Asteroid grazes past Earth in ‘critical’ rehearsal

PARIS: A house- sized asteroid grazed past Earth yesterday, passing harmlessly inside the Moon’s orbit, as predicted, to give experts a rare opportunity to rehearse for a real strike threat in future.

Dubbed 2012 TC4, the object’s passing allowed scientists to practice spotting incoming objects, predicting their size and trajectory, and tracking their passage with a global network of telescopes and radars.

“We pretended that this was a critical object and exercised our communication,” said Detlef Koschny of the European Space Agency’s Near- Earth Object programme.

The trial run was “a big success,” he said, despite some instruments not working as planned.

A radar system in Puerto Rico, for example, was out of service due to damage from the recent hurricane there.

“This is exactly why we do this exercise, to not be surprised by these things,” Koschny told AFP.

The asteroid flitted past around 0541 GMT at less than 44,000 kilometres from Earth’s surface – just above the 36,000 km plane at which hundreds of geosynchronous satellites orbit our planet.

This was about an eighth of the distance between the Earth and the Moon.

Scientists had predicted that TC4 was between 10 and 30 metres wide. In the end, it measured some 10-12 metres – the smaller end of the range.

“This means it must be very bright,” to make it appear bigger, said Koschny. Observations also revealed that TC4 spins around its axis in about 12 minutes, ‘which is quite fast’. — AFP