There are two distinct sides (or faces) of the Moon: one is largely marked with craters, while the other is chock full of open basins. Now, a new study suggests that an ancient celestial body is the cause of this mysterious "anomaly."
Published in the Journal of Geophysical Research: Planets, the study suggests that a "large body," perhaps an ancient planet or asteroid, crashed into the Moon and gave it its distinctive features.
"Recent remote sensing observations suggest that (1) the crust on the farside highlands consists of two layers: a primary anorthositic layer with thickness of ~30‐50 km and on top a more mafic‐rich layer ~ 10 km thick; and (2) the nearside exhibits a large area of low‐Ca pyroxene that has been interpreted to have an impact origin," the study's abstract reads. "These observations support the idea that the lunar nearside‐farside asymmetries may be the result of a giant impact."
In the research, scientists put measurements from NASA's Gravity Recovery and Interior Laboratory (GRAIL) mission in 2012 into a computer and ran 360 simulations of various collisions that could have caused the distinct sides. In running the simulations, they found the most likely scenario would have been a celestial body about 480 miles in diameter smacking the Moon at a speed of roughly 14,000 miles per hour.
"That would be the equivalent of an object a bit smaller than the dwarf planet Ceres moving at a speed about one-quarter as fast as the meteor pebbles and sand grains that burn up as 'shooting stars' in Earth’s atmosphere," the statement reads.
They also called out a similar-sized object, with a diameter of 450 miles going 15,000 miles per hour as a potential candidate.
With the object hitting the Moon at such a forceful rate, it likely would've caused the material to kick up and spread to the far side of the satellite.
“Our model can thus explain this isotope anomaly in the context of the giant impact scenario of the Moon’s origin,” the researchers wrote in the study.
Steve Hauck, a professor of planetary geodynamics at Case Western Reserve University, said in the statement that the paper is very "provocative."
Hauck added that by understanding the different sides of the Moon and their origins, it becomes "a fundamental issue in lunar science. Indeed, several planets have hemispherical dichotomies, yet for the Moon we have a lot of data to be able to test models and hypotheses with, so the implications of the work could likely be broader than just the Moon.”
Return to the Moon
Further study of the Moon looms large in our future. The Trump administration has called for the U.S. to return to the Moon by 2024, with or without the help of NASA.
NASA's plans to return to the Moon, including its plans to set up a lunar base, future rocket launches and the cost of these missions were leaked earlier this week. They were subsequently confirmed by the government space agency.
As part of its plans to build a Moon base by 2028 and have several launches, NASA's leaked documents show the agency believes it will need an additional $4.7 billion to $8.2 billion per year to fulfill these journeys. NASA's current budget is approximately $20 billion per year.
The race to get back to the Moon is also drawing the attention of private companies, including Elon Musk's SpaceX and Jeff Bezos' Blue Origin. Bezos, the richest man in the world, recently unveiled plans for his space exploration company to send a spaceship to the Moon, "this time to stay."
Fox News' James Rogers contributed to this story.