When does a sea become an ocean? Don't worry, it's not an existential riddle, we're merely pondering the surface of the moon. You see, the Ocean of Storms, or Oceanus Procellarum, is so vast, spanning over 2,500 km, that it's earned the regal title of "ocean" instead of settling for a mere "sea" status.

Initially, astronomers suspected that this gigantic area was the result of an asteroid's impact, but recent data from the Grail mission has led to a new theory. Rather than something hitting the moon, the data suggests that underneath all that dark lava in the Ocean of Storms, there are hidden "rift valleys". Scientists believe these rifts acted as cosmic pipelines, transporting lava to the surface during ancient lunar eruptions.