Cosmology

Cosmology

A colorful, spinning galaxy with a bright orange core, existing for 12 billion years, is surrounded by smaller galaxies and star clusters against a black space background.
Large, massive, rotating galaxies like the Milky Way are common today. So how could one form a mere ~2 billion years after the Big Bang?
A cartoon of three cosmic phenomena (CMB, Baryon Acoustic Oscillations, Supernovae) pulling on a triangle. Text below reads: "Something has to give...
DESI, by mapping galaxies, has claimed they see evidence for dark energy evolving by getting weaker. But that's only one interpretation.
Colorful galaxy with dark dust lanes and bright stars, set against a deep space background.
Someday, we'll look back and see a young galaxy forming stars for the first time. JADES-GS-z14-0, the farthest ever, isn't early enough.
Einstein's general relativity has reigned supreme as our theory of gravity for over a century. Could we reduce it back down to Newton's law?
A grid of six Hubble Space Telescope images showcases different types of colorful nebulae with intricate shapes against a starry backdrop.
Some nebulae emit their own light, some reflect the light from stars around them, and some only absorb light. But that's just the beginning.
A tilted spiral galaxy gracefully tipped towards the viewer reveals a bright core and dark, dusty rings, set against the infinity of deep blue space.
When we see spiral galaxies, some are face-on, others are edge-on, but most are tipped at an angle. But which side is closest to us?
Composite image of spiral galaxy NGC 300. Left: wide view with area highlighted. Right: close-up of highlighted area. Bottom: magnified star field view. NASA and the Hubble Heritage Team.
The tiniest galaxies of all are the most susceptible to violence by their larger, bullying siblings. That's why we need them in isolation.
A vivid image of a bright, colorful galaxy with swirling red, blue, and white clouds of gas and dust, where galaxies collide amid distant stars in the dark, expanding universe.
The Universe is expanding, and individual, bound structures are all receding away from one another. How, then, are galaxies still colliding?
Text "Cosmic Origins" over a bright, colorful explosion effect with star-like patterns in the background.
Since the dawn of history, humans have pondered our ultimate cosmic origins. Now in the 21st century, science has gone beyond the Big Bang.
Green glowing orbs and funnel-shaped structures with light patterns floating in a vibrant green misty background.
There are some 26 fundamental constants in nature, and their values enable our Universe to exist as it does. But where do they come from?
Two images of the Sombrero Galaxy reveal its beauty: one with a bluish hue showcasing visible details, and the other with a reddish hue highlighting a different spectrum. Captured by JWST, these images offer an unmatched view of this spiral galaxy's complex structure.
One of the most promising dark matter candidates is light particles, like axions. With JWST, we can rule out many of those options already.
Laser guide star
Astronomers see spiral and elliptical nebulae nearly everywhere, except by the Milky Way's plane. We didn't know why until the 20th century.
warp field stars
Perhaps the most well-known equation in all of physics is Einstein's E = mc². Does mass or energy increase, then, near the speed of light?
anitmatter annihilation
From the tiniest subatomic scales to the grandest cosmic structures of all, everything that exists depends on two things: charge and mass.
A spacecraft with a large reflective dish orbits above Earth, exploring the starry galaxy and cosmic backdrop. Its mission? To map galaxies and teach us what the CMB can't, unlocking cosmic mysteries.
The CMB gives us critical information about our cosmic past. But it doesn't give us everything, and galaxy mapping can fill in a key gap.
MACS J0717 galaxy cluster dark matter
Dark matter doesn't absorb or emit light, but it gravitates. Instead of something exotic and novel, could it just be dark, normal matter?
Diagram illustrating how small fundamental particles are, showing scaling sizes from macroscopic matter to quarks. It details crystal, atom, atomic nucleus, and nucleon sizes in meters, ranging from 10^-9 m to
When we divide matter into its fundamental, indivisible components, are those particles truly point-like, or is there a finite minimum size?
black hole merger
The ultimate multi-messenger astronomy event would have gravitational waves, particles, and light arriving all at once. Did that just occur?
Astronomical image of a young star system with labeled features: jet, conical outflow, dark lane, possible spiral, disk, tail, and a scale marking 300 astronomical units.
A young, nearby, massive star, whose protoplanetary disk appears perfectly edge-on, was just viewed by JWST, with staggering implications.
View of Earth rising over the Moon’s surface against a black space backdrop, captured during an Apollo mission.
If humanity lives in an otherwise barren Universe, we'll have to forge philosophy that fills the void.
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?