June 20, 2012
Evidence For Ice On Moon’s South Pole Found
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Lee Rannals for redOrbit.com
Little did Neil Armstrong know back on July 21, 1969 that while he was taking his first foot-steps on our celestial neighbor, water was actually accompanying him on the Moon, researchers say.
They found that the area around the Moon´s Shackleton crater could host small reservoirs of frozen water.
The team used a laser altimeter on the Lunar Reconnaissance Orbiter (LRO) spacecraft to find that the crater's floor is brighter than that of nearby craters, indicating the presence of ice.
They calculated that ice may make up 22 percent of the material within a micron-thick layer on the crater's floor.
The crater, which was named after the Antarctic explorer Ernest Shackleton, is more than 12 miles wide, and two miles deep.
The team reported in the journal Nature that they were able to map the crater's elevations and brightness in extreme detail by using LRO's path.
The NASA spacecraft orbits the Moon from pole to pole, and with each orbit is mapping out a different slice of the Moon, each of which contains measurements of both poles. The team used the spacecraft's orbit to gather more than 5 million measurements of the polar crater from over 5,000 orbital tracks.
They used LRO's laser altimeter to determine the crater's elevations based on the time it took for the laser to bounce light back from the Moon's surface. These measurements allowed the group to map the crater's floor and the slope of its walls.
The researchers were able to measure the brightness of the crater by sending out pulses of infrared light at a specific wavelength. The surface of the crater absorbed some light, and reflected back the rest to the spacecraft. The team calculated the difference, and mapped out the relative brightness throughout the floor and walls of Shackleton crater.
Maria Zuber, the team´s lead investigator and the E.A. Griswold Professor of Geophysics in MIT´s Department of Earth, along with colleagues found that while the crater's floor was relatively bright, the walls were even brighter.
They determined that seismic shaking brought on by collisions, or gravitational tides from Earth, may have caused the crater walls to crumble off the older, darker soil, helping to unveil the brighter soil beneath.
Although finding ice on the Moon may ultimately lead some to believe it leads to a better chance for discovering extraterrestrial life, Zuber warned of those thoughts, saying the research does not give implications to alien life on the Moon..
"In general water is interesting because of its implications for life, but water in the frozen form is not very helpful in that regard," Zuber told redOrbit in an email. "This finding does not increase the highly remote chance of indigenous life on the Moon."
She said the water near the Moon's surface is believed to have been delivered by comets.
She said the group's topographic map could help researchers understand crater formation and study other areas of the Moon that are uncharted.
“I will never get over the thrill when I see a new terrain for the first time,” Zuber said in a statement. “It´s that sort of motivation that causes people to explore to begin with. Of course, we´re not risking our lives like the early explorers did, but there is a great personal investment in all of this for a lot of people.”
Zuber went on to envision what the next step scientists could take in furthering her and her colleagues' research.
"The next step will be to probe deeper beneath the surface to see if there is deeper water, and we intend to do this in the GRAIL extended mission," she told redOrbit.