While there is a little wiggle room, the planets in our solar system really are orbiting on mostly the same level. Why do ...

Why don't planets fall into the stars they orbit if they're constantly being pulled by gravity?Lindsey CoughterRocky Mount, North Carolina This is a brilliant question because the notion of an orbit ...

Which way is ‘down’ has a different answer depending on where you are on Earth, in the solar system, in our galaxy and beyond ...

In the remote outer reaches of planetary systems, far beyond the orbit of known planets, enormous and mysterious worlds silently loop around their stars. Some drift as far as 10,000 times the distance ...

This is a brilliant question because the notion of an orbit is counterintuitive. We know that massive objects (really, any objects with mass) gravitationally attract other massive objects; Newton's ...