(iStock / The Washington Post Illustration / Prism Filter)
The night sky is full of stars, but it's also full of garbage.
Humans set up many satellites there – about 1,700 working spacecraft are in orbit around our planet – and not every machine comes back immediately when their job is done. Many fly through the sky again and again, long after the scientists have lost contact, so they easily collide and break into small pieces. National Aeronautics and Space Administration (NASA) estimates that there are about 23,000 space debris larger than 10 centimeters (or about four inches), about 500,000 larger than an inch, and about 100,000,000 larger than a millimeter.
A piece of metal that is smaller than a sesame may not sound dangerous, but even those tiny pieces can pose a great risk. The International Space Station navigates the paths of the most dangerous piles of rubble, but tiny patches of paint have smashed the ship's four-fold windows. That's because space debris moves fast.
"Due to the extremely high impact speed – more than ten times faster than a 250-mile bullet – even sub-millimeter-spaced astronauts could threaten astronauts if they deploy a spaceborne vehicle outside the International Space Station," says JD Harrington, NASA Public Affairs Officer.
Small debris can punch a hole in a satellite, while larger debris can shatter one completely – causing even more debris.
"The orbital debris threat is real," says Harrington. "Because of ongoing space activities, the orbital waste problem is expected to worsen in the future and pose an even greater threat to future space missions."
An increase in orbital traffic – it will be easier and cheaper for private companies and research groups to send objects up – means that our space corner has less and less space.
NASA has no plans to clean up what is there, but the agency is working to make the problem worse by ensuring that each new mission includes clear arrangements for the disposal of non-functioning spacecraft and their ejected parts ,
And there are possible solutions in the works of others: at the 2017 European Conference on Space Debris, the moderators discussed how to dump the garbage into a higher orbit and trap it with nets and harpoons or magnets and other ideas. In May, the International Space Station will commission a test project called RemoveDEBRIS that will capture multiple pieces of fake trash before it burns in the earth's atmosphere.
But while we wait for someone to develop the ultimate space vacuum, are people on Earth safe from the risk of falling debris? The short answer is yes. The garbage falls down again and again: 200 pieces of debris returned to the atmosphere in 2016 alone. Most of it burns and breaks down, and the pieces left over will probably do no harm. Most of the earth is either covered in the ocean or has a lot of open space, so there is a high likelihood that junkies will hit points without hurting people there. There is only one known case in which a person was hit by a spaceship – Lottie Williams of Tulsa, Oklahoma, 1997 – and did not even get a bruise from the accident. They are much more likely to be struck by lightning.