Though we tend to focus much of our attention on Mars when it comes to the search for signs of life on other planets, NASA is busy checking out our other planetary neighbors, too, and today they announced a huge discovery. Mercury, the closest planet to the sun, has water.
In a press conference Thursday the team responsible for NASA's MESSENGER (Mercury Surface, Space Environment, Geochemistry, and Ranging spacecraft) probe, which has been orbiting Mercury since last year announced that areas of "water ice" and other "volatile materials" have been found at Mercury's poles. It might seem strange to think of ice, or even liquid water, so close to the sun, but because Mercury's orbit has almost no tilt, there are areas of the planet at the poles that remain completely free of sunlight at all times, and it's those areas where the ice was found.
"For more than 20 years the jury has been deliberating on whether the planet closest to the sun hosts abundant water ice in its permanently shadowed polar regions. MESSENGER has now supplied a unanimous affirmative verdict," said Sean Solomon, principal investigator for the MESSENGER mission.
Past observations through telescopes dating as far back as 1991 had hinted at water on the planet, but more direct observations were required to confirm the theory. Now MESSENGER has confirmed it through three different methods.
"Three independent lines of evidence support this conclusion: the first measurements of excess hydrogen at Mercury's north pole with MESSENGER's Neutron Spectrometer, the first measurements of the reflectance of Mercury's polar deposits at near-infrared wavelengths with the Mercury Laser Altimeter (MLA), and the first detailed models of the surface and near-surface temperatures of Mercury's north polar regions that utilize the actual topography of Mercury's surface measured by the MLA," NASA announced via its website.
The ice was also accompanied by "volatile" and "dark" materials at the planet's poles, which, according to the MESSENGER team's findings, is "likely a mix of complex organic compounds delivered to Mercury by the impacts of comets and volatile-rich asteroids, the same objects that likely delivered water to the innermost planet.The organic material may have been darkened further by exposure to the harsh radiation at Mercury's surface, even in permanently shadowed areas."
Though the discovery of water on Mercury is the big find today, the MESSENGER team will now focus more effort on unraveling the mystery of this other material.
"But the new observations have also raised new questions," Solomon said. "Do the dark materials in the polar deposits consist mostly of organic compounds? What kind of chemical reactions has that material experienced? Are there any regions on or within Mercury that might have both liquid water and organic compounds? Only with the continued exploration of Mercury can we hope to make progress on these new questions."
So, we just found water on the planet closest to our blazing-hot sun, and it was frozen. What will we find next?