Universe Expansion

Universe Expansion

Illustration of a galactic collision, showing one galaxy colliding with the Milky Way, creating a loop of stars and cosmic material against a black background.
Even with just a momentary view of our galaxy right now, the data we collect enables us to reconstruct so much of our past history.
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.
A digital visualization displays particle collision results with colored tracks and trails diverging from a central point against a black background, hinting at how B-mesons might break the standard model.
We have very specific predictions for how particles ought to decay. When we look at B-mesons all together, something vital doesn't add up.
Two images of the Sombrero Galaxy viewed edge-on. The top image, captured by JWST, shows a glowing blue center, while the bottom reveals a bright core with dust lanes.
The Sombrero is the closest bright, massive, edge-on galaxy to us. JWST's new image, taken with MIRI, finally shows what's under its hat.
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.
gravitational wave effects on spacetime
Gravitational waves are the last signatures that are emitted by merging black holes. What happens when these two phenomena meet in space?
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?
heavy neutral atom
There are a few small cosmic details that, if things were just a little different, wouldn't have allowed our existence to be possible.
When we see pictures from Hubble or JWST, they show the Universe in a series of brilliant colors. But what do those colors really tell us?
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.
pulsar orbiting a low-mass star in an X-ray binary system
In astronomy, a star's initial mass determines its ultimate outcome in life. Unless, that is, a stellar companion alters the deal.
Bright cosmic explosion with flames and smoke surrounded by stars against a dark, starry background.
Black holes are the most massive individual objects, spanning up to a light-day across. So how do they make jets that affect the cosmic web?
wormholes
Humans, when we consider space travel, recognize the need for gravity. Without our planet, is artificial or antigravity even possible?
A Rubik's cube with a red X floats in space, next to a planet and moon—each marked with green checkmarks—that boast their perfect round shape.
All the stars, stellar corpses, planets, and other large, massive objects take on spherical or spheroidal shapes. Why is that universal?
Two individuals examine a large panel of wires and components. Overlaid on the right is a chart with arrows and symbols, possibly depicting a scientific process or experiment.
Why hasn’t matter fallen apart over billions of years? The mystery might start with protons.
A vivid cosmic scene reveals colorful nebulae and stardust in vibrant shades of blue, purple, and orange, set against a backdrop of space. NASA observatories capture this celestial beauty, unveiling hidden holes in the vast tapestry of the universe.
NASA's space telescopes and observatories bring humanity unrivaled science images and scientific discoveries. Here's what should be next.
A vibrant cosmic explosion with bright colors radiating outward, set against a starry space background, captures the mystery of a bizarre supernova.
In the year 1181, a "guest star" was recorded in the constellation of Cassiopeia. Its modern supernova remnant is weirder than we imagined.
Diagram of the expanding universe concept with cosmic inflation, light cone, and time axis.
Almost everyone asserts that the Big Bang was the beginning of everything, followed by inflation. Has everyone gotten the order wrong?
ring nebula hubble jwst nircam miri
More than two years after JWST began science operations, our Universe now looks very different. Here are its biggest science contributions.
A panoramic image of the Milky Way galaxy, with an inset showing a zoomed view of distant galaxies, tells a cosmic story. This region, highlighted in textured detail, echoes the exploration themes of the Euclid mission.
What are dark matter and dark energy? The large-scale structure of the cosmos encodes them both, with ESA's Euclid mission leading the way.
Friedmann equation
The most common visual depictions of the history of the Universe show the Big Bang as a growing tube with an "ignition" point. Why is that?
The fabric of spacetime is four-dimensional, with three for space and only one for time. But wow, time sure is different from space!