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Earth's orbit has a bit of a litter problem. Hank outlines a few ways scientists have thought of to help clean things up.

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(Intro plays) Hank Green: Space is a big place. So you'd think that it'd be pretty easy to just launch a bunch of garbage out into space and never see it again, like "Sayonara, trash!" Unfortunately, it turns out, not the case. 'Cause while space is infinite, the area around the earth that things can be in orbit in is not. Ever since the Russians sent up Sputnik back in 1957, Earth's orbit has been collecting litter: defunct satellites, ejected pieces of old rockets, nuts and bolts and scrap metal from things smashing together and ripping apart up there. Sometimes, pieces of junk make it low enough into Earth's atmosphere that they burn up, but for the most part, they just hang out, which is why our planet now has a bad case of the space trash. At this point, it's estimated that 10 million pieces of man-made debris are floating around in Earth's low orbit, which puts us in danger of achieving what's called Kessler Syndrome. This is a scenario named after NASA physicist Donald Kessler who in 1978 warned that the overcrowding of our orbit with space trash would only make itself worse over time with individual pieces crashing together to create more pieces of trash until there's so much space trash that nobody can get a spacecraft out of orbit because it's wall-to-wall garbage up there. For now, larger pieces of orbiting junk are being tracked and can be avoided. The International Space Station, for example, can change its orbit to get around debris, but with everything up there moving crazy fast, it actually makes it kind of dangerous. Even a tiny paint chip moving at hypervelocity can put a tiny hole in a satellite or spacecraft. Check out what one paint fleck did to the window of the space shuttle Challenger. So we're already seeing evidence of the Kessler Syndrome, and man-made debris in Earth's orbit is on track to triple by 2030. Now, we just have to figure out how to keep ourselves from getting stranded here on Earth within our cloud of garbage. But not to worry! Scientists are busy coming up with ideas for getting us out of this particular pickle. For instance, scientists with the US Defense Department want to figure out a way to send robots up into orbit with new commercial satellite launches to scavenge parts off defunct satellites and refurbish them so they work again. Another idea, of course, is to send up a trash collection satellite, which would grab all the stuff it can and then plunge back down into Earth's atmosphere, burning itself and its haul up in the process. Other plans, uh, sending up cargo freighter, basically space garbage trucks. And for its part, NASA wants to use lasers, which could be installed at one of the Earth's poles, not to like, burn up the space trash, but just to nudge it out of the way so satellites can get a path through. So, from my perspective, that's probably a pretty good arsenal to start with, but if you got any better ideas, please be sure to let us and NASA know. Thank you for watching this episode of SciShow. If you have any questions or ideas or comments, we're on Facebook and on Twitter, and of course, down in the comments below, and if you want to keep getting smarter with us here at SciShow, you can go to and subscribe. (endscreen plays)