The answer to the dark-matter mystery may be under our feet.

The sun is a roiling, boiling ball of plasma, constantly churning and turning itself inside out.

Double sunsets may be just as common in our galaxy as the solitary kind that we know on Earth, and this has big implications for our search for life outside the solar system.

The five main string-theory candidates may all just be pieces of a larger, cohesive whole — and M-theory could bring them together.

A new research paper has found a new potential type of abode for life: a rocky planet orbiting just past the event horizon of a rapidly spinning supermassive black hole.

As far as cosmologists can tell, the mysterious force behind the accelerated expansion of the universe, a force that we call dark energy, remains constant. But it may not have done so in the past.

All four outer planets in our solar system sport at least a few rings, but so far, we haven't observed any such features around exoplanets. That's confusing.

Earth is safe from such a catastrophe — almost.

String theory is a purported theory of everything that physicists hope will one day explain … everything.

A dark web ties the universe together. Now, we can see it.

But also super-mysterious.

Life for the 19th-century astronomer was kind of monotonous, 200 years after Galileo's revolutionary work with the telescope.

As far as we can tell, we're alone. But it could be that we're looking in the wrong places.

These supremely stable particles could explain dark matter.

It was a big moment for our cosmos when the first stars awoke, but it's an elusive one for scientists.

The world of the teensy-tiny, the quantum realm, could have a favorite flavor. Here's why that's a big deal.

String theory is a powerful idea, unfinished and untested, but one that has persisted for decades despite inauspicious beginnings.

Physicists have certainly achieved a lot, but many mysteries about the universe remain.

What if I told you that our universe was flooded with hundreds of kinds of nearly invisible particles and that, long ago, these particles formed a network of universe-spanning strings?

Researchers recently released simulations of the Large Magellanic Cloud — a satellite galaxy of the Milky Way — and found that cosmic rays from a starburst event are starting to rip it apart.

If we want to learn new things about everything from the first galaxies to the chance for life on other planets, the James Webb is our only hope.

Gamma-ray bursts are even worse than we thought.

We have much to learn from the rocks of the asteroid belt.

Scientists are on the verge of being able to detect the "memory" left behind by gravitational waves.