Saturday, March 19, 2016

2 Comets To Come Very Close To Earth On March 21-22

A green glowing comet, 252P/Linear, will pass near Earth on March 21, 2016. Image credit: NASA/JPL

Two comets are going to pass near Earth on March 21, 2016, and March 22, 2016. The second comet will come closer to Earth than any comet has in over 200 years.

The larger comet measuring 750 feet in size will safely miss Earth by 3.3 million miles (5.3 million kilometers) at 8:14 a.m. Eastern Daylight Time on Monday - which is 14 times the distance between the Earth and the Moon. Named 252P/Linear by astronomers, the comet glows green but won't be visible to the naked eye, according to NASA.

Comet Pan-STARRS (P/2016 BA14) will be the closest comet to near Earth in 246 years. Image credit: NASA/JPL

The smaller comet, Comet Pan-STARRS (P/2016 BA14), will come much closer to Earth at 10:30 a.m. Eastern Daylight Time on Tuesday. Comet Pan-STARRS is predicted to come as close as 2.2 million miles (3.5 million kilometers) to Earth, just 9 times the distance between the Earth and the Moon. According to Sky & Telescope, the last comet to come this close to Earth was 246 years ago when Lexell's comet passed Earth by only 1.4 million miles in 1770.  This will be the third closest flyby of a comet in recorded history next, according to NASA.

Pan-STARRS is named after the telescopic survey that discovered it - "Panoramic Survey Telescope and Rapid Response System" which sits atop the Haleakala volcano in Hawaii. It was initially thought to be an asteroid, but follow-up observations by astronomers showed a faint tail, revealing that the discovery was, in fact, a comet. 

Because the two comets have extremely similar orbits, some astronomers believe that they may have been part of the same comet that broke apart.

"Comet P/2016 BA14 is possibly a fragment of 252P/LINEAR. The two could be related because their orbits are so remarkably similar," said Paul Chodas, manager of NASA's Center of NEO Studies (CNEOS) at the Jet Propulsion Laboratory in Pasadena, California. "We know comets are relatively fragile things, as in 1993 when comet Shoemaker-Levy 9 was discovered and its pieces linked to a flyby of Jupiter. Perhaps during a previous pass through the inner-solar system, or during a distant flyby of Jupiter, a chunk that we now know of as BA14 might have broken off of 252P."

Observations made by the Hubble Space Telescope of comet 252P/LINEAR, and by NASA's Infrared Telescope Facility of comet P/2016 BA14 will further investigate their possible twin nature.