Cosmology

Cosmology

warm-hot intergalactic medium sculptor wall
Here in our Universe, both normal and dark matter can be measured astrophysically. But only normal matter can collapse. Why is that?
Diagram showing the cosmic microwave background radiation with satellites COBE, WMAP, and Planck, illustrating improvements in observational detail and resolution.
First discovered in the mid-1960s, no cosmic signal has taught us more about the Universe, or spurred more controversy, than the CMB.
A dark nebula with dimming T Tauri stars nestled among dust and gas. The nebula casts a shadowy silhouette against a backdrop of numerous smaller stars in space.
It's the ultimate game of cosmic "cover up," as the dimming occurs when a circumbinary disk from a nearby star passes in front of T Tauri North.
Illustration of the periodic table with a human silhouette reveals how heaviest elements shape us. Elements are color-coded, depicting the percentage composition of the body: 73% oxygen, 16.5% carbon, 9.5% hydrogen, and 1% others.
Matter is made up largely of atoms, where atomic nuclei can contain up to 100 protons or more. But how were the heaviest elements made?
CMB polarization Planck
Cosmic inflation, proposed back in 1980, is a theory that precedes and sets up the hot Big Bang. After thorough testing, is it still valid?
An abstract geometric pattern of spirals and interlocking squares in white on a black grid background evokes the elegant precision often found at the intersection of mathematics and science.
Physicist Don Lincoln explains why mathematics is a powerful tool for scientific modeling, but is not a science itself.
Six mesmerizing images, bathed in red hues, reveal distant galaxies—JWST's little red dots. Each is precisely labeled: CEERS 14448, NGDEEP 4321, PRIMER-COS 10539, CEERS 20320, JADES 9186, and PRIMER-UDS 17818—alongside their corresponding redshift values.
The discovery of ultra-bright, ultra-distant galaxies was JWST's first big surprise. They didn't "break the Universe," and now we know why.
Visualization of a section through the large-scale structure of the universe highlighting cosmic web patterns and distributions.
Our Universe isn't just expanding, the expansion is accelerating. Instead of dark energy, could a "lumpy" Universe be at fault?
A planet's horizon illuminated by a bright sun against a backdrop of stars in space.
A recent measurement has simultaneously settled an ongoing scientific debate while puzzling scientists.
An abstract green fractal pattern resembling interconnected neural pathways on a black background evokes the complexity of a fractal universe.
On larger and larger scales, many of the same structures we see at small ones repeat themselves. Do we live in a fractal Universe?
It's not only the gravity from galaxies in a cluster that reveals dark matter, but the ejected, intracluster stars actually trace it out.
In the depths of space, a spiral galaxy twists like a cosmic Kraken, its bright core and distinct arms encircled by a sea of stars against the dark expanse.
Did the Milky Way form by slowly accreting matter or by devouring its neighboring galaxies? At last, we're uncovering our own history.
Our galactic home in the cosmos — the Milky Way — is only one of trillions of galaxies within our Universe. Is one of them truly our "twin?"
elements
When three wise men gifted baby Jesus with gold, frankincense, and myrrh, they had no idea one was made from colliding neutron stars.
Bright orange star surrounded by a dense field of smaller white stars in space.
Carl Sagan was far from the first to declare we are the children of ancient stars.
A person in a red shirt stands next to "Waves in an Impossible Sea," the 2024 science book by Matt Strassler. The background displays a blurred bookshelf.
Matt Strassler's journey into fundamental physics culminates in a brilliant explanation of the Higgs field. Enjoy this exclusive interview.
The image showcases the JWST observations of the Firefly Sparkle galaxy alongside UGC 12158, a modern Milky Way analogue. It includes a reconstructed galaxy reminiscent of a baby Milky Way, beautifully interpreted through a lens model.
The Firefly Sparkle galaxy was only spotted because of gravitational lensing's effects. Yet galaxies like these brought us a visible cosmos.
evolution universe cosmic history big bang
From a hot, dense, uniform state in its earliest moments, our entire known Universe arose. These unavoidable steps made it all possible.
black hole
50 years ago, Stephen Hawking showed that black holes emit radiation and eventually decay away. That fate may now apply to everything.
Betelgeuse visualization
The closest known star that will soon undergo a core-collapse supernova is Betelgeuse, just 640 light-years away. Here's what we'll observe.
Diagram of atomic orbitals showing various shapes and labels, including s, p, d, and f orbitals, organized in a triangular structure with coordinate axes x, y, z.
One of the fundamental constants of nature, the fine-structure constant, determines so much about our Universe. Here's why it matters.
A telescope beneath a colorful, abstract visualization of the universe, with a starry night sky in the background.
DESI has allowed astronomers to create an unprecedented 3D map of the Universe representing 20% of the entire sky.
lookback time galaxies
For nearly 60 years, the hot Big Bang has been accepted as the best story of our cosmic origin. Could the Steady-State theory be possible?
how much dark matter
Two parts of our Universe that seem to be unavoidable are dark matter and dark energy. Could they really be two aspects of the same thing?
Close-up of an analog weight scale needle pointing to zero grams, with a black background.
"A person’s mass is made not of 'stuff' in the way we normally think about it, but rather our mass is made of energy."
CMB polarization Planck
Since the mid-1960s, the CMB has been identified with the Big Bang's leftover glow. Could any alternative explanations still work?
Three red, cloud-like structures are set against a starry background in space.
The most massive early galaxies grew up faster, and have more stars, than astronomers expected, according to JWST. What does it all mean?
elements Cas A remnant Chandra X-ray
The last naked-eye Milky Way supernova happened way back in 1604. With today's detectors, the next one could solve the dark matter mystery.
Animation of a star being engulfed by another star, emitting bright light and gas in space.
Since 1930, type Ia supernovae have been thought to arise from white dwarfs exceeding the Chandrasekhar mass limit. Here's why that's wrong.
Abstract image of a dark central circle surrounded by radial green and yellow light streaks resembling an eye or vortex.
The race to find dark matter could grow more complex with high-energy neutrino interference.