Space

Huge metallic anomaly detected buried beneath the Moon's largest crater

Huge metallic anomaly detected...
The huge South Pole-Aitken basin on the Moon can be seen in this topographical map, as blue areas represent lower regions. The white dotted outline shows the location of the mass anomaly
The huge South Pole-Aitken basin on the Moon can be seen in this topographical map, as blue areas represent lower regions. The white dotted outline shows the location of the mass anomaly
View 1 Image
The huge South Pole-Aitken basin on the Moon can be seen in this topographical map, as blue areas represent lower regions. The white dotted outline shows the location of the mass anomaly
1/1
The huge South Pole-Aitken basin on the Moon can be seen in this topographical map, as blue areas represent lower regions. The white dotted outline shows the location of the mass anomaly

Although it looks like a boring, barren place, the Moon is home to some pretty amazing landmarks. The South Pole-Aitken basin, for example, is the largest impact crater in the solar system, measuring about 2,500 km (1,550 mi) across at its widest point. And now scientists have detected something strange buried under the crater.

The discovery was made by researchers studying differences in the strength of gravity in different parts of the Moon. Those measurements were made by NASA's Gravity Recovery and Interior Laboratory (GRAIL) mission, and combined with data on the Moon's topography taken by the Lunar Reconnaissance Orbiter (LRO). That data revealed a huge mass of material buried several hundred miles below the surface of the basin.

"Imagine taking a pile of metal five times larger than the Big Island of Hawaii and burying it underground," says Peter James, lead author of the study. "That's roughly how much unexpected mass we detected."

So what's down there? The team says that the crater itself is basically a four billion-year-old smoking gun, and the material was most likely deposited there by the object that left the scar on the lunar surface. Computer simulations showed that if the impactor was a large asteroid with an iron-nickel core, that metal may still be intact after all these years.

"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," says James. "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."

Of course this isn't the only possible explanation. Another suggestion is that the mass may be a dense lump of oxides, left over from when an ocean of magma was solidifying.

The answer could be revealed through further study of the South Pole-Aitken basin by GRAIL, the LRO, and China's Chang'e-4 lander, which touched down in the crater early this year.

The research was published in the journal Geophysical Research Letters.

Source: Baylor University

7 comments
FabianLamaestra
That's not a Moon!
amazed W1
Firstly, wouldn't the asymmetrically buried mass of metal be partly if not totally responsible for the same part of the moon always facing the Earth? And secondly, if the theory that the moon was gouged out of an earlier Earth by a collision with an "object", might it not contain what was formerly part of the Earths magnetic core in the form of this buried lump? (I am not an academic publishing a new theory, so please readers feel free to be rude about this one!)
ljaques
It looks like China gets the honors of being the Moon Metal Monger of the Millennium.
JeffK
I know it's the wrong crater, but c'mon Michael, not even a passing reference to the possibility of a giant, black monolith (or should it be Moonolith)?
apprenticeearthwiz
Daaah Daaah Daaah Dadaaaaah
neutrino23
Could this be a large, buried obelisk? Shades of 2001 a Space Odyssey.
Cody Blank
Only came here for the Deathstar and secret Nazi Moon Base jokes. 1/2 disappointed.