NASA's MESSENGER spacecraft has found new evidence of water ice near Mercury's shadowed polar craters, a finding that scientists say supports the hypothesis that the planet contains lots of water and frozen materials.
Even though Mercury is the closest planet to the sun, it has pockets near its poles that are never touched by sunlight and could be cold enough for ice to remain unmelted, NASA explained.
"For more than 20 years, the jury has been deliberating whether the planet closest to the sun hosts abundant water ice in its permanently shadowed polar regions," said Sean Solomon, principal investigator for the project, in a press release last week. "MESSENGER now has supplied a unanimous affirmative verdict."
NASA's MESSENGER spacecraft - short for MErcury Surface, Space ENvironment, GEochemistry, and Ranging - has been observing Mercury since it was launched in March 2011, and the images it has captured so far confirm the water ice hypothesis.
"The new observations from MESSENGER support the idea that ice is the major constituent of Mercury's north polar deposits," NASA said. The spacecraft measured neutrons and excess hydrogen from Mercury's north pole region.