As Earthlings, most of us don’t spend a lot of extra time thinking about the gravity on our home planet. Instead, we go about our days only occasionally dropping things or tripping over furniture but ...

Human bodies are exquisitely tuned to one world, and it is not a forgiving one. Strip away our technology and even Earth would kill us in minutes in the wrong place, yet our home planet is still the ...

How do you explore the interior of a planet without ever touching down on it? Start by watching the way the planet spins, then measure how your spacecraft orbits it — very, very carefully. This is ...

All of the objects in our solar system are acted upon by forces. Forces are pushes or pulls. Every force has both a strength and a direction. Applying a force on something–like pushing a toy car–can ...