Meteoroid strikes eject water from Moon

Meteoroid strikes eject water from Moon

Meteoroid strikes eject water from Moon

In March this year, NASA said small batches of water around the surface were excited during lunar daytime enough to break away from the Moon's surface.

They found that water spiked in the thin lunar atmosphere at the same times the Moon found itself being pummeled by meteor streams.

Benna and his colleagues described their discovery this week in the journal Nature Geoscience. Until now, astronomers have been well-aware of lunar water at the Moon's chilled polar caps, in some of its permanent surface shadows and within its ancient volcanic craters.

Now, scientists are thrilled to learn more about how meteor streams help populate the Moon's thin atmosphere with water vapour. The science of how water got to the moon and how much there is, however, remains unsettled.

A separate study that month, showed that the surface of the moon holds more water than we thought.

"Most of the geological processes we deal with in planetary science are very slow - we nearly never get to see something respond dynamically over the scale of hours like we did here", lead author Mehdi Benna, a planetary scientist at NASA Goddard Space Flight Center in Greenbelt, Maryland, told Between November 2013 and April 2014, the Lunar Atmosphere and Dust Environment Explorer recorded occasional spikes in the numbers of particles, including water molecules, that were lofted off the moon.

Dr Benna said: "We traced most of these events to known meteoroid streams, but the really surprising part is that we also found evidence of four meteoroid streams that were previously undiscovered".

One explanation is ionised hydrogen carried to the Moon on solar winds from the Sun could explain the presence of water. To sustain this amount of loss over time, they suggested that this water either was present when the moon formed, about 4.5 billion years ago, or was delivered by cosmic impacts from water-laden rocks soon after the moon was born.

"The Moon doesn't have significant amounts of H2O or OH in its atmosphere most of the time", Richard Elphic, the LADEE project scientist at NASA's Ames Research Center in California's Silicon Valley said.

As to the question of where the water originates, the team says it has eliminated the possibility of it coming from the meteorites themselves: "We know that some of the water must be coming from the Moon, because the mass of water being released is greater than the water mass within the meteoroids coming in", said the second author of the research, Dana Hurley of the Johns Hopkins University Applied Physics Laboratory. To release water, the meteoroids had to penetrate at least 8 centimeters below the surface.

But where does the water come from? As such, any water on the rocks was likely fragile and hard to hold onto during the return trips, Benna said.

"With our measurements, we could see exactly the water extracted from the moon in a very dynamic way by micrometeroid impacts, and by analyzing the data, see how much water was stored in the lunar reservoir and where it was going", Benna said.

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