Nasa Earth defence specialists are closely monitoring the approach of an asteroid that is due to make a staggeringly close pass of Earth on Thursday.
Experts are convinced it will not impact, but say it will skim earth at a distance of about 6 800km, which is a cat’s whisker in astronomical terms.
Asteroid 2012 TC4 is estimated to be 30m in size.
The 20m Chelyabinsk meteor exploded in the atmosphere above the Russian city unexpectedly on February 15 2013.
Space agencies had no idea it was approaching before the explosion ripped through the air.
Most injuries sustained were from flying broken glass from buildings damaged by the strength of the explosion – 26 to 33 times as much energy as the atomic bomb dropped on the Japanese city of Hiroshima in 1945.
Nasa scientists said they were excited about what could be learnt from TC4.
A spokesperson said: “They plan to use its close approach to Earth as an opportunity to test Nasa’s network of observatories and scientists who work with planetary defence.
“Even though scientists cannot yet predict exactly how close it will approach, they are certain it will come no closer than 6 800km from the surface of Earth.”
Michael Kelley, programme scientist and Nasa Headquarters lead for the TC4 observation campaign, said: “Scientists have always appreciated knowing when an asteroid will make a close approach to and safely pass Earth because they can make preparations to collect data to characterise and learn as much as possible about it.
“This time, we are adding in another layer of effort and will use this asteroid flyby to test the worldwide asteroid detection and tracking network, assessing our capability to work together in response to finding a real asteroid threat.” – The Express