Near-Earth objects are comets or asteroids in orbits that allow them to enter Earth's neighborhood.

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Which is why, after a comet struck Jupiter in 1994, NASA decided to launch a research programme into Near-Earth Objects.

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Although scientists know a lot about the path of 2012 DA14, there are many undiscovered near-Earth objects still out there.

CNN: While you were working: An asteroid just flew by

Some 95% of the near-Earth objects larger than 1km have been discovered.

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Near-Earth objects are asteroids or comets, believed to be remnants from the formation of the planets, whose orbits brings them close to the Earth.

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More than 1, 300 near-Earth objects have been classified as potentially hazardous to Earth, meaning that someday they may come close or hit our home planet.

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Science editor Alan Boyle's blog: NASA's top expert on near-Earth objects says that new telescope systems are gradually getting a handle on potentially threatening asteroids.

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Many teams of astronomers are using electronic cameras to find these near-Earth objects, but according to NASA, the entire effort consists of fewer than 100 people.

CNN: While you were working: An asteroid just flew by

But Cheng says balloons can offer an inexpensive way to rapidly respond to exciting targets of opportunity like newly-detected near-earth objects, sun-grazing comets, or dust storms on Mars.

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"Today's event is a strong reminder of why we need continuous efforts to survey and identify near-Earth objects, " said Thomas Reiter, European Space Agency's Director of Human Spaceflight and Operations.

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