temperature

Swimming season opens when the water feels tolerable. But everyone has their own threshold: one person shivers at twenty degrees, another swims comfortably at fifteen. Scientists decided to figure out where this difference comes from. They compared a swimmer's body to a house trying to keep heat in while a cold wind blows outside.

In a superconductor, where electrons move in pairs without resistance, special waves can run along the edges, like ripples along the edge of a carpet. The number of such waves is an important characteristic of the material, but measuring it directly is difficult.

A superconductor is a material in which electricity flows without loss, like water through a perfectly smooth pipe. But if you squeeze it slightly, like a spring, its properties change. Scientists have long wanted to measure how much heat such a compressed material absorbs, but instruments couldn't fit into the cramped setup. Now they've devised a way around this obstacle.

A translator who has memorized all the lines in advance responds instantly — no need to listen to the whole conversation again. That's how the new model works: instead of running atoms through a computer for hours, it immediately outputs the crystal's free energy at any temperature and pressure.

A translator who has memorized all the lines in advance responds instantly — no need to listen to the whole conversation again. That's how the new model works: instead of running atoms through a computer for hours, it immediately outputs the crystal's free energy at any temperature and pressure.

In the kitchen, when a pan heats up, your hand feels the heat before you even touch it. A solar telescope picks up similar invisible heat — only from a star, not a stove. The instrument, called HATS, captures radiation in the terahertz range, which was previously little studied due to technical difficulties.

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).

A conventional computer computes by shuttling electric charges along wires. But can you compute with heat? A network of pipes carrying hot and cold water can perform simple logic operations if the pipes are connected in the right order.

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.

Drop an ice cube into a glass of water — within a minute it melts, and the temperature evens out. That's thermal equilibrium in action: energy spreads evenly, and the system "forgets" its past.

A black hole is not an absolutely black bag. In 1974, Stephen Hawking showed that it glows — faintly, but continuously. This radiation is born not inside, but outside, right at the boundary from which even light cannot escape. A new study sharpens the picture.

A pot of boiling water is covered with two lids — an inner and an outer one. The thermometer under each shows its own temperature, but their harmonic mean (a special averaging method where you add the reciprocals) always remains unchanged. Heat seems to obey an invisible rule.

In a glass of water, oil gathers into droplets: that's equilibrium separation dictated by chemistry. But there are systems where order arises not from rest but from a constant flow of energy.

In a room, air touches the skin, and we feel its temperature. But if your body suddenly accelerated at a colossal rate, heat would come even from absolute emptiness. This is not fiction but a strict consequence of quantum field theory: for an accelerating observer, the vacuum becomes a warm bath.

In a soup pot, you only need two thermometers to gauge the temperature everywhere — if you know heat travels in circles from the bottom. Science works the same way: from a handful of measurements, you want to reconstruct the full heat picture. The system captures the gist of heat flow, compressing it into a handful of governing numbers.

Heat is all around us: from a car's exhaust pipe to the casing of a running laptop. Thermoelectric materials could turn that waste heat into electricity.

Textbooks divide particles into two camps: bosons love to crowd into the same state, fermions absolutely refuse. But nature allows a third option. Anyons are quasiparticles whose behavior lies somewhere in between. They can 'remember' how they were exchanged and obey a nonstandard exclusion principle.

Tea in a cup cools quietly on the table. But if you zoom past at near-light speed, the thermometer will read higher — even though no one heated the tea. Calculations confirm: the needle will creep up. A century ago, physicists split into three camps.

A light ray skims along the horizon of a black hole: that invisible boundary from which nothing can escape. The closer the ray gets to the horizon, the slower its own 'time' stretches — a special measure of path called the affine parameter.

An ice cube in hot tea melts strictly at zero degrees. But what if the ice is made of subatomic particles and the tea is scorching nuclear matter? The authors studied the rho meson, a particle made of a quark and an antiquark that lives for just 4×10⁻²⁴ seconds, and searched for its 'melting temperature'.

Billions of tiny motors hum inside every living creature. Cells ceaselessly pump substances, burn sugar, and build new proteins, and all this invisible motion warms us from within. To maintain order, life must dissipate heat into the environment, like a stove that never goes out. The power of this internal heating is almost independent of size.

If you stick two identical thermometers into a pot of hot water, they'll both read the same, and we relax, thinking the temperature is measured correctly. But in a rarefied gas heated to millions of degrees, this trick stops working.

