Incredibly cold comet captured on camera
Water ice there is frozen like a rock
An in-bound comet 1.5 billion miles from the sun has been pictured making the long journey from the edge of the solar system.
The lump of frozen water, gas and dust, with a nucleus less than 12 miles across, is the most distant active incoming comet ever seen.
Known as C/2017 K2 (PANSTARRS) or “K2”, the comet has already been travelling for millions of years from its birthplace in the Oort Cloud, a shell of icy objects on the solar system’s outermost fringes.
For the next five years it will continue into the inner solar system before reaching its closest approach to the sun just beyond the orbit of Mars. There is no chance of the comet colliding with Earth.
Because it is already being slightly warmed by the sun the comet has started to develop a coma, an 80,000 mile-wide fuzzy halo of dust.
Lead researcher Dr David Jewitt, from the University of California at Los Angeles, said: “This comet is so far away and so incredibly cold that water ice there is frozen like a rock.
We know for sure that the activity – all the fuzzy stuff making it look like a comet – is not produced by the evaporation of water ice. Instead, we think the activity is due to the sublimation (a solid changing directly into a gas). That’s why it’s special.”