reissner nordstrom black hole

A black hole is not just a dark sphere. In string theory, it can grow 'hair'—extra scalar fields such as the axion and the dilaton. These fields gently alter the geometry of space around the hole.

A black hole rings like a bell after being struck. This ring is the gravitational waves that detectors pick up. But what changes if the space around the hole is curved not only by its mass but also by an additional quantum correction?

An invisible scaffold holds galaxies together, keeping them from flying apart. This is dark matter — matter that doesn't shine and barely interacts with ordinary stuff. Astrophysicists have long debated what it's made of.

In the far reaches of space, there exists a hypothetical object: an ultracold black hole. It is charged and resides in an expanding universe (de Sitter space). Its temperature hovers just above absolute zero — about one trillionth of a degree above it.

Drop a stone into a calm lake, and ripples spread in even circles. Spacetime around a massive body behaves similarly: if the body is perfectly round, the disturbances it causes are symmetric. A black hole in general relativity resembles a perfectly smooth mirror of water.

A black hole is not a vacuum cleaner. By itself, it doesn't pull everything in more strongly than an ordinary star of the same mass. But if there's a magnetic field nearby and charged particles flying around, an interesting game begins.

A black hole is like a perfect safe: everything that falls in disappears without a trace. But quantum mechanics whispers that on the microscopic level, information is not lost but recorded on an invisible "surface." Understanding this record means unraveling the fabric of gravity.

A rotating black hole is no calm whirlpool. Space around it shudders and rings at the slightest disturbance, like a guitar string after a pluck. These oscillations are described by the Teukolsky equation — a complex mathematical construct that physicists have studied for half a century. Recently, a strange symmetry was noticed in this equation.

A black hole is not silent. When perturbed, it rings like a bell, and that ring is its quasinormal modes — damped oscillations. Physicists delved into the world of charged black holes in anti-de Sitter space (a universe with negative curvature, like a saddle).

Usually, a black hole is described as a frozen frame: there's mass, there's charge, and it's all static. But real objects live in time. They radiate, lose energy, and change.

Two metal plates in a vacuum attract each other without any magnets or charges. This is the Casimir effect: the void is not empty; particles constantly pop in and out of existence, and there are fewer of them between the plates than outside. The pressure difference pushes the plates together.

A pair of black holes circles in a dance, gradually drawing closer. They lose energy and spin — a process known as angular momentum radiation. In standard Einstein theory, only gravitational waves carry away angular momentum.

A rotating black hole is like a whirlpool in a river — spacetime swirls around it, dragging along everything nearby. In some gravity theories, this whirlpool also includes an extra field — a vector field. At each point, it has a direction and a length, like a compass needle.

A taut trampoline sheet dips under a heavy ball. If the ball spins quickly, the sheet begins to twist around it. Spacetime near a rotating black hole behaves similarly: it is not just curved, but also dragged along by the rotation, like water swirling around a whirlpool.

A black hole usually hides its singularity behind an event horizon — an invisible boundary from which not even light can escape. But sometimes this 'cloak' is absent, and the singularity, a point where familiar physics breaks down, is exposed to an outside observer.

A stone drops into a pond — ripples spread and fade. Strike a bell, and it hums at its own pitch. A black hole, after being perturbed, also 'rings,' emitting gravitational waves of a decaying tone.

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.

Every river has an estuary — the place where its waters meet the sea. Spacetime, too, has its own 'shore': it is called future infinity, and it lies where all signals, light, and gravitational waves ultimately go.

A black hole is where the usual rules break down. At its center, according to classical physics, lurks a singularity: a point of infinite density where everything that falls in gets crushed. Quantum theory was supposed to soften this picture.

An ordinary black hole is surrounded by a thin photon sphere — a place where light can loop around before falling in or escaping. In the new work, this region has puffed up into a whole layer packed with massless particles that zip around at nearly the speed of light and don't press against the walls.

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.

