Today, several ways have already been announced for direct study and analysis of objects that originate outside the solar system, and now our satellite is in the same row with them.
Since the Moon is practically devoid of atmosphere and is a geologically quiet world, its surface can be in the public domain with a large amount of extraterrestrial material and building blocks of extraterrestrial life, scientists say in the study, presented on the server of preprints arxiv org.
"We predict that the amount of extrasolar material in the lunar soil should reach thirty parts per million, and extrasolar organic carbon and building blocks of extraterrestrial life, such as amino acids, three parts per ten million and thirty parts per billion, respectively," the authors write the study.
The discovery of the first-ever interstellar site in 2017, subsequently designated as Oumouamois, has led to a significant increase in the estimate of the quantity and density of the distribution of its free-floating analogs along the Milky Way, compared to previous projections.
Also, in 2019, it was announced about the identification of the extrasolar wanderer burned in the atmosphere of our planet on January 8, 2014. This, in turn, helped to set the upper limit on the number of objects from distant star systems reaching the Earth and the Moon.
However, the question of understanding their nature and origin remains open.
Today, scientists have proposed several ways to directly study and analyze objects that originate outside the solar system.
For example, it is possible to send spacecraft to study interstellar dust in the vicinity of the Earth, to try to catch up with any of Oumaumua's analogues (although here you need to be able to find it in advance), or to identify asteroids and comets captured by our system and send probes to them, as well as, finally, to make a flight to the nearest exoplanet - Proxima b.
Another possibility is related to remote sensing of interstellar meteors that burn in the Earth's atmosphere or are destroyed by the Sun.
"We suggest a third way to study lunar rock images in search of extrasolar material. In principle, this approach is also true for asteroid comets," says leading author of the study Manashvi Lingam, an astrophysicist and astrobiologist at Harvard University (USA).
The moon is better than the Earth
When searching for traces of extrasolar objects, the Moon differs favorably from the Earth, because, firstly, it has a very thin atmosphere, therefore, interstellar meteorites reach the surface without burning, and, secondly, it does not show significant geological activity, which guarantees, unlike our planet, the safety of its "history", which originates from the moment of formation about 4.5 billion years ago.
From a practical point of view, these two advantages make the lunar soil an excellent subject of research when searching for extrasolar material and building blocks of extraterrestrial life.
Traces of life on the moon
The authors claim that a combination of analysis of isotope ratios, in particular oxygen, elemental analysis, and other diagnostic methods, will help to distinguish between "native" and "alien" material for the solar system, and the subsequent laboratory study of an extraterrestrial sample installed in the lunar soil will make it possible to identify organic compounds, if any, such as carbonic acids, amino acids, and nucleic bases, as well as molecular biosignatures that are markers of extraterrestrial life.
In general, the results will provide important knowledge in astrobiology. Even the "simple" discovery of inorganic extraterrestrial material will provide new opportunities for research. For example, by studying its chemical composition, one can impose restrictions on models of planetary formation, assess the chance of inhabitation of young star systems, and determine their chemical diversity.
Scientists note that humanity already has almost 400 kilograms of lunar rocks, delivered to Earth during the mission "Apollo", so you should start with them. Also, the initiatives to return people to the Moon to create bases on it, voiced by both space agencies and private companies, are gaining momentum.
"It is expected that the study of our satellite "on the ground" will enhance knowledge in areas as diverse as high-energy physics, medicine, planetology, and astrobiology. We believe that this list should include the search for extrasolar material and, as the ultimate goal, building blocks of extraterrestrial life," the authors conclude.