Mass anomaly detected under the moon's largest crater

According to a Baylor University research, a mystery enormous quantity of material has been found beneath the Moon's South Pole-Aitken basin, the biggest crater in our solar system. This mass of material may include metal from the asteroid that slammed into the Moon and caused the crater.

"Consider burying a five-times-larger mass of metal underground, comparable in size to Hawaii's Big Island. We found about that much unexpected mass," lead author Peter B. James stated.

Ph.D., associate professor in the College of Arts & Sciences at Baylor University teaching planetary geophysics.The crater is oval in form, a few miles deep, and as wide as 2,000 kilometers, or about the distance between Waco, Texas, and Washington, D.C. It is on the far side of the Moon, therefore even with its size, it is invisible from Earth.

In the journal Geophysical Research Letters, the paper titled "Deep Structure of the Lunar South Pole-Aitken Basin" was published.

Researchers examined data from satellites employed in the National Aeronautics and Space Administration's (NASA) Gravity Recovery and Interior Laboratory (GRAIL) mission to determine minute variations in the intensity of gravity surrounding the Moon.

"We found the unexpectedly large amount of mass hundreds of miles underneath the South Pole-Aitken basin when we combined that with lunar topography data from the Lunar Reconnaissance Orbiter," James added. "The metal from the asteroid that formed this crater is still embedded in the Moon's mantle, which is one explanation for this extra mass."

By more than half a mile, he claimed, the massive mass—"whatever it is, wherever it came from"—is weighing the basin floor down. The upper mantle, which is the layer between the Moon's crust and core, may receive fragments of an asteroid's iron-nickel core if certain circumstances are met, according to computer models of big asteroid impacts.

James explained, "We did the math and showed that, instead of sinking to the Moon's core, an asteroid that made the impact could remain suspended in the Moon's mantle until the present day."

An alternative explanation for the huge mass might be that it represents a concentration of thick oxides related to the last phase of the solidification of the lunar lava ocean.

According to James, the biggest intact crater in the solar system is the South Pole-Aitken basin, which is estimated to have formed around 4 billion years ago. Larger impacts may have happened on Earth as well as other places in the solar system, but the majority of their remnants have vanished.

Speaking of the basin, James described it as "one of the best natural laboratories for studying catastrophic impact events, an ancient process that shaped all of the rocky planets and moons we see today."