From another thread:

Subject: Dark Matter
From: banjoman - PM
Date: 16 Jan 18 - 06:30 AM

I know that there may have been a previous thread somewhere, but I was asked this question by a 10 year old and had a problem answering it.
If the universe is made up mainly of Dark matter and it weighs a lot, then why don't space rockets and satellites bump into it, or isn't it solid???