Observations made earlier this year from the Subaru Telescope in Hawai’i are providing astronomers with a better sense of how the Yarkovsky effect is influencing the orbital path of asteroid 99942 Apophis.
The estimate on the Palermo Technical Impact Hazard Scale suggests there’s a 1 in 150,000 chance of Apophis hitting Earth on April 12, 2068 (mark your calendars).
When the near-Earth asteroid was discovered in 2004, for example, astronomers initially assigned a horrific 2.7% chance of an Earth impact in 2029.
As for the 2068 encounter, that cannot be ruled out, at least not yet, owing to how the Yarkovsky effect is influencing Apophis.
More observations should improve the estimates, including a better characterization of how the Yarkovsky effect is influencing Apophis’s drift rate.
29075 (1950 DA) has a 1 in 8,300 chance (0.012%) of hitting Earth in 2880, and Bennu, which is currently being investigated by NASA’s OSIRIS-REx spacecraft, has a 1 in 2,700 (0.037%) chance of an Earth impact between the years 2175 and 2199.
Only a small handful of objects are known to pose a serious threat to Earth, and the gigantic asteroid Apophis is one of them