Space debris (aka Space Garbage) are damaged or decommissioned objects floating in space made up of fragments, parts or satellites.
Figure 1 - Image created by the European Space Agency (Not in Scale!)
I understand that it sounds like a no brainer but I’d like to elaborate on the scale of debris. According to the European Space Agency (“ESA”), they are as small as “millimetres” in size. Nasa states that debris (in Low Earth Orbit) travel around 15,000 miles an hour. That’s wicked fast.
A problem with this comes down to the Kessler Effect (or Kessler Syndrome). Basically, fragments crash into existing bodies which break up into smaller pieces, flying super fast crashing into more objects in space causing a chain reaction of destruction of existing infrastructure.
This is a known issue for decades, but now is when the Government of Canada is investing big in Space this year and the foreseeable future. Below is a cool Resource by the ESA showing more statistics on Space Debris and space stuff in general.
https://sdup.esoc.esa.int/discosweb/statistics/