gas accretion

In a village smithy, the blacksmith pumps the bellows, and sparks fly into the darkness. So too in the galaxy AEON-z5, an active nucleus, like a red-hot forge, hurls metal-enriched material far beyond the stellar disk. The James Webb Space Telescope caught this process just a billion years after the Big Bang, when the universe was still in its infancy.

A filament of the cosmic web stretches through the young universe, and strung along it like beads on a necklace are galaxies. In the core of the SSA22 protocluster, which in a few billion years will become the center of a massive cluster, these beads are still hot and dusty: stars are being born inside them, and cold gas serves as fuel.

A hydrogen bubble on a platinum electrode behaves like a swimmer trying to surface, but every time it almost breaks free, something below grabs its legs. In the lab, high-speed cameras captured this behavior: a millimeter-sized bubble hangs near the surface, even though buoyancy pulls it upward with a force thousands of times stronger than surface tension can hold.

A harbor lives by the tide schedule. Water rises and falls, and with it everything changes: the level at the dock, the composition of the sediment on the bottom, even the salinity in the far corners. A galaxy works similarly, except instead of water it has gas, and instead of the Moon, it has its own stars and neighboring clouds.

A ground-based image of a distant galaxy looks like a view through frosted glass: the atmosphere smears details, hiding the internal structure. Astronomers have long wanted to know where exactly star formation shuts off in galaxies, but ground-based telescopes could not resolve the subtle color gradients.

At the center of the Milky Way, where the supermassive black hole Sagittarius A* churns gas clouds like a millstone, astronomers have caught an irregular pulse. Gamma-ray emission, the most energetic light in the universe, arrives not as a smooth wave but with a break, as if the Galaxy's heart beats with arrhythmia.

At the center of a galaxy, where a supermassive black hole spins a disk of scorching gas around itself, giant stars sometimes form. They are unlike ordinary stars: the disk continuously feeds them with matter, and a star can grow to hundreds of solar masses, staying bright as long as the gas flow lasts.

Around every galaxy lies an invisible corona of cold gas. It extends far beyond the stellar disk and serves both as a fuel depot for new stars and as a graveyard for ejected material.

In the first half-billion years after the Big Bang, galaxies grew like crazy. Gas fell in rapidly and collapsed into stars without any resistance. This period is called 'unimpeded star formation.' It's like frying pancakes on a scorching skillet without a lid: splatters fly, but nothing holds them back.

Around a just-ignited star swirls a vortex of dust and gas. This vortex, the protoplanetary disk, grows by accreting material from the surrounding cloud.

A bright lantern in thick fog seems dim, while a weak flame in clear air can be seen a kilometer away. A similar oddity baffled astrophysicists almost half a century ago.

The JWST spectrograph caught a barely perceptible dip in the spectrum of a distant galaxy — two lines, like shadows cast by cold gas. These are the sodium lines, the very yellow light of streetlamps. Here, at the edge of the visible Universe, they betray the slow exhalation of a galaxy returning matter to space.

Ten billion years ago, the universe was speckled with strange crimson sparks. The JWST spotted them in images at distant redshifts — compact sources blazing like entire galaxies yet no larger than a tiny central region. Astronomers nicknamed them “little red dots.” Their nature long defied explanation.

In the center of almost every large galaxy lurks a supermassive black hole, whose gravitational abyss was first mathematically described by Karl Schwarzschild. When it swallows gas, a dazzling active nucleus is born — a quasar.

Massive gas outflows from active galactic nuclei are a key regulator of galactic evolution. They sweep out the interstellar medium, quench star formation, and dictate the growth of supermassive black holes.

A giant baby planet is still pulling in leftover building material from its surrounding cloud. That's the scene the Hubble Space Telescope captured when it aimed its cameras at an object catalogued as SR 12 c. This companion planet orbits a young star at a wide distance — farther out than Neptune is from the Sun.

The stellar halo of the Milky Way is a galactic palimpsest: an ancient manuscript where earlier layers lie hidden beneath the visible text. For a long time, the Gaia-Sausage-Enceladus (GSE) structure was thought to be the final entry in this manuscript, the scar of a single catastrophic merger.

Among the icy chunks hurtling through the void, there are special travelers — interstellar comets. They were born around distant stars and happened to wander into our neighborhood. One of them, 3I/ATLAS, came under the gaze of telescopes as it approached the Sun. Its material, frozen gases and refractory dust, began to evaporate, leaving a glowing tail behind.

Globular clusters are dense 'balls' of hundreds of thousands of stars that orbit the center of the Milky Way. Some were born in our Galaxy, others were captured when the Milky Way swallowed dwarf satellite galaxies. They can be distinguished by chemical composition, but astronomers now have a new tool — dynamical age.

A galaxy is like a glowing pancake studded with stars. If you look at it face-on, you see everything at once — both the bright spiral arms and the dark dust lanes. But tilt the pancake, and the picture changes: layers overlap, light blends together. This very effect, it turns out, creates the illusion of a tight link between radio and gamma-ray emission in distant star systems.

A fountain shoots from the center of the city at a speed thousands of times faster than a courier bike. Such a 'fountain'—a stream of gas accelerated to 5500 kilometers per second — has been spotted by astronomers in the galaxy GLIMPSED-329380.

Through a telescope, you can see a galaxy that looks like a giant glowing pinwheel. Its disk stretches thirty thousand light-years across — a third of the diameter of our Milky Way. But the most astonishing part: this pinwheel already existed just two billion years after the birth of the universe.

The mystery of how black holes grew so fast in the early Universe might be solved by quasi-stars. These are giant gas cocoons with a black hole tucked inside. Matter falling into the hole heats up and blasts out so much light that it prevents the cocoon from collapsing. Such an object weighs thousands of Suns and outshines an entire galaxy.

A distant galaxy, similar to our Milky Way, is blowing gas into space like a hair dryer blowing dust off a table. Seven beams of light from an even more distant object pierced this gas cloud, and astronomers saw that the gas flow is narrow, like a jet from a hose, not wide like a fan.

Deep in the constellation Ophiuchus lies the galaxy NGC 6447. Until recently, it was quiet and unremarkable, like a house with its windows dark. But over the past 14 years, something has ignited at its center, and now it's visible in infrared light.

The young star RY Tau is like a finicky spinning top. Around it whirls a flat disk of gas and dust — the leftovers of the cloud from which the star was born. The star pulls some of the disk's matter toward itself like a vacuum cleaner, and flings some back out in a narrow wind cone like a fountain.

In the dark cloud G318.049+00.086, where no star has yet formed, dust and gas have arranged themselves into four long filaments. They converge into a dense central hub, like four rivers emptying into a lake. Gas flows along these filaments toward the center: the flow speed reaches 10–20 kilometers per second per parsec of length.

At the center of galaxy VV 340a lies a supermassive black hole — an object with gravity so strong that even light cannot escape it. It emits a relativistic jet: a narrow stream of matter accelerated to near-light speeds.

Back in the last century, Vera Rubin discovered that stars on the outskirts of galaxies rotate too fast, as if held by some invisible substance. Since then, dark matter has remained a puzzle. Usually, its origin is linked to new particles or forces. But a new study points to a simpler source — the geometry of space itself.

The young binary star IRS 44 in the constellation Ophiuchus resembles a bustling kitchen: streams of gas, like jets of dough, fall onto a rotating disk, and where they strike, heat is born.

In the first moments after the Big Bang, the universe may have given rise to objects unlike the familiar stars — dark stars.