Scientists Suspect Moon’s South Pole Anomaly to Be Caused by Metal

  • Scientists Suspect Moon’s South Pole Anomaly to Be Caused by Metal

Scientists Suspect Moon’s South Pole Anomaly to Be Caused by Metal

On the far side of the moon, buried nearly two hundred miles under the South Pole-Aitken basin (the largest preserved crater in our solar system), is a mysterious mass. Peter B. James and his team of scientists from Baylor University believe it could be the metal core of an asteroid which head-butted the moon and left that 1,242-mile-wide crater behind.

Scientists have discovered a huge, mysterious mass of material beneath a large crater on the Moon. "That's roughly how much unexpected mass we detected", said lead author Peter B. James, Ph.D., assistant professor of planetary geophysics in Baylor's College of Arts & Sciences.

The far side of the Moon contains an enormous and very weird structure at its South Pole.

However it formed, the fact that the mass anomaly is still so prominent and that it seems to be located about 186 miles (300 km) down also offers scientists an intriguing idea: These facts suggest that the moon's insides can't be all that gooey; if they were, the moon's gravity would pull the massive patch into the lunar center.

The Chinese lander Chang'e-4 and its Yutu-2 rover are now exploring the Von Karman crater within the South Pole-Aitken basin, and NASA also wants to target the South Pole for future exploration.

Measuring about 1,553 miles (2,500 kilometers) wide, the South Pole-Aitken crater is already one of the moon's largest mysteries.

Researchers studied data obtained from the spacecrafts used for NASA's Gravity Recovery and Interior Laboratory (GRAIL) mission. James also said that the crater, which is believed to have been developed roughly four billion years ago, is the largest preserved crater in the solar system.

"One of the explanations of this extra mass", James said, "is that the metal from the asteroid that formed this crater is still embedded in the Moon's mantle". The dashed circle shows the location, size and depth of the mass anomaly under the basin.

The anomaly - "whatever it is, wherever it came from", James added - is weighing down the basin floor by more than half a mile.

The researchers' simulations imply the material could be an asteroid's iron-nickel core, which, if dispersed into the upper mantle, could be weighing down the basin.

Another possibility is the mass might be a concentration of dense oxides associated with the last stage of lunar magma ocean solidification.

Whatever the mass is, the team believes it can explain some of the features of the South Pole-Aitken basin-specifically that the central depression of the crater is being weighed down by this mass, rather than being caused by the contraction of the "melt sheet"-found where impacts take place".

An image of the lunar surface showing its various basins.

Finding out how the South Pole-Aitken basin formed is important to understanding the history of the moon and its evolution.