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Cosmology
Dark energy is one of the biggest mysteries in all the Universe. Is there any way to avoid "having to live with it?"
In the 20th century, many options abounded as to our cosmic origins. Today, only the Big Bang survives, thanks to this critical evidence.
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?
Practically all of the matter we see and interact with is made of atoms, which are mostly empty space. Then why is reality so... solid?
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 "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.
Some physicists are besot with the multiverse, but if we can't detect these other universes, how seriously should we take them?
In the infant Universe, particle physics reigned supreme.
A deep dive into the chaotic journey of star formation.
A great many cosmic puzzles still remain unsolved. By embracing a broad and varied approach, particle physics heads toward a bright future.
Even if you aren't in the path of totality, you can still use the solar eclipse to measure how long it takes the Moon to orbit Earth.
There are a wide variety of theoretical studies that call our Standard Model of cosmology into question. Here's what they really mean.
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?
Here's the case for why science can't keep ignoring human experience.
Ground-based facilities enable the greatest scientific production in all of astronomy. The NSF needs to be ambitious, and it's now or never.
To Fred Hoyle, the Big Bang was nothing more than a creationist myth. 75 years later, it's cemented as the beginning of our Universe.
JWST has puzzled astronomers by revealing large, bright, massive early galaxies. But the littlest ones pack the greatest cosmic punch.
The second law of thermodynamics tells us that entropy always increases. But that doesn't mean it was zero at the start of the Big Bang.