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Universe Expansion
For some reason, when we talk about the age of stars, galaxies, and the Universe, we use "years" to measure time. Can we do better?
The JWST's observations of well-developed galaxies early in universal history may coincide with accepted astronomical theory after all.
The most common element in the Universe, vital for forming new stars, is hydrogen. But there's a finite amount of it; what if we run out?
Life arose on Earth very early on. After a few billion years, here we are: intelligent and technologically advanced. Where's everyone else?
Total eclipses are a product of a strange and almost eerie cosmic coincidence — one that makes Earth an even rarer world in the galaxy and, by proxy, in the Universe.
Our Universe requires dark matter in order to make sense of things, astrophysically. Could massive photons do the trick?
The Universe is expanding, and the Hubble constant tells us how fast. But how can it be a constant if the expansion is accelerating?
Here's what recent DESI measurements suggest — and why it's too early to update conventional predictions about the Universe's distant future.
In all the Universe, only a few particles are eternally stable. The photon, the quantum of light, has an infinite lifetime. Or does it?
Yes, the Universe is expanding, but if you've ever wondered, "How fast is it expanding," the answer isn't in terms of a speed at all.
Is the Universe finite or infinite? Does it go on forever or loop back on itself? Here's what would happen if you traveled forever.
The majority of the matter in our Universe isn't made of any of the particles in the Standard Model. Could the axion save the day?
The Universe is 13.8 billion years old, going back to the hot Big Bang. But was that truly the beginning, and is that truly its age?
The center of the galaxy doesn't just host stars and a black hole, but an enormous set of rich gassy and dusty features. Find out more!
The "first cause" problem may forever remain unsolved, as it doesn’t fit with the way we do science.
From before the Big Bang to Voyager 1, particle physicist Harry Cliff takes us on a whiz-bang tour of the Universe's evolution.
In the infant Universe, particle physics reigned supreme.
A deep dive into the chaotic journey of star formation.
First derived by Emmy Noether, for every symmetry a theory possesses, there's an associated conserved quantity. Here's the profound link.
A great many cosmic puzzles still remain unsolved. By embracing a broad and varied approach, particle physics heads toward a bright future.
In logic, 'reductio ad absurdum' shows how flawed arguments fall apart. Our absurd Universe, however, often defies our intuitive reasoning.
Physicists just can't leave an incomplete theory alone; they try to repair it. When nature is kind, it can lead to a major breakthrough.
You can only create or destroy matter by creating or destroying equal amounts of antimatter. So how did we become a matter-rich Universe?
Because of dark energy, distant objects speed away from us faster and faster as time goes on. How long before every galaxy is out of reach?
Given enough time, all galaxies will expel their star-forming material and wind up dead. Is this the earliest one, or is it just asleep?
Galaxies don't simply feed their central supermassive black holes, but the activity generated inside affects the entire galaxy and more.
Ground-based facilities enable the greatest scientific production in all of astronomy. The NSF needs to be ambitious, and it's now or never.
The Multiverse fuels some of the 21st century's best fiction stories. But its supporting pillars are on extremely stable scientific footing.
JWST has puzzled astronomers by revealing large, bright, massive early galaxies. But the littlest ones pack the greatest cosmic punch.
When cosmic inflation came to an end, the hot Big Bang ensued as a result. If our cosmic vacuum state decays, could it all happen again?