Scientists have discovered an unknown material on the moon's largest crater, and they are not yet sure what to make of it. "That's roughly how much unexpected mass we detected", said Dr. Peter B. James, a planetary researcher with Baylor University and the Lunar and Planetary Institute.
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.
When it comes to the South Pole-Aitken basin, the topography is particularly striking.
The South Pole-Aitken basin on the far side of the moon is said to be the largest crater in the solar system and extends several miles deep.
The mysterious mass of material is found buried under South Pole-Aitken basin, the moon's largest crater, and may contain substances from an asteroid that crashed into the Moon and created the crater, the statement quotes the Baylor University Study.
The Moon's South Pole-Aitken (SPA) basin and mass anomaly are pictured here in this false-color graphic.
The dense mass - "whatever it is, wherever it came from" - is weighing the basin floor downward by more than half a mile, James said.
So, some 4 billion years ago, a mostly metallic asteroid hit the moon and remains embedded in the mantle to this day. The mass is five times bigger than Hawaii's Big Island and is located hundreds of miles beneath the lunar surface.
Using computer simulations of large asteroid impacts, researchers could recreate conditions where an iron-nickel core of an asteroid could be dispersed into the layer between the Moon's crust and core during an impact.
With humans headed back to the Moon sooner rather than later, the crater could be an interesting location for further study, though NASA and other space-faring organizations already have plenty of scientific objectives on their plates.
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.
Earth's moon may be hiding a giant metallic lump beneath an impact crater called the South Pole-Aitken Basin.
Even though larger impacts could have occurred throughout the solar system, including on our planet, most traces of larger impacts are no longer available. Or, intriguingly, the extra mass could suggest the presence of an enormous metal core deposited in the Moon mantle, left over from the impact.