lcdm model

Light from a distant galaxy reaches us through its own dust. This dust is not a smooth haze but ragged clouds, like wisps of cotton. Old models treated it as a uniform mist, and then the galaxy didn't add up energetically: too much light disappeared in the ultraviolet and too little came back in the infrared. Astronomers did what a cook does when they dice a potato instead of tossing it in whole.

The universe is like dough rising in an oven. Galaxies are flying apart, and the rate of this expansion is accelerating. To explain the accelerating expansion, cosmologists came up with dark energy — a mysterious force that pushes space apart from within. The standard recipe, called Lambda-CDM, works pretty well, but it has its inconsistencies.

The universe is constantly sending us signals, but many are too faint to notice. Relic neutrinos, particles left over from the Big Bang, pass through Earth by the billions every second, yet catching even one is a feat on the edge of possibility. We need a detector that can sense energy a thousand times smaller than what it takes to move a speck of dust.

Imagine a huge stadium packed with people dressed in black. You're standing outside, trying to figure out what's happening inside, even though you can't see a single person. But if two people bump into each other and exchange bright T-shirts, you'd spot a flash of color.

The cosmological standard model is like a recipe for a cake where everything is strictly measured: dark matter is like flour without a single lump (zero pressure), and dark energy is like the perfect leavening agent (equation of state exactly minus one). But what if the flour is a bit damp and the leavening agent has lost its oomph?

In the first moments after the Big Bang, the universe was a searing 'soup' of particles. As it cooled, phase transitions occurred — much like water turning to ice. At one such moment, magnetic monopoles of dark matter could have been born: tiny clumps of field with a single magnetic pole.

The universe is like a vast invisible scaffold. We don't see it directly, but we know it's there: galaxies and clusters hold together thanks to it. This scaffold is dark matter. The most popular version says it is "cold," made of heavy, slow-moving particles.

Cosmology has landed in an interesting pickle. The two main ways to look back into the universe's past, via the early glow (the cosmic microwave background) and via later objects like supernovae, yield different numbers for the expansion rate (the Hubble constant) and for how clumpy matter is distributed.

Eight bright spots on the radio sky. They are all the same quasar HS 0810+2554, whose light passed through a gravitational lens — a massive foreground galaxy.

Through three minutes after the Big Bang, the Universe played its first symphony. It was the big bang nucleosynthesis — the formation of light nuclei, where each element sounded its own note, and the tempo was set by the expansion of space.

Three invisible strings oscillate in the intergalactic void. This is not poetry, but a hypothesis about the nature of dark matter — an ultralight quantum field with spin 1, carrying three polarizations.

A cold, black mirror — that's what the sea of dark energy, the invisible substance driving the expansion of the universe, looked like for billions of years. But the DESI spectrograph has caught a faint ripple.

To capture every detail of a statue's shape, you could break it into millions of tiny cubes and describe each one — slow, heavy, and your computer's memory would groan at the seams. That's how 3D medical scans are usually handled: a CT or MRI is a huge array of such cubes (voxels), and to create or improve an image, the machine has to plow through all of them.

The Universe is a giant concert hall, where instead of walls and balconies, invisible clouds of dark matter float. This architectural ensemble is not static: it refracts and scatters the 'music' rushing through it — gravitational waves from merging black holes.

Dark energy — the mysterious substance responsible for the accelerated expansion of the universe — may not be a constant factor but a variable force.

The universe is a grand orchestra, with dark energy conducting the expansion. Ten billion years ago, the conductor changed its gesture: the negative pressure that had been holding back galaxy assembly gave way to accelerating expansion — the very phenomenon discovered by [scientist:Saul…

When a giant planet grows, it pulls in gas. Some of that gas swirls around it into a small disk — called a circumplanetary disk. It is in such disks that moons are thought to form. For the planet PDS 70 c, located 370 light-years away, such a disk was directly observed using the ALMA antenna array in the millimeter range.

