flare

A beacon at the edge of the galaxy blinks without a schedule: sometimes silent for years, sometimes emitting hundreds of flares in a single day. Such a beacon needs a watchman who never sleeps and never gets distracted.

In active galactic nuclei, supermassive black holes are surrounded by a dense ring of dust that acts like a curtain: it hides everything happening at the center. If a star ventures too close to the black hole, tidal forces tear it apart, and the resulting flare is usually visible in optical and X-ray light.

In a pot on the stove, water starts to churn from the bottom long before the whole thing boils. Bubbles of steam rise from the base even though the burner itself hasn't heated up yet.

Inside a solar flare, magnetic field lines snap like stretched rubber bands and reconnect — releasing in minutes enough energy to power humanity for millions of years. In the lab, this process, magnetic reconnection, could long be triggered but not stopped. Now physicists have a switch.

An avalanche in a sandpile starts with a single grain. No one knows exactly where it will slip or how big the slide will be. But if you keep pouring sand, the pile itself reaches a state where avalanches of all sizes, from tiny trickles to massive collapses, follow the same law.

On the surface of the Moon and asteroids, you can find pits smaller than a pinhead but with shiny, melted rims. Such marks are left by tiny meteorites, but the exact impact speed at which melting occurs remained unclear.

A black hole paired with a star works like a pump: it pulls gas from its companion, swirls it into a glowing disk, and occasionally ejects some of that matter in two narrow jets. In 2021, the system 4U 1543-475 put on such a show.

The night sky looks smooth, but it's actually clumpy — vast communities of galaxies that bend light from distant objects like lenses. When a short, powerful radio burst goes off somewhere in the universe, its path to an Earth telescope can pass near such a clump.

The solar corona lives its own turbulent life. Magnetic fields here are governed by the motions of the dense surface — the Sun's photosphere — but occasionally they rewrite the magnetic pattern themselves.

At the center of a distant galaxy, where a supermassive black hole weighing a hundred million suns spins, space is threaded with magnetic fields. They coil into tight vortices, like a drain in a sink, but instead of water, there's plasma whipped up to near-light speeds.

A branch falls into a whirlpool. It gets spun and broken, but sometimes a powerful fountain of water bursts from the center. Similarly, a black hole tears apart a passing star, and occasionally a blinding plasma jet, a jet, shoots into space.

The death of a massive star is not just the flash of a supernova, but also the birth of a black hole.

The cosmos is full of screams we can't hear. Every time a black hole tears a star apart, a blinding flash is born, and often — a narrow relativistic jet, shooting out thousands of light-years. But if that searchlight is aimed away from Earth, we see only a faint afterglow — a radio echo arriving with a delay.

In the quiet of cold molecular clouds, where interstellar gas under gravity condenses into dense clumps, the birth of massive stars is one of the great puzzles of astrophysics.

The flash lasts a thousandth of a second, but in that instant it releases as much energy as the Sun emits in a day. Such signals, fast radio bursts, have been caught by telescopes since 2007, and their source remains a mystery. A new study offers an elegant answer: it's all about a cosmic amplifier.

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.

In 2017, the Antarctic neutrino telescope IceCube detected a particle with an energy of about 290 TeV arriving from deep space.

Somewhere deep in space, a radio beacon flashes for a fraction of a second, and then goes dark. Such signals are called fast radio bursts. They come from other galaxies and last from microseconds to milliseconds.

Active galactic nuclei (AGN) are the universe’s powerhouses: their X-ray coronae blaze millions of times hotter than stellar atmospheres. But what strikes the spark? A ten-day X-ray campaign by the XRISM and XMM-Newton satellites, aimed at NGC 3783, provided the answer: it’s actual thunderstorms.

The enigma of fast radio bursts (FRBs) is not just a question of 'what exploded?' It’s a drama of energy transfer under extreme conditions, where the slightest stumble leads to collapse.

A lighthouse sends its beam through a storm of its own mirrors: that's roughly how fast radio bursts behave when trying to leave a magnetar's vicinity. A magnetar is a neutron star with a magnetic field a quadrillion times stronger than Earth's.

