Collision in Space
Earthlings take a closer look at the space junk circling the planet after two satellites crash into each other
The area around the Earth is a very crowded place.
There are thousands of human-made satellites in Earth's orbit. Some of these objects collect scientific data about what's happening in outer space. Others research Earth's air and oceans. And some allow humans to use gadgets like cell phones and computers.
Last week, 485 miles above Earth, two of those satellites collided.
The American Iridium 33 communications satellite and an old Russian satellite, Kosmos-2251, were circling Earth at a speed of 25,200 miles per hour (mph). When their paths crossed, they smashed into each other and sent a cloud of debris into Earth's orbit.
Humans have been sending satellites into orbit since 1957. This was the first time two satellites crashed into each other.
Scientists say the collision occurred in a low orbit around Earth that is especially crowded. There are a lot of satellites in this region. There are also bigger objects. The Hubble Space Telescope is about 372 miles above Earth. The International Space Station is in an orbit 220 miles above Earth. Shuttle missions usually take place here too.
But it's the small stuff crowding Earth's orbit that has scientists concerned.
There are billions of pieces of space junk circling Earth. Every time a space shuttle or satellite or space station is sent into space, humans leave a little bit of garbage behind. This trash can include pieces of booster rockets and insulation, bolts, paint chips, and even bags of tools.
Some of this debris is tiny, while other pieces are bigger. Scientists at places like the National Aeronautics and Space Administration (NASA) say they are tracking at least 17,000 objects in orbit that are four inches or bigger, 200,000 objects that are between one and three inches, and billions of things that are smaller than an inch.
When the two satellites collided last week, another 400 to 500 large pieces of debris were added to the clutter in a low orbit around Earth. And scientists say this new cloud of space junk could stay in Earth's orbit for 10,000 years.
NASA says that the debris poses little risk to shuttle missions. The shuttle Discovery is scheduled to launch on February 22, and NASA says it will not cancel the flight.
But the dangers could increase as more stuff is sent into orbit.
"Today's environment is all right, but the environment is going to get worse," said Nicholas Johnson, chief scientist at NASA's Orbital Debris Program Office.
Right now, scientists say they are keeping an eye on how much trash is floating above Earth. But the recent satellite crash has made them take a closer look at how to clean up Earth's cluttered outer reaches.
Discover more about the final frontier in the News From Outer Space Special Report!
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