cosmological phase transition

A honeycomb made not of wax but of atoms is graphene — a flat crystal just one atom thick. Electrons in it are like runners at an intersection: they speed up here, slow down there, but never get stuck at the edge. Physicists call such a sheet "topologically trivial," meaning its edges are perfectly ordinary, with no special properties. Now, let's knock out a single atom from the honeycomb.

An atomic nucleus is not just a ball of protons and neutrons. It has a shape, and that shape can change. The tin-116 nucleus was long considered almost perfectly spherical: it has 50 protons — a 'magic' number that usually gives a nucleus spherical symmetry. But a new ultra-precise measurement showed otherwise.

In the first moments after the Big Bang, the Universe was like a supercooled bottle of champagne. In addition to ordinary matter, it concealed a dark sector — an invisible sparkling “wine” of fields and particles, candidates for dark matter.

In the first moments after the Big Bang, the Universe was not a silent void but a seething cauldron of plasma, threaded with sound waves. As the temperature dropped, the cosmos underwent phase transitions — spontaneous reorganizations that gave birth to bubbles of a new phase.

The story began with a missing mass. In the 1930s, Fritz Zwicky, measuring velocities in galaxy clusters, first suspected the presence of invisible matter. Later, Vera Rubin showed that the outskirts of spiral galaxies rotate too fast for the visible matter.

The universe is expanding faster and faster thanks to dark energy. But measurements of the rate give contradictory results. A new explanation: in the past, dark energy acted as a brake, slowing the galaxies' recession, and then switched to acceleration. Like a car that first rolls backward and then lunges forward.

Ice, water, steam — phase transitions we all know. But what happens if you squeeze and heat an atomic nucleus itself? Theorists think protons and neutrons inside it 'melt,' releasing smaller building blocks — quarks and gluons.

A compressed spring can sit for years without moving. It seems frozen forever, but inside the metal, atoms slowly rearrange, and one day the spring clicks, settling into a new, more relaxed position.

Inside the proton, life is boiling. Quarks don't just sit there: they're glued together by carrier particles called gluons (from the word glue). Usually, this glue is spread evenly, like butter on a skillet. But when energies become enormous, gluons start clumping together. This is the gluon condensate — an ultra-dense state of the gluon field.

An inflating balloon starts out slowly, then suddenly expands faster and faster, as if someone is pumping it up from inside. That's roughly how our universe behaves: galaxies are receding with acceleration. The culprit behind this acceleration is called dark energy.

Hot tea in a freezer doesn't freeze all at once. First, tiny ice needles dart around — forming and melting until the temperature drops enough for the ice to set solid. The early universe behaved similarly as it cooled and changed its internal structure.

After the Big Bang, the Universe simmered as a fiery 'soup' of fundamental particles. Expanding and cooling, the soup gradually 'solidified' into protons and neutrons — much like crystallization. Had the solidifying been instantaneous, like a lake cracking in a deep freeze, the fabric of spacetime would have convulsed.

Dark energy is usually seen as an innate property of the cosmos, at work from the very first moments. But a new model suggests it behaved like water on the verge of boiling: long unnoticed, then suddenly kicking in at a critical moment. This scenario is called 'late activation': around 5–7 billion years ago, a shift occurred, and the universe’s expansion began to accelerate.

A spring compressed to the limit breaks. Likewise, classical gravity theory leads to a singularity — a point where all laws break down. Quantum mechanics turns this end into an elastic bounce.

Ten microseconds after the Big Bang, the Universe resembled a pot of boiling broth. Floating in it were quarks and gluons — the particles that would later assemble into protons and neutrons. As the broth cooled, at some point the quarks clumped together into lumps — the very protons and neutrons that make up all visible matter.

Fresh after the Big Bang, the Universe fizzed like a freshly poured soda. All of space was filled with bubbles — regions of new vacuum, the kind governed by the Standard Model, pushing out the old unstable state. The walls of these bubbles accelerated to near light speed, and in head-on collisions they crumpled and burst, unleashing monstrous energy.

Dark matter is the invisible scaffold of the cosmos, its existence betrayed by whirls of galaxies to Fritz Zwicky and Vera Rubin. What it is made of remained a mystery for half a century. A new hypothesis paints an unusual picture.

A snowflake falling from a cloud chooses between a left-handed and a right-handed form. The difference between them is almost imperceptible, like a breath of wind, yet it is that very breath that decides which pattern will grow.