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October 26, 2020 - Water on the moon may be more abundant and accessible than previously thought, a discovery that could prove important to future lunar missions.
While previous observations have indicated millions of tons of ice in the permanently shadowed craters of the moon’s poles, a pair of studies in the journal Nature Astronomy take the availability of lunar surface water to a new level.
More than 40,000 square kilometers of lunar terrain have the capability to trap water in the form of ice, according to a team led by the University of Colorado’s Paul Hayne. That’s 20% more area than previous estimates, he said.
These ice-rich areas are near the moon’s north and south poles. Temperatures are so low in these so-called cold traps – minus 163 degrees Celsius – that they could hold onto the water for millions or even billions of years.
Using data from NASA’s Lunar Reconnaissance Orbiter, the researchers identified cold traps as small as a few meters across and as wide as 30 kilometers and more, and used computer models to get all the way down to micrometers in size.
For a second study, scientists used NASA's airborne infrared observatory Sofia to conclusively identify water molecules on the sunlit portions of the moon, just outside the polar regions. Most of these molecules are likely stored in the voids between moon dust and other particles or locked inside glassy volcanic material.
Scientists believe all this water on the moon came from comets, asteroids, interplanetary dust, the solar wind or even lunar volcanic eruptions. They'll have a better idea of the sources “if we can get down on the surface and analyze samples of the ice,” Hayne said.
The lead researcher, Casey Honniball, a postdoctoral fellow at NASA’s Goddard Space Flight Center, said at a news conference that she wanted to make it clear the Sofia study had not found puddles on the moon. Rather, the identified hydrogen and oxygen molecules are so far apart, they are neither in liquid or solid form, she noted.
NASA is under White House direction to put astronauts back on the moon by 2024. The space agency wants its new Artemis moon-landing program to be sustainable, unlike the Apollo program a half-century ago.