Water-ice found on comet for first time

Comet 67P (BBC / Facebook)
Comet 67P (BBC / Facebook)

Previously "conspicuously absent" ice has been found on well-known comet 67P, a study published today says.

The report, published in Nature, says exposed water-ice on the nucleus of the comet was identified, though water vapour had previously been seen in the nebulous cloud.

The Rosetta spacecraft has confirmed the presence in a dusty region of the comet by bouncing infrared light off the surface which reflects back in different ways depending on the material.

Researchers say this is consistent with their theory the comet has a "dry, crunchy coating" over an ice-layered core.

Gianrico Filacchione and colleagues used measurements taken by the VIRTIS-M instrument onboard the Rosetta in a dusty region called Imhotep, located on the nucleus of comet 67P.

The group estimates there is plenty of water-ice and grain size in the region of the 67P which shows millimetre-sized pure water-ice grains — larger than those in all previous observations — and 50-micrometre-sized grains, mixed with dark material.

67P was first discovered by Soviet astronomers in 1969.

It has been the subject of much interest for scientists since then, with NASA attempting to put the Philae lander on the comet's surface.

It has also previously been revealed its rubber duck shape was formed after the collision of two objects, rather than the result of erosion.

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