The mysterious far side of the moon It is very different from its near side, which we see in the night sky, and now scientists think they know why.
The moons near the side and the far side were once thought to be relatively similar. But, with missions from robotic observers and Apollo astronauts over the past six decades, scientists discovered they have significantly different characteristics, many related to the geological activity of the moon. In fact, observations have shown that only about 1% of the far side of the moon is covered in mary or craters caused by volcanic activity in Moon. This strongly contrasts the near side of the object, 31% of which is covered in mary.
According to the giant impact hypothesis, about 4.5 billion years ago the earth and the moon formed when an object the size of Mars crashed into proto-Earth. Previous theories suggested that the moon, because it was a smaller object, cooled faster than Earth after this impact and geologically “froze”. But the idea that the moon “froze” after this event is an idea that has been questioned as studies have shown evidence of relatively recent geological activity on the moon, with evidence of volcanic and magnetic activity on the moon occurring some time ago. barely a billion years. does.
Related: How the Moon Was Formed: 5 Wild Lunar Theories
In the new study, researchers from the Earth-Life Science Institute at the Tokyo Institute of Technology, the University of Florida, the Carnegie Institution for Science, Towson University, NASA Johnson Space Center and the University of New Mexico investigated the moon’s geological history and found a new explanation for the asymmetry between its far and near sides.
Through a series of experiments, computer modeling, and the use of existing observations of the lunar surface, these researchers discovered that concentrations of radioactive elements on the moon could help explain the asymmetry between the near and far sides of the moon.
This study showed that radioactively unstable elements such as potassium (K), thorium (Th), and uranium (U) create heat through the process of radioactive decay. This heat can melt the rocks where these elements are located.
“Due to the relative lack of erosion processes, the moon’s surface records geological events from the early history of the solar system. In particular, the regions on the near side of the moon have concentrations of radioactive elements such as U and Th a unlike anywhere else on the moon. Understanding the origin of these local U and Th enrichments can help explain the early stages of moon formation and, as a consequence, conditions on early Earth, “co-author Matthiew Laneuville , a planetary scientist at the Earth Life Science Institute, he said in a statement.
Furthermore, the researchers found that asymmetry is also linked to a property of KREEP, a rock signature that is short for potassium-enriched rock (chemical symbol K), rare earth elements (REE, which includes cerium, dysprosium, erbium , europium, among others) and phosphorus (chemical symbol P), which is associated with the lunar maria. KREEP was first identified with NASA’s manned Apollo missions to the lunar surface and is associated with Maria, and thus with volcanic and other geological activities.
According to this study, in addition to the heating caused by the radioactive decay of unstable elements, the KREEP-enriched material on the lunar surface has lower melting points. This only added to the expected geological changes.
The combined results of this study suggest that KREEP-enriched Maria has been changing the lunar landscape since the rocky satellite formed billions of years ago.
This work was published on March 30 in the journal Nature Geoscience.
Email Chelsea Gohd at [email protected] or follow her on Twitter @chelsea_gohd. Follow us on twitter @Spacedotcom and in Facebook.
