Rachel Courtland writes in New Scientist that the asteroid Apophis, previously thought to be on course for impact with Earth in 2036, is now more likely to hit us in 2068. (As an aside, Alexandra Bruce writes about Apophis and other Near Earth Objects (NEOs) that we may like to worry about in the disinformation book 2012: Science or Superstition.) From New Scientist:
The chances of the asteroid Apophis hitting Earth in 2036 are lower than we thought. But those worried about deep impacts should add a new entry to their calendar: 2068.
When Apophis was first spotted in 2004, the 250-metre-wide rock was briefly estimated to have a 2.7 per cent chance of hitting Earth in 2029. Further observations quickly showed that it will miss Earth that year – but should it pass through a 600-metre-wide “keyhole” in space, it will return to hit Earth in 2036.
For the past several years, the probability of such a collision has been considered to be 1 in 45,000. But new calculations suggest the chance of an impact in 2036 is far lower – about 1 in 250,000.
The revised estimate is in part a result of additional observations of the asteroid as well as refinements on the position of Apophis in older data…