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Galaxy Formation
Contracting gas clouds don't just make a single star, but a spectrum, with all different masses. Early on, that spectrum differed. But why?
It's the Universe's ultimate chicken-and-egg question: what came first, the galaxy or the black hole? One Little Red Dot proves the answer.
Astronomers study our cosmic history through stellar and galactic archaeology. But we can't conduct archaeology in space. At least, not yet.
In physics, we reduce things to their elementary, fundamental components, and build emergent things out of them. That's not the full story.
Messier 77 is one of the largest nearby spiral galaxies, with an active, brilliant core. Here's what JWST's incomparable eyes saw inside it.
On cosmic scales, only dark matter (or something equivalent) gives us the Universe we observe. Now, the Sunyaev-Zel'dovich effect agrees.
Most massive galaxies are spiral or elliptical shaped. But peculiar galaxies showcase the beautiful violence that helps explain our cosmos.
Over billions of years, fewer stars form, galaxies mutually recede, and the Universe becomes ever darker. Here's how fast it all happens.
The discovery of CDG-2, a galaxy that's more than 99.9% dark matter, could reveal a new population of ultra-faint galaxies. But is it real?
Forget about the terawatt lasers we're making on Earth. The Universe makes natural ones thousands of times more powerful than the Sun.
Long after the last star burns out, the Universe will experience its end state: a heat death. Will everything prior then be meaningless?
Here in our modern Universe, it's cosmic dust that forms planets, complex molecules, and enables life. But how did the Universe create it?
Many collaborations have used JWST to take deep-field images: some wider and some deeper than others. Here's how it can surpass them all.
The Universe formed stars, galaxies, and even galaxy clusters extremely early on in our cosmos. This new marvel is one more JWST surprise.
Just like animals, galaxies often have bizarre, unusual, or even unique properties. But finding many, all at once, really does raise alarms.
Outer space begins just over 100 kilometers up, but what we can see extends for billions of light-years. Here's what all of it looks like.
Even in an expanding Universe, we expect both redshifted and blueshifted galaxies. But nearly every one we see is redshifted. Here's why.
Back in 1604, Johannes Kepler discovered the Milky Way's last naked-eye supernova. Here's how NASA's Chandra sees it over the 21st century.
Even the youngest galaxies are often dust-rich, even with very low levels of heavy elements. Nearby dwarf galaxy Sextans A explains why.
Astronomers have found starless gas clouds before, but Cloud 9 might be the most pristine one of all, with big lessons for cosmic history.
In a galaxy less than 300 million years after the Big Bang, oxygen's presence abounds. That's expected; its absence would truly be profound.
There will always be "wolf-criers" whose claims wither under scrutiny. But aliens are certainly out there, if science dares to find them.
Our Universe doesn't just expand and cool, but the expansion itself is accelerating. Can stars form under such structure-erasing conditions?
Although American Thanksgiving only comes once a year, the scientific rules that make our Universe possible are always worth appreciating.
Such massive, early supermassive black holes have puzzled astronomers for decades. At last, we've finally figured out how they form.
Spirals, ellipticals, and irregulars are all more common than ring galaxies. At last, we know how these ultra-rare objects are made.
Weird-looking galaxies, with tentacle-like tails or prominent dual streams, appear like jellyfish or bunny ears. But that’s just the start.
For over 10 billion years, the cosmic star-formation rate has been dropping and dropping. Someday, the final star in the Universe will die.
Stellar streams are faint trails of stars that appear to "stream" out of galaxies. A new one, escaping galaxy M61, may point to many others.
The planet, the Solar System, and the galaxy aren't expanding. But the whole Universe is. So where does the dividing line begin?