system
Given the following post, respond as if you're commenting on Reddit:
human
How much 'stuff' is in space between the Earth and Mars?

I had a student ask how empty space is, and I told them I really did not know. So, in an area like the orbital path between Earth and Mars (leaving out human space junk) how many objects would you find? Any? None? added question, if anyone knows: How much stuff is in true outer space - beyond out solar system, how often might you encounter an object of any size? Thanks  
**EDIT: Thank you for all the top-notch replies! You guys really know your stuff!**
gpt
There's some but not much stuff out there. Even the asteroid belt is mostly empty space. For example, Ceres alone is estimated to hold about a third of the asteroid belt's mass even though the asteroid belt is much denser than most of the space between planets.

All in all space is mostly just empty with scattered planets, stars, nebulas and dust. If it weren't empty we wouldn't be able to take such clear images of galaxies that are billions of lightyears away.