Andrew Yee[_1_]
July 9th 08, 07:24 PM
Media Relations
Brown University
Contact:
Richard Lewis, (401) 863-3766
July 9, 2008
Brown-Led Team Finds Evidence of Water in Moon’s Interior
A Brown-led research team has for the first time found evidence of water
deep within the Moon. In a paper published in the July 10 issue of the
journal Nature, the researchers believe the water was contained in lunar
magmas ejected more than 3 billion years ago. The discovery strongly
suggests that water has been a part of the Moon since its early
existence -- and perhaps since it was first created.
PROVIDENCE, R.I. -- A Brown University-led research team has for the
first time discovered evidence of water that came from deep within the
Moon, a revelation that strongly suggests water has been a part of the
Moon since its early existence -- and perhaps ever since it was created
by a cataclysmic collision between the early Earth and a Mars-sized
object about 4.5 billion years ago.
In a paper published in the July 10 issue of the journal Nature, the
team, led by Alberto Saal, assistant professor of geological sciences at
Brown, believes that the water was contained in magmas erupted from fire
fountains onto the surface of the Moon more than 3 billion years ago.
About 95 percent of the water vapor from the magma was lost to space
during this eruptive "degassing," the team estimates. But traces of
water vapor may have drifted toward the cold poles of the Moon, where
they may remain as ice in permanently shadowed craters.
NASA plans to send its Lunar Reconnaissance Orbiter later this year to
search for evidence of water ice at the Moon’s south pole. If water is
found, the researchers may have figured out the origin.
The water clue came from lunar volcanic glasses, pebble-like beads
collected and returned to Earth by NASA’s Apollo missions in the late
1960s and early 1970s. In the decades since, scientists have sought to
determine the content and origin of a class of chemical elements known
as volatiles in the multicolored glasses. In particular, they searched
the glasses for signs of water. But such evidence had remained elusive,
consistent with the general consensus that the Moon is dry.
Now, that evidence has been found.
"What is important for me is it’s telling me something about the origin
of the Moon and the Earth and the presence of water at very early
times," said Saal, the paper’s lead author.
Three other researchers from the Department of Geological Sciences at
Brown -- professors Reid Cooper and Malcolm Rutherford, and graduate
student Mauro Lo Cascio -- contributed to the research. Erik Hauri from
the Carnegie Institution for Science developed the analytical technique
used to identify water and the other volatiles. James Van Orman from
Case Western Reserve University also participated in the work.
Based on their observations that nearly all the water in the lunar magma
was lost to space during the eruptions, the researchers calculated that
the pre-eruption magma may have contained water up to 750 parts per
million -- similar to the water content of primitive magmas that erupted
on the Earth’s seafloor at midocean ridges.
"This suggests the very intriguing possibility that the Moon’s interior
might have contained just as much water as the Earth’s depleted upper
mantle," Hauri said.
Hauri used secondary mass ion spectrometry, a technique that measures
the elemental composition of solid materials, to detect the minute
amounts of water in the samples.
"We developed a way to detect as little as five parts per million of
water," Hauri said. "We were really surprised to find a whole lot more
in these tiny glass beads, up to 46 parts per million."
The team then confirmed through a series of tests that hydrogen had been
present all along, and the samples had not been infused by hydrogen-rich
solar winds or tainted by other volatiles.
"This confirms that water comes from deep within the mantle of the
Moon," Saal said. "It has nothing to do with secondary processes, such
as contamination or solar wind."
The research also may yield additional insight into how long water has
been on Earth, Saal added.
"It suggests that water was present within the Earth before the giant
collision that formed the Moon," Saal said. "That points to two
possibilities: Water either was not completely vaporized in that
collision or it was added a short time -- less than 100 million years --
afterward by volatiles introduced from the outside, such as with
meteorites."
The researchers this summer will study volcanic glasses gathered from
other Apollo missions for evidence of water.
NASA’s Cosmochemistry Program funded the research.
