Earth is like the Pig-Pen of the solar system: more than 100,000 objects bigger than a centimeter wide hover around our planet, accounting for 4 million pounds of junk that befoul our atmosphere and threaten the expensive satellites we actually want in orbit. What if we could just burn up the junk like a meteor hitting the atmosphere? Scientist Dr. Kristen Gates says we can — by sending gigantic space balloons into the atmosphere.