It was the biggest asteroid to strike Earth in more than a century, yet no one saw the Chelyabinsk meteor coming. When the space rock smashed into western Russia in February 2013 it generated a shockwave as strong as 35 Hiroshima atomic bombs, leaving more than 1,600 people injured.
But how come no one detected the 60ft (19 meters)-wide meteor heading straight for us? The answer, experts say, is that it was hidden by the glare of our sun. Worst still, it will not be the only one, as they warn that an ‘unknown’ number of space rocks could be heading for Earth undetected. ‘Asteroids the size of the Chelyabinsk meteor strike Earth roughly every 50-100 years,’ warned Richard Moissl, the European Space Agency’s head of planetary defence.
‘Injuries caused by airbursts or similar events could be prevented if people are informed of an oncoming impact and its predicted effects. ‘With advance warning, local authorities would be able to advise the public to keep well away from windows and glass.’ So just how can astronomers spot these ‘invisible’ asteroids lurking in the sun’s glare?
Well, the European Space Agency is set to launch its NEOMIR (Near Earth Object Mission in the Infra-red) orbiting observatory later this decade, which will act as an early warning system to detect and monitor any asteroid coming towards Earth from the sun’s direction.
NEOMIR will be located at the ‘L1’ Lagrange point between Earth and the sun. Undisturbed by Earth’s atmosphere, its infrared telescope will be able to spot asteroids 65ft (20 meters) and larger currently lurking in the sunlight.
Moissl added: ‘ESA’s upcoming NEOMIR mission will detect asteroids like Chelyabinsk coming from the same region in the sky as the sun, filling a vital gap in our current abilities to predict and plan for hazardous impacts.’
The space agency admits that there is a possibility that an asteroid even bigger than what NEOMIR will be able to detect could impact Earth from the dayside, but such a scenario is less likely.
This is because the larger the asteroid, the fewer there are in the Solar System and the easier they are to detect. So much so that almost all asteroids larger than half a mile wide (one km) have already been discovered.
Scott Sheppard, from the Carnegie Institution for Science in Washington DC, has previously said that the discoveries of near-Earth objects (NEOs) are only just beginning, in part because of the history of our observatories.
Most telescopes tend to look away from our planet so they can avoid the glare of the sun. However, new surveys are beginning to peer in the other direction and revealing more NEOs – including never-before-seen asteroids. (SOURCE)
