star formation gas

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 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.

At the center of an ultra-compact dwarf galaxy, a very dense stellar system spanning tens of light-years, there is a vacuum cleaner at work. But instead of dust, it sucks in gas shed by dying stars. This gas does not fly off in all directions; instead, it spirals into a funnel, a rotating disk that gradually settles onto the black hole.

Three cabinets full of rocks. In one, metallic grains and the gray mineral enstatite; in the second, the same grains but with rusty streaks; in the third, layered clays swollen with water. All three sets were pulled from meteorites that fell to Earth: chondrites. They were born in the same gas-and-dust disk around the young Sun, yet somehow turned out so different.

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 coldest, darkest corners of space, dust grains get covered in ice, like a window on a frosty day. This ice isn't just frozen water: it also contains carbon monoxide and carbon dioxide. From such ice, comets and planets may eventually assemble. But until now, it was unclear how the dust grain itself affects the ice that forms on it.

Red giants in the center of the Milky Way resemble distant lighthouses that brighten and dim. Their light pierces through dense dust, but standard distance-measuring methods fail here: the stars are too bright and unstable, and dust distorts the picture. Astronomers found a workaround.

In the dark kitchen of the Taurus molecular cloud, 450 light-years away, dozens of planetary systems are being prepared. Each young star is a chef, and its protoplanetary disk is a counter piled with flour-like dust and steam-like gas.

The explosion of a massive star is not just a flash: it's a blow to the surrounding gas. But until now, no one had looked at how the gas itself moves at the sites of such explosions. Now astronomers have gathered data on 33 nearby supernovae and for the first time measured the turbulence of the cold molecular gas around them.

At a concert, moving through a dense crowd is tough — the tighter the pack, the less you want to move. That's how active matter usually behaves: swarms of bacteria or robot flocks freeze in tight quarters. But one research group found the opposite effect.

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.

In the furnace of star formation, the heat reaches 900 degrees Celsius, like a glowing blast furnace. It is in this hellish heat that cosmic crystals are born. Astronomers have for the first time caught the moment when crystalline dust appears right during an accretion flare (when the star gobbles up surrounding gas) at the very young star EC 53, still cocooned in dense gas.

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.

Fifteen years of observations by the Gamma radiation telescope Fermi have revealed a crack in the floor of the Galaxy.

The mystery of antimatter in space has long puzzled astrophysicists: where do positrons come from, settling like snowflakes into our detectors? The answer might lurk in the most ubiquitous gamma-ray background. The Universe is soaked in diffuse light — the cosmic photon background (CPB).

Deep space, galactic center. A supermassive black hole is surrounded by a scorching disk of gas and dust. And then, through this fiery veil, a star shoots by every few hours — like an arrow loosed from the bow of gravity. Each passage triggers a dazzling X-ray flare that for a moment outshines the entire galactic nucleus.

Imagine an ancient manuscript, where a new story is written over an old text. Over time, the upper layer wears thin, and lines of the past show through. That’s exactly how globular clusters, the oldest stellar systems in the Universe, are structured, like a palimpsest.

Tiny seeds of life can cross the black void on icy wanderers like comet 3I/ATLAS. The James Webb Space Telescope found water and methane on it for the first time, and light analysis revealed an unusual gas composition.

In 2019, an unusual visitor, comet 3I/ATLAS, zoomed into the Solar System. It came from another star, and for the first time, astronomers were able to see what its dusty tail is made of.

A pot of porridge boiling over a high flame: bubbles carry grains from the bottom to the surface. A similar mechanism works on a neutron star. As it accumulates hydrogen and helium from a companion star, it occasionally triggers a powerful nuclear explosion — an X-ray burst.

Stars are born in cold clouds of cosmic dust and hydrogen. Inside these cocoons, protostars — the cores of future suns — were long thought to be just hot clumps. But it turns out many of them are powerful accelerators: they shoot out narrow jets of gas that, slamming into surrounding matter, produce invisible gamma-ray light.

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.

