Unless you've actually been to space, you might not realize this. But it's a mess up there. It's basically full of junk.
Nasa estimates there are at least half a million objects - one to ten centimetres long orbiting the Earth.
There are more than 100 million objects up there that are smaller than a centimetre. But there's bigger stuff too.
According to the European Space Agency, there are 22,000 objects bigger than a coffee cup floating around. Only 1,000 of those are working satellites.
That means there are more than 20,000 fairly sizeable objects up there, doing nothing except getting in the way of the International Space Station.
And here's the thing - it's dangerous. There are chunks of metal up there, flying around at hundreds of metres per second - essentially as fast as a bullet.
So, the crew on the Space Station is constantly having to keep an eye out and get out of the way so it doesn't get hit.
Plus, if all these objects crash into each other, the smaller the pieces become and the harder it is to clean up.
So, what to do?
Well, a space company called Astrium UK is working on a plan to use harpoons. Apparently, the idea is to fire these harpoons from satellites specifically designed to chase down objects orbiting the Earth.
The satellites would be controlled by officials on the ground watching a video feed, who would then decide which objects to go after.
When they find a target, they would fire the harpoon which would attach itself to the space junk and drag it down into the atmosphere, where it would burn up.
The company says the harpoons would be fairly small, only 30cm long. Anything bigger could knock away the space junk, or smash it into smaller pieces - which kind of defeats the purpose.
Here's a report from Al Jazeera on how it would work.
A number of organisations are said to be working on plans to clean up space junk. The European Space Agency has even launched a Clean Space Initiative to try and find new ways to do it.
As well, Wired is reporting that Nasa has looked at using high-powered lasers to zap the junk as it flies past. And it says Boeing has filed a patent to send up a satellite filled with heavy gases.
When those gases would be sprayed on the pieces of junk, it would slow them down enough so they'd fall back into the atmosphere.
Of course, the bigger question is - what do we do about the pigs?