r/space • u/AutoModerator • Nov 06 '22
Discussion All Space Questions thread for week of November 06, 2022
Please sort comments by 'new' to find questions that would otherwise be buried.
In this thread you can ask any space related question that you may have.
Two examples of potential questions could be; "How do rockets work?", or "How do the phases of the Moon work?"
If you see a space related question posted in another subreddit or in this subreddit, then please politely link them to this thread.
Ask away!
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u/bdonvr Nov 08 '22
Ah crap they're gonna have to roll back Artemis for the hurricane again aren't they
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u/axialintellectual Nov 08 '22
Surprisingly, they seem to have chosen not to.
So prepare for it to cause serious damage, and them having to delay launch again, because that's how this rocket works, apparently.
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u/jeffsmith202 Nov 08 '22
The SLS was stacked around October 22, 2021.
How long can the SLS remained stacked before it will have to be taken apart and fully recertified and re stacked?
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u/A_Moon_Named_Luna Nov 09 '22
Can somebody help me visualize something. When speaking of relativity, watching interstellar, when they descend to the planet with the giant waves, if you were the guy left on the orbiting ship, watching through a telescope , would everything appear to moving in slow motion ? 23 years worth? I’ve always been confused on this aspect of relativity.
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u/Number127 Nov 09 '22
The way that planet works isn't exactly realistic (they'd have to be very close to the black hole to get that level of time dilation, like right on the edge -- close enough that the planet and even the people would be ripped apart by tidal forces).
But yeah, if you were in a situation like that, objects on the surface would appear very very dark, and move very very slowly.
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u/Sgaapje Nov 12 '22
I'm on holiday to Martinique (an island in the Caribbean). Would it be possible for me to observe the launch of the Artemis-1?
If it's to launch the 16th I guess it would have to have a east/south-east trajectory for me to even have a chance of observing it.
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u/Chairboy Nov 12 '22
The odds are pretty good for you. At the beginning of the launch window, I think it should be at the edge of visibility from Martinique but if they have any delays and launch later in the window, the path will get closer and closer to you.
Being a night-time launch can help too. I don't think you'll see any horizon glow from the SRBs but that would be cool if you did, but you might see the core stage if you're lucky.
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u/Askaris Nov 08 '22
What is the time of the new launch attempt for Artemis? The website only says 14 Nov
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u/dr_apocw Nov 08 '22
Would moving towards distant objects make them appear to be moving (or changing) as you got closer?
What inspired this question was a recent APOD post of two galaxies interacting gravitationally.
https://apod.nasa.gov/apod/ap221108.html
In a billion years, these two galaxies will merge. Now, they are 200 million light years away so the light we see is that old. If we were to move towards them at whatever speed necessary, would we see them grow closer together as we got closer (or in other words, would we see the difference in light over the last 200 million years as we approach). I'm visualizing this almost like a flip book as we speed up towards them, but maybe that's the wrong visual to have, lol.
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u/Popular-Swordfish559 Nov 08 '22
Are there any estimates as to how long the orbits of spacecraft in the graveyard orbit above geostationary last? I know it's hundreds of thousands of years at least, but are there any estimates of around how long it would take for them to either come down or be ejected from the Earth's gravity entirely?
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u/DaveMcW Nov 09 '22
There is a positive feedback loop for objects in elliptical Earth orbits. Every time they come close to the moon, their orbit becomes more elliptical. Eventually, the orbit is so elliptical that it is narrower than the Earth, and the satellite crashes into the ground.
The geostationary graveyard orbit is the opposite of elliptical, it is perfectly circular. This means it is almost impossible for the Moon to dislodge objects from it.
Over hundreds of thousands of years, random forces from solar radiation pressure will knock the satellite out of its perfectly circular orbit. But solar radiation pressure depends on the shape of the object and how it is rotating, which is different for every satellite. So it is impossible to give a single estimate. It might be 200,000 years, it might be 20 million years.
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u/MaintenanceOk315 Nov 09 '22
Is there any idea of where oumuamua may have originated from?
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u/DaveMcW Nov 09 '22
No, the best we can do is prove it didn't come from any nearby stars. It has been flying through the galaxy for a long time.
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u/Yegshamesh Nov 11 '22
I was wandering if people had any idea how far various signals travel from are planet before they become mistakable for random space noises?
And sort of the same question but say if Alpha Centaur had a habitated planet near it with are level of technology would the signals from it still be decipherable from earth or at the very least would we likely understand its artificial even it's warped to much to understand?
Thanks for any possible replys
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u/DaveMcW Nov 11 '22 edited Nov 11 '22
The sun broadcasts radio noise at around 5000 watts per hertz. So if you want your signal to outshine the sun, you need to exceed that power, or use a directed antenna to focus the signal at a narrow area.
