NASA’s Osiris-Rex spacecraft is now just a few miles from a skyscraper-sized asteroid, Bennu, which has the potential to hit Earth in just over 150 years time.
The spacecraft is to investigate the asteroid, which is a third of a mile wide, and is thought to be rich in organic molecules dating from the start of the solar system.
Scientists believe that asteroids may have delivered the ingredients for life to the young Earth – and hope to analyse samples from Bennu to prove the theory.
Scientists estimate there is a one-in-2,700 chance of the asteroid crashing into Earth 166 years from now.
Mission spokeswoman Erin Morton said, ‘By the time we collect the sample in 2020 we will have a much better idea of the probability that Bennu would impact Earth in the next 150 years.’
If all goes well, scientists should get the samples in 2023.
Launched more than two years ago, Osiris-Rex used Earth’s gravity as a slingshot to put it on a path towards the asteroid Bennu.
If Bennu hit our planet, it would explode with more force than all the nuclear weapons detonated in history, and could start fires across an area four times the size of Britain.
Professor Dante Lauretta of the University of Arizona said that an impact with Bennu would release, ‘three times more energy than all nuclear weapons detonated throughout history”.
‘The impact would release energy equivalent to 1,450 megatons of TNT.’
‘For comparison, the fission bombs used in World War II had an energy release of roughly 20 kilotons of TNT each and the most powerful nuclear weapon ever detonated, the Russian Tsar Bomba, had a yield of 50 megatons.’