triple system

Galaxy NGC 4254 lies 1.5 million light-years from the center of the Virgo cluster. It drags a long stream of cooling hydrogen — a sign that it's plowing headlong into the hot gas. Losing cold fuel quenches the birth of new stars.

The temperature at the center of a galaxy cluster reaches a hundred million degrees. These largest gravitationally bound systems are natural laboratories where nature hides 85% of its mass in invisible dark matter.

Two figure skaters on a lake frozen to the horizon. They are so far apart that their silhouettes turn into dots, and their mutual attraction becomes almost an article of faith. By Newton's law, they should circle in an unimaginably slow waltz. But telescopes see otherwise.

The three-body problem is the eternal stumbling block of celestial mechanics. Even Poincaré realized in the late 19th century that its chaos defies general analytical solutions. In this gravitational madness, islands of regularity appear only rarely — periodic orbits.

Two black holes smash head-on at full speed — while a third one circles nearby. In ordinary life, such a crash would produce a burst of gravitational waves (ripples in space, like the ripples from a stone thrown into a pond). But here, part of the ripple passes by the massive neighbor, and changes, like light in a funhouse mirror.

A huge rotating pancake of gas and dust surrounds a young star. In such a "maternity ward" for planets, rings and gaps are often seen, as if an invisible plow had carved furrows. These are usually attributed to already-formed planets that clear paths with their gravity.

Under sunlight, molecules inside bacteria, like the beaters of a kitchen mixer, capture energy and spin electrons in the right direction. But sometimes the spin gets disrupted — 'stuck' triplet particles appear. It's as if the beater momentarily froze and then jerked backward, splashing hot liquid and scalding the walls.

The binary star TIC 287869463 is a close pair: one star pulsates like a bell, while the other's gravity stretches it like an ocean tide. Usually, pulsations travel across a star as waves, but here one wave has frozen in place. Astronomers sifted through three years of data from the TESS telescope — light from 50,000 stellar pairs.

Two stars orbit a common center, accreting gas from a surrounding cloud. Rotating disks of gas form around each star and around the pair as a whole. From these disks, jets shoot out like hoses. Inside the disks, gas is constantly churned — that's the magnetorotational instability at work.

In the star cluster NGC 2158, which is over a billion years old, astronomers have counted how often stars live in pairs. The Hubble telescope stared at the cluster for a long time to catch even the faintest stars: those lighter than one-third of the Sun.

Two spotlights placed side by side: from a distance, their light blends into one patch, and it seems there's a single source. The same happens in space: about 10–20% of faint stars are actually close pairs of identical stars. Individually, they can't be resolved, but together they shine noticeably brighter than a single star with the same parameters.

Wide binary stars are like two dancers holding hands but standing at opposite ends of the hall. Their bond is weak, and any passerby can break them apart. Astronomers found 26 such pairs and tested how tightly they hold on. It turned out that 12 pairs dance by Newton's rules: their orbits can be calculated like those of planets around the Sun. But three pairs move too fast.

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.

In a star cluster, like on a crowded dance floor, massive stars rarely stay single. More often they whirl in pairs or triples, and the distance between them can be less than from Earth to the Sun. But how do they manage to get so close to each other? Simulations showed: it's all about the disk of gas and dust that envelops the pair. This disk, like a drain funnel, swirls the stars and slowly pulls them inward.

In the dark cloud NGC 6334I-North, 5500 light-years from Earth, the ALMA radio interferometer spotted something unexpected: around a young massive star, a disk of gas and dust is swirling, and inside it are seven dense clumps. Each one could become a star. This is what the birth of a stellar family looks like, and an unusually large one at that.

In the dark room of the early Universe, the first spark flickered. A few hundred million years after the Big Bang, when space was filled only with hydrogen and helium, Population III stars were born: metal-free giants whose light first tore through the primordial darkness.