Earth's oceans help make our planet different from every other planet in the solar system. As far as we know, no other place is the right temp for liquid water, the most essential ingredient for life to exist. The oceans are Earth's primary stabilizing force, and their immense power helps to shape the appearance and behavior of the entire planet and everything living on it. And they are also the planet's great unknown - their deepest points have been visited less than the surface of the moon.