Two-Faced

The moon has two distinct faces; gravity readings of the moon’s surface by a lunar orbiting satellite suggest that not long after formation of the original surface, another dwarf-planet-like object smacked into it causing the impacted side to be thrown upward and back to fold itself onto the back side of the moon.
The best fit of some 360 simulations run by Meng Hua Zhu at the Space Science Institute of Macau University of Science and technology suggest an object about 480 miles in diameter and traveling at 22,500 mph, hit with enough force to re-surface the back side of the moon with up to six miles of layers from the front side.
While the back or far side is commonly referred to as the “dark side,” the moon receives equal amount of sunlight on each side, during the lunar day.
Only one side of the Moon is visible from Earth because the Moon rotates on its axis at the same rate that the Moon orbits the Earth – a situation known as synchronous rotation, or tidal locking.
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