tidal heating

A vacuum cleaner sucks in dust even if there is more of it near the nozzle. The same happens in a tokamak: plasma particles are drawn toward the center, even though their density is higher at the edge. This phenomenon is called particle pinch, and it contradicts the usual rule that everything tends to move from dense regions to sparse ones.

The solar wind is a continuous stream of charged particles flowing from the Sun. It has two main components: protons (hydrogen nuclei) and alpha particles (helium nuclei, four times heavier).

Drop a pebble into a pond, and ripples spread across the water. In much the same way, any body, even the tiniest, perturbs the gravitational field around it. In empty, cold space, these perturbations, like ripples on a calm surface, make two nearby objects always repel each other.

Space is expanding, and that expansion is accelerating. But what if, in the first instants after the Big Bang, gravity behaved differently? The authors of a new study added an invisible field to Einstein's equations that siphons energy from ordinary matter and radiation.

The early Universe was like a tightly coiled spring. In the first moments, it expanded at an unimaginable rate — a phase called inflation. Usually, this is attributed to a special field, but there's another idea: spacetime itself twists like a spring, and this twisting (in physics, torsion) becomes the engine of expansion.

27 days at the equator, 32 at the poles. Five days' difference, and over a year, the equator gains almost a week. A gas ball 1,4 million kilometers in diameter spins like a layered top: each layer moves at its own speed.

In the first moments after the Big Bang, the Universe hummed like a bell. Inflation, the epoch of rapid expansion confirmed by measurements of the cosmic microwave background, ended, and the inflaton field began oscillating around the minimum of its potential.

Every 165 days, the giant planet dives toward its star, nearly grazing its fiery corona, then flies off into the icy void. This is TIC 241249530 b — an exoplanet with a record eccentricity of 0,94.

A ball, almost weightless for its size, circles its star every four days. Planet TOI-2195 A b is a real riddle: by mass it's slightly heavier than Neptune, yet bloated to Jovian volumes. If there were an ocean big enough, this exoplanet would float on its surface like a giant inflatable ball.

At the center of attention are tiny stellar cities: ultra-faint dwarf galaxies. They resemble sparse swarms of fireflies circling within a vast invisible cloud. This cloud is a halo of ultralight dark matter. Its particles are so light that they behave not like billiard balls but like waves.

In the deep oceans of icy moons, water is not still. Warm plumes rise from the rocky seafloor, but the planet's rotation twists them into long, slanted rolls stretched along the rotation axis. Previously, this process could not be included in global models: it was too complex.

Young Earth was a boiling sphere of liquid rock, while Theia, which crashed into it, had had time to cool and solidify. It’s like dropping a chunk of cold butter into a pot of soup: the soup splashes out, but the butter barely moves. Similarly, Earth’s interior spewed into space, forming a cloud of cosmic dust and debris.

A pot of boiling soup is shaken hard — the liquid sloshes, waves crash against the walls. Something similar happens inside a gas planet when it swings past its star on an elongated orbit. The star's gravity excites powerful internal waves in the planet, known as tidal fundamental modes. These waves can completely change the planet's fate.

A pebble the size of a grape enters the atmosphere almost tangentially and skims across the sky without falling. That's exactly what happened to a meteoroid weighing about 45 grams. It came in at such a shallow angle that it traveled 164 kilometers at an altitude of 92 kilometers — where the air is a million times thinner than at the surface.

Stephen Hawking imagined that the universe was born not from an explosion, but by smoothly emerging from a quantum 'nothing.' In worlds with concave geometry (anti-de Sitter space), such a birth acquires a rim, like the hoop of a drum.

At the edge of the solar system, far beyond Neptune's orbit, something is knocking icy chunks off their paths. Their orbits are stretched and tilted in the same way, as if an invisible hand arranged them in a pattern.

Europa's surface is an icy armor continuously bombarded by charged particles from Jupiter's magnetosphere. Electrons slam into the ice's crystal lattice, lose energy, and kick off chemical reactions. Until now, there was no tool to show how deep such bombardment pierces the ice.

The James Webb Space Telescope is gazing more and more at exoplanets — worlds orbiting alien stars. Some of them are scorching rocky spheres, tidally locked with one side forever facing their star. There, rock melts into oceans of liquid lava. How does this lava move?

Beneath Enceladus's icy crust churns an ocean, acting like a perfect heat pump. It pushes heat from the equator to the poles, spending a thousand times less energy than it transports — like a perpetual motion machine built into the moon. The secret lies in salt.

Planets are born from dust. In a disk around a young star, tiny dust grains collide, stick together, and gradually grow like a snowball rolling down a hill. But there's a catch: the gas in the disk moves faster than the dust and drags on it, preventing it from clumping into large chunks. For dust to stick together, there needs to be enough of it.

A quiet tube with a heated grid inside. The voltage on the grid is suddenly raised, and the tube starts to hum, sustaining itself. This is not a malfunction but a transition to another stable state, like a ball rolling over a hill into a neighboring hollow.

