system
Given the following post, respond as if you're commenting on Reddit:
human
Standing on a rock at the absolute edge of the Milky Way, facing away from the galaxy. What do I see above me?

*For the naked eye.*

Is the sky filled with stars? Do I only see light from the local cluster, or is it mostly pitch black?

Also, if you have any material on this I’d love a link.
gpt
It would be mostly pitch black.

There is no absolute edge of the Milky Way - there's just fewer and fewer stars as you go further out. So once you're far enough out that there's no stars close enough to be visible as individual stars "in front" of you, you're in a region that's so lacking in stars that there's there's no stars close enough to be visible as individual stars "behind" you either.

With the naked eye, you can only see stars (as individual points of light) within 2000 light years or so, but most of what we see is much closer than that - it's only the most extremely bright stars that are visible at that distance. The Milky Way is like 100,000 light years across, so all the stars you see as individual points of light are stars just in the neighbourhood of our Sun.

If you take away those stars, you can still see *something* though. You can see the Milky Way galaxy, and some other galaxies too. However, galaxies are dim. As they are mostly empty space, the surface brightness is low - and the surface brightness of a resolved object doesn't depend on distance (a wall doesn't get brighter as you walk towards it!). So nearby galaxies are pretty faint cloudy patches. You'll also only see nearby galaxies - if a galaxy is small enough to be a point, it's no longer resolved, and its brightness does depend on distance. As they aren't very bright to start with, you're not going to see those distant galaxies with the naked eye.

So the main thing you'll see is the big band of the Milky Way behind you - you might make out the bulge, and dust lanes, depending on where you are. You'll also see three other galaxies. There's the Small and Large Magellanic Clouds, which are two massive dwarf galaxies orbiting the Milky Way, and Andromeda, which is about as massive as the milky way, but looks smaller because it's much further away. Personally I've found the LMC is the nicest to see from Earth, but you do have to see it from the Southern Hemisphere. Our hypothetical astronaut won't have a planet in the way and shouldn't have this issue!

But that's about it. All you'll see is the Milky Way behind you, and a few faint cloudy patches for other nearby galaxies, and that's it. Mostly black. And this is still within the Local Group - if you get away from our little family of galaxies into the void between clusters & groups, you'll quite likely see nothing at all.