This is one of those perplexing astronomical news that make history and I can't but mention. US scientists have found, with the help of scout satellite MESSENGER, that not just suspected Mercury's polar water ice (in shadowed craters) is indeed that but also that confusing dark regions around it are complex organic materials, possibly darkened by the intense solar radiation that bathes the small inner planet.
The team found that the probe's reflectance measurements, taken via laser altimetry, matched up well with previously mapped radar-bright regions in Mercury's high northern latitudes. Two craters in particular were bright, both in radar and at laser wavelengths, indicating the possible presence of reflective ice. However, just south of these craters, others appeared dark with laser altimetry, but bright in radar.
This confused scientists for a while but eventually they realized that the puzzling regions actually hold water ice at a meter's depth into the soil, where the heat of the sun can't reach so easily.
|Radar-reflectant regions (ice) show in yellow|
The most interesting part however is that the astronomers are almost certain now that the dark material must be complex organic matter, darkened by the extreme solar radiation.
Is there life in Mercury?
Source: Science Daily.
- David A. Paige, Matthew A. Siegler, John K. Harmon, Gregory A. Neumann, Erwan M. Mazarico, David E. Smith, Maria T. Zuber, Ellen Harju, Mona L. Delitsky, and Sean C. Solomon. Thermal Stability of Volatiles in the North Polar Region of Mercury. Science, 29 November 2012 DOI: 10.1126/science.1231106
- Gregory A. Neumann, John F. Cavanaugh, Xiaoli Sun, Erwan M. Mazarico, David E. Smith, Maria T. Zuber, Dandan Mao, David A. Paige, Sean C. Solomon, Carolyn M. Ernst, and Olivier S. Barnouin. Bright and Dark Polar Deposits on Mercury: Evidence for Surface Volatiles. Science, 29 November 2012 DOI: 10.1126/science.1229764