A large and mysterious mass of material has been discovered under the Moon's South Pole-Aitken basin, a study by the Baylor;s College of Arts and Sciences in Texas shows. Scientists have said that the anomaly beneath what is considered the largest crater in our solar system, may contain metal from an asteroid that crashed into the moon and formed the crater.
The oval-shaped crater itself is roughly 2000 kilometres wide and several miles deep. The crater, which is believed to have been created about 4 billion years ago, is on the far side of the moon. Despite its gigantic size, we cannot see it from Earth.
“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,” said lead author Peter B. James in a press release. James is assistant professor of planetary geophysics at Baylor’s College.
The research study titled "Deep Structure of the Lunar South Pole-Aitken Basin”, was published last month in the journal Geophysical Research Letters. The study was supported by NASA's Gravity Recovery and Interior Laboratory (GRAIL) science team.
The dense mass — “whatever it is, wherever it came from” — is weighing the basin floor downward by more than half a mile, James said.
“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,” James said.
Scientists say that a large concentration of dense oxides associated with the last stage of lunar magma ocean solidification could also be a probable reason behind the anomaly.
James called the basin “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.”