Universe Expansion

Universe Expansion

Astronomical image showing a galaxy cluster with multiple bright glowing sources and smaller points against a deep blue and purple space background.
We normally think of dark matter as the "glue" that holds galaxies and larger structures together. But it's so much more than that.
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.
A vibrant image of the Horsehead Nebula captured by JWST, featuring a radiant blue and white glow against a deep red starry background.
The most iconic "dark nebula" of all lights up under JWST's infrared gaze. Here's what's newly discovered inside.
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?
timeline of the universe history
From the earliest stages of the hot Big Bang (and even before) to our dark energy-dominated present, how and when did the Universe grow up?
A textured, circular black center is surrounded by radiating blue patterns and lines, resembling an abstract eye or a solar eclipse.
6mins
Physicist Sean Carroll on entropy, complexity, and the origins of life:
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?
first contact
Life arose on Earth very early on. After a few billion years, here we are: intelligent and technologically advanced. Where's everyone else?
A sequence showing the phases of a solar eclipse, culminating in totality, against a dark background.
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.
cosmic ray blazar
Our Universe requires dark matter in order to make sense of things, astrophysically. Could massive photons do the trick?
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?
Annotated map of the milky way's center in multiple wavelengths with identified regions and sources.
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!
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.
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.
A split image showing Emmy Noether with equations on the left, and a "before and after" physics diagram illustrating symmetry conserved quantity on the right.
First derived by Emmy Noether, for every symmetry a theory possesses, there's an associated conserved quantity. Here's the profound link.