What exists in the space between galaxies?

Question

Are there stray stars, planets, or black holes? Or is it simply "space?"

Answer 1

Chaos, entropy and nothing.

Entropy leads to chaos, and the ultimate chaos is nothing :D

Basically, the theory of entropy states that things start ordered and slowly get more and more chaotic until they end up as nothing. The probability of things suddenly becoming ordered and existent is very small, but still possible.

This pretty much makes sense in everyday life.

Anyway, one theory of the universe is that the "universe" is an infinite expanse of total chaos, or nothing altogether. Because it is so huge, things suddenly become ordered (despite the probability being so small). Everything we know, our "universe", is a small 'pinch' of order.

Randomly, out of nothing and chaos, a pinch of order appears and atoms are made, which clump into stars, which explode to make planets, which makes solar systems, which clump to make galaxies and superclusters. Black holes are formed inside huge galaxies, star gradually become denser and denser until everything in the universe becomes black holes, which 'evaporate' to leave nothing, or chaos, again.

So in between galaxies, there is chaos and nothing, where stars have evaporated and disappeared, or clumped into nearby galaxies.

A thin THIN film of hydrogen is floating around, but should be gone soon :)

Answer 2

That is what is called "Deep Space".  So far as we know, there is NOTHING there.  Oh, the odd asteroid might zip by once in a while, or a rogue comet, but other than that there is NOTHING there.

Well . . . .scientists think that on the average there are three (3) hydrogen atoms per cubic meter of Deep Space.

But no one and no thing (from earth) has ever been ther to measure it.

Answer 3

Intergalactic space is filled with almost nothing but not quite.  Between the galaxies there exists hydrogen and helium spread out over the huge volume of space, probably leftovers of the big bang that never had enough mass or gavity to collapse and form galaxies.  Believe it or not we can "see" these clouds through the spectral absorption line they cause in the spectrum (rainbow) of very far away sources of light such as quasars or gamma ray bursts.  A single spectral line is spread out into a line for each cloud between the galaxies by the fact the universe is expanding so each cloud is at a different redshift.  An example of this is called the Lyman Alpha forest.  

Answer 4

Nothing other than a few cosmic debris.

Answer 5

Don't have an answer, but kudos for a very interesting question.

Answer 6

Most of the mass of the universe, in the form of dark matter. And a few start clusters.

Answer 7

There is a very, *very* thin hydrogen gas that permeates the intergalactic voids.

Other than a few hydrogen and helium atoms, though, the only thing you'll find out there is the cosmic background radiation and a scattering of photons from stellar emissions.

Answer 8

there is no true vacuum anywhere, not even intergalactic space.  the density is indeed very low, but there is a lot of space. there is actually more matter outside galaxies than in them, by quite a large margin.