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Many
people know that rubbish is a big problem on planet Earth. What many people
don't know is that junk has become a problem in outer space too.
According to BBC News, there are more than
22,000 pieces of space junk floating around the earth. And these are just the
things that we can see from the surface of the earth by telescopes (望远镜). There are also millions of
smaller pieces of junk that we can't see.
Objects,
like bits of old space rockets or satellites, move around the planet at very
high speeds, so fast that even a very small piece can break important
satellites or become dangerous to astronauts. If the smallest piece of junk
crashed into a spaceship, it could damage it.
To make
things worse, when two objects in space crash, they break into many smaller
pieces. For example, when a U.S. satellite hit an old Russian rocket in 2009,
it broke into more than 2,000 pieces, increasing the amount of space junk.
To reduce
additional space junk, countries have agreed that all new space tools can only
stay in space for 25 years at most. Each tool must be built to fall safely into
the earth's atmosphere after that time. In the upper parts of the atmosphere,
it will burn up.
Many
scientists are also suggesting different ways to clean up space junk. In
England scientists are testing a metal net that can be fired into space junk.
The net catches the junk and then pulls it into the earth's atmosphere to burn
up. The Germans are building robots that can collect pieces of space junk and
bring them back to Earth to be safely destroyed.
"The
problem is becoming more challenging because we're sending more objects into
space to help people use their mobile phones and computers," says Marco
Castronuovo, an Italian space researcher.
"The
time to act is now. The longer we leave the problem, the bigger it will
become," he says.
