NASA says asteroid to pass close to Earth on March 5

A small asteroid that harmlessly flew past the Earth two years ago is swinging around once more next month and, this time, it'll be a lot closer than before. Thankfully, NASA still insists that humans are in no immediate danger of collision-induced extinction.

Asteroid 2013 TX68 is predicted to fly by the Earth on March 5, 2016 at a distance of anywhere between 14 million kilometres and 17,000 kilometres. Last year, it zipped past two million kilometres away. The wide scope of possible ranges is due to the fact that there are any number of trajectories the asteroid could take. When the asteroid was discovered on October 6, 2013, NASA didn't have enough time to track its path, and was only able to predict when it would come back. 

But even though TS68's flight path is relatively unknown, scientists at NASA's Centre for Near Earth Object Studies (CNEOS), at the Jet Propulsion Laboratory in California, say the chance of a collision with Earth is about one in 250 million. Later flybys in 2046 and 2097 are predicted to have an even lower probability of impact. "The possibilities of collision on any of the three future flyby dates are far too small to be of any real concern," said Paul Chodas, manager of CNEOS. "I fully expect any future observations to reduce the probability even more."

Asteroid 2013 TX68 is estimated to be about 30m in diameter, slightly larger than the meteor that burned up in the atmosphere over Chelyabinsk, Russia, three years ago, which measured 20m in diameter. NASA estimates that, if an asteroid the size of TX68 were to enter Earth's atmosphere, it would produce an air burst with about twice the energy of the Chelyabinsk event, which itself was compared to the energy released from 30 Hiroshima bombs.