At and beyond the current frontiers of knowledge, many physicists have strongly held opinions. Can surveys point the way to breakthroughs?

The original idea of the Big Bang was synonymous with a singularity: a point of zero volume. In this Universe, things never got that small.

The distance ladder and the CMB give incompatible values for the expansion rate. A new study shows just how robust the Hubble tension is.

Is dark energy evolving with at least 99.99% confidence? Despite the quality of recent data, scientists have every reason to be skeptical.

In a 13.8 billion year old Universe, a few seconds hardly seems like it matters. But these minuscule changes sure do add up over time.

Early on, the Universe needed near-perfect flatness, or atoms, stars, and galaxies couldn't form. What happens once dark energy takes over?

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?

Over billions of years, fewer stars form, galaxies mutually recede, and the Universe becomes ever darker. Here's how fast it all happens.

Smashing things together at unprecedented energies sounds dangerous. But it's nothing the Universe hasn't already seen, and survived.

Long after the last star burns out, the Universe will experience its end state: a heat death. Will everything prior then be meaningless?

The Universe is expanding, the expansion is accelerating, and some galaxies even recede faster-than-light. Can we see a change in real time?

Outer space begins just over 100 kilometers up, but what we can see extends for billions of light-years. Here's what all of it looks like.

Even in an expanding Universe, we expect both redshifted and blueshifted galaxies. But nearly every one we see is redshifted. Here's why.

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?

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?

The method you use to measure the expanding Universe determines which of two answers you'll get. Lensed supernovae can't resolve that issue.

Scientific truths remain true regardless of belief. These 10, despite contrary claims, remain vitally important as 2025 draws to a close.

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.

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

For over 10 billion years, the cosmic star-formation rate has been dropping and dropping. Someday, the final star in the Universe will die.

We've now detected hundreds of gravitational waves with LIGO, Virgo, and KAGRA. What if we tried Weber's original method in the modern day?

There's some, but not overwhelming, evidence that dark energy is evolving. What would it take for a "Big Crunch" to be our cosmic fate?