Space travel
Gerst: There could be traces of terrestrial life on the moon
Alexander Gerst is a possible candidate for the US missions “Artemis 4” and “Artemis 5” to the moon planned in a few years. photo
© Jens Kalaene/dpa
Time and again throughout Earth’s history, celestial bodies have knocked out large amounts of rock from the planet. Researchers suspect that some of the fragments fell on the moon. Could early life have traveled along?
Astronaut Alexander Gerst hopes that missions to… Moon could provide more information about the development of life on Earth.
“Perhaps we will find meteorites on the moon that came from the Earth, i.e. rock fragments that were catapulted out of the Earth by a large impact at some point in the past and then landed on the moon,” said Gerst to the German Press Agency Berlin. The 47-year-old is a possible candidate for the US missions “Artemis 4” and “Artemis 5” to the moon, which are planned in a few years.
Gerst explained that traces of early terrestrial life, such as microbes, could potentially be trapped in rocks on the moon. “That would be extremely exciting.” Because of plate tectonics, such traces can hardly be found on Earth anymore. The moon, on the other hand, has been geologically quiet for billions of years.
Thrown up, turned over, melted down
Through tectonic movements, rock on Earth, including all traces it contains, is thrown up, turned over and melted in a continuous process. “We have almost nothing from the early days of the Earth, and what little we have is geologically heavily influenced,” said Matthias Nieuwenhuis from the Max Planck Institute for Solar System Research in Göttingen. “On the moon, however, nothing happens.”
According to current knowledge, the oldest evidence of life on Earth is around 3.5 billion years old. According to current assumptions, the moon was formed at least 4.46 billion years ago from debris from the collision of the primordial Earth with the Mars-sized celestial body Theia. This could make it a valuable archive for early life on our planet.
Material from Earth on the Moon
Analyzes had shown that a moonstone brought to Earth by astronauts during the Apollo missions in 1971 could contain material from Earth. The composition of the small fragment is typical for Earth, but unusual for the Moon, explained Nieuwenhuis. It is estimated that in the last 3.9 billion years alone, around 36 to 61 kilograms of earth’s rock per square kilometer may have reached the moon, and in certain places even half a ton per square kilometer.
The planetary scientist explained that the impact speed of such material is rather low at around three kilometers per second. “That’s why fossils from early Earth history could actually still be found there.” Traces of early earth microbes may have been preserved on the moon to this day in the form of biological and chemical markers.
Astronaut versus robot
Nieuwenhuis believes it is realistic that at some point an astronaut and not a robot will find the corresponding rock. “An appropriately trained astronaut has a special eye for his surroundings: What doesn’t fit here, what’s unusual?” He could head straight for unusual rock, which increases the chance of a spectacular find.