NASA announced Thursday the major discovery of water ice at the polar regions on Mercury, the planet closest to the sun.
NASA’s MErcury Surface, Space ENvironment, GEochemistry, and Ranging (MESSENGER) spacecraft, which has been studying Mercury in unprecedented detail since its historic arrival there in March 2011, provided the new ground-breaking information.
Scientists suggested decades ago there might be water ice and other frozen volatiles trapped at Mercury’s poles.
“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 MESSENGER principal investigator Sean Solomon of Columbia University’s Lamont-Doherty Earth Observatory in Palisades, N.Y.
“MESSENGER now has supplied a unanimous affirmative verdict,” he added.
Researchers involved with the mission said the MESSENGER provided more support for scientists’ beliefs that the planet has water ice in many of the dark craters at its poles.
Given its proximity to the sun, Mercury would seem to be an unlikely place to find ice. However, the tilt of Mercury’s rotational axis is less than 1 degree, and as a result, there are pockets at the planet’s poles that never see sunlight.
NASA says the MESSENGER spacecraft has yielded measurements of excess hydrogen and reflectance, as well as information that has helped them understand temperatures of Mercury’s north polar regions.
“We estimate from our neutron measurements the water ice lies beneath a layer that has much less hydrogen,” said David Lawrence, a MESSENGER participating scientist at the Johns Hopkins University Applied Physics Laboratory (APL) in Laurel, Md.
“The surface layer is between 4-8 inches thick,” Lawrence added.
The ice is thought to be at least 1½ feet deep and possibly as much as 65 feet deep.
Lawrence says there’s probably enough polar ice on Mercury to bury an area the size of Washington, D.C., by two to 2½ miles deep.
Solomon stressed that no one is suggesting that Mercury might hold evidence of life, given the presence of water. But the latest findings may help explain some of the early chapters of the book of life elsewhere in the solar system, he said.
MESSENGER was launched in 2004, and it took seven years for the craft to reach Mercury.
Researchers said MESSENGER’S observations will help them better understand how Mercury and other planets in the solar system formed some 4.5 billion years ago.
The new findings are detailed in three papers published online in Science Express.
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