IMAGE CAPTION:
[http://news.brown.edu/files/imagecache/main_image/files/article_images/Saal%202007-10-10405-Lunar%20green%20glass%20S79-32188.jpg
(16KB)]
Watery Glasses Researchers led by Brown geologist Alberto Saal analyzed
lunar volcanic glasses, such these gathered by the Apollo 15 mission,
and used a new analytic technique to detect water. The discovery
strongly suggests that water has been a part of the Moon since its early
existence -- and perhaps since it was first created. Credit: NASA
Brown University
Contact:
Richard Lewis, (401) 863-3766
July 9, 2008
Brown-Led Team Finds Evidence of Water in Moon’s Interior
A Brown-led research team has for the first time found evidence of water
deep within the Moon. In a paper published in the July 10 issue of the
journal Nature, the researchers believe the water was contained in lunar
magmas ejected more than 3 billion years ago. The discovery strongly
suggests that water has been a part of the Moon since its early
existence -- and perhaps since it was first created.
PROVIDENCE, R.I. -- A Brown University-led research team has for the
first time discovered evidence of water that came from deep within the
Moon, a revelation that strongly suggests water has been a part of the
Moon since its early existence -- and perhaps ever since it was created
by a cataclysmic collision between the early Earth and a Mars-sized
object about 4.5 billion years ago.
In a paper published in the July 10 issue of the journal Nature, the
team, led by Alberto Saal, assistant professor of geological sciences at
Brown, believes that the water was contained in magmas erupted from fire
fountains onto the surface of the Moon more than 3 billion years ago.
About 95 percent of the water vapor from the magma was lost to space
during this eruptive "degassing," the team estimates. But traces of
water vapor may have drifted toward the cold poles of the Moon, where
they may remain as ice in permanently shadowed craters.
NASA plans to send its Lunar Reconnaissance Orbiter later this year to
search for evidence of water ice at the Moon’s south pole. If water is
found, the researchers may have figured out the origin.
The water clue came from lunar volcanic glasses, pebble-like beads
collected and returned to Earth by NASA’s Apollo missions in the late
1960s and early 1970s. In the decades since, scientists have sought to
determine the content and origin of a class of chemical elements known
as volatiles in the multicolored glasses. In particular, they searched
the glasses for signs of water. But such evidence had remained elusive,
consistent with the general consensus that the Moon is dry.
Now, that evidence has been found.
"What is important for me is it’s telling me something about the origin
of the Moon and the Earth and the presence of water at very early
times," said Saal, the paper’s lead author.
Three other researchers from the Department of Geological Sciences at
Brown -- professors Reid Cooper and Malcolm Rutherford, and graduate
student Mauro Lo Cascio -- contributed to the research. Erik Hauri from
the Carnegie Institution for Science developed the analytical technique
used to identify water and the other volatiles. James Van Orman from
Case Western Reserve University also participated in the work.
Based on their observations that nearly all the water in the lunar magma
was lost to space during the eruptions, the researchers calculated that
the pre-eruption magma may have contained water up to 750 parts per
million -- similar to the water content of primitive magmas that erupted
on the Earth’s seafloor at midocean ridges.
"This suggests the very intriguing possibility that the Moon’s interior
might have contained just as much water as the Earth’s depleted upper
mantle," Hauri said.
Hauri used secondary mass ion spectrometry, a technique that measures
the elemental composition of solid materials, to detect the minute
amounts of water in the samples.
"We developed a way to detect as little as five parts per million of
water," Hauri said. "We were really surprised to find a whole lot more
in these tiny glass beads, up to 46 parts per million."
The team then confirmed through a series of tests that hydrogen had been
present all along, and the samples had not been infused by hydrogen-rich
solar winds or tainted by other volatiles.
"This confirms that water comes from deep within the mantle of the
Moon," Saal said. "It has nothing to do with secondary processes, such
as contamination or solar wind."
The research also may yield additional insight into how long water has
been on Earth, Saal added.
"It suggests that water was present within the Earth before the giant
collision that formed the Moon," Saal said. "That points to two
possibilities: Water either was not completely vaporized in that
collision or it was added a short time -- less than 100 million years --
afterward by volatiles introduced from the outside, such as with
meteorites."
The researchers this summer will study volcanic glasses gathered from
other Apollo missions for evidence of water.
NASA’s Cosmochemistry Program funded the research.
IMAGE CAPTION:
[http://news.brown.edu/files/imagecache/main_image/files/article_images/Saal%202007-10-10405-Lunar%20green%20glass%20S79-32188.jpg
(16KB)]
Watery Glasses Researchers led by Brown geologist Alberto Saal analyzed
lunar volcanic glasses, such these gathered by the Apollo 15 mission,
and used a new analytic technique to detect water. The discovery
strongly suggests that water has been a part of the Moon since its early
existence -- and perhaps since it was first created. Credit: NASA