When massive bodies accelerate (say, two stars orbiting each other) the space around them doesn't stay calm. It trembles like the surface of a pond after a stone is thrown. These tremors are called gravitational waves. They carry energy away, and the source gradually loses mass.

Two magnets collide in a dark room, stick together into a clump, and a dull thud echoes. Black holes behave much the same way, except instead of magnets they carry electric charge, and instead of a thud, there's a burst of gravitational waves. But there's a third player in this story — an invisible field that physicists call scalar.

Strike a tuning fork with a mallet — it vibrates, and the sound gradually fades. A black hole behaves much the same way when disturbed: it emits gravitational waves — ripples in spacetime itself — and then settles down.

A black hole is not a deaf wall. Give it a gentle tap, and it will respond. Physicists call this 'tidal deformability'—an object's ability to change shape under an external force. For a static black hole, this ability is zero: a static field doesn't bend it.

Deep inside a star compressed to its limit, particles behave like the strings of an unusual musical instrument. Their oscillations obey a complex equation that for nearly a century no one could solve exactly.

A flashlight beam travels straight into the dark: that's how we usually think of light. But near a massive body, like a star or a black hole, space is curved, and the beam bends smoothly, as if guided by an invisible hand. The authors of a new study have worked out exactly how gravity alters the familiar laws of electricity and magnetism.

A neutron star is the leftover core of an exploded giant, compressed to the size of a city. A teaspoon of its matter weighs a billion tons. Inside such a star, particles are packed so tightly that quantum effects start to show. One of them is the intrinsic rotation of particles, or spin.

In the quantum world, dark matter particles can merge into a single superfluid droplet — a state where matter flows without friction, like an ideal fluid. When near a black hole, this droplet doesn’t just disappear into it but twists into stable vortices, like water swirling around a rock in a stream.

A massive top spins so fast that space itself twists into a spiral around it. This is a black hole — only instead of wood and metal, it's made of pure gravity. Add an unusual electromagnetic field that slightly changes the rules of the game, and you get a 'deformed' black hole: its shape and behavior differ a bit from the familiar ones described half a century ago.

Drop an ice cube into boiling water, and it will melt away until nothing is left. A black hole in space behaves much the same way — except the 'boiling water' is space itself, which continuously siphons energy out of the hole.

Two electrically charged spheres attract each other with a certain force. If you replace their charges with magnetic poles, a spring scale shows exactly the same force. Black holes, it turns out, behave the same way — except instead of springs, the fabric of spacetime itself does the work.

Right after the Big Bang, space swelled at an unimaginable speed — that's inflation. Now expansion has slowed, but galaxies are moving apart faster and faster. The culprit behind the acceleration has been named dark energy.

Modern detectors of gravitational waves confirm that black holes are real. Spacetime can be compared to a giant trampoline: massive stars make it sag.

In the searing plasma of the newborn Universe, when space itself still rang with the echo of the Big Bang, objects may have emerged that challenge gravity itself. Not ordinary black holes — but electrically charged giants, astrons.

Hold a magnet near a pile of iron filings, and they line up along invisible lines — the field wraps around the magnet from pole to pole. In a similar way, you can visualize gravity around massive bodies: instead of filings, it's space itself; instead of a magnet, a star or a black hole. The authors propose decomposing gravity into two fields.

A stone falls into a pond, and ripples spread across the water. If the pond is choppy, with waves coming from all directions, the pattern gets more complicated. That's roughly how spacetime behaves around a black hole when something perturbs it: it vibrates, emitting gravitational waves.

Black holes aren't faceless devourers. Sometimes they behave like water: they can 'freeze' or 'boil', changing their internal state. Scientists described this by modeling light near a black hole as a gas.

A magnetic field can hold a star against complete collapse: that's the idea behind a new kind of black hole. Instead of the usual point of infinite density, inside there is a field that prevents space from crunching down to zero. It's like a spring: the harder you squeeze, the more it pushes back.

You can poke a pencil through a folded sheet of paper, and the path between two points becomes shorter. That's roughly how the idea of a wormhole works: a tunnel in space connecting distant regions.