Universe Expansion

Universe Expansion

Two visualizations map the cosmos, displaying color-coded cosmic microwave background radiation. Blue and orange patches indicate temperature variations across a spherical and an oval projection.
It's difficult to project a sphere onto a flat, two-dimensional surface. All maps of the Earth have flaws; the same is true for the cosmos.
We understand many things about our Universe, and our home within it, extremely well. The number of stars in the Milky Way isn't among them.
Map highlighting an area in Europe, centered on the Netherlands and surrounding countries, with a red overlay labeled "PDF.
Common knowledge says the maximum size of a PDF is as big as 40% of Germany — but that’s a gross underestimate.
branching parallel universes
The Multiverse isn't just a staple of science fiction; there's real-life science behind it, too. Here are 10 facts to expand your mind.
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?
Over a century after we first unlocked the secrets of the quantum universe, people find it more puzzling than ever. Can we make sense of it?
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?
Two side-by-side images of the Pillars of Creation in the Eagle Nebula showcase different views with vibrant colors and star-filled backgrounds, embodying the great paradox of beauty within science.
Our scientific instruments are constantly improving, revealing nature's workings as never before. Without them, we'll remain in the dark.
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.
Illustration shows a supermassive black hole with a captured star and hypervelocity star, near the Large Magellanic Cloud, with double star orbits labeled. Earth is visible in the foreground.
Just 165,000 light-years away, the Large Magellanic Cloud is suspected to house a supermassive black hole. At last, evidence has arrived.
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.
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.
A galaxy with bright stars and swirling clouds of dust creates the largest galactic mosaic, set against a dark space backdrop.
The full extent of the Andromeda galaxy, the nearest large galaxy to our own, has been entirely imaged with Hubble's exquisite cameras.
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?
A spiral galaxy with a luminous core, surrounded by swirling arms and smaller galaxies, forms a mesmerizing bullseye ring galaxy, set against a backdrop of stars in space.
Ring galaxies are rare, but we think we know how they form. A new, early-stage version, the Bullseye galaxy, provides a new testing ground.
first contact
Only 5% of the Universe is made of normal "stuff" like we are. Could there be dark matter or dark energy life, or even aliens, out there?
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.
super earth mini neptune transit spectroscopy
Seeking life beyond the Solar System, we first look to the closest star systems with Earth-like planets. Here's why that's not good enough.
A colorful cosmic scene features a bright super star cluster with glowing stars surrounded by swirling red, orange, blue, and gray nebulous clouds.
There are only four super star clusters in all the Local Group: rarities today. Here's what the youngest, the just-discovered N79, shows us.
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.