Penrose process

A black hole pulls in anything that gets too close. But if you toss in not one object but a pair, one of them can fly back out, carrying off some of the hole's rotational energy. This trick, devised by Roger Penrose in 1969, works only because a black hole has a horizon — a boundary beyond which nothing returns. Now it turns out the horizon isn't necessary.

A black hole pulls in anything that gets too close. But if you toss in not one object but a pair, one of them can fly back out, carrying off some of the hole's rotational energy. This trick, devised by Roger Penrose in 1969, works only because a black hole has a horizon — a boundary beyond which nothing returns. Now it turns out the horizon isn't necessary.

When you blow up a balloon too quickly, its surface starts to quiver. Something similar happened to space in the first moments after the Big Bang: the universe expanded rapidly, and the very fabric of space began to ripple.

A spinning top whirls so fast that the air around it starts to rotate in unison. A black hole behaves in much the same way: if it spins, it can transfer its energy to particles that happen to be nearby. This process is called superradiance: it's like an echo in the mountains, but instead of sound, new particles are born.

Somewhere in the center of a galaxy, a black hole is spinning. It doesn't hang in a void — around it swirls an invisible swarm of dark matter particles. Until now, this swarm was described for non-rotating holes, but in reality, holes always rotate.

Somewhere in the center of a galaxy, a black hole is spinning. It doesn't hang in a void — around it swirls an invisible swarm of dark matter particles. Until now, this swarm was described for non-rotating holes, but in reality, holes always rotate.

A whirlpool gulps down water, but splashes most of it back out. That's roughly how a black hole behaves when too much matter falls onto it. In a new study, astrophysicists ran 32 computer simulations to understand how a black hole's parameters — mass, spin, and "appetite"—control these cosmic fountains.

A black hole is not a perfect vacuum cleaner. It is surrounded by a swarm of particles and fields, and this swarm alters its fate. In a new study, astrophysicists examined how a massive vector field, a hypothetical form of dark matter, behaves near a rotating black hole.

A whirlpool gulps down water, but splashes most of it back out. That's roughly how a black hole behaves when too much matter falls onto it. In a new study, astrophysicists ran 32 computer simulations to understand how a black hole's parameters — mass, spin, and "appetite"—control these cosmic fountains.

Light from afar bends around a black hole like a cyclist taking a sharp turn. Get closer, and it starts looping around an invisible sphere of photons. Every black hole has such a sphere, but usually it's wobbly: the slightest nudge sends light flying away or falling in.

Imagine a factory capable of producing a million parts per hour, yet it only makes a hundred. That's roughly how our Universe behaves when viewed through the lens of entropy — a measure of disorder that, according to physics, must only increase. The main "machines" of this factory are supermassive black holes.

295 000 meters per second. Not even particles in solar coronal ejecta move that fast. But at the center of the galaxy cluster H1821+643, hot gas does exactly that. The quasar at its heart takes a breath, and its breath stirs everything around for 60 thousand light-years.

The fastest wind in the Universe travels at 0,58 times the speed of light. It covers the distance from Earth to the Moon in two seconds. This wind is not a jet stream but a broad flow of gas erupting from the center of a galaxy. Not all black holes work the same: some create such hurricanes, while others produce narrow plasma beams.

A black hole is a place from which nothing can escape. But some theories allow that deep inside, at the quantum level, it might bounce and turn into its opposite — a white hole, which only spews out matter and light. A group of physicists built a computer model of such a transformation.

Water turns to ice at zero degrees — sharply, with no intermediate states. Something similar happens to complexity when we take a random quantum state of an entire system and look only at a part of it. As long as that part occupies less than half the system, its complexity grows smoothly. But as soon as the fraction crosses 50%, a jump occurs.

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.

The agony of a solitary black hole lasts forever. But in its final moments, as its mass evaporates according to the law discovered by Hawking, it manages to send a radio farewell signal. Not a quantum whisper, but a classical hum — if only there's a magnetic field nearby.

For a long time, cosmology was dominated by the belief, originating from Hawking: during the radiation era, primordial black holes do not grow.

Quantum vacuum is not absolute emptiness. It is more like a taut membrane that constantly ripples from invisible particles popping in and out of existence. Even in total darkness, this membrane trembles. Physicists decided to see how it behaves around a thin spherical shell, inside which is ordinary flat space, like in our room.

Imagine a steam engine where instead of a steel piston there is an event horizon, and the cylinder is curved space itself. This metaphor has gained mathematical flesh: physicists have for the first time constructed a complete set of reversible heat cycles with a Schwarzschild black hole confined in a spherical cavity.

A black hole is not just a vacuum cleaner. It glows faintly, emitting particles — this idea was proposed by Jacob Bekenstein, who connected the hole's temperature to its degree of disorder. Detecting such radiation in space is incredibly difficult.

A cosmic ray approaches a black hole almost tangentially. Instead of falling straight in, it lingers on an unstable orbit, like an acrobat balancing on a tightrope over an abyss. After a few loops, the light finally escapes toward a distant observer. Such rays produce multiple images of the same source, known as higher-order images.

Observations by James Webb showed: already 500 million years after the Big Bang (at redshifts z~10), the Universe was aglow with black holes with masses of billions of solar masses. This baffles theories of gradual growth: matter would not have time to 'feed' the seeds at the required rate.

A figure skater spins on the ice, gradually spiraling inward. Similarly, a small star or black hole orbiting a massive black hole loses energy. It emits gravitational waves — ripples in spacetime that detectors on Earth pick up. But the dance of this pair is more intricate than it seems. The small companion isn't just a point.

A black hole with a magnetic field resembles a whirlpool in a river, where water doesn't flow into the vortex but swirls in place. Usually, the hole's rotation picks up waves and amplifies them: this is called superradiance. But add a magnetic field, and everything changes.

At the centers of many galaxies lurk giant rotating black holes. Astrophysicists have long suspected that these objects are remarkably resilient: after swallowing a star or merging with another hole, they quickly settle down and forget the catastrophe.

In the scorching plasma of the infant Universe, right after inflation, conceived by Alan Guth, the kinetic dominance epoch reigned.

At the center of a galaxy, a huge black hole is shrouded in an invisible cloud — a swarm of ultralight particles that it itself spawned. Into this cloud dives another black hole, about the size of a star, and begins a long spiral dance. The approach takes millions of years, but the most dramatic events unfold right at the horizon.

Ordinary gravity, as described by general relativity, behaves like a soft rubber membrane. When a massive star exhausts its fuel and collapses, it deforms this membrane so strongly that a black hole forms — a region where spacetime curvature becomes infinite, and nothing, not even light, can escape.

Black holes can emit heat. They have a temperature, entropy (a measure of disorder), and other thermodynamic properties. Usually, to compute these, you first have to construct the black hole itself — solve the complicated equations of curved spacetime.

A rapidly spinning black hole, where spacetime is curved to the limit, resembles a bell that can hum for centuries. Its special oscillations barely decay, losing energy incredibly slowly.

Two black holes circle in a slow dance, gradually drawing closer. Their motion perturbs spacetime itself, like two heavy balls rolling on a stretched sheet, making it tremble. These tremors are what we call gravitational waves.

A black hole is not an eternal vacuum cleaner. It slowly evaporates, radiating energy, and along with it, as physicists believe, it should return the swallowed information. But when exactly does that start happening? The answer is given by the so-called Page curve — a graph that shows how much information the hole has already released and how much it still holds inside.

A supermassive black hole drifts through a cloud of dark matter. In the usual picture, this invisible substance just adds mass and barely interacts with ordinary matter. But dark matter particles could have intrinsic rotation — spin.

A black hole is not just a dark spot in space. It is a region where gravity compresses matter so intensely that even light cannot escape. Among all possible black holes, one stands out — the rotating Kerr black hole. Its description was long thought to be tied to Einstein's equations, like a recipe tied to a specific cookbook.

A black hole is like a spinning top: the faster it spins, the more noticeable its behavior. It has two boundaries — the outer and inner horizons, the edges beyond which even light cannot return. In the new work, physicists looked inside a rotating charged black hole and multiplied the areas of these two surfaces.

A spinning top whirling so fast that it forces light around it into spirals: that's a fitting image for what happens near a black hole's horizon. Hot plasma falls in and emits radio waves. Their polarization (the plane in which the wave oscillates) becomes an arrow pointing in the direction of energy flow.

Gravitational waves from a tiny body falling into a black hole work like an X-ray image. Only instead of a bone, they illuminate the curved spacetime itself.

Gravitational waves — the cosmic tremors from distant cataclysms — are so faint that detecting them is like trying to hear a whisper in a hurricane. But a black hole can amplify that whisper many times over.

Nearly 12 billion years ago, when the Universe was experiencing the turbulent 'cosmic noon'—the era of record-breaking star formation — at the heart of one galaxy, the quasar WISSH13 was flaring up.