In 1867, James Clerk Maxwell proposed an image that still stirs physicists today. Two compartments of gas are separated by a door. Molecules dart about chaotically: fast and slow. A tiny gatekeeper opens the door only for fast ones, letting them through to one side, and slow ones to the other. The hot compartment gets hotter, the cold one colder.

On the surface of a tiny sphere live two invisible fields, like two kinds of ripples on a soap bubble. These fields don't just oscillate on their own: they constantly influence each other, like musicians playing in unison. In a new study, physicists derived exact equations that describe how this ripple changes over time, heats up, and descends into chaos.

A hot spoon in a cup of tea — heat runs along the metal from the hot end to the cold one. Textbooks describe this process as atoms jiggling and passing on their jolts to each other. But atoms don't just jiggle: they also spin, like tiny tops. Until now, physicists had no common language to describe both motions at once. The authors of the work built such a language.

A tiny glass bead hangs in a laser beam like a speck of dust in sunlight. Around it is a rarefied gas: atoms of krypton, xenon, and heavy molecules of sulfur hexafluoride. They collide with the bead, and each hit transfers a tiny impulse, like a pea thrown at a taut sheet makes it tremble. Impulse is a measure of motion: mass times velocity.

Hot tea cools down, and its temperature is the same throughout the cup. But in many systems (for example, in the rarefied gas between stars or in plasma) temperature is not uniform: in one place particles are faster, in another slower. Physicists call such systems "superstatistical": it's as if the tea consisted of many small regions, each with its own temperature.

In a thin semiconductor channel, electrons behave not like lone runners but like a crowd at rush hour. They constantly bump into each other, and these collisions determine how easily heat and electric current pass through the material.

An aluminum pot on the stove melts at 660 degrees Celsius — everyone knows that. But what happens if you heat aluminum a hundred times hotter? The liquid starts to boil, and here's the puzzle: at what exact temperature does that happen?

Water can be ice, liquid, or steam. Physicists call these states phases. In theory, each phase has its own measure — a way to describe how likely it is. But not every measure you can imagine occurs in nature. Some phases are real, while others are just mathematical illusions. Scientists have found a simple criterion that separates reality from mirage.

A red-hot piece of metal in a furnace is like a frying pan on the stove: the hotter it gets, the faster heat travels to your hand if you touch it. But at temperatures where the metal is close to melting, measuring that speed is very tricky: sensors don't make good contact, heat escapes into the air, and the glowing sample confuses the instruments. This new method sidesteps those obstacles.

In helium cooled to near absolute zero, the liquid stops rubbing against itself and begins to flow without any resistance.

If you keep chocolate at the wrong temperature, it turns gray and crumbly. It all comes down to how cocoa butter molecules pack together. At different temperatures, they form six different crystal forms, and only one of them, form V, gives a glossy bar that snaps crisply and melts in your mouth. The other forms are that white bloom and crumbliness.

The magnetic refrigerator of the future won't hum with a compressor. Instead, it will cool your groceries by exploiting a special material that heats up in a magnetic field and cools down when the field is removed. This cycle resembles the compression and expansion of gas in a conventional fridge, but here a magnet does the work of a piston.

A piece of aluminum alloy is heated, and it quietly tells you about its strength. You just need to listen to that story in how the metal absorbs heat. The usual way to find out how strong an alloy is — pull it until it breaks. That takes time and destroys the sample.

Gas is nearly invisible, but it has a temperature, and you can read it from how the gas 'shadows' the thermal background. In the experiment, a camera looks at a warm screen through a jet of carbon dioxide. If the gas is cooler than the background, it appears as a dark spot; if warmer, it appears bright.

Quantum materials are like finicky flowers: they only bloom in the cold. At room temperature, they hide their unusual properties, but when deeply cooled, they become superconductors or change their magnetic behavior. To understand how they work, you need to examine their atoms in the very cold where these properties reside.

Water in a pot, when heated, doesn't boil: it turns into ice. That's roughly how ultracold atoms behave in an optical lattice — a light-based crystalline grid that holds atoms in place. Scientists simulated this system on a computer to understand how order changes as temperature rises.

An ordinary heat engine is like a mill between the hot and cold banks of a river: the greater the drop, the stronger the current. Here, the drop is tiny, just one or two degrees, but water can still turn the wheel. The secret is that water is made to boil not by heating but by a sudden drop in pressure, so steam bursts out even from barely warm liquid.

The gas in a galaxy glows like a neon sign, and by the color of that glow, astronomers can tell how hot it is. The logic is simple: the more heavy elements (which astronomers call metals) in the gas, the better it cools. So galaxies rich in metals should have cooler gas. But new observations show the opposite.