An asteroid first sighted yesterday has most likely plunged directly into our planet's atmosphere and burned up. The object's name, 2014 AA, highlights the fact that it was the very first asteroid discovered this year.
Based on the asteroid's trajectory when it was discovered, "it is virtually certain that 2014 AA hit the Earth's atmosphere on 2014 Jan. 2 ," wrote Gareth V. Williams of the International Astronomical Union's Minor Planet Center.
The asteroid was probably around 4 meters in diameter, about the height of double-decker bus. It is not uncommon for objects of this size to impact Earth, generally happening at least once a year. The combination of the asteroid's small size and our planet's thick atmosphere means that it mostly disintegrated in the air, with perhaps only a few small chunks reaching the ground. Anything surviving fell within a large swath of the surface, stretching from Central America over the Atlantic to Africa (see image above).
While the impact is not unusual, actually spotting an asteroid before it hits the Earth is quite rare. The only other asteroid seen before atmospheric entry is 2008 TC3, which came down in October 2008. That asteroid's impact was widely recorded and set off a race to find fresh chunks on the ground, which turned up in the Sudan desert.
Below is an animation of 2014 AA as it approached the Earth's nightside, so you can see what it feels like to slam right into our planet.
Animation: Pasquale Tricarico via Ernesto Guido
