Two small comets — or rather two chunks of the same comet — will slip by Earth on March 21 and March 22, each on a different side of the planet. Comet 252P/LINEAR passed at a distance of about 5.2 million kilometers (13.5 times as far as the moon) around 8:14 a.m. Eastern on Monday, while comet P/2016 BA14 (PANSTARRS) will fly by at 10:30 a.m. Tuesday, coming no closer than about 3.5 million kilometers, just over nine times the distance to the moon. Neither comet poses any danger to Earth.
Comet BA14 was discovered in January. Its orbit is strikingly similar to that of fellow traveler252P, a comet first seen 16 years ago. Researchers suspect that both bodies are fragments of a larger comet that broke apart. Despite their close approach, neither comet is visible to the naked eye.