See 'twin' comets buzz Earth hotter and brighter than expected

Two comets, perhaps fragments of the same larger space rock, will make two of the closest passes in modern history, one right after the other.

There's something truly unique happening in the space around our planet this week as a pair of comets, which may be "twin" space rocks that broke apart at some point, make two of the closest passes by Earth in modern history.

To add a little to the cosmic drama, the larger of the twins is coming in much brighter than expected. So bright, in fact, that it may be possible to see it with the naked eye.

Comet P/2016 BA14 was first spotted by the PanSTARRS telescope in Hawaii in January and was originally assumed to be an asteroid. But a second round of observations by a University of Maryland and Lowell Observatory team revealed a faint tail that led astronomers to conclude the object was actually a comet.

When the new comet's orbit was cross-referenced with other known comets, it was found to be more or less tracing the path of another comet known as 252P/LINEAR, first discovered in 2000. This could be a coincidence, of course, or it could be evidence that the two comets are related.

"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 Near-Earth Object Studies (CNEOS). "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."

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Where the two comets will pass by the Earth on Tuesday.

NASA

Earth won't quite be hosting a family reunion, but the two comets will be passing by in pretty quick succession, especially on the galactic scale. First up is 252P/LINEAR, approximately 750 feet (230 meters) in size, flying by us on Monday at a distance of about 3.3 million miles (5.2 million kilometers). Then on Tuesday, the newly discovered comet P/2016 BA14 will pass us at a distance of about 2.2 million miles (3.5 million kilometers). This will be the third-closest flyby of a comet in recorded history.

Comet 252P/LINEAR has already started to surprise astronomers like Tanya Hill at the University of Melbourne in Australia, who says the comet is around 100 times brighter than expected.

"It's even beginning to push the limits of being visible to the naked eye from a dark location," Hill writes in The Conversation. "It won't be a show-stopper but it's certainly a lovely target for binoculars and astro-photographers."

Hill says the southern hemisphere will offer some of the best viewing opportunities for the pair of peripatetic comets, but space-gazers will be fighting the brightness of a full moon.

If you'd rather not battle the moon and geography, kick back and watch the flybys via the below embedded video from The Virtual Telescope Project. The robotic observatory will be hosting a few watching sessions, starting Monday at 1 p.m. PT.

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