Animation of the near-Earth asteroid 2012 TC4 passing Earth in October 2017. Measurements indicate that the 20-metre asteroid may pass as close as 6800 kilometres during this approach, less than 2% of the distance to the Moon. The asteroid was discovered in October 2012, when it passed some 94, 800 kilometres from Earth. It has been calculated that there is a 1-in-14, 000 chance that 2012 TC4 will hit Earth within the next 100 years. It is a member of the Apollo class of asteroids, whose elliptical orbits take them closer and further away from the Sun than Earth. The meteor that exploded over the city of Chelyabinsk in February 2013, injuring some 1500 people, was a member of the same class, and a similar size. While that asteroid was undetected until the impact, the approach of 2012 TC4 will be closely studied, to help test and refine the effectiveness of the current systems in place for detecting potential impact threats. |