Asteroid ‘2012 TC4’ is estimated to be 45 to 100 feet (15 to 30 metres) in size. Orbit prediction experts say the asteroid poses no risk of impact with Earth. Nonetheless, its close approach (22,000 km – a few inches on earth – Ed.) is an opportunity to test the ability of a growing global observing network to communicate and coordinate their optical and radar observations in a real scenario.
Based on the observations they were able to make in 2012, asteroid trackers predicted that it should come back into view in late 2017.
Since then, observers around the world have been tracking the rock as it approaches Earth and reporting their observations to the Minor Planet Center based at the Harvard-Smithsonian Center for Astrophysics in Cambridge, Massachusetts.