How much empty space is there in the universe?

Answer 1

That depends on what you mean by "empty". But frankly, I don't feel like going there

just now.

When you talk about volumes on the order of the universe, you can pretty well

approximate it to be empty. Period. There's some energy in it, which really doesn't

equate to a whole lot of mass. And there are some particles here and there, but

when you look at the internal structure of atoms, you realize that THEY're mostly

empty space. So the question of how much empty space is in the the universe is

really very nearly the question of how much universe is in the universe.

That, we don't know. We can see perhaps 14 billion light years away from our place,

and we don't see any sign of the universe ending in any direction we look.

That space alone figures out to something like 2,463 billion billion cubic light years.

So that's my estimate, and I'm sticking to it. Please drop me a line if it turns out

to be wrong.

Answer 2

Nearly all of it. Or nearly none of it, depending on what you mean.

A hundred square meters is more than enough for a person to live in. There are about 500 trillion square meters of land area on earth, enough for about 7000 times as many people as are alive today.

However, the problem is that assumes they don't need to eat. Or breathe. And it's counting places that aren't really habitable, like the top of Mount Everest, Antarctica, and the Sahara desert. We're kind of pushing the limits of sustainable human population now.

Answer 3

The universe is mostly empty space, with empty space making up about 99.9999999% of it. This empty space is known as the vacuum of space, which contains very few particles.