Blazars are long-lasting beams from black holes at the centers of galaxies. Gamma-ray bursts are the briefest flashes from supernova explosions or neutron star mergers. The former act like eternal spotlights, the latter like camera flashes.

A tightly twisted phone cord snaps and scatters sparks. Magnetic fields on the Sun behave the same way: they twist, break, and reconnect, powering flares. For the first time, astronomers have witnessed this process directly. One loop was twisted by 540 degrees — one full turn and then half again. That’s three times more than previously thought possible.

A sunspot cools, and above it a dark filament, a prominence, hangs for weeks. Inside it, like a compressed spring, hides the magnetic field. It can be laid out in neat arches, or it can be twisted into a tight rope.

A radio telescope is not just an antenna, but a computing machine that builds an image from millions of equations. This mathematical prism is as fragile as glass: one wrong digit in the calibration, and the real sky splits, spawning phantom sources.

The Sun is a boiling cauldron of hydrogen and helium, where scorching gas is caught in magnetic snares. When invisible ropes reconnect, energy comparable to billions of thermonuclear explosions is released. Where does it go?

Since their discovery in 2007, fast radio bursts (FRBs) have teased astrophysicists with their elusive nature. These millisecond signals arrive from distant galaxies and carry colossal energy: for an instant, they radiate as much as the Sun does in a month.

A bonfire that no one sees, but everyone feels the warmth: that's how astronomers found a flare in a distant galaxy. Not by its light, but by the infrared radiation of heated dust. The galaxy SDSS J010320.39+140152.5 caught attention when its center suddenly blazed in the infrared, as if someone had thrown logs onto an invisible fire.

A black hole rips apart a star, and we see a dazzling flare. Then, a couple of years later, when everyone has forgotten about it, radio telescopes suddenly pick up a new signal, like an echo from the past.

A streetlamp flickers as someone walks past. That's roughly how our nearest star, Proxima Centauri, behaves: it flares in response to the motion of its planets. Astronomers observed the star with a highly sensitive instrument, the ESPRESSO spectrograph. It captures light and splits it into colors, much like a prism.

A tiny black hole, no larger than an atomic nucleus, hovers in a cloud of hydrogen. It doesn't swallow everything around it; instead, it slowly radiates away, losing mass with every moment.

In December 2011, Comet Lovejoy boldly raced through the searing corona of the Sun. Right after — a flare. Scientists checked whether the comet could have caused it. The atmosphere of the Sun is threaded with taut magnetic loops, like a drawn bowstring.

A giant cauldron that barely smolders most of the time, but occasionally spits out showers of sparks. That is roughly how the supermassive black hole at the center of our galaxy — Sagittarius A*—behaves. It weighs four million times as much as the Sun and lies 26,000 light-years away.

At the center of many galaxies sits a supermassive black hole. When gas falls onto it, the gas heats up and shines brighter than an entire galaxy: this is an active galactic nucleus. Sometimes a true hurricane erupts from there: a stream of ionized gas racing at tens of percent of the speed of light.

At the center of the Milky Way lurks something invisible but extremely massive — about four million times heavier than the Sun. It is usually called a black hole and designated Sagittarius A*. But astronomers are not letting their guard down: what if it is not a hole but something more exotic, like a giant ball of ultralight particles — a boson star?

Two neutron stars — these are ultra-dense remnants of dead stars, each the size of a city but heavier than the Sun. Their existence was predicted back in 1934 by Fritz Zwicky. A teaspoon of this matter weighs billions of tons. When two such objects draw close before merging, their magnetic fields twist and snap like taut strings.

Around small, cool, but extremely restless red dwarfs, planets the size of Earth often orbit. Such a star is like a temperamental stove that intermittently erupts flares: powerful streams of light and particles batter the planet's atmosphere, as if someone splashed fire into a simmering soup pot.

A stream of scorching gas races away from a star, and suddenly stalls, as if it hit an invisible wall. That's exactly what researchers saw when they tried to reproduce a stellar eruption on a laboratory scale. They used a laser to create a plasma jet and shot it through a magnetic field — first weak, then strong, like that of many stars.

In a distant galaxy, at a distance that light takes 11 billion years to cross, something flashed. The Einstein Probe X-ray telescope caught a brief, needle-prick-like burst: it lasted only a few dozen seconds.