Australian scientists discovered some spherules in May. These give evidence that the earth was hit by an asteroid. Although chances of another asteroid hitting the earth are remote, the National Aeronautics and Space Administration (NASA) is exploring the possibility of a clash with asteroid Bennu.
Bennu was an asteroid that was spotted by researchers in 1999. As it crosses the earth's orbit once in six years, it has inched closer to us, with a sporadic shift of 100 miles.
The asteroid is expected to travel between the earth and the moon in 2135. Due to its nearness, it is expected that the earth's gravity will impact its orbit, according to Dante Lauretta, professor of planetary science at Arizona University.
NASA concludes that the possibility of being hit by Bennu may be just 1 in 2,500. However, experts estimate that Bennu's attack would be about 200 times as strong as the Hiroshima atomic attack, or even about as high as 3 billion tonnes of high explosives.
Bennu is certainly within the threshold of causing a "global catastrophe" due to its massive size, according to Professor Mark Bailey of Armagh Observatory in Northern Ireland.
NASA's Osiris-Rex probe mission will be launched in September. It will first revolve around the sun for a year and then "slingshot" around the earth again, and align the earth's orbit with Bennu by August 2018.
Hence, it used the Yarkovsky effect or the force that can send asteroids orbiting the solar system and then the earth.
NASA would be able to get parts of a carbonaceous asteroid. As Bennu is an ancient relic filled with organic molecules, scientists have measured Bennu's density and speculate that space inside the asteroid can make the body a "rubble pile", or a loose conglomeration of "dust, rock, and boulders," according to Edward Beshore, deputy principal investigator for Osiris-Rex.
"We need to know everything about Bennu - its size, mass, and composition," said Lauretta. "This could be vital data for future generations."
