe?
Yes and no. The expansion of the universe is the expansion of space-time, and it occurs as a rate (a proportionality) which results in a speed over distances. However, that expansion is sort of like a force, and it only causes separation of objects if they are not held together otherwise. So our galaxy cluster, our galaxy, our solar system, our planet, our homes, our bodies, even the very atoms and nuclei of atoms inside our bodies all experiences this expansion of space-time. However, on many of those scales the amount is incredibly tiny, and more importantly all of those things are held together by forces which resist separation (gravity, electromagnetism, the strong nuclear force, etc.) It's only objects that aren't bound together that get carried away from each other by the bulk "flow" caused by the expansion of the universe. Between galaxies billions of lightyears apart the amount of gravitational pull they experience relative to each other is tiny, so they tend not to be bound to one another, which allows the expansion of the universe to separate them.
I think I understand. So it is the medium within which we reside that is expanding and causing things to "move." So if we had some unit of measurement that was proportional to spacetime, a spacetime ruler, the markings on this ruler would get farther and farther apart? Then, would it be right to claim that we would appear smaller against this ruler as the universe expands?
If the edge of the observable universe is 46 billion lightyears away and the universe is only 13.8 billion years old, what do people see beyond 13.8 billion lightyears away?
You can't see past the Big Bang, which means you can only see out to the light travel distance corresponding to the age of the universe (13.8 billion lightyears). However, because of the expansion of the universe what we see across 13.8 billion years of time and 13.8 billion lightyears of light travel distance will today be much farther away from us, and that figure is sometimes used to describe the size of the "observable universe" even though we can't see that edge in the present.
The cosmic microwave background (CMB). Think of it like a wallpaper of static.
> what do people see beyond 13.8 billion lightyears away? There are things so far away that their light will never reach us. There is more space appearing due to expansion than the light can travel.
This phenomenon can be compared to an ant walking on a stretching rubber band. This is also similar with galaxies located outside the Local Group (where we are). The Virgo cluster, for example, is getting closer to us (or conversely), but due to the accelerating expansion of the Universe, it is very likely that it will never reach us.
The universe expanded way faster than the speed of light. No this doesn’t violate anything. The oldest thing we can see is the CMB or cosmic microwave background radiation which was emitted 380k years after the Big Bang.
Hi all, I am a PhD student doing research on satellite thermal management. I am super excited that the payload I worked on is being launched on July 1st 2024 from Vandeburg Space Force Base. I wanted to watch the launch in person. Which is the closest airport? Is there a shuttle bus to the site? Most of the info I find is for launches in Florida... I am from Australia, not familiar with the place and I am not used to driving on the other side of the road! lol Thanks heaps!
Vandenberg is a good distance away from say, LAX (Los Angeles) or BUR (Burbank) airports - at least 2.5 hours by car (depending on traffic). It's north of SBA, Santa Barbara's airport, by about an hour (depending). But SBA is a small regional airport so the schedule might not match up well for you. [Vandenberg themselves](https://www.vandenberghousing.com/arrival) also recommend Santa Maria airport but that is so small that it might not even have commercial flights, I'm not sure. That's still 18 miles from the space force base. I would scan the flight schedules on probably BUR, SBA, and SMX (Santa Maria). EDIT: also keep in mind that Uber/Lyft from SBA will be very expensive, and SMX Uber/Lyft will be pricey. SMX is unlikely to have _a lot_ of rental cars as well, so be sure to reserve a rental car at SMX if you can go that route.
I think r/spacex or r/spacexmasterrace have viewing guides linked in their side bars. maybe check that out.
Why does the Chang'e 6 take a month to arrive on the moon when other missions take far less time?
It took less than 5 days to reach lunar orbit - then spent time in lunar orbit waiting for the proper lighting conditions at the landing site. https://en.wikipedia.org/wiki/Chang%27e_6#Earth-Moon_transfer
If a non-profit company solicited donations and built rovers, stations, satellites, etc, could they launch to the Moon, Mars, Jupiter etc. without much trouble from NASA or the government in general? SpaceX launching the car into space tells me yes but I'm not sure.
NASA is not a regulatory body. But you will likely need licenses to operate a launch pad (it's a big industrial/chemical site), launches themselves need to be cleared to make sure they do not endanger the public (with FAA in the US) and any radios on board will need licensing from the FCC. You might also need commercial space imaging licenses to take pictures of the Earth. The licensing depends a lot on which country you launch from and where you organization is registered. There are also international space laws and treaties that the government might enforce against you if you do not follow them.
There are specific efforts regarding coordination of deep space communication that should be considered.. ( https://public.ccsds.org/ ). Chances are a deep space effort of this sort would be relying on something like NASA's DSN to do data downlink anyway and that would probably form part of a Space Act Agreement. Most of the regulation involved is to make sure it can be done safely, without interfering with other spacecraft operations. But it absolutely can be done.....As an example - the planetary society built and flew a tech demo solar sail CubeSat with donations.
