Expert Voices

If this fundamental symmetry of the universe doesn’t hold, it could break open new physics.

The Planetary Society's LightSail 2 spacecraft is finally ready to attempt flight by light. Here's what to expect from the June 24 launch!

Unifying all the forces and particles would require a particle accelerator far more powerful than humans have ever built.

April 26, 1803 was an unusual day in the small town of L'Aigle in Normandy, France — it rained rocks.

The universe really likes its information — but black holes pose a huge paradox physicists can't yet solve.

The moon has always served as an inspiration for humanity, and there are many potential benefits for further exploration of our planet's rocky satellite.

At the very largest scales — zooming out from solar systems, stellar clusters and even galaxies — a surprising pattern emerges in nature.

The big move could help our rocky planet escape the expanding sun and prevent a collision with Jupiter.

It's a perennial sci-fi favorite: other worlds, other universes, other possibilities, right beyond the bounds of the known cosmos or just a flick of a magic device away.

The democratization of space began 20 years ago with Beanie Babies.

As society contemplates going to the moon or Mars, there's a rising debate as to whether it's worth the money.

The situation in question in March 2019 was NASA's cancellation of an all-female spacewalk.

All four known forces of nature have their own unique place — and the strong nuclear force governs the very small.

Fortunately, we're getting to the point where we can see potentially hazardous objects coming — and maybe even do something about it.

So there's this stuff called "antimatter." But a weirdly small amount of it.

Neutrinos are the changelings of the subatomic world, but physicists are getting closer to pinning down the particles' true identities.

The concept of atoms had been floating around off and on for a few millennia, but it took some clever experimentation to pinpoint their existence.

We don't understand the concept of time much at all.

Imagine astronauts on Mars, tasked with picking rock samples that will be used by scientists to search for signs of life. But they can only transport a limited number back to Earth.