Why is the earth four times larger in diameter than the moon?
The moon has to be some size, and the Earth has to be some size. The precise number is 3.66 times bigger. There’s no special reason for the Moon to be 4 times smaller, it could have been the same size, or practically any size down to about 10 km diameter. If it was any smaller, it would have been knocked out of orbit by some random meteor hit sometime in the past few billion years.