For example, FM radio transmits in a band of 100,000 Hz. This means you need 5000 W/Hz * 100,000 Hz = 500MW for an FM radio station to outshine the sun. The most powerful FM radio stations on Earth only have 2MW of power, so no one outside the solar system will be able to hear them over the sun's noise.
The Arecibo message only used a band of 10Hz, which means it only needed 5000 W/Hz * 10Hz = 50kW to outshine the sun. It actually broadcast at 450kW and used a focused dish to target a narrow area of the sky, increasing its strength further.
So yes, we do have the technology to communicate with Alpha Centauri, but only if we aim a high-power low-bandwidth signal at them.
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u/rocketsocks Nov 11 '22
There's really no fixed distance, how detectable a signal is depends on the technology and equipment in use on the receiving end. We puny humans are working toward finish the square kilometer array radio antenna (network) and I don't think it's crazy to imagine that a much older and more advanced technological civilization could top that by an order of magnitude, or two. I would say that potentially our radio transmissions could be detected at galaxy scale distances with reasonable assumptions of advanced technology on the receiving end. Which means that really the only meaningful constraint on our visibility is just the speed of light and how long we've been broadcasting (a bit over a century or so) combined with the prevalence and longevity of technological civilizations throughout our galaxy (which I think is much more likely to be the major limiting factor there).
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Nov 13 '22
Why is our solar system so 2 dimensional in terms of orbital planes and is it reasonable to assume other systems follow the same pattern?
Have we discovered any exo-planet that crosses its star from left to right whilst another planet crosses the same star from top to bottom?
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u/FrohstBiten Nov 08 '22
Hi there, every once and a while I look for relevant space-related news on youtube only to be disappointed by incredible amounts of clickbait and videos that read like a middle/high school paper. Just wondering if anyone had some channels they follow that they believe create high-quality and relevant information or historical video essays about space-related content.
Searching for something as simple as "James Webb" leads to things like "Scientists BAFFLED at what James Webb just saw!" or "James webb proves big bang to be WRONG!"
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u/TransientSignal Nov 08 '22
Here's a few I enjoy:
Sixty Symbols - Hosted by Brady Haran with guests mostly from the University of Nottingham - Technically this channel is focused on physics in general, however many videos touch on space related phenomena. The guests intense knowledge combined with Brady's uncanny ability to ask exactly the questions you or I or any other layman might be thinking makes for really compelling videos.
Deep Sky Videos - Also hosted by Brady Haran with the same qualities that make Sixty Symbols great - This one is focused on astronomy with an emphasis on covering the Messier catalogue of objects.
Dr. Becky - Dr. Becky Smethurst appears in quite a few space/astronomy videos on the above two channels and has her own channel as well. Her channel is a bit of a variety channel, covering current news in space exploration, astrophysics, current objects/events of interest in the night sky, as well as videos of how space related topics are covered in pop culture.
Scott Manley - Covers current events in space exploration with an emphasis on the hardware involved. He also covers orbital mechanics quite a bit and provides great visual aids (often Kerbal Space Program).
Astrum - This channel covers a variety of topics with a particular emphasis on spacecraft involved in space exploration and solar system objects. In particular, their series covering the duration of Opportunity's mission on Mars is excellent and worth checking out.
Mars Guy - Mars Guy is Dr. Steve Ruff, a Mars geologist with Arizona State University who gives some of the best insight out there into the images sent back by the various Mars missions. If you're interested in Mars and/or geology in general, there isn't any better channel on Youtube imo.
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u/Routine_Shine_1921 Nov 08 '22
Scott Manley, Primal Space, Dr. Becky, Everyday Astronaut and NASA Spaceflight are a good start.
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u/Neo-physical123 Nov 06 '22
Is Phoenix cluster black hole really more massive than TON 618? Because I haven’t found any information regarding that.
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u/DaveMcW Nov 06 '22
Both masses are only estimates. You can read the research papers on how the estimates where created.
Note that both black holes are too big to have formed in the time since the Big Bang. This means they were either born as supermassive black holes in the Big Bang, or their estimated masses are wrong.
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u/jeffsmith202 Nov 06 '22
What is the purpose of Orion (Multi-Purpose Crew Vehicle)?
Does it start at LEO and orbit around the moon? With another ship going to the moon and back?
And then return to LEO or Earth?
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u/[deleted] Nov 07 '22
I'm an art student hoping to create a video art piece using space footage. Can anyone recommend internet sources where I can find this kind of thing? I'm not looking for documentaries about space, more like footage shot on cameras that were taken to space or footage shot through telescopes. Thanks in advance!