A MASSIVE 20-metre asteroid will fly well within the moon’s orbit on Thursday and scientists will use the close call as practice for a collision as the giant rock passes so close to Earth.
Asteroid 2012 TC4 poses no threat to Earth but it will be used as a chance to prepare for a collision with inner planets.
The rock will pass about 50,000 kilometres above Earth and will serve as a stark reminder to the Chelyabinsk meteor which exploded above Russia, shattering windows and leaving thousands injured in February 2013.
Comet Shoemaker-Levy 9 crashed into Jupiter in 1992 and alerted the public to the fact we live in a cosmic shooting gallery, however Chelyabinsk brought the reality of the dangers of asteroids closer to home.
Peter Brown, Professor of physics and astronomy at Western University in London, said: “Shoemaker-Levy 9 brought home the fact that impacts happen.
“So people started taking the asteroid threat more seriously, and a lot more surveying was done after that.
“But until Chelyabinsk, it was’t really brought home at a governmental level that this is something we have to prepare for.”
An asteroid like 2012 TC4 enters Earth’s atmosphere on average once ever 20 years and one passes between Earth and the moon every few weeks, according to Professor Brown.
This particular asteroid is named after the year it was detected and has gathered a lot of attention from the astronomical community.
Professor Brown said: “Normally something like this would only be detected a week or two out.
“Its main utility is it’s going to be used as a sort of dry run for a lot of planetary defence processes and procedures internationally.
“It’s a very fast-moving, relatively faint kind of object. Exactly the kind of object you’d expect to impact Earth. So it’s an excellent chance to test this thing out.”
The asteroid will come closest to Earth at 1.42am ET (6.42am BST), over the South Pacific Ocean.
The next close pass of this asteroid will be in 2075 and astronomers predict a chance of impact then at only one in 2,000.
The orbit of an asteroid can be changed by several factors, including sunlight – known as the Yarkovsky effect.
This one’s will change as a result of it passing so close to Earth.
“The orbit will be very significantly changed by this close approach,” Professor Brown said.
“And that, together with the uncertainty of the Yarkovsky, are the things that really make this encounter in the 2075-2079 time range most uncertain still.
“Some time in the next few years, we’ll have a conversation where it’s going to be, ‘This thing will hit in two days, and what are we doing?’ And a lot of what we’re doing will be learned in this exercise this week.”
NASA has estimated more than a dozen observatories, universities and laboratories around the world will be watching the asteroid on Thursday.