cosmic string

Right after the Big Bang, space cooled unevenly. In some places, folds could have formed — threads of energy as thin as a hair but incredibly dense. Physicists call them cosmic strings. They oscillate, collide, and emit gravitational waves — ripples in the fabric of space itself.

In the first fractions of a second after the Big Bang, the universe was a stage of rapid change. A stretched rubber sheet that cools quickly becomes covered with microscopic cracks. A similar process on a cosmic scale could have given rise to cosmic strings — ultra-thin but super-dense threads of energy stretching across the entire universe. These strings are not just defects in space.

The early Universe was like a rapidly cooling ocean. At colossal temperatures, everything was one — quarks, electrons, forces all blended into a symmetric 'steam.' But as it expanded and cooled, this steam condensed, phase transitions cascading one after another like water turning to ice.

Pluck a guitar string, and it will vibrate and quickly fade. Now imagine a cosmic string: an ultra-thin filament of pure energy left over from the Big Bang, trillions of times thinner than an atom and denser than a neutron star. Strike it, and it might sing for billions of years.

In mathematics there is a sieve that sifts not dust, but infinity itself. It’s called a Q-space: here any subset turns out to be a Gδ set — a countable intersection of open sets, as if sifted through an unimaginably fine mesh.

An object cannot be a point. At least, not in Einstein's gravity. The equations of general relativity require that the source of the field, matter, be smeared out in space, not concentrated in an infinitesimal volume. Otherwise, infinities appear in the formulas, and a smooth spacetime cannot be constructed.

The hot broth of the early universe cooled unevenly. At some point, bubbles of a new phase began to pop within it, like steam bubbles in boiling water. But these bubbles weren't made of steam; they were made of a new state of matter in which particles of the dark sector clumped into larger lumps. That's how dark matter could have been born.

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

The early universe was a restless place. Space trembled with gravitational waves — ripples in the very fabric of reality. In this churning cauldron, dark matter is thought to have been born. But the newborn particles had no mass: it had to come from somewhere. Usually, the Higgs field is responsible for mass.

It all began not with emptiness, but with a boiling ocean of plasma. In that primordial broth, sound waves raced through the fiery matter, colliding and compressing it. Sometimes a clump grew so dense that light could no longer escape, and right out of the scorching gas, a primordial black hole was born.

In the early Universe, tiny black holes could have been born — mountain-mass but atomic-nucleus-sized. Today they could serve as factories for dark matter. There are two mechanisms: the familiar evaporation (Hawking radiation) and the lesser-known superradiance.

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.

The Universe behaves like a soap bubble swelling in a multidimensional foam. The dark bubble model explains why it's expanding ever faster: the spacetime bubble grows, and its membrane gains a tiny thickness — about a micron, like a bacterium. At such distances, gravity 'blurs' across this thickness and weakens.

A black hole is not just a cosmic vacuum cleaner. It is a region with such strong gravity that even light cannot escape it. But place it in a perfect fluid of dark matter and add a cloud of strings, thin filaments stretched across all of space, and the picture gets more complicated.

Immediately after the Big Bang, in the seething cauldron of the cooling Universe, much like in unevenly hardening glass, stresses appeared — hairline cracks in reality, cosmic strings. Picture a tightrope walker balancing on an invisible cable stretched across the abyss of warped spacetime.

A fundamental string plucked at the moment of the Big Bang doesn't just hum a single note — waves run along it, and occasionally tiny loops peel off. These loops, like tuning forks, begin to ring at their own frequency, producing a very high-pitched sound.

A crystal is like a row of soldiers on a parade ground: every atom is in its place, and electrons march through it in neat waves. An amorphous material is like a crowd at a train station, where there is no order, just a jostling throng. In such a crowd, an electron usually gets stuck quickly, like a person trying to push through a dense mass of people.

The mystery of dark matter, first glimpsed in the stellar whirlpools by Vera Rubin, has been tormenting physics for nearly a century. One of the boldest hypotheses: primordial black holes, born in the scalding broth of the early universe.

For a long time, dark energy, the mysterious force prodding the expansion of the Universe, was considered eternal and unchanging, like yeast that never loses its activity. But explaining such constancy through the laws of the microcosm proved impossible, and scientists began to suspect that the “leaven” might be going flat.

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.