A vast city lights new streetlamps every night. But then a hurricane sweeps in, rips all the fuel from the warehouses, and the lamps go out one by one. Something similar has been spotted by astronomers in a galaxy whose light has traveled 12.5 billion years to reach us.

The Universe is singing. Not in the usual sense: its symphony is recorded in tiny density variations from which galaxies and ourselves grew. After the Big Bang, space was almost uniform, but quantum fluctuations during inflation left a faint pattern — slightly more matter here, slightly less there.

Elliptical galaxies are quiet stellar metropolises in retirement. By all rights, their light should be calm, reddish, like a sunset. But their spectra scream otherwise: in the far ultraviolet, these old-timers blaze like holiday lights. For three decades, astronomers have puzzled over this 'ultraviolet upturn' (UV upturn).

The James Webb Space Telescope peered into the era when the expansion of the Universe stretched the light of distant objects into the red, and found a scattering of strange sources — 'little red dots'. Their spectra broke the usual patterns: they are blue in the ultraviolet, but deep red in the optical, as if seen through a cherry veil.

Imagine a spinning top the size of a city, weighing more than the Sun and making hundreds of revolutions per second. That's a neutron star — the remnant of an exploded star. Occasionally, its rotation suddenly speeds up, as if something inside has switched. Astronomers call these jumps glitches and suspect that invisible vortices in the star's superfluid interior are to blame.

A pot of boiling porridge, where instead of grains there are layers of oxygen and silicon, and the fire beneath is about to go out, and the star will collapse in on itself. Until now, astrophysicist cooks have used a simplified recipe: they assumed that bubbles and eddies in the porridge obey one and the same average temperature throughout the depth.

The JWST telescope has spotted a multitude of bright galaxies in the young universe. Their ultraviolet light was barely absorbed by cosmic dust — defying previous expectations.

A galaxy is not a static picture but a bubbling cauldron where new stars are constantly born from tenuous gas. To understand how long this boiling will last, astronomers weigh the key ingredient — cold molecular hydrogen. It is invisible itself, but it is betrayed by carbon monoxide (CO), which shines in the radio range.

At the very heart of the Milky Way, something is glowing, but not with starlight; with gamma rays invisible to the eye.

In the scorching solar corona, where temperatures soar past a million degrees, float cold, dense clouds — solar prominences. They hang for weeks, neither falling nor dissolving, like icebergs in a boiling ocean. How they got there is a question that has puzzled astronomers for decades.

Chondrules look like frozen raindrops made of stone. They're about the size of a grain of sand, but they record the history of the first few million years of the Solar System. Once, these droplets floated in the scorching gas around the young Sun, then clumped into asteroids and fell to Earth as meteorites.

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.

An old chest of family heirlooms opens, and inside lie jewels that were thought to be as old as great-grandmother. But suddenly it turns out: the gold was remelted, the stones were recut, and this happened much later than thought. A similar story happened to the oldest particles in meteorites — calcium-aluminum inclusions, or CAIs.

Be stars are rapidly rotating luminaries with bright gas disks. Usually, a companion star spins them up: mass flowing from the neighbor whirls the star like a bullet in a rifled barrel. But there are also lone Be stars without a partner: their origin long remained a mystery. New research shows that solitaries can be born from a supernova explosion.

A star weighing a hundred thousand Suns lives bright and brief. Its finale is a rapid collapse into a black hole. But just before the end, it manages to wrap itself in a dense gas cocoon.

A river flows toward a whirlpool, but a dam with a notch blocks the way. Most water piles up before the dam, but some, gaining height, leaps over it and falls straight into the funnel. So it is with gas in a galaxy: it streams toward the center but hits a ring of stars and gas, like a dam. Usually, everything stops there, swirling into a dense vortex.

A newborn star is like a kitchen mixer: it whips up the surrounding cloud, and splatters fly in all directions. Only instead of batter, it's gas and dust. Previously, astronomers had only seen gas jets, and dust was considered too fragile: the shock wave should shatter dust grains into atoms.