solar system

The family album of this stellar pair has been filling up for 45 years, but the pictures were blurry and the captions contradictory. Now astronomers have pulled out the old photographs, taken new sharp shots, and put everyone back in their proper places. Gamma Cephei is a bright star visible to the naked eye, and it has an invisible companion that orbits it every 70 years.

An old city gains new suburbs. In the center, narrow streets where life has nearly stopped, while on the outskirts construction is booming. That is what a spiral galaxy looks like when its core stars have long aged and new stars are still being born in the outer disk.

Three cabinets full of rocks. In one, metallic grains and the gray mineral enstatite; in the second, the same grains but with rusty streaks; in the third, layered clays swollen with water. All three sets were pulled from meteorites that fell to Earth: chondrites. They were born in the same gas-and-dust disk around the young Sun, yet somehow turned out so different.

On a sunny street, there's a house with a big family: a giant father who always sits by the window and a small child running around the yard. That's the TOI-4468 system: a gas giant hot Jupiter hugs the star, while a bit farther out circles a sub-Neptune — a planet smaller than Neptune but larger than Earth.

Among the scorching exoplanets that circle perilously close to their stars lies the secret of their birth. Nearly three decades ago, Michel Mayor and Didier Queloz discovered the first such world, and since then astronomers have been tormented by the question: how does a gas giant end up pressed against…

Remember the sensational comet 1I/‘Oumuamua — the first object to come to us from another star? Its hyperbolic trajectory left no doubt: it was a wanderer from the interstellar void. But astronomers wondered: could some of these visitors not be strangers at all, but our own, escaped from the Solar System millions of years ago?

Every star is a living archive, and its spectrum a multilayered manuscript. Over billions of years, the history of the galaxy is written into it: the galactic chemical evolution of the Milky Way leaves a smooth trace in elemental abundances.

For years, the Sun teased astrophysicists. In its atmosphere, refractory elements, like spices in a basic recipe, were slightly less abundant than in nearly identical twin stars. Suspicion arose: could our star be modest, skipping the planetary "dessert" that others devour with gusto?

When we peer deep into space, we see the past. Edwin Hubble’s law turns redshift into a time machine: light from galaxy UDS 12999 traveled to us for 7.6 billion years — more than half the age of the Universe.

When a star dies, it turns into a white dwarf — a dense ball of carbon and oxygen the size of Earth. Predicted by Subrahmanyan Chandrasekhar, these objects were long thought to be lifeless graveyards.

The giant cloud of icy chunks on the outskirts of the Solar System, the Oort cloud, resembles a transparent bubble stretched to a light-year across. Usually, these chunks hang quietly in their distant corners, but sometimes something disturbs them. Most often, it's the tidal influence of our Galaxy.

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.

In 5 billion years, the Sun, having exhausted its fuel, will start to swell, turning into a red giant. Like a balloon losing air, the star will weaken its gravitational grip, and Earth — a grain of sand on an invisible thread — will drift to a more distant orbit.

In the catalogs of exoplanets, there are many worlds with sizes between Earth and Neptune. They are divided into two groups: rocky super-Earths and gaseous mini-Neptunes. The Solar System has none of these, and scientists debate where they come from. The authors of the study looked into each planet's 'passport'—its orbit.

On the periphery of the Solar System lurk thousands of objects comparable in size to an exoplanet — a body of planetary mass not bound to our star. Their orbits are chaotic, and from time to time the trajectory of such a wanderer crosses Earth's path.

Moments before totality, swift shadow bands glide across the ground, like ripples from pebbles tossed into water. For centuries, this phenomenon baffled scientists. It turns out the key is that light is a wave. The Sun isn't a pinpoint lamp but a vast disk. When the Moon nearly covers it, a thin glowing crescent remains.

The stellar halo of the Milky Way is a galactic palimpsest: an ancient manuscript where earlier layers lie hidden beneath the visible text. For a long time, the Gaia-Sausage-Enceladus (GSE) structure was thought to be the final entry in this manuscript, the scar of a single catastrophic merger.

Putting together the Solar System is like crafting a high-end tasting menu: the recipe isn't always set in stone — sometimes the final ingredient is added while the dish is already cooking.

Eight hundred million years ago, in the main asteroid belt, a giant inkwell shattered. The parent body, over a hundred kilometers in diameter, made of primitive carbonaceous chondrites, suddenly broke apart near the J3:1 resonance with Jupiter.

At the edge of the solar system, where the Sun is barely brighter than other stars, icy boulders, trans-Neptunian objects, circle around. Their orbits resemble hoops scattered by someone. But look closer: twelve of these hoops are not just floating in the void.

