NASA's Hubble Space Telescope has managed to capture the glimpse of the farthest active inbound comet that has the world has ever seen. According to a study published in the Astrophysical Journal Letters, the telescope captured the image of the comet at a distance of 1.5 billion miles from the Sun, reported Firstpost. It has already started developing an 80,000-mile-wide cloud of dust, which is called a coma. It's wrapping up the solid nucleus of frozen gas and dust, added the study.

As per the report, these recent observations show the earliest signs of activity that have ever been seen in a comet entering the solar system's planetary zone for the first time. The concerned comet, dubbed C/2017 K2 (PANSTARRS) or "K2", has been travelling for millions of years in the frosty (minus 226 degrees Celsius) outer reaches of the solar system, mentions the report.

Asteroid
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Comets are essentially the frozen bits and pieces that were left behind after the formation of the solar system around 4.6 billion years ago.

"K2 is so far from the Sun and so cold, we know for sure that the activity -- all the fuzzy stuff making it look like a comet -- is not produced, as in other comets, by the evaporation of water ice," said lead researcher of the study, David Jewitt of the University of California, Los Angeles.

"Instead, we think the activity is due to the sublimation (a solid changing directly into a gas) of super-volatiles as K2 makes its maiden entry into the solar system's planetary zone. That's why it's special. This comet is so far away and so incredibly cold that water ice there is frozen like a rock," he added.

According to Jewitt, the Hubble Telescope's observations of K2's coma suggest that sunlight is heating the frozen volatile gases, like oxygen, nitrogen, carbon dioxide, and carbon monoxide, which cover the comet's frigid surface. These gases lift off from the comet's surface and release dust, which then forms the coma.

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"I think these volatiles are spread all through K2, and in the beginning billions of years ago, they were probably all through every comet presently in the Oort Cloud," Jewitt said. "But the volatiles on the surface are the ones that absorb the heat from the Sun, so, in a sense, the comet is shedding its outer skin. Most comets are discovered much closer to the Sun, near Jupiter's orbit, so by the time we see them, these surface volatiles have already been baked off. That's why I think K2 is the most primitive comet we've seen," said Jewitt.