The Universe is an orchestra playing the symphony of the Big Bang. For a long time, the conductor was thought to be dark energy — an unwavering metronome setting the pace of expansion.

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.

A teaspoon of neutron star matter weighs as much as a mountain. But this mountain may have an invisible twin. Deep inside a neutron star, ordinary matter is compressed to unimaginable densities. There, protons and neutrons can dissolve into a quark soup.

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.

A large underground tank of liquid xenon waits for a rare event — a nudge from a dark matter particle. Normally, gravity is too weak to notice such a nudge. But if space has hidden dimensions, everything changes: at tiny distances, gravity suddenly strengthens, and the chance of catching an elusive particle grows.

The universe is expanding at an accelerating rate, like dough that keeps rising faster even though the yeast ran out long ago. For twenty years, astronomers have been searching for the cause and call it dark energy. But what it is remains a mystery. New work proposes an unexpected source: the vacuum inside the atomic nucleus.

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 giant cloud of invisible matter acts like a funhouse mirror — distorting the light from a distant galaxy. From these distortions, astronomers can weigh the cloud and peer into its depths.

The Universe grows like a metropolis: galaxies skyscrapers are erected on an invisible scaffold of dark matter: its gravity pulling in construction material. Meanwhile, dark energy makes the city itself continuously expand.

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.

The late-stage Universe can be thought of as a crowd dispersing after a concert. In the standard cosmological model ΛCDM, people shuffle away quietly, not bothering each other. But what if thousands of concertgoers suddenly start gently nudging their neighbors?

The Universe resembles a dense forest: up close, individual galaxy-trees are visible, gathered into groves, but from a distance everything merges into a solid green canopy. The boundary beyond which the cosmos becomes homogeneous is called the angular scale of homogeneity: it's the size of a patch of sky from which galaxies are distributed evenly.

Since the late 20th century, astronomers have known that the recession of galaxies is accelerating, as if pushed by an invisible tailwind.

In the 1930s, Fritz Zwicky first noticed that galaxies in clusters were moving too fast — something invisible was holding them. Later, Vera Rubin measured the rotation of spiral galaxies, confirming that space is permeated by dark matter.

A stone thrown into water leaves ripples. A satellite orbiting Earth also leaves a trace — not on water, but in the laws of physics. Its orbit is not a frozen line: it slowly rotates, like the hand of a giant clock.

The Universe follows strict rules, like players at a table. One of them: gravity always attracts, and energy cannot be negative.

On the kitchen counter, there's a flour scale and a measuring cup for water. Individually, they're precise, but when you bake bread, the recipe calls for the perfect ratio. Astronomers have a similar dispute about the universe's expansion rate.

A fluffy ball of invisible web envelops a black hole. This web is dark matter, which doesn't shine but, through its weight, governs the motion of stars on the outskirts of galaxies. Astrophysicists have long seen such 'fluffy' clouds around cosmic objects and have mapped their profiles — how density falls from the center to the edge.

A magnifying glass focuses sunlight into a bright point. If the glass has a tiny flaw, the spot of light becomes distorted. Gravitational lensing works in a similar way: a massive galaxy bends light rays from a more distant source, creating an enlarged and sometimes distorted image.

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.

Dark matter is invisible, but its gravity governs the motion of galaxies. What it's made of is a mystery. One idea: it consists of ultra-light particles akin to axions.

The universe is permeated by an invisible substance, dark matter, whose gravitational influence is obvious, but whose composition remains a mystery. One hypothesis suggests it consists of ultralight particles so light that they exhibit wave-like behavior, forming a kind of cosmic ripple.

Two clocks tell different times. One sits on our desk, the other lies far in the past, in the glow left over from the Big Bang. The first, looking at nearby galaxies, ticks off the expansion rate of the universe — about 73 kilometers per second per megaparsec of distance. The second, peering into ancient light, gives a noticeably lower value — roughly 67.