Our Solar System isn't an island in the void: it's a sensitive web stretched in a dark cosmic corner. Planets circle their orbits like dewdrops on threads, and we are the spider sensing the faintest tremor. That tremor betrays the approach of the catastrophe astronomers call the Big Rip.

A huge rotating pancake of gas and dust surrounds a young star. In such a "maternity ward" for planets, rings and gaps are often seen, as if an invisible plow had carved furrows. These are usually attributed to already-formed planets that clear paths with their gravity.

Chondrules look like frozen raindrops made of stone. They're about the size of a grain of sand, but they record the history of the first few million years of the Solar System. Once, these droplets floated in the scorching gas around the young Sun, then clumped into asteroids and fell to Earth as meteorites.

An old chest of family heirlooms opens, and inside lie jewels that were thought to be as old as great-grandmother. But suddenly it turns out: the gold was remelted, the stones were recut, and this happened much later than thought. A similar story happened to the oldest particles in meteorites — calcium-aluminum inclusions, or CAIs.

A stone thrown into a pond creates ripples that spread far. But if you throw it into thick jelly, the waves die out almost immediately. That's roughly how an additional gravity field behaves under different mathematical descriptions. The authors built a unified approach to calculate how such a field manifests itself in the Solar System.

Every 1151 years, seven planets of the Solar System, from Mercury to Neptune, find themselves at almost the same points in their orbits. Their positions scatter by less than a degree, as if the celestial mechanism is wound to the same tune. This rhythm was discovered by comparing planetary positions over 2600 years using precise tables of celestial motion.

Other galaxies are just ancient snapshots, but we watch the Milky Way live. Comparing data over 30 years, scientists found that the Galaxy’s center is, like, speeding up: the supermassive black hole got heavier, swallowing the mass of a large asteroid each year; the stellar bar (a huge beam of billions of suns, like the…

The Kepler telescope spent years watching thousands of stars, spotting planets by the tiny dips in starlight when a planet passes in front of its star. Such a passage, or transit, lets us measure the planet's size but not the shape of its path.

When a baker kneads dough, the grains of flour can tell you which mill they came from. It's the same with Earth: the composition of iron in its depths preserves a memory of where the pieces that assembled the planet were born.

A sugar cube sits on a saucer next to a cup of hot tea. Drop it in, and it dissolves within minutes. But if you lower it slowly, the sugar melts gradually, releasing its sweetness into the drink. Something similar is happening in two newly discovered stellar pairs, except the sugar is a brown dwarf and the tea is a star.

In the southern sky, the star Acrux shines brightly — the lowest point of the Southern Cross constellation. It is not a single star but a whole family. New observations revealed that it contains not five, but seven stars bound by gravity, like children holding hands in a circle dance.

GJ 504, a star almost the same age as our Sun, is spinning with remarkable vigor: it completes a full rotation in just 3.4 Earth days, while actively emitting X-rays. For comparison, typical stars of the Sun's age rotate much more slowly, as if they've lost their youthful energy. GJ 504, however, behaves like a figure skater who has received a powerful push and launched into a rapid spin.

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.

Blue giant stars are usually born in tight stellar nurseries — open clusters within the thin disk of our Galaxy. But sometimes such stars are found high above the disk, as if thrown out of their home. How did they get there?

The icy body Arrokoth looks like a snowman: two spheres pressed together. Many such two-headed objects exist beyond Neptune's orbit, in the Kuiper Belt. For a long time, it was thought they formed from the slow collision of two separate bodies. New simulations show a different path. A cloud of small pebbles around the young Sun collapses under its own gravity.

A star nine times heavier than the Sun ignites a zone around it where liquid water could slosh on a planet's surface. But this zone is like a narrow strip of beach at low tide: it will vanish in 30 million years. Such stars live bright and die young, leaving life no time for the long journey from microbes to complex beings.

130 light-years away, four giant planets orbit the young star HR 8799—each 5 to 10 times more massive than Jupiter. They lie far from the star, at distances from 15 to 70 astronomical units (one astronomical unit is the distance from Earth to the Sun).

Saturn's system 300 million years ago resembled a crowded dance floor. The most massive moon, Titan, began to migrate, and this movement threw its neighbors off balance. One moon crashed into Titan; the debris swirled into a vortex, gathering into Hyperion.

Two stars circle each other like a pair of figure skaters on ice. Both resemble the Sun, but one shines brighter and has puffed up, while the other remains compact. Astronomers peered into their light using spectrographs, instruments that split light into colors, and found something odd: one star is clearly poorer in heavy elements than the other.

Jupiter is a colossal ball of gas that sits five times farther from the Sun than Earth. Now imagine a similar ball, but around another star, at a distance tens of times greater. These are called cold Jupiters, and they remain a puzzle: how did they get there? Astronomers studied four such planets around distant stars.