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BrianBoitano
Nov 15, 2006

this is fine



New forum needs a new catchall thread, says I!

Rules:

  • Post questions and/or answers
  • Keep derails space related
  • Pedantry allowed, just don't be a dick about it

Remember this website has goons so caveat emptor

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BrianBoitano
Nov 15, 2006

this is fine



I'll start! Is the Cosmic Microwave Background basically the edge of the observable universe?



As I understand it, it is the radiation released by the sliiiightly uneven soup of energy just as it condensed into matter/particles, red-shifted due to the expanding universe. Since it's radiation and travels at the speed of light, wouldn't the CMB only be visible from the edge of the observable universe, and everything which emanated from closer than that would've already passed us?

e: or has somehow any of it been slowed down or echoed back by gravity?

That Works
Jul 22, 2006

Every revolution evaporates and leaves behind only the slime of a new bureaucracy


Have you ever seen Uranus?

Ventral EggSac
Dec 3, 2019

How long can someone survive exposed to vacuum? Would your eyes burst, your anus evert and your lungs collapse? Or did the Expanse get it right?

Eat My Ghastly Ass
Jul 24, 2007

Ventral EggSac posted:

How long can someone survive exposed to vacuum? Would your eyes burst, your anus evert and your lungs collapse? Or did the Expanse get it right?

it’s actually pretty neat:

https://www.scientificamerican.com/article/survival-in-space-unprotected-possible/

Ventral EggSac
Dec 3, 2019


Wow thanks, I guess that we have some time is a good thing. I didn't realize we had done those experiments, but make sense. Hard to imagine them. I had already invoked certain imagery in my question I suppose.

Ajaxify
May 6, 2009

BrianBoitano posted:

I'll start! Is the Cosmic Microwave Background basically the edge of the observable universe?



As I understand it, it is the radiation released by the sliiiightly uneven soup of energy just as it condensed into matter/particles, red-shifted due to the expanding universe. Since it's radiation and travels at the speed of light, wouldn't the CMB only be visible from the edge of the observable universe, and everything which emanated from closer than that would've already passed us?

e: or has somehow any of it been slowed down or echoed back by gravity?

The observable universe is a constantly expanding sphere, so the CMB is the constantly expanding surface of that sphere. It represents light from the moment of recombination when the plasma suffusing the universe cooled enough allow neutral atoms to form and light to travel great distances without running into something. As you said, that light eventually got redshifted into the microwave portion of the spectrum.

Here's some videos to help explain some of the cool things about the CMB, including showing the orange color it would have appeared if you had been alive to observe it at the moment of recombination.
https://www.youtube.com/watch?v=3tCMd1ytvWg
https://www.youtube.com/watch?v=C4CKtEQJGMY

Saint Isaias Boner
Jan 17, 2007

hi how are you

hi space facts thread there happens to be a humble bundle at the moment which is just a big pile of e-books about space, probably everything you could possibly want to know about space. I got it and am too stupid to understand much of it but you might be able to figure out some of its mysteries.

BrianBoitano
Nov 15, 2006

this is fine



Ajaxify posted:

The observable universe is a constantly expanding sphere, so the CMB is the constantly expanding surface of that sphere. It represents light from the moment of recombination when the plasma suffusing the universe cooled enough allow neutral atoms to form and light to travel great distances without running into something. As you said, that light eventually got redshifted into the microwave portion of the spectrum.

Here's some videos to help explain some of the cool things about the CMB, including showing the orange color it would have appeared if you had been alive to observe it at the moment of recombination.
https://www.youtube.com/watch?v=3tCMd1ytvWg
https://www.youtube.com/watch?v=C4CKtEQJGMY

That is really neat and exactly what I was looking for, thank you! This related video to the second one was also really cool, I didn't know the inflationary period d-d-d-dropped the bass:

https://www.youtube.com/watch?v=PPpUxoeooZk

blue squares
Sep 28, 2007

what does RSF stand for

HOTLANTA MAN
Jul 4, 2010

by Hand Knit
Lipstick Apathy
If you nut in space do it push you backwards

Kevin Palpatine
Dec 20, 2017
If you have a gas giant (like Jupiter) does that mean there's nothing solid there at all? Like if we tried to land there, would there be anything to 'land on', as such?

Eat My Ghastly Ass
Jul 24, 2007

HOTLANTA MAN posted:

If you nut in space do it push you backwards

yes

BrianBoitano
Nov 15, 2006

this is fine




But you must aim mostly downwards so your thrust vector passes through your center of mass, or else you'll spin more than zoom along

Note that "downwards" in space is hard to gauge as your balls are no longer plumb

Shwoo
Jul 21, 2011

Kevin Palpatine posted:

If you have a gas giant (like Jupiter) does that mean there's nothing solid there at all? Like if we tried to land there, would there be anything to 'land on', as such?
Some do and some don't, I think. Jupiter's core is currently believed to be liquid, but Saturn's core is believed to be solid. Either way, you couldn't land on them, because they're under so much pressure that anything you tried it with would be crushed before it got close.

Eat My Ghastly Ass
Jul 24, 2007

BrianBoitano posted:

But you must aim mostly downwards so your thrust vector passes through your center of mass, or else you'll spin more than zoom along

Note that "downwards" in space is hard to gauge as your balls are no longer plumb

my balls are always plumb

Frances Nurples
May 11, 2008

What is space, and why?

BrianBoitano
Nov 15, 2006

this is fine



Frances Nurples posted:

What is space, and why?

Space is the simplification of spacetime that makes the most sense to folks who didn't experience relativistic effects during their evolution. The universe is the way it is because if it wasn't the way it is then we wouldn't be here to notice it.

Pimpcasso
Mar 13, 2002

VOLS BITCH
Could tom brady beat a team of aliens in space football

That Works
Jul 22, 2006

Every revolution evaporates and leaves behind only the slime of a new bureaucracy


Pimpcasso posted:

Could tom brady beat a team of aliens in space football

He'd be playing for the aliens so no

Ventral EggSac
Dec 3, 2019

Pimpcasso posted:

Could tom brady beat off a team of aliens in space

DamnCanadian
Jan 3, 2005

Perpetuating the stereotype since 1978.

BrianBoitano posted:

That is really neat and exactly what I was looking for, thank you! This related video to the second one was also really cool, I didn't know the inflationary period d-d-d-dropped the bass:

https://www.youtube.com/watch?v=PPpUxoeooZk

At a school star party a kid asked me if I could show him where in the sky the Big Bang happened. I told him I can’t, because the Big Bang didn’t fill an empty void with matter; spacetime itself expanded from the Big Bang. I tried to explain for a couple more minutes, then his eyes glazed over and he walked away

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babyeatingpsychopath
Oct 28, 2000
Forum Veteran

BrianBoitano posted:

Space is the simplification of spacetime that makes the most sense to folks who didn't experience relativistic effects during their evolution. The universe is the way it is because if it wasn't the way it is then we wouldn't be here to notice it.

I, too, like the anthropic principle.

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