“It would be tantalizing to find microfossils of extraterrestrial forms of life on the moon. Even more exciting would be to find traces of technological equipment that crashed on the lunar surface a billion years ago, amounting to a letter from an alien civilization saying, “We exist,” speculated Harvard University’s chief astronomer Avi Loeb, asking can the moon provide clues for extraterrestrial life?
“The absence of a lunar atmosphere,” writes Loeb in “The Moon as a Fishing Net for Extraterrestrial Life”, “guarantees that these messengers would reach the lunar surface without burning up. In addition, the geological inactivity of the moon implies that the record deposited on its surface will be preserved and not mixed with the deep lunar interior. Serving as a natural mailbox, the lunar surface collected all impacting objects during the past few billions of years. Most of this “mail” comes from within the solar system.”
Apollo 14 Discovery –At the edge of Cone Crater
Less speculative is the discovery of a rock found by astronaut Astronaut Alan Shepard at the Apollo 14 landing site near the edge of Cone Crater, where it had rested for millions of years, and brought it back to Earth for analysis. A rock formed on the Earth and brought to the surface of the moon as a meteorite generated by a massive asteroid hitting Earth about four billion years ago, ejecting material into space and to the moon. Apollo 14 was the last of NASA’s “H missions“, landings at specific sites of scientific interest on the Moon for two-day stays with two lunar extravehicular activities –EVAs or moonwalks.
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 (below), where it was collected by Shepard.
In 2019 findings published in science journal Earth and Planetary Science Letters, confirmed that the sample collected during the 1971 Apollo 14 lunar mission contained 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 granite, which is extremely rare on the moon but common on Earth.
Similar to the oldest rocks 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 analyzed 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 oxidized 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,” he concluded, “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.”
The Daily Galaxy, Avi Shporer, Research Scientist, MIT Kavli Institute for Astrophysics and Space Research via Curtin University. Avi was formerly a NASA Sagan Fellow at the Jet Propulsion Laboratory (JPL).
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