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Lorenzo von Matterhorn
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Moon rock recovered by astronauts likely originated on Earth
January 25, 2019
https://phys.org/news/2019-01-moon-recovered-astronauts-earth.html
In findings published overnight in science journal Earth and Planetary Science Letters, a sample collected during the 1971 Apollo 14 lunar mission was found to contain traces of minerals with a chemical composition common to Earth and very unusual for the moon.
The sample was on loan from NASA to Curtin University, where it was investigated in cooperation with researchers from the Swedish Museum of Natural History, Australian National University and Lunar and Planetary Institute in Houston.
Research author Professor Alexander Nemchin, from Curtin's School of Earth and Planetary Sciences, said the 1.8 gram sample showed mineralogy similar to that of a granite, which is extremely rare on the moon but common on Earth.
"The sample also contains quartz, which is an even more unusual find on the moon," Professor Nemchin said.
"By determining the age of zircon found in the sample, we were able to pinpoint the age of the host rock at about four billion years old, making it similar to the oldest rocks on Earth.
"In addition, the chemistry of the zircon in this sample is very different from that of every other zircon grain ever analysed in lunar samples, and remarkably similar to that of zircons found on Earth."
Professor Nemchin said the chemistry of the zircon lunar sample indicated that it formed at low temperature and probably in the presence of water and at oxidised conditions, making it characteristic of Earth and highly irregular for the moon.
"It is possible that some of these unusual conditions could have occurred very locally and very briefly on the moon and the sample is a result of this brief deviation from normality," Professor Nemchin said.
"However, a simpler explanation is that this piece was formed on the Earth and brought to the surface of the moon as a meteorite generated by an asteroid hitting Earth about four billion years ago, and throwing material into space and to the moon.
"Further impacts on the moon at later times would have mixed the Earth rocks with lunar rocks, including at the future Apollo 14 landing site, where it was collected by astronauts and brought back home to the Earth."
Apollo Astronauts May Have Found the Oldest-Known Earth Rock on the Moon
25 Jan 2019
https://www.livescience.com/64590-earth-oldest-rock-moon-apollo-14.html
One of Earth's oldest rocks may have been dug up on the moon.
A chunk of material brought back from the lunar surface by Apollo astronauts in 1971 harbors a tiny piece of Earth, a new study suggests. The Earth fragment was likely blasted off our planet by a powerful impact about 4 billion years ago, according to the new research.
"It is an extraordinary find that helps paint a better picture of early Earth and the bombardment that modified our planet during the dawn of life," study co-author David Kring, a Universities Space Research Association (USRA) scientist at the Lunar and Planetary Institute in Houston, said in a statement.
(Biologists generally believe that life got a foothold on Earth between 4.1 billion and 3.8 billion years ago.)
The research team — led by Jeremy Bellucci, of the Swedish Museum of Natural History, and Alexander Nemchin, of the Swedish Museum and Curtin University in Australia — analyzed lunar samples collected by members of the Apollo 14 mission, which explored the lunar surface for a few days in early February 1971.
The scientists found that one rock contained a 0.08-ounce (2 grams) fragment composed of quartz, feldspar and zircon, all of which are rare on the moon but common here on Earth. Chemical analyses indicated that the fragment crystallized in an oxidized environment, at temperatures consistent with those found in the near subsurface of the early Earth, study team members said.
The available evidence suggests that the fragment crystallized 4.1 billion to 4 billion years ago about 12 miles (20 kilometers) beneath Earth's surface, then was launched into space by a powerful impact shortly thereafter.
The voyaging Earth rock soon made its way to the moon, which was then about three times closer to our planet than it is today. (The moon is still retreating from us, at a rate of about 1.5 inches, or 3.8 centimeters, per year.) The fragment endured further trauma on the lunar surface. It was partially melted, and probably buried, by an impact about 3.9 billion years ago, then excavated by yet another impact 26 million years ago, the researchers said.
This latest collision created the 1,115-foot-wide (340 meters) Cone Crater, whose environs Apollo 14 astronauts Alan Shepard and Edgar Mitchell explored and sampled 47 years ago. (The third Apollo 14 crewmember, Stuart Roosa, stayed in lunar orbit aboard the mission's command module.)
An Earth origin for the ancient fragment isn't a slam dunk, study team members stressed. However, it is the simplest explanation; a lunar birth would require a rethink of the conditions present in the moon's interior long ago, the researchers said.
