NASA says the moon is shrinking and experiencing "moonquakes"
NASA says the moon is shrinking and it may be creating so-called "moonquakes." Scientists say the moon's interior is cooling and causing it to shrivel up like a raisin. The shrinking has caused ridges on the moon's surface called "thrust faults" -- where one section of crust is pushed up over a neighboring part. Scientists now believe those faults are to blame for the tremors.