The moon's slight lemon shape, according to researchers in a new study published this week in the science journal Nature, has developed over millions of years with the help of Earth's own gravitational pull on its celestial satellite.
Scientists said they believe, through their research, that the Earth's tidal forces during the early formation of the solar system, when both bodies were still forming, influenced not only the moon's lemon shape, but most of its topography,
reported Space.com.
Far from being perfectly round, the moon has a strange shape, with a highland bulge on the side facing the Earth and another bulge on its far side,
according to AFP. Astronomers say looking from a different angle, it would look very slightly like a lemon.
Researchers believe the new information could lead scientists to solve questions about the moon's dark volcanic deposits on its near side and other lunar mysteries.
Urgent: Do You Approve Or Disapprove of President Obama's Job Performance? Vote Now in Urgent Poll
"What is the origin of that asymmetry?" Ian Garrick-Bethell, of the University of California, Santa Cruz and lead author of the Nature study, told Space.com. "Chipping away at this problem of the shape of the moon can give us insight into those types of fundamental geology problems."
"This happened a long time ago, when the moon was not completely solid. This was in the first 100 to 200 million years of lunar thermal evolution," Garrick-Bethell added.
In an interview with BBC News, Garrick-Bethell said Earth's impact on the moon has been profound through the centuries. He said the Earth causes the moon to shift on its axis.
"For the Earth and Mars and other bodies, we know that the dominant shape of the planet is due to its spin," Garrick-Bethel told BBC News. "If you take a water balloon and start spinning it, it will bulge out at the equator, and on the Earth, we have something very similar to that."
Garrick-Bethell said, though, that the Earth's gravitational pull alone is not the total reason why the moon is shaped the way it is.
"It's spinning really slowly, and it's really far from the Earth, so it's not like tides today could be causing that," Garrick-Bethell told BBC News.
Garrick-Bethel said it was actually a 2013 University of Texas study researching how Jupiter's tidal heating had on the warmer liquid water on its moon Europa that nudged his team look at if something similar could have happened with Earth and the moon.
"We did a lot of work to estimate the uncertainties in the analysis that result from those gaps (in the data)," said Garrick-Bethell.
Urgent: Assess Your Heart Attack Risk in Minutes. Click Here.
Related Stories: