xrism

In the basement of the laboratory, an 8 tesla magnet hums. Inside it, like a bell in a bell tower, hangs a hollow copper cylinder tuned to a single note. If an axion, a dark matter particle, flies by, the cylinder responds with a faint ring. The trouble is that ordinary copper muffles this ring: at high frequencies, current flows only through a thin skin of the metal, and losses grow.

A globe sits on a table, and a ruler lies beside it: one is curved, the other straight. X-ray telescopes have lived with this mismatch for years. Their mirrors gather light onto a curved surface, like the globe, while the detectors that catch that light have been flat, like the ruler.

The electron beam of a microscope usually flies through emptiness, like a courier on an empty highway. Any air molecule is a bump that makes it bounce and lose direction. So before, to examine a sample, you had to freeze it, dry it, or coat it with metal—and still you could only look in a vacuum.

The night forest is full of fireflies, but before, we only saw those that happened to be in the beam of a flashlight. That was the case with ultraluminous X-ray sources: points in other galaxies that shine in X-rays more brightly than a stellar-mass black hole can steadily emit. Telescopes looked at galaxies chosen for other purposes, missing most of the fireflies.

Gamma rays are the most energetic light in the Universe. But one part of them, the medium-energy range, long remained invisible: instruments couldn't catch them, leaving a gaping hole in the sky. Scientists call it the "MeV gap," named after the unit of energy these rays carry. The new camera works like a three-layer detective.

The night sky is full of deceptive lights. Astronomers were searching for galaxies that ignited in the first few hundred million years after the Big Bang: their light has traveled to us for nearly 13 billion years. Six faint smudges were selected from images taken by the Hubble and Spitzer space telescopes.

A synchrotron beam is like a jet of water from a hose: wide and awkward for fine work. To examine a tiny sample, you need a fine needle, not a hose. In the new setup, the needle is a glass capillary — a tube through which light glides, reflecting off the walls like a voice echoing down a long corridor.

The universe is like a vast invisible scaffold. We don't see it directly, but we know it's there: galaxies and clusters hold together thanks to it. This scaffold is dark matter. The most popular version says it is "cold," made of heavy, slow-moving particles.

May 2022. The space polarimeter IXPE, the spectroscope NuSTAR, and the monitor NICER simultaneously stared at one spot in the sky — at the black hole in the Cygnus X-1 system, where it orbits a blue supergiant in a close binary system with a period of 5.6 days.

Four faint streaks on an image — that's all an astronomer sees. Like a sculptor reconstructing the shape of invisible glass from four shadows.

At the heart of the giant galaxy Hydra-A, there's a hive of activity. A supermassive black hole shoots out two powerful plasma jets. They punch through the surrounding cloud of hot gas and inflate giant bubbles within it.

X-ray magnetic circular dichroism is a precise tool that has long allowed the separation of spin and orbital magnetic moments. However, the classical approach resembles judging an orchestra by its volume: it relies on sum rules, reducing the entire fine structure of the spectrum to a couple of integrals.

The Universe is a giant labyrinth of curved mirrors. The mass of galaxies and clusters distorts the light of distant quasars, as if toying with our perception of the cosmos. Hidden in this hall of mirrors is the key to the greatest mystery: dark energy, which is pushing space apart ever faster.

A tiny star spirals around a giant rotating black hole. Slowly, it moves closer in a spiral, and this dance lasts thousands of years. All the while, waves ripple through space, like ripples on water, but these are gravitational waves. They can be "heard" with special detectors.

A powerful laser strikes a diamond like a sledgehammer, with matter itself serving as the anvil. The impact lasts only an instant but generates pressures a million times greater than atmospheric. Physicists have long dreamed of peering into that moment to see how atoms rearrange under the onslaught. The X-ray beam here is like a camera flash.

A fire hose blasts into a snowdrift. The water doesn't just shove the snow aside — at the point of impact, spray, steam, and a roar are born. That's roughly how jets behave: narrow streams of matter shooting out from around a black hole at enormous speeds.

A tiny coin circles a heavy bowling ball. The coin is a small black hole or a neutron star, and the ball is a supermassive black hole at the center of a galaxy.

In galaxy NGC 3583, telescopes detected an unusual X-ray source: its brightness periodically spikes and then fades almost completely.

A giant city of thousands of galaxies is shrouded in an invisible cloud of scorching gas. This gas is like the air in a room: it can be calm, or it can churn with drafts. Astronomers aimed the latest X-ray "thermometer" at such a city — the cluster Abell 1795—and measured how fast the gas moves there.

Listening to the cosmos requires patience and a finely tuned ear. Astronomers chose the most sensitive low-frequency instrument for this: the OVRO–LWA antenna array — 352 dipole antennas scattered across two and a half kilometers of California desert.

A neutron star is a city the size of Manhattan, compressed to such a density that a teaspoon of its material weighs as much as Mount Everest. To understand what it's made of inside, scientists measure its radius. But there's a catch: many measurements suffer from systematic errors, like trying to measure the height of someone who keeps fidgeting and bending over.

Tiny invisible bullets pass straight through the Sun, barely noticing its matter. These are axions — hypothetical particles so light and elusive that they are often compared to ghosts.

When a planet slips behind the edge of its star, the star backlights the planet's atmosphere, just as a setting sun illuminates clouds on the horizon. This brief moment, lasting only minutes, carries the imprint of the gases through which the starlight has passed.

A flashlight beam aimed through frosted glass turns into a blurry spot with every extra millimeter of thickness. Scintillators, materials that convert X-rays into visible light, behave much the same way. They underpin medical imaging, baggage screening, and detectors at particle accelerators.

Dark matter is invisible, but its gravity governs the motion of galaxies. What it's made of is a mystery. One idea: it consists of ultra-light particles akin to axions.

A lighthouse that changes the color of each flash in time with its rotation: that's one way to describe what astronomers saw when they pointed the latest X-ray telescope, XRISM, at the pulsar Hercules X-1. This object is a neutron star pulling matter from a companion ordinary star.

The solar wind, a stream of charged particles from the Sun, slams into the tenuous gas that fills the space between the stars. The collision produces a faint X-ray glow. For astronomers, this is like fog in front of headlights: it obscures distant objects.

When matter is heated to millions of degrees, it turns into plasma — a mix of free electrons and ions, like a boiling soup of charged particles. You can't measure the temperature of such a 'soup' with an ordinary thermometer, but you can shine X-rays through it.

A handful of coins accelerates to one-fifth the speed of light. That's what Coracle interstellar probes will be like — tiny spacecraft weighing just a few grams, each with an ultrathin sail film. A powerful laser beam pushes them forward: light presses on the sail like wind fills a yacht's sails, except instead of air, it's a stream of photons.

Warm rock and cold sand cool at different rates at night. An instrument orbiting Mars measures this heat, revealing whether the surface is loose dust, a dense crust, or solid rock. But thermal images have a resolution of 100 meters per point: an entire football stadium fits into a single pixel. Fine details (the beds of ancient streams, the edges of lava flows) are simply invisible.

The neutron star 4U 1735-44 is gobbling up matter from a companion star. The matter spirals into a flat disk, like water going down a bathtub drain. But this disk shines in X-rays, and astronomers have for the first time measured how "combed" those rays are: that is, how polarized.

At the very heart of the Milky Way, something is continuously glowing in gamma rays. This light is special: its energy is exactly 511 thousand electronvolts. Such energy is produced when an electron meets its antimatter counterpart, a positron, and they annihilate, leaving behind a flash of light.

Conventional X-ray fluorescence analysis works like a meticulous scribe: to learn the composition of a picture, it walks over every square centimeter and logs whether lead or copper is present. For a flat sheet, that's tolerable, but for a three-dimensional object, it's torture.

An ordinary camera flash lingers for hundredths of a second, but for atoms, that's an eternity. Inside molecules, electrons jump in attoseconds: billionths of a billionth of a second. To capture that, you need a light pulse shorter than the event itself. Physicists take an electron beam in a linear accelerator and compress it so that individual bunches become thinner than a hair — in time.

Light from distant stars travels for millions of years, but X-rays can't be caught with ordinary glass: they pass right through it like a bullet through paper. That's why X-ray telescopes need special lenses: stacks of tiny prisms that gently deflect the rays and focus them to a single point.

At the center of the distant galaxy MCG-6-30-15 lies a supermassive black hole. Around it swirls a disk of incandescent gas, and above the disk hangs a cloud of even hotter particles — the corona. In February 2024, three X-ray telescopes (XRISM, NuSTAR, and XMM-Newton) observed this system simultaneously.

The center of our galaxy is a crowded kitchen where several dishes are simmering at once, and their steam blends into a single cloud. X-rays from the exploded star's remnant, from the stellar wind around the supermassive black hole, and from hot gas between stars all overlap.

In the first few hundred million years after the Big Bang, the cosmos was like a noisy teen club: galaxies flared up, collided, and churned out stars by the hundreds.

When an exoplanet briefly eclipses its star, starlight passes through its air and absorbs its chemical taste. This technique, the transit method, is the core of how the James Webb telescope works.

When a massive star dies, a supernova explosion occurs, so powerful that a single flash outshines an entire galaxy. In this fire, billions of axions are born — invisible particles that leave almost no trace. Every second, trillions of these tiny things fly right through each of us, completely unnoticed.