January 25, 2019
https://phys.org/news/2019-01-moon-recovered-astronauts-earth.html
In findings published overnight in science journal Earth and Planetary Science Letters, a sample collected during the 1971 Apollo 14 lunar mission was found to contain traces of minerals with a chemical composition common to Earth and very unusual for the moon.
The sample was on loan from NASA to Curtin University, where it was investigated in cooperation with researchers from the Swedish Museum of Natural History, Australian National University and Lunar and Planetary Institute in Houston.
Research author Professor Alexander Nemchin, from Curtin's School of Earth and Planetary Sciences, said the 1.8 gram sample showed mineralogy similar to that of a granite, which is extremely rare on the moon but common on Earth.
"The sample also contains quartz, which is an even more unusual find on the moon," Professor Nemchin said.
"By determining the age of zircon found in the sample, we were able to pinpoint the age of the host rock at about four billion years old, making it similar to the oldest rocks on Earth.
"In addition, the chemistry of the zircon in this sample is very different from that of every other zircon grain ever analysed in lunar samples, and remarkably similar to that of zircons found on Earth."
Professor Nemchin said the chemistry of the zircon lunar sample indicated that it formed at low temperature and probably in the presence of water and at oxidised conditions, making it characteristic of Earth and highly irregular for the moon.
"It is possible that some of these unusual conditions could have occurred very locally and very briefly on the moon and the sample is a result of this brief deviation from normality," Professor Nemchin said.
"However, a simpler explanation is that this piece was formed on the Earth and brought to the surface of the moon as a meteorite generated by an asteroid hitting Earth about four billion years ago, and throwing material into space and to the moon.
"Further impacts on the moon at later times would have mixed the Earth rocks with lunar rocks, including at the future Apollo 14 landing site, where it was collected by astronauts and brought back home to the Earth."
Apollo Astronauts May Have Found the Oldest-Known Earth Rock on the Moon
25 Jan 2019
https://www.livescience.com/64590-earth-oldest-rock-moon-apollo-14.html
One of Earth's oldest rocks may have been dug up on the moon.
A chunk of material brought back from the lunar surface by Apollo astronauts in 1971 harbors a tiny piece of Earth, a new study suggests. The Earth fragment was likely blasted off our planet by a powerful impact about 4 billion years ago, according to the new research.
"It is an extraordinary find that helps paint a better picture of early Earth and the bombardment that modified our planet during the dawn of life," study co-author David Kring, a Universities Space Research Association (USRA) scientist at the Lunar and Planetary Institute in Houston, said in a statement.
(Biologists generally believe that life got a foothold on Earth between 4.1 billion and 3.8 billion years ago.)
The research team — led by Jeremy Bellucci, of the Swedish Museum of Natural History, and Alexander Nemchin, of the Swedish Museum and Curtin University in Australia — analyzed lunar samples collected by members of the Apollo 14 mission, which explored the lunar surface for a few days in early February 1971.
The scientists found that one rock contained a 0.08-ounce (2 grams) fragment composed of quartz, feldspar and zircon, all of which are rare on the moon but common here on Earth. Chemical analyses indicated that the fragment crystallized in an oxidized environment, at temperatures consistent with those found in the near subsurface of the early Earth, study team members said.
The available evidence suggests that the fragment crystallized 4.1 billion to 4 billion years ago about 12 miles (20 kilometers) beneath Earth's surface, then was launched into space by a powerful impact shortly thereafter.
The voyaging Earth rock soon made its way to the moon, which was then about three times closer to our planet than it is today. (The moon is still retreating from us, at a rate of about 1.5 inches, or 3.8 centimeters, per year.) The fragment endured further trauma on the lunar surface. It was partially melted, and probably buried, by an impact about 3.9 billion years ago, then excavated by yet another impact 26 million years ago, the researchers said.
This latest collision created the 1,115-foot-wide (340 meters) Cone Crater, whose environs Apollo 14 astronauts Alan Shepard and Edgar Mitchell explored and sampled 47 years ago. (The third Apollo 14 crewmember, Stuart Roosa, stayed in lunar orbit aboard the mission's command module.)
An Earth origin for the ancient fragment isn't a slam dunk, study team members stressed. However, it is the simplest explanation; a lunar birth would require a rethink of the conditions present in the moon's interior long ago, the researchers said.
