The moon’s complex geological history could serve as a pointer to understanding other rocky worlds in the universe, including those that are potentially habitable, according to a new pair of research papers.
The NASA-backed studies are based on data from the agency’s long-standing Lunar Reconnaissance Orbiter (LRO) – which has spent the past twelve years mapping the moon in high resolution – as well as old data from the lunar prospector. retired NASA and Indian Chandrayaan- 1 space missions.The results of the new studies show how pieces of the moon’s mantle – that is, the layer of the interior just below the visible crust – were thrown to the surface as asteroids and comets pounded the surface of the moon over the eons.
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Although the moon itself is not habitable, it has a mantle just like the Earth. Scientists are using the moon as a proxy to better understand the evolution of rocky planets in general, even those potentially habitable light years away that we can only see as bright spots in high-tech telescopes.
The hunt for the lunar mantle was complex, incorporating theory, modeling, and a new map of the likely locations of mantle material using three datasets: the Chandrayaan-1 Lunar Mineralogy Mapper which showed composition and l abundance of minerals, and LRO imagery and topography.
“Understand these [mantle] the processes in more detail will have implications for important follow-up questions, ”said Daniel Moriarty, lead author of both papers and a NASA postdoctoral fellow at the agency’s Goddard Space Flight Center in Maryland, in a statement. communicated.
Moriarty added that questions addressed could include, “How does this early warming affect the distribution of a planet’s water and atmospheric gases?” ? ”
Understanding where the lunar mantle came from has not only scientific value, but possibly exploration value as well. Lately, NASA has pivoted its work to include more exploration of the moon – including a series of robots under the Commercial Lunar Payload Services (CLPS) program.
Some of these robots are tasked with possibly picking up pieces of the lunar mantle from the surface to return to Earth, in a larger effort to understand the history of the moon by studying lunar samples up close, NASA said. If all goes according to plan in terms of tech development and budget, humans could arrive with landing missions as part of the Artemis program in the mid-2020s, although that is not certain yet.
Artemis targets its lunar exploration around impact craters in the Lunar South Pole, and that’s where the new findings come in. Studies have focused on a strange radioactive signature in a 2,600 kilometer region called the Pole South Aitken Basin. As a huge impact crater, the basin is a prime region for researching the excavated lunar mantle and for theorizing how it formed, NASA said.
Rocky planets are believed to develop by accretion, as dust grains and smaller rocks come together under their mutual gravity. The various collisions generate a lot of heat, aided by radioactive elements which release heat during their natural decomposition. In the largest of rocky objects, such as planets or the largest moons, enough heat is released for oceans of magma to form.
However, the theory lacks details, including how the magma oceans change as they cool, and when and how the minerals in those oceans crystallize. These processes are important because they indicate the makeup of mantle rocks and where you might find them on the surface of a rocky world.
At the South Pole, for example, the team’s work shows that the composition of the radioactive anomaly is consistent with what they call “sludge,” or materials that form in the upper mantle when the magma ocean finishes cooling and crystallizing. Previously, scientists believed that the so-called mud – which includes dense combinations of rocks such as iron and ilmenite (or titanium ore) – would sink deeper under the lighter crust, out of reach of surface exploration.
“The bottom line is that the evolution of the lunar mantle is more complicated than originally thought,” Moriarty said. “Some minerals that crystallize and sink early are less dense than minerals that crystallize and sink later. This leads to an unstable situation with light materials near the bottom of the mantle trying to go up while heavier materials closer to the top go down. This process, called “gravitational reversal”, does not take place in an orderly and orderly fashion, but becomes disorderly, with a lot of mix-ups and unexpected laggards. “
Both papers were published Monday in Nature Communications and in the Journal of Geophysical Research in January.
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