Spacetime sometimes resembles a sheet of paper in which you can punch a hole and connect the edges with a short tube: you get a wormhole. In the simplest mathematical models of such wormholes, massless scalar fields appear — something like an invisible fog filling everything around.

When hot soup cools, clumps form on the surface — similarly, as the early universe cooled, it gave birth to threadlike clumps of energy: cosmic strings. Some of them are like a stretched rubber band: as long as it's intact, it's stable. But if you nick the band, it snaps.

A magnet with only one pole (north, without a south) is not a fragment but a particle in its own right. Physicists call it a magnetic monopole (a carrier of a single magnetic charge). Such visitors could have been born in the early universe, when the forces were just separating.

After the Big Bang, the Universe resembled a tightly inflated balloon: pressure prevented matter from clumping together. But hypothetical superheavy particles — sort of ‘heavyweights’ of the microcosm — momentarily made the balloon less stiff. Matter easily clumped, giving birth to black holes with masses from a billion to a billion billion tons.

Drops from a leaky faucet beat a clear rhythm. A similar rhythm, only on the scale of the universe, has been found by astrophysicists: the formation of primordial black holes — tiny objects born in the first moments after the Big Bang — also proceeds not chaotically, but in a strictly measured way.

A giant whirlpool spins at tremendous speed. If you toss a rope into it, securing one end at the rim and leaving the other outside, the whirlpool will wind the rope around itself, making it spin. That's roughly how a cosmic string behaves near a rotating black hole.

In the first moments after the Big Bang, the cosmos resembled a giant cooling pond. Just as water, when freezing, becomes covered with a network of cracks, so the cooling universe could have cracked — not into ice, but into the thinnest filaments of pure energy. These filaments are called cosmic strings.

From 2016 to 2018, at the Large Hadron Collider at CERN, protons collided at energies of 13 teraelectronvolts, as if two peas were accelerated to speeds where their impact spawns a whole swarm of new particles.

The Universe is a colossal web of invisible dark matter and galaxies, stretched by the expansion of space. Neutrinos, nearly intangible ghost particles, barely cling to the threads, but their collective mass subtly shifts the tension of the entire network.

The James Webb Space Telescope has spotted tiny, unnaturally bright red objects in the early universe. Their light outshines by a hundredfold what you’d expect from ordinary galaxies of that era.

Black holes are famous for their dark silhouette against a bright glow. It's not actually a shadow, but severely bent light curving around the object. Yet the cosmos also hosts impostors — ultra-dense bodies without an event horizon that warp light in their own distinct way. These distortions can reveal the ruse.

The Big Bang was like a cosmic thunderclap that set the fabric of space vibrating. These vibrations — gravitational waves — still echo through the Universe like a fading rumble from that ancient event. The louder the initial 'bang,' the more primordial black holes should have formed.

According to theories beyond the Standard Model, our best description of elementary particles and their interactions, pairs of magnetic monopoles were born in the first instants after the Big Bang. These hypothetical particles carry only one magnetic pole—'north' or 'south'—unlike familiar magnets where poles are inseparable.

When two black holes merge, the newborn hole should ring like a bell, emitting gravitational waves — ripples in space. Yet before the ring, a silence can fall: the black hole gets caught in a phantom trap, as if an invisible hand grips the bell’s clapper.

The universe can behave like a spring: compressing to microscopic sizes and then expanding again. In this cycle of contraction and bounce, black holes and dark matter are born.

A rotating black hole is a cosmic whirlpool that sucks in everything around it. Some of these holes have invisible threads that stretch from the event horizon like spokes from a wheel. Scientists have long debated what these threads are and whether they can be observed. In a new study, physicists have shown that these threads are not just a mathematical artifact.

At the center of galaxy NGC 1600, 200 million light-years away, astronomers spotted a dense cluster of stars. It looked like a bright knot against the diffuse glow, and that was unexpected.

A waterfall doesn't ask if you're ready to jump. Its flow accelerates, and at some point even light can't escape back. A McVittie black hole is such a waterfall, but not in an ordinary river; it's in an expanding universe: the water here is space itself, which continuously stretches, carrying galaxies apart from each other.

The universe is expanding faster and faster, and the standard explanation is a positive cosmological constant, that is, a de Sitter vacuum. String theory, which aspires to be the theory of quantum gravity, should be able to describe such a vacuum, but after decades of effort, no reliable construction has emerged.