A mysterious mass of material has been discovered by scientists near the Moon’s South Pole that is altering the Moon’s gravitational field. It is hidden beneath the largest lunar crater in the Aitken basin. According to the researchers from Baylor University in the US, the mass may contain metal from the asteroid that had crashed into the Moon and formed the crater.
Peter B James, an assistant professor at the Baylor University said “Imagine taking a pile of metal five times larger than the Big Island of Hawaii and burying it underground. That’s roughly how much unexpected mass we detected.”
It is a 2000 kilometres wide and several miles deep oval-shaped crater. Being in the far side of the Moon, it is not visible from Earth.
“When we combined that with lunar topography data from the Lunar Reconnaissance Orbiter, we discovered the unexpectedly large amount of mass hundreds of miles underneath the South Pole-Aitken basin,” said Peter B James.
The subtle changes in the strength of the gravity around the Moon was measured by researchers by analysing data from spacecrafts used for the National Aeronautics and Space Administration (NASA) Gravity Recovery and Interior Laboratory (GRAIL) mission.
“One of the explanations of this extra mass is that the metal from the asteroid that formed this crater is still embedded in the Moon’s mantle,” he added.
According to a research published in the journal Geophysical Research Letters, this dense mass is weighing the basin floor downward by more than half a mile.
“We did the math and showed that a sufficiently dispersed core of the asteroid that made the impact could remain suspended in the Moon’s mantle until the present day, rather than sinking to the Moon’s core,” added James.
It can also be a concentration of dense oxides associated with the last stage of lunar magma ocean solidification. Aitken basin might be the largest preserved crater in the solar system, created almost four billion years ago.
The basin is “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,” according to James.