Why is the moon shrinking and what does it mean for the Earth?

The moon appears to have changed shape significantly over the past few hundred million years and the contractions have raised doubt about the feasibility of establishing colonies on the moon because of the likelihood of moonquakes.

The discovery comes after the unsuccessful project, which was intended to be the first US commercial mission was aborted after the spacecraft lost propellant and it burnt up as it re-entered the Earth's atmosphere on January 18.