Asteroid 2012 XE54 might undergo an eclipse by Earth’s shadow on the night of December 10-11, 2012.

Bottom line: Asteroid 2012 XE54 might undergo an eclipse by Earth’s shadow on the night of December 10-11, 2012. Eclipse may begin at 7:22 CST on December 10 (01:22 UTC on December 11) and end at 8:00 p.m. CST on December 10 (02:00 UTC on December 11). The asteroid will come closest to Earth a few hours later, passing a little more than half the moon’s distance away.


If the eclipse occurs as Dr. Tricarico suggests, 2012 XE54 will enter Earth’s shadow at 7:22 CST on December 10 (01:22 UTC on December 11) and leave Earth’s shadow at 8:00 p.m. CST on December 10 (02:00 UTC on December 11). Will it be like a lunar eclipse, during which the moon passes through Earth’s shadow? No. At a lunar eclipse, observers on Earth see a dark bite taken from one edge of the moon, which slowly crawls across the moon’s face. An asteroid eclipse can’t be like that, because asteroids appear starlike from Earth – like points of light, even through telescopes. Those watching an asteroid eclipse see the asteroid’s light suddenly dim.

The actual closest approach of the asteroid will occur on December 11, 2012 at 4:10 a.m. CST on December 11 (10:10 UTC).

[link to earthsky.org]