Moon rocks collected by the Apollo 17 astronauts – brought back to Earth nearly half a century ago – have revealed new information about the Moon’s complicated history.
49 years ago, on December 14, NASA’s Apollo 17 mission left the Moon to return to Earth and humans have not returned to our natural satellite since.
In a new study, scientists examined a Moon rock collected by astronauts during the Apollo 17 mission.
By measuring the composition of the rock, dubbed troctolite 76535, scientists have found patterns that point to a cooling period lasting 20 million years in the Moon’s history, despite previous understandings. on the evolution of the Moon.
Study leader William Nelson from the University of Hawai’i at Mānoa, USA, told Space: “Our findings give the lunar scientific community a new look at the specimen.”
Moon rock analysis
The team chose this rock sample to study because it is exceptionally pristine.
“It hasn’t been drastically altered by impacts during its time on the lunar surface. That’s very rare for lunar rocks,” Nelson said.
The team was measuring phosphorus in the sample when they discovered interesting patterns of chemical change in the mineral grains of the rock, including the minerals olivine and plagioclase.
“This was surprising, as previous studies reported that neither of these minerals had any chemical changes,” said Nelson.
Until now, it was still thought that, at some point after the formation of the Moon, it had undergone a period of 100 million years of cooling.
But when we studied the specimen, we found that it could take no more than 20 million years for the sample to cool to the point of complete solidification. If the sample cools slowly, as previously suggested, there should be no change in the phosphorus content, Nelson said.
This discovery changes our understanding of the Moon’s history and evolution over 80 million years.
Studying the past
Studying Moon rocks requires you to take some serious precautions. Not only to watch out for the human health risks associated with lunar dust, or regolith, but chemists also want to be careful with these samples because they’re extremely hard to find.
“We wear gloves when handling the specimen and always touch it gently. The sample is always kept in a safe place, either on one of us or inside a device. For long-term storage, The lunar sample management team at NASA’s Johnson Space Center will preserve such samples and make them available for scientific research purposes,” said Nelson.
Despite the number of years since it was collected, Nelson insists that much can still be learned from the samples collected during NASA’s Apollo program.
The new study was published December 14 in the journal Nature Communications.