Space is polluted. According to The Guardian, international space agencies have identified 23,000 pieces of space junk hurtling through the sky. These pieces of old rockets and spacecraft hardware measure larger than 10 centimeters—and they’re likely only a small part of the problem. Experts estimate that a half-billion debris fragments spanning one to 10 centimeters are also floating around, and that trillions of even smaller bits are clogging up our solar system.

While remote and scattered, this trash poses a special threat to international security.The Guardian reports that scientists are worried that space junk will create political friction between nations—or possibly even prompt armed conflict—if it hits a military satellite. It would be very difficult to differentiate between a satellite damaged or destroyed by an intentional attack and one felled by an accidental collision, explains Vitaly Adushkin at the Russian Academy of Sciences in Moscow in the journal Acta Astronautica.

Debris in low Earth orbit, the number of which has risen greatly throughout the past 60 years of space exploration, are the biggest threat, both because of the speed at which they can slam into spacecraft—more than 30,000 mph—and because this region is where most military satellites are located. 

If we don’t clean it up, chunks of debris might hit one another and break into smaller bits, further increasing the risk of threat against satellites. In light of recent incidents—for example, when the Russian satellite BLITS was disabled by debris in 2013—this is a possibility that scientists insist can't be ignored.

[h/t The Guardian]