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Universe Expansion
Two supermassive black holes on an inevitable death spiral push the limits of Einstein's relativity. New observations reveal even more.
On the largest scales, galaxies don't simply clump together, but form superclusters. Too bad they don't remain bound together.
The Big Bang was hot, dense, uniform, and filled with matter and energy. Before that? There was nothing. Here's how that's possible.
When the Hubble Space Telescope first launched in 1990, there was so much we didn't know. Here's how far we've come.
Once you cross a black hole's event horizon, there's no going back. But inside, could creating a singularity give birth to a new Universe?
From high school through the professional ranks, physicists still take incredible lessons away from Newton's second law.
No matter what it is that we discover about reality, the fact that reality itself can be understood remains the most amazing fact of all.
Will we build a successor collider to the LHC? Someday, we'll reach the true limit of what experiments can probe. But that won't be the end.
The relic signal that first proved the Big Bang has been known and analyzed for 60 years. Join us at the frontiers of modern cosmology!
The CMB has long been considered the Big Bang's "smoking gun" evidence. But after what JWST saw, might it come from early galaxies instead?
Looking at a dark, night sky has filled humans with a sense of awe and wonder since prehistoric times. But appearances can be deceiving.
In just its first 10 hours of observations, the Vera Rubin observatory discovered more than 2000 new asteroids. What else will it teach us?
For over 50 years, it’s been the scientifically accepted theory describing the origin of the Universe. It’s time we all learned its truths.
For hundreds of millions of years, a cosmic fog blocked all signs of starlight. At last, JWST found the galaxies that cleared that fog away.
Massive galaxy cluster Abell S1063, 4.5 billion light-years away, bends and distorts the space nearby. Here's what a JWST deep field shows.
Is the Universe's expansion rate 67 km/s/Mpc, 73 km/s/Mpc, or somewhere in between? The Hubble tension is real and not so easy to resolve.
Different methods of measuring the Universe's expansion rate yield high-precision, incompatible answers. But is the problem robustly real?
A few physical quantities, in all laboratory experiments, are always conserved: including energy. But for the entire Universe? Not so much.
If you want to understand the Universe, cosmologically, you just can't do it without the Friedmann equation. With it, the cosmos is yours.
Viewing Uranus's largest moons with Hubble, astronomers hoped to find darkening on the trailing side. They found the exact opposite instead.
The first galaxies were irregular blobs of gas and stars. But modern features, like spiral arms and bars, appeared earlier than expected.
If the Universe is 13.8 billion years old today, but different ages the farther we look back, what does it mean for a star to be the first?
The COSMOS-Web has just finalized their release of their full field: larger and deeper than any other JWST program. Here's what's inside.
When theory and experiment disagree, it could mean new physics. This time, they solved the muon g-2 puzzle, and saved the Standard Model.
For decades, astronomers have claimed the Milky Way will merge with Andromeda in ~4 billion years. Here's why, in 2025, that seems unlikely.
In our Universe, dark matter outmasses normal matter by a 5-to-1 ratio, shaping the Universe as we know it. What if it simply weren't there?
It rotates on its axis, revolves around the Sun, moves throughout the Milky Way, and gets carried by our galaxy all throughout space.
The long-elusive neutrino was shown to have a bizarre property no one expected: mass. New, tightest-ever limits have profound implications.
Many were hoping that JWST would find the first stars of all. Despite many hopeful claims, it hasn't, and probably can't. Here's how we can.
Here in our Universe, time passes at a fixed rate for all observers: one second-per-second. Before the Big Bang, things were very different.