Birth Of The Moon: Did Earth Have 20 Little Moons Earlier?

• comments
• 
• 

New simulations suggest that Earth's moon is not a result of a single massive collision but a mash-up of several tiny moons. Researchers think that over millions of years these little moons coalesced into one giant moon.

 The Science News reports that the proposed hypothesis, published by Nature Geoscience on January 9, 2017, explains why the chemical makeup of Moon and Earth is so alike each other.

Earlier, it was thought that the Earth collided with a Mars-sized planet called Theia around 4.5 billion years ago, which created debris that later pulled together as Moon. However, since the Moon and Earth have similar composition, it is difficult to think that the material for Moon might have come from another planet.

Now, planetary scientist Raluca Rufu of the Weizmann Institute of Science in Rehovot, Israel, and his colleagues propose that the moon might have resulted from multiple impacts instead. This is a decades-old theory which has been simulated by the researchers once again. The scenario shows that the young Earth was hit by a number of objects that were one-hundredth to one-tenth of Earth's mass. The resulting debris created a disk around Earth which molded into about 20 little moons with time.

The Space magazine also reports that these moons moved away from the Earth due to tidal interaction but eventually settled at a distance known as Hill Radius. In the next few centuries, these little moons coalesced together to form one larger moon which is very much like Earth (because Moon was made from the material of the Earth). The researchers' simulations present a theory which is more likely to produce the right lunar mix as we know it.

Check out the video to see how the debris in several disks around Earth settled into the Hill radius and coalesced to form one big moon: