On Earth, we have to contend with our own gravity well when we launch rockets and spacecraft; if a rocket isn't powerful enough to escape its gravity well, it will fall back to Earth.

On Earth, we have to contend with our own gravity well when we launch rockets and spacecraft; if a rocket isn't powerful enough to escape its gravity well, it will fall back to Earth.

NASA scientists have discovered an electric field encompassing Earth’s atmosphere that is as "fundamental" as gravity -- and could even give clues about possible life on other planets.

An artist's impression of Earth's gravity well. The idea that gravity is the result of the curvature of space-time is a core principle of Einstein's theory of general relativity.

An newly discovered asteroid will be captured by Earth's gravity this fall. The "mini-moon" will spend about two months in Earth's orbit, before being flung back on its normal path around the sun.