Since 1957 humans have put more and more items into space, from satellites to rockets from space missions.
When things such as satellites become unusable they are simply left to orbit earth until they burn up in our atmosphere.
On Earth we only track objects larger than 5cm (2-inches) and at the moment there are around 20,000 pieces of tracked debris circling the Earth.
The actual total number of bits of debris up there is estimated to be close to 171 million, with 170 million of those smaller than 1cm (0.4-inches).
Space debris travels around the earth at 1,000’s MPH and so coming into contact with the materials would be fatal and is a growing problem for NASA who track it to keep those onboard the Internal Space Station safe.