First Comet To Swerve Closer To Earth Than Any Other Comet In Centuries

On Monday, March 21, an emerald-green comet will brush the Earth, followed one day later by a kissing cousin that will swerve closer to the planet than any other comet in nearly 250 years, reports USA Today.

The first of the comets will be visible Monday in the southern hemisphere, if you live outside of the city, that is. To see the larger of two comets, stargazers in the U.S. will only need a set of binoculars. Scientists, however, are taking out the big guns for this one. The Hubble Telescope, the powerful ground-based Gemini telescopes and others will be set up to get an extraordinary close-up of the comets.

This is one for the record books," Michael Kelley of the University of Maryland, told USA Today."It's a fantastic opportunity for professionals to learn more about comets, and if you have a chance to try to find them… it's a fantastic chance to see part of history as it happens."

According to University of Maryland's Matthew Knight, the first comet – known as comet 252P/LINEAR – is a bright green color caused by the carbon gas it's puffing out. 252P will slide past Earth at a distance of roughly 3 million miles, putting 252P in the top 10 of closet-approaching comets.

Amateur comet-hunter Michael Mattiazzo of Australia says that 252P wasn't expected to get terribly bright, but it has been "surpassing all expectations." Mattiazzo claims that the comet may even be visible to the unaided eye in the southern hemisphere suburbs where the light pollution is low.

Astronomers discovered 252P's co-comet just a few months ago. P/2016 BA14 was shrugged off as an asteroid at first, but after careful consideration astronomers dubbed the object a comet. Meaning BA14 and its larger companion 252P "are among the closest comets to pass by Earth in recorded history," says Knight.

The only comet known to have skimmed past Earth at a smaller distance was Lexell's Comet in 1770.

Scientists are still unsure of the relationship between 252P and its partner.

"The two could be related because their orbits are so remarkably similar," Paul Chodas, manager of NASA's Center of NEO Studies (CNEOS) at the Jet Propulsion Laboratory in Pasadena, Calif., said in a NASA news release.

"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."

Follow-up observations of the comets completed by the NASA/ESA Hubble Space Telescope and NASA's Infrared Telescope Facility will try to find further hints to the comets' origins.

According to Discovery News, neither comet poses a threat to Earth.

"March 22 will be the closest comet P/2016 BA14 gets to us for at least the next 150 years," Chodas continued. "Comet P/2016 BA14 is not a threat. Instead, it is an excellent opportunity for scientific advancement on the study of comets."

[Photo by Christopher Furlong/Getty Images]