https://www.youtube.com/watch?v=px17aCS5KHk
Astronauts on the International Space Station dissolved an effervescent tablet in a floating ball of water, and captured images using a camera capable of recording four times the resolution of normal high-definition cameras. You can see here that water can naturally form a sphere (and propagate waves) in a zero-gravity environment. This unique cohesive property of water molecules, combined with the effect of gravity, is exactly how oceans exist on a globe.
-video courtesy of the International Space Station and Youtube user PublicDomainTV on Youtube.com