|NASA has released spectacular pictures of asteroid Bennu. NASA’s OSIRIS-REx spacecraft arrived at asteroid Bennu on 3 December 2018. Branded an "apocalypse asteroid", Nasa says it has a one in 2,700 chance of hitting our planet between 2175 and 2199. |
It is about 500 metres across and would be capable of an explosive blast of 1,200 megatons in TNT equivalent, about 80,000 times the bomb dropped on Hiroshima.
|Bennu will pass 750,000 km; 460,000 mi from Earth on 23 September 2060. The close approach of 2060 causes divergence in the close approach of 2135. On 25 September 2135, the nominal approach distance is 300,000 km; 190,000 mi from Earth, but Bennu could pass as close as 100,000 km; 65,000 mi.|
The 2135 approach may cause Bennu to pass through a gravitational keyhole which could create an impact scenario. The keyholes are all less than 55 km wide.
|In 2196 the odds are 1 in 11,000 of an Earth impact.|
|Nasa has issued a "close approach" alert for an asteroid – and says it'll even be joined by a second Earth-skimming asteroid on the same day. The good news is that asteroids regularly pass close to Earth. What Nasa considers 'close' in the case of 2013-CW32 is around 3,119,690 miles – about 14 times the distance between the Earth and the Moon.|
That's a very good thing because 2013-CW32 is around 820 feet across (253 meters) and travelling at 36,775 mph. (59183 kph) For perspective, the 2013 Chelyabinsk meteor was estimated to be 20m and it caused an explosion 30 times stronger than the atom bomb over Hiroshima.