On cosmic scales, only dark matter (or something equivalent) gives us the Universe we observe. Now, the Sunyaev-Zel'dovich effect agrees.

When what we predict and what we measure don't add up, that's a sign there's something new to learn. Could it be a new fundamental force?

Not everyone accepts the scientific consensus; some even make careers out of challenging it. But only a select few do it the right way.

The discovery of CDG-2, a galaxy that's more than 99.9% dark matter, could reveal a new population of ultra-faint galaxies. But is it real?

The fundamental building blocks of reality are indivisible: quanta that cannot be split or divided. Our understanding remains incomplete.

Here in our modern Universe, it's cosmic dust that forms planets, complex molecules, and enables life. But how did the Universe create it?

Our great hope is that today's indirect, astrophysical evidence will someday lead to successful direct detection. What if that's impossible?

Many view the development of fringe, alternative theories as a useless waste of time. But when they can be tested, it shows what reality is.

The seeds of cosmic structure that were planted back during the Big Bang grew into the cosmic web we see today. What is it telling us?

When objects are gravitationally bound, they cannot escape from one another's influence. How does that work within the expanding Universe?

Astronomers have found starless gas clouds before, but Cloud 9 might be the most pristine one of all, with big lessons for cosmic history.

Perhaps the most remarkable fact about the Universe is simply that it, and everything in it, exists. But what's the reason why?

While humanity has been skywatching since ancient times, much of our cosmic understanding has come about only recently. Very recently.

Our Universe doesn't just expand and cool, but the expansion itself is accelerating. Can stars form under such structure-erasing conditions?

Our Standard Model of the Universe, for both particle physics and cosmology, remains intact for now. When will its foundations crack?

As the lightest baryon in the Universe, the proton is thought by many to be eternally stable. But if it isn't, can we observe it decaying?

We have a picture of how and when it will all come to an end. These three big ideas could still profoundly change how our cosmos evolves.

Science has assembled an incredible story outlining our Universe's whole history. Despite its unrivaled success, 9 profound gaps remain.

Everything ever seen — every star, mountain, and face — makes up less than 5 percent of the universe. Astrophysicist Janna Levin reminds us that the rest — dark matter and dark energy — is invisible, mysterious, and everywhere. We are the luminous exception in a universe of darkness.

From white holes to dark stars and multiverses, James Riordon explores the bizarre exhibits of general relativity's "cryptozoo."

Spirals, ellipticals, and irregulars are all more common than ring galaxies. At last, we know how these ultra-rare objects are made.

Wavelengths stretch, distances grow, and temperatures cool as the Universe expands with time. How are the various cosmic parameters related?

Weird-looking galaxies, with tentacle-like tails or prominent dual streams, appear like jellyfish or bunny ears. But that’s just the start.

Nearly 100 years after being theorized, the strange behavior of the neutrino still mystifies us. They could be even stranger than we know.

A look at how criminals are using unrestricted chatbots and how cyber defenders are fighting back.

For 13.8 billion years, the Universe has been expanding. But that couldn't have been the case for an eternity, and science has proven it.

Dark matter has never been directly detected, but the astronomical evidence for its existence is overwhelming. Here's what to know.

Inflation's two main criticisms, that it can predict anything and that the "measure problem" remains unsolved, can't erase its successes.

As the Universe ages, it continues to gravitate, form stars, and expand. And yet, all this will someday end. Do we finally understand how?

From the Big Bang to a prior period of cosmic inflation, our cosmic origins are clearer than ever. Yet these 5 big mysteries still remain.