Otherwise, it can be bathed in a liquified form of the second material until all of the voids created by the laser are filled in.

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And as the decayed material has an extremely high water content Mr Hansen said that most of the laser's energy is absorbed by the infected tissue, which is then vaporised.

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But further measurements using a laser and looking for reflections showed that much of the ice is covered with a layer of dark material tens of centimetres thick.

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