Scientists believe the mystery over the Man in the Moon face has been solved and is due to a volcanic eruption rather than an asteroid crash as previously thought.
It is a phenomenon which has baffled the scientific world for decades with many believing the 'Man in the Moon' image on the moon's surface was created by a large asteroid.
Now latest research suggests it could have been caused by volcanoes.
The largest dark spot, which resembles a face, could have been caused by lava rising from the interior of the moon rather than from an asteroid collision.
The area called Oceanus Procellarum, which is Latin for Ocean of Storms, stretches 1,800-mile-wide.
Researchers used data from NASA's 2O12 Gravity Recovery and Interior Laboratory (GRAIL) mission probes to create a high-resolution map of the area and discovered its border is not round but has sharp angles which could not have been created by an asteroid.
They say the angular outline was produced by huge tension cracks as the crust cooled around an upwelling of hot material from deep inside.
Subsequent asteroid collisions in the same area then created smaller craters on top of it.
Professor Maria Zuber, of Massachusetts Institute of Technology, says as the cracks occurred they formed a "plumbing system" in the moon's exterior through which magma could meander to the surface.
Magma eventually filled the region's smaller craters creating what we see today as dark spots.
Prof Zuber, principal investigator at the GRAIL, said: "A lot of things in science are really complicated but I've always loved to answer simple questions.
"How many people have looked up at the moon and wondered what produced the pattern we see - let me tell you, I've wanted to solve that one!"
To carry out the investigation, which is published in the journal Nature, researchers measured the distance between the probes as they chased each other round the moon.
The map was created using twin probes that orbited the moon from January to December 2012 and was used to determine where the lunar crust thickens and thins.
The mapping revealed Procellarum is composed of edges of 12O degree angles compared to asteroid impacts which tend to produce circular or elliptical craters.
The researchers say some time after the moon formed and cooled a large plume of molten material rose from the lunar interior - around where Procellarum is today.
The steep difference in temperature between the magma plume and the surrounding crust caused the surface to contract over time - creating a pattern of fractures that provided a conduit for molten material to rise to the surface.
The scientists tested their hypothesis and their results matched the results generated by the GRAIL research
Using the distances between the probes the researchers were able to determine the strength of gravity across the surface to create a highly detailed map which they then used to determine where the lunar crust thickens and thins.
But scientists are still puzzled about how such a plume could be created.
Prof Zuber added: "How such a plume arose remains a mystery. It could be due to radioactive decay of heat-producing elements in the deep interior.
"Or conceivably a very early large impact triggered the plume. But in the latter case all evidence for such an impact has been completely erased.
"People who thought all this volcanism was related to a gigantic impact need to go back and think some more about that."
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