Astronomers Watch Special Comet Form During Big Journey

Scientists are tracking a comet that is 1.5 billion miles away from our sun and hope to learn more about our solar system as it cruises toward the center.

The great distance of the comet is what makes it so special — the University of California, Los Angeles, explained that it is the farthest a comet has ever been detected and astronomers will be watching the comet’s “developing activity … over an extraordinary range of distances.” Right now it is at a point between the orbits of Saturn and Uranus but the comet has already made of journey of billions of miles, over millions of years, as it races toward the sun from its position in the Oort Cloud, a large area at the farthest reaches of the solar system where scientists believe there are many comets, as well as other icy objects.

The Oort Cloud is so large and far from the sun that its closest point is 465 billion miles away and it extends to an area trillions of miles away. With the sun’s heat and light so far in the distance, that area’s temperature is hundreds of degrees below zero.

Astronomers have already begun watching the comet, which is nicknamed K2, with the Hubble Space Telescope, according to a study in the Astrophysical Journal Letters.

“Because K2 is so far from the sun and so cold, water ice there is frozen like a rock, and we know for sure that the activity — all of the fuzzy stuff making it look like a comet — is not produced by the evaporation of water ice, as it is in other comets,” UCLA astronomer David Jewitt said in the statement.

But the comet is heating up as it gets closer, forming a large cloud of dust that is the signature of a comet, called a coma, around its frozen center.

That center is about 12 miles across but the coma is 80,000 miles wide — 10 times wider than Earth.

Another key feature of a comet is its tail, but K2 hasn’t formed one yet. Those tails trail a comet when the pressure of energy coming from the sun forces back particles coming off the comet’s surface.

“It should become more and more active as it nears the sun and presumably will form a tail,” Jewitt said.

K2 will reach an area near the Mars orbit in 2022, its closest point to the sun. This is the earliest we have observed a comet that is going to visit our planetary neighborhood.

According to Jewitt, scientists normally detect comets when they are closer in, such as around Jupiter. By that time, the frozen volatile gases on its surface, like oxygen, carbon dioxide and nitrogen, have already burned off. With K2, that process is not complete.

“That’s why I think K2 is the most primitive comet we’ve seen,” Jewitt said.

K2 represents a chance to watch the sun heat up those elements, making them “lift off from the comet and release dust,” as UCLA describes.

According to Jewitt, “In a sense, the comet is shedding its outer skin.”