Ice slips away from under a skate blade like a bar of soap in wet hands. For a hundred years, scientists argued about where this slipperiness comes from. Some said there is already a thin layer of water on top: it acts as a lubricant. Others countered that water only appears when you start moving, due to friction.

A hot chain of atoms lined up in a row behaves like a tiny black hole. Such a chain is a series of particles, each resembling a tiny magnet. At normal temperatures, the little magnets flip randomly, but when cooled, they align in a uniform order. Physicists have discovered that when heated, this simple system reproduces the strange properties of black holes.

A galaxy plunges into a dense cluster like a runner into a crowd. The oncoming gas, known as the intracluster medium, strips away its own gas, stretching it into a long, glowing tail. Astronomers call these galaxies jellyfish: they have a body and flowing tentacles of stripped material. But only in a few do new stars ignite within those tentacles.

For exoplanets that always face their star with one side, the night side is doomed to eternal cold. But mountains can turn things around. Surface irregularities shake up the ocean of air, steering moisture flows across the day-night boundary. Once in the dark, water freezes into clouds, and clouds act like a blanket: they trap heat and keep the world from cooling down.

The young Solar System resembled a giant construction site: around the newborn Sun swirled a disk of gas and dust, and from this dust gradually assembled stones, boulders, and then planetary embryos — planetesimals. Today, their fragments fall to Earth as meteorites.

Deep beneath us, hundreds of kilometers down, lies a layer that can absorb water like a sponge. The minerals there, wadsleyite and ringwoodite, can hold up to 1–2% water by weight within their crystal lattices.

Rogue planets, ejected from star systems, may harbor life on their moons. A moon of such a planet can preserve heat and liquid water for billions of years. The whole secret lies in a reliable "blanket" and an internal "stove." The stove is tidal forces: they squeeze and stretch the moon's interior, heating it up like kneading clay.

A giant planet circles too close to its star. With each orbit, it tugs on the star with its gravity, and waves are born deep inside the star, like ripples from a stone dropped into water. These waves damp the planet's orbit, and it spirals into the star. The star swallows the planet and starts spinning faster. Stellar rotation is the key clue.

In the northern part of Arabia Terra, there are fields that look like a giant brain: ridges and troughs wind like convolutions. On Earth, similar patterns form in cold regions when water in the soil freezes and thaws, causing stones to sort themselves into stripes. But the Martian ridges are taller — averaging 3.29 meters — while Earth's mechanisms produce less than half a meter.

Glaciers don't just darken from soot. Their surfaces host tiny algae that, as temperatures rise, bloom and turn the ice dark. Dark ice absorbs more sunlight, melts faster, and further warms the planet. It's like how a black t-shirt in the sun gets hotter than a white one. The second player in overheating is forests.

Inside giant planets like Jupiter and Saturn, heat doesn't always rise freely. Heavy elements, which are more abundant in some layers than others, prevent hot fluid from floating up. This creates semiconvection — a type of mixing where heat and composition spread at different rates.

An exoplanet — a planet outside our solar system — follows a slightly elongated orbit. With each revolution, it swings closer to its parent star and then farther away.

A thin stream of water flows down a cold inclined board and, before your eyes, turns into an ice ridge. At first, the water paves itself a straight icy path, as if reinforcing its own banks. Then the trickle starts to meander, and the ice quickly spreads sideways. Finally, the ridge stops growing outward and begins to thicken, smoothing out irregularities.

Hot Jupiters, exoplanets giants snuggled up to their stars, are mysteriously puffed up. Their radii often exceed standard models by 50–100%. New models, based on transiting data (transit method), flip our understanding: heat doesn't come from the interior but from the upper atmosphere.

Lunar rocks brought a puzzle: their age is 4.35 billion years, but the Moon itself should have appeared 150 million years earlier. The missing time is hidden in tidal heating. When the Moon hung closer to Earth, Earth's gravity acted like tireless hands: it constantly kneaded and bent the satellite.

The planet's gravity rhythmically squeezes and kneads the moon like dough: from this constant 'kneading', the interior heats up, and oceans of water can persist under the icy crust for ages. In the Galaxy, there are plenty of rogue planets, thrown out by supernova explosions.

The most common type of planet in our Galaxy — rocky worlds around other stars, or exoplanets, shrouded in the simplest gas hydrogen. Their innards remained a mystery until scientists recreated the conditions of the interior in the lab.

After the Moon's birth, Earth resembled a sizzling lump of dough: a continuous liquid magma and a dense shroud of gases. The Moon acted like a giant spoon, constantly kneading this lump with its gravity. Friction generated heat, delaying cooling.

Many planets around other stars — exoplanets — have elongated orbits. With each close approach, the star’s gravity squeezes and stretches them, like kneading dough. Friction heats up the interior to the point where rock melts, creating underground oceans of magma.