Aliens built a giant dam.
In space there is no up and no down. It is purely a fluke of human development and expansion throughout the world that our maps of Earth have "ups" and "downs" to them.
Water, and air, and humans, etc, stick to the Earth because of gravity.
On a sphere, there is no "top and bottom".
There are only "toward the center" and "away from the center."
Gravity keeps the water attempting to get as close to the center as it can.
there is a big bucket underneath to catch it
Gravity acts the same in all directions, pulling everything toward the center of the Earth. The only "down" is toward the center, and what we have decided to call "down" in relation to the orbit of the solar system. We could just as well have called it "up." When you look at a map, south is usually "down," but you can actually draw a map with "up" and "down" anywhere you want.
So gravity keeps it from running off the "bottom"
The same reason we are not thrown into space Gravity.
g: 9.80665 m/s^2 or 32.2 ft/s^2
It works in all kind of directions but it all has this one purpose to be pulling one down towards the center of the earth.
If we take the rotation of the Earth in consideration as well, none is thrown off due to the rotation of the Earth is incredibly slow (0.0007 RPM).
So gravity and lacking centrifugal force are the reasons why we (and water or any other object *unless flown off past our atmosphere*) are not thrown off of the Planet Earth and into space.
Uhhhh because the Earth is flat duh LMAO
Because the ocean has an ocean floor under it. It's where underwater caves are, which you can easily explore with just a few days of training.
Gravity, you imbecile