Life online today exists thanks to satellites, but outer space is getting dangerously crowded, putting those satellites at risk.

More than 20,000 pieces of space junk are orbiting planet Earth, putting our communications satellites in serious danger. At last, The Pentagon is taking it seriously, with the military finally tracking hundreds of satellites to watch for collisions. Is it too little, too late, or is the Pentagon onto something?

"We were in denial before February 10th," notes Michio Kaku, professor of theoretical physics and the author of "Physics of the Impossible." On that date, a collision in space between a dead Russian satellite and a US Iridium communications satellite knocked out the satellite and sent a shower of debris into the surrounding space.

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Satellites travel at 18,000 miles per hour, and this type of collision at such speeds could pierce the hull of the Space Shuttle.

Following this collision, alarm bells went off in the Pentagon, which hadn't been tracking all that junk on a regular basis. The military learned the hard way how important that is – and how limited the area around Earth is.

"We basically forgot the location of the satellite!" Kaku lamented. Now the Pentagon says that 800 satellites will be monitored every day, and up to 1,300 satellites by the end of the year. But space junk is still a problem.

"There's 20,00 pieces of space junk! Everything from paint flecks to screwdrivers to tool bags to booster rocket parts" is orbiting the planet, notes Kaku, pointing out that if more satellites are damaged, communications could be set back 80 years or more.

"Television, the Internet, Wall Street. The Pentagon could not fight wars, you couldn't get online, Wall Street could not make transactions without satellites."

Some space objects are maneuverable, meaning the Pentagon can reposition them if it senses a collision. A cosmic "vacuum cleaner" could clear up the rest of the gunk, though that would be costly and impractical. Laser beams are another option, though we don't have a laser capable of such activity. And neither solution is imminent. Meanwhile, the odds of another collision are high.

"It's an accident waiting to happen," notes Kaku, "and now is the time to do something about it."