Asteroid (488490) 2000 AF205 passed by the Earth at a distance of about 12 849 000 km (33.5 times the average distance between the Earth and the Moon, or 8.59% of the distance between the Earth and the Sun), slightly after 4.45 am GMT on Friday 18 December 2020. There was no danger of the asteroid hitting us, though were it to do so it would not have presented a significant threat. (488490) 2000 AF205 has an estimated equivalent diameter of 86-270 m (i.e. it is estimated that a spherical object with the same volume would be 86-270 m in diameter), and an object at the upper end of this range would be predicted to be capable of passing through the Earth's atmosphere relatively intact, impacting the ground directly with an explosion that would be about 45 000 times as powerful as the Hiroshima bomb. Such an impact would result in an impact crater roughly 4 km in diameter and devastation on a global scale, as well as climatic effects that would last years or even decades.
(488490) 2000 AF205 was discovered on 8 January 2000 by the Massachusetts Institute of Technology's Lincoln Near Earth Asteroid Research Laboratory in Socorro, New Mexico. The designation 2000 AF205 implies that it was the 5031st asteroid (asteroid F205 -
in numbering asteroids the letters A-Y, excluding I, are assigned
numbers from 1 to 25, with a number added to the end each time the
alphabet is ended, so that A = 1, A1 = 26, A2 = 51, etc., which means that F205 = (25 X 205) + 6 = 5031) discovered in the first half of January 2000
(period 2000 A - the
year being split into 24 half-months represented by the letters A-Y, with I being excluded), while
the designation 488490 implies that it was 488 490th asteroid ever
discovered (asteroids are not given this longer designation immediately
to avoid naming double or false sightings).
