Cosmology

Cosmology

separation normal matter dark matter galaxy cluster
There are many theories of gravity out there, and many interpretations of wide binary star data. What have we really learned from it all?
Raisin bread expanding Universe
The evidence that the Universe is expanding is overwhelming. But how? By stretching the existing space, or by creating new space itself?
elements
In 2017, we detected gold being forged in a neutron star-neutron star merger. Now, in 2024, the amounts created simply don't add up.
Interior of a particle physics laboratory showing a complex particle accelerator setup with multiple cables, detectors, and machinery designed to study glueball particles.
Glueballs are an unusual, unconfirmed Standard Model prediction, suggesting bound states of gluons alone exist. We just found our first one.
A detailed image contrasting a fiery asteroid on the left with a cool, intricate snowflake on the right against a dark background.
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Humanity has two giant collisions to thank for its existence, explains biologist Sean B. Carroll.
Holograms preserve all of an object's 3D information, but on a 2D surface. Could the holographic Universe idea lead us to higher dimensions?
A bright flash of light in the Universe
In general relativity, white holes are just as mathematically plausible as black holes. Black holes are real; what about white holes?
X-ray style image of a human head with brain highlighted by luminous, branching electric currents made of particles against a dark background.
At a fundamental level, only a few particles and forces govern all of reality. How do their combinations create human consciousness?
dark energy
Dark energy is one of the biggest mysteries in all the Universe. Is there any way to avoid "having to live with it?"
universe temperature
In the 20th century, many options abounded as to our cosmic origins. Today, only the Big Bang survives, thanks to this critical evidence.
how many planets
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?
A technician in a clean suit inspects a large, segmented, hexagonal mirror inside a circular gray structure.
The JWST's observations of well-developed galaxies early in universal history may coincide with accepted astronomical theory after all.
wolf rayet wr 31a
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?
atom quantum
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?
distant quasar
The Universe is expanding, and the Hubble constant tells us how fast. But how can it be a constant if the expansion is accelerating?
A vibrant space image showing a star-forming region with clusters of bright stars and colorful nebulas in shades of red and green.
Here's what recent DESI measurements suggest — and why it's too early to update conventional predictions about the Universe's distant future.
pulse light quantum tunnel barrier
In all the Universe, only a few particles are eternally stable. The photon, the quantum of light, has an infinite lifetime. Or does it?
space expanding
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.
travel straight line
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.
axions
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?
cosmic epochs lookback hubble 13.8 billion
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?
Abstract representation of a cosmic event with a burst of particles emanating from a central point, blending astrophysical imagery with geometric designs.
The "first cause" problem may forever remain unsolved, as it doesn’t fit with the way we do science.
A bright star illuminates the surrounding space with a spectrum of colors in a nebula.
From before the Big Bang to Voyager 1, particle physicist Harry Cliff takes us on a whiz-bang tour of the Universe's evolution.
Four earth-like planets from a multiverse, in varying colors, aligned in space against a starry background.
Some physicists are besot with the multiverse, but if we can't detect these other universes, how seriously should we take them?
A digital image of a star's structure superimposed on a futuristic tunnel with neon arrow accents.
In the infant Universe, particle physics reigned supreme.
Colorful interstellar gas and dust form towering pillars in a star-forming region of space.
A deep dive into the chaotic journey of star formation.
standard model structure
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.
MACS J0717 galaxy cluster dark matter
There are a wide variety of theoretical studies that call our Standard Model of cosmology into question. Here's what they really mean.
quantum gravity
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.