does space junk brake down in space or does it just keep floating around space?

Question: does space junk brake down in space or does it just keep floating around space?
- Keywords:
  space,
  space junk
Asked by fluffy.pig to Dominic on 8 Mar 2017.
- Dominic Doyle answered on 8 Mar 2017:
  
  Space junk is very diverse.
  In general materials do break down in space, but very very slowly over many many years.
  The only way they really breakdown and dissappear is when their orbits become low enough that they burn up in the atmosphere.

Question: does space junk brake down in space or does it just keep floating around space?