Polar Ice?
That a planet just a stone’s throw away from the blazing sun would have ice on it seems paradoxical, yet there is good evidence for this scenario. Ground-based radar has revealed very reflective material – much like water ice — sitting in deep craters at Mercury’s north pole.
These craters might be deep enough to remain in permanent shadow, allowing them to trap ice within. Recently, the MESSENGER spacecraft measured the length of shadows in these craters to estimate their depth and has found that they are deep enough to remain in permanent shadow. Radar measurements from the probe also corroborate the finding that there is highly reflective material in these impacts.
“We can’t yet confirm this is water ice, but the polar cold trap theory is holding up,” said geophysicist Sean Solomon.
Image: NASA/Johns Hopkins University Applied Physics Laboratory/Carnegie Institution of Washington
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