LOS ANGELES — Scientists picking up signs of water on the moon’s surface typically attribute them to deposits left by comets, asteroids and other heavenly objects. But a new analysis of lunar samples brought back to Earth by Apollo astronauts in the early 1970s indicates that the moon’s interior may have been a little damp in its early days.

The findings, published online Sunday in the journal Nature Geoscience, support mounting evidence that the moon once contained some “native” water — throwing a wrench into current beliefs about how Earth’s companion formed.

Prevailing theories hold that the moon was created when a Mars-sized body crashed into the young Earth and broke off debris that eventually coalesced. In the process, much of the water would have evaporated into space, leaving Earth’s new satellite quite arid.