Scientists have worked out the reasons for the distorted shape of our Moon.
A US team calculated the effect on the shape of the early Moon of tidal and rotational forces.
They say its own spin and the tidal tug of the Earth created a “lemon-shaped” satellite.
Lead researcher Ian Garrick-Bethell, from the University of California Santa Cruz, said this shape-shifting occurred when the Moon was mostly liquid beneath a thin outer crust of rock.
This interaction with the Earth also caused the Moon to shift slightly on its own axis.
“For the Earth and Mars and other bodies, we know that the dominant shape of the planet is due to its spin,” he said.
“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 o that.”
