Asteroid 2012 TC4 zips through Moon orbit, some satellites

The passing of the asteroid relatively close to Earth is being used by asteroid trackers around the world to test their ability to operate as a coordinated global asteroid warning network.

"We are going to use this asteroid to practice the system that would observe an asteroid, characterize it and compute how close it is going to come, in case some day we have one that is on the way inbound and might hit", CNEOS manager Pal Chodas told BBC.

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

"This campaign is a team effort that involves more than a dozen observatories, universities and labs around the globe so we can collectively learn the strengths and limitations of our near-Earth object observation capabilities", campaign leader Vishnu Reddy, an assistant professor at the University of Arizona's Lunar and Planetary Laboratory, said in a statement.

Asteroid 2012 TC4 whizzed by at 44,000 km (27,000 miles) at a speed of 30,000 miles per hour, coming well inside the orbit of the moon and other man-made satellites circling the Earth, Reuters reports.

That represents about an eighth of the distance between the Earth and the Moon.

Observations also revealed that TC4 spins around its axis in about 12 minutes, "which is quite fast".

In 2013, a meteor which was about the same size as TC4 exploded in the atmosphere over the city of Chelyabinsk in central Russian Federation with the kinetic energy of about 30 Hiroshima atom bombs.

The 66-foot Chelyabinsk meteor struck Earth's atmosphere, injured 1,500 people and destroyed more than 7,000 buildings. It wil likely return in 2050 and 2079 as it continually loops around the sun.

TC4 will make its closest approach to Earth just before 0541 GMT on Thursday, at a point south of Australia, according to ESA and NASA.

NASA has tested out Earth's planetary defences as Asteroid 2012 TC4 zoomed past Earth this morning.

Ahead of its approach, scientists had stressed there was no risk of collision from the asteroid.

In fact, they first noticed the traveling rock five years ago but, back then, it was on a different orbit.

Many scientists believe the Earth will once again be hit by a space rock of the size that wiped out the dinosaurs, though nobody knows when.

But even if we become better at predicting a strike, there is very little we can do about it.

Vanessa Coleman