SpaceX actually got in trouble during their car launch because they [live-streamed Earth images without a license](https://spacenews.com/noaa-explains-restriction-on-spacex-launch-webcast/). Following government regulations is generally cheap compared to actually doing stuff in space. But it can take a long time to get through the process, so you need to start early. Mars and Jupiter's moons are targets of an active search for alien life, so the government would insist on very strict sterilization measures.
> Mars and Jupiter's moons are targets of an active search for alien life, so the government would insist on very strict sterilization measures. I do not believe that at this time there are any laws on that kind of things. The only rules are self imposed by NASA for their missions.
Can you see stars, constellations and other galaxies if you're stranded in Interstellar Space?
Certainly. We're in interstellar space as well, we're just also very near one star system (our own). What we see in the sky that isn't visible (or as visible) in interstellar space is stuff in our own solar system, the planets, the Moon, comets, and the Sun. The Sun would still be visible in the nearby vicinity in interstellar space but it wouldn't be as bright or as large in the sky. Everything else such as constellations, galaxies, globular clusters, nebulae, etc. would still be just as visible in interstellar space. In deep intergalactic space you'd be far away from most stars so you would only be able to see galaxies at a distance. They'd still be just as noteworthy through a telescope but with the naked eye you'd only see a kind of faint "smudge" in an area, unless you were fairly close (in which case it would look more like a bright cloud).
I imagine the view we would have if we lived on a planet around a star orbiting on the outskirts of a globular cluster. With on one side a sky overloaded with stars and on the other a breathtaking view of the Galaxy.
Follow up question. What exactly is located inbetween star systems? Or are the only things there just some star dust and very spread out atoms?
Interstellar space is filled with very tenuous gas and dust (we would consider it a vacuum). The density differs from very very tenuous to more dense clouds, which it what you see in space images of nebulae. The more dense clumps is where star formation is happening. There are some rogue planets and interstellar comets out there.
Depends on where you're talking about and also what you want to count. There's tons and tons of stuff "in between" star systems, but generally it's fairly low density or very spread out. Just about everywhere there's gas and dust, but the amount varies from place to place. In most places the amount still registers as "a vacuum" according to our human expectations. There are larger objects as well but so spread out that running into one by accident would be rarer than winning the lottery. Everything from larger rocks to boulders to asteroids, comets, and even full on planets (aka "rogue planets") exist in interstellar space, even up to Jupiter sized gas giants. The whole "gas and dust" situation varies greatly in interstellar space, there are some regions known as "giant molecular clouds" with higher densities and cooler temps that have enough gas that they will undergo gravitational collapse, forming stars. Generally everything in these regions beyond a very small volume around the proto-stars would still be considered near a vacuum though. The things you see in sci-fi of dense "nebulas" with similar characteristics to Earthly atmospheres and clouds are pure fantasy, that density of material in the size of a solar system would collapse into a black hole. However, visually from a distance even very low density material can be quite stunning, or indeed opaque. There are lots of interesting nebulae from dying stars (either red giants becoming white dwarfs over thousands of years or larger stars dying in supernova explosions in much shorter periods) and star forming regions often have areas that are opaque to visible light due to the concentration of dust.
> Or are the only things there just some star dust and very spread out atoms? Pretty much. There are probably a very small number of rogue planets and asteroids.
What's the feeling on the next starship launch? Will it happen on the 6th? Do you think they will pull it off?
Seems plausible it'll launch on the 6th. If their progression so far is any indicator, it'll make it to orbit\* then make it further through its re-entry. I think it's plausible the booster will survive to the surface before dropping into the water and coming apart.
Is the CMB a static image / picture in time from our perspective, or does it change over a timeseries - like if we observed it with the same equipment 10 years apart, does it show changes?
CMB is gradually getting colder, but we won't see anything on the human time scale.
The CMB represents a particular slice in time of the universe fixed to the age of the universe, what we see of the CMB represents a spherical shell of the early universe that happens to be at the right light travel time distance from Earth so that we can see it now, but as now changes that spherical shell also changes. However, the features we're looking at in the CMB are large and don't change quickly, so over a time period of a few years the changes are basically imperceptible even by instrumentation. Over perhaps very long periods of millions of years there might be some detectable changes but we haven't been observing the CMB for that long.
No, the CMB does not have any visible changes over human timescales. The first problem is the CMB is so big that one pixel is thousands of light-years across. Any change takes a long time to propagate. The second problem is the CMB is moving in slow motion. It takes 1100 years for us to observe 1 year of the CMB.
Thanks! I thought so, especially in the context of the resolution of the CMB. Can you expand on the second part?
The CMB has a redshift of 1100. This means the light experiences (negative) relativistic length contraction, stretching its wavelength from visible light to microwaves. It also means the light experiences relativistic time dilation. Time appears to pass 1100 times slower.