NASA, which is coordinating the radar and optical observations to test its planetary defences, says amateurs will need to be on their toes: "the asteroid will be very hard for backyard astronomers to see, as current estimates are that it will reach a visual magnitude of only about 17 at its brightest, and it will be moving very fast across the sky". This asteroid was discovered by the Panoramic Survey Telescope and Rapid Response System (Pan-STARRS) in Hawaii in 2012.
"It's very important these things are done, it's a big sky, things could come from any direction and there could be an asteroid with our name on in it", added Glenn. But 2012 TC4 asteroid is different.
Although it travelled out of the range of asteroid-tracking telescopes shortly after it was discovered, it had been predicted that it would return to view in late 2017. Observers with the European Space Agency and the European Southern Observatory were the first to recapture 2012 TC4, in late July this year, using one of their large 8-metre aperture telescopes.
This may sound like a long way away, yet it's a short distance in planetary terms and around one eighth of the distance between the Earth and the Moon.
This animation depicts the safe flyby of asteroid 2012 TC4 as it passes under Earth on October 12, 2017. Harris underlines that even if this asteroid crashed into the Earth, it would not cause any major damage.
The meteor that exploded over the Russian city of Chelyabinsk in February 2013, injuring 1,500 people and damaging over 7,000 buildings, was about 66 feet (20 meters) wide. The scientists said that although the asteroid does not pose any threat to Earth but still this close approach will help them to track its orbit and give them a rare chance to rehearse for a real-life asteroid which could enter Earth's atmosphere and pose a threat to our planet.
"The October pass will bring the asteroid up to magnitude 14, so extensive physical studies will be possible, but only briefly".