Galaxy Formation

Galaxy Formation

Side-by-side comparison of the Pismis 24 nebula as seen by Hubble (top left) and JWST (bottom right), with an overlay highlighting image differences.
JWST isn't the first telescope to peer into this factory of star-birth some 5500 light-years away, but its views are the most educational.
An artist's impression of a cluster of stars.
With several seemingly incompatible observations, cosmology faces many puzzles. Could early, supermassive stars be the unified solution?
As we look to larger cosmic scales, we get a broader view of the expansive cosmic forest, eventually revealing the grandest views of all.
A grainy black and white image shows SPHEREx comet 3I/ATLAS gleaming at the center, surrounded by stars appearing as streaks due to long exposure.
Designed to map galaxies, the SPHEREx mission's first science result is instead about interstellar interloper 3I/ATLAS. No, it's not aliens.
An image of an ancient black hole
At the center of Hubble's famous "cosmic horseshoe," a very heavy supermassive black hole has been robustly measured. How is it possible?
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On the largest scales, galaxies don't simply clump together, but form superclusters. Too bad they don't remain bound together.
A dense field of distant galaxies and bright stars against a black background, as captured in a JWST early galaxies deep space telescope image.
Originally, the abundance of bright, early galaxies shocked astronomers. After 3 years of JWST, we now know what's really going on.
A dense star field and distant galaxies with bright galaxy clusters and several white squares highlighting specific points in the image.
For hundreds of millions of years, a cosmic fog blocked all signs of starlight. At last, JWST found the galaxies that cleared that fog away.
The tiniest galaxies of all are the most severely dominated by dark matter. Could black holes be the cause of the extra gravity instead?
Image of two large elliptical galaxies surrounded by several smaller, colorful galaxies and stars against a dark background in space.
The first galaxies were irregular blobs of gas and stars. But modern features, like spiral arms and bars, appeared earlier than expected.
An artist's impression of a cluster of stars.
If the Universe is 13.8 billion years old today, but different ages the farther we look back, what does it mean for a star to be the first?
A split image shows a star field on the left and a COSMOS-Web survey area diagram on the right, with labeled NIRCam and MIRI footprints alongside the moon for scale, highlighting galaxies explored by JWST science.
The COSMOS-Web has just finalized their release of their full field: larger and deeper than any other JWST program. Here's what's inside.
Edwin Hubble and Andromeda galaxy
For decades, astronomers have claimed the Milky Way will merge with Andromeda in ~4 billion years. Here's why, in 2025, that seems unlikely.
A digital 3D visualization shows translucent blue shapes in front of a blue wall and floor, illustrating an abstract concept—perhaps a universe without dark matter.
In our Universe, dark matter outmasses normal matter by a 5-to-1 ratio, shaping the Universe as we know it. What if it simply weren't there?
An artist's impression of a cluster of stars.
Many were hoping that JWST would find the first stars of all. Despite many hopeful claims, it hasn't, and probably can't. Here's how we can.
A colored pixelated grid with rectangular outlines; a legend in the top right labels blue as F115W, green as F200W, and red as F277W—capturing data from the JWST to record a distant galaxy.
Coming from just 280 million years after the Big Bang, or 98% of cosmic history ago, this new, massive galaxy is a puzzle, but not a mirage.
Two bright, irregularly shaped nebula clouds with blue, purple, and pink gases dominate the dark space background, where dazzling stars twinkle—reminding us that in space, appearances can deceive.
There's an old saying that "what you see is what you get." When it comes to the Universe, however, there's often more to the full story.
Scatter plot with dark blue data points and black dashed elliptical contours centered on the origin, with axes labeled ξ (') horizontally and vertically—similar to plots used by astronomers in studies of the smallest galaxy ever discovered.
With stars, gas, and dark matter, galaxies come in a great array of sizes. This new one, Ursa Major III/UNIONS 1, is the smallest by far.
A dense field of stars and galaxies is visible against a black background, with some bright stars showing lens flares.
The COSMOS-Web survey is now complete, combining JWST and Hubble infrared data. Its spectacular views show us the Universe as never before.
A vast view of deep space, captured in one of NASA's most important images, displays numerous galaxies of varying shapes and colors against a dark backdrop scattered with distant stars.
The Hubble Space Telescope, launched in 1990, was originally seen as a colossal mistake. This one image, taken in 1995, changed everything.
The spiral galaxy, surrounded by dim stars and interstellar dust, stands out against a dark background, shining brighter than astronomers once imagined.
The most famous Hubble images show glittering stars and galaxies amidst the black backdrop of space. But more was captured than we realized.
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?
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.
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?
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.
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.