system
Given the following post, respond as if you're commenting on Reddit:
human
If we went out into space and created a closed glass sphere, would it be a more perfect vacuum than anything we could create on Earth?
gpt
At extremely high vacuums, what really ends up limiting the vacuum is outgasing from the walls. The best ultra-high vacuum chambers we can make now are ones where the walls are cooled to liquid-helium temperatures so that there is almost nothing coming off the walls and anything that hits the walls will stick to it. If you managed to do what you are suggesting with space (which has about 10^5 times better vacuum than our best) and a cryogenic chamber, then for a short time you would probably have an ultra high vacuum, but very quickly the pressure would rise from the few molecules that can escape from the walls.