gravity

Astronomers have been scouring the outer solar system for signs of a hypothetical ninth planet for almost a decade, without success. However, we may finally be on the cusp of finding it, experts say.

The three-body problem is a physics conundrum that has boggled scientists since Isaac Newton's day. But what is it, why is it so hard to solve and is the sci-fi series of the same name really possible?

A new theory of quantum gravity, which attempts to unite quantum physics with Einstein's relativity, could help solve the puzzle of the universe's expansion, a theoretical paper suggests.

Do galaxies, including our own Milky Way, orbit anything in the universe?

Spacecraft have visited and photographed the far side of the moon, but why can't we see it from Earth?

Cats are masters of contortion — and the laws of physics — which helps them stick the landing more times than not.

The moon controls the tides, impacts marine ecosystems, and subtly influences time on Earth. So what would happen if the moon suddenly disappeared?

The location of the solar system's outer boundary is a point of contention among astronomers. There are three possible candidates, which "all have merit." But which one is best?

The idea of emergent gravity is still new and requires a lot of assumptions in its calculations to make it work. But if experimental evidence ever proves it real, we would need to totally rewrite the laws of physics.

A new geological study suggests that Mars' gravitational field pulls the Earth closer to the sun over cycles lasting millions of years, warming our climate.