rogue planet

The night sky seems unchanging, but galaxies constantly exchange matter. The Milky Way, like a great river, absorbs smaller streams — dwarf galaxies. Along with their stars, planets may also come to us.

The birth of a moon is a cosmic car crash. Two young planets collide, and a cloud of scorching debris swirls around the surviving world. From this disk, like clay on a potter's wheel, a satellite gradually takes shape. That's probably how our Moon came to be.

In 2024, the team led by David Charbonneau pointed the Magellan telescope with the WINERED spectrograph at LHS 1140. During transit, high-resolution spectroscopy caught the absorption line of metastable helium at 10833 Å.

The Moon is an airless sphere of dense rocky grit called regolith. When fast particles from space slam into it, muons are born in the soil — unstable relatives of electrons, but two hundred times heavier. Most fly downward and fade away in the depths. But those that pop upward into the vacuum can travel tens of kilometers before decaying.

In the Galactic bulge, where the light of billions of stars merges into a continuous glow, four cold giants passed unnoticed. You can't see them through a telescope — too far, too dim.

In the young Universe, about ten billion years ago, galaxies resembled endless fields after a thunderstorm: everywhere, giant — thousands of light-years across — clumps of star formation were boiling up, where young stars were born with unbridled energy. Today, these patches are an almost vanished species: in nearby galaxies, raucous hotbeds are rare.

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?

The light of a distant star is no perfect beacon. Passing through the gravitational field of another star, it bends, splits, and magnifies, creating a fleeting Einstein ring in the sky. This is how gravitational microlensing manifests, predicted by Fritz Zwicky back in the 1930s.

Like an exquisite clockwork mechanism, a multi-planet system responds sensitively to the slightest nudge. And when the star at the heart of this mechanism dies, shedding its envelope and turning into a white dwarf, even a modest kick at a speed of 0.75 km/s can trigger a cascade of events, flinging entire worlds into interstellar emptiness.

A planet the size of Neptune wandered too close to its star. The star begins to pull the planet's outer layers onto itself — gas streams off the planet like water from an overflowing bucket. This process is called Roche-lobe overflow (astronomers use this term for the boundary beyond which a star can tear material away from a planet).

Imagine a person in an old photograph standing in a crowd while spinning — guessing their age would be nearly impossible. That's roughly how astronomers determine the ages and masses of distant stars, and they often get it wrong. For stars slightly heavier than the Sun (from 1.4 to 2.5 solar masses), standard methods like chemical-composition 'clocks' work poorly.

Interstellar space is not a cosmic desert, but a super-fast highway. Trillions of asteroids and comets from other systems race past us, yet camera-telescopes only catch a few. Imagine a night highway: the headlights of a distant car flash brightly, but if it zooms by too fast, the camera shutter can't click in time.

The cosmic accounting has hit a snag. The bookkeeper is balancing the books: in one column, all the planets astronomers have counted in the galaxy; in the other, the stockpile of building material in the dusty cocoons of newborn stars. The numbers don't line up. Even if you gathered every last grain of dust and molded it into planets, there wouldn't be enough material.

A research probe is planned for the nearest black hole — a region of spacetime whose gravity traps even light. After a hundred years of flight, the spacecraft will enter orbit around the mysterious object to answer a key question: are we looking at a black hole or a neutron star — the ultra-dense remnant of a massive star, compressed to nuclear…

The first exoplanet was discovered around an unusual cosmic lighthouse — a neutron star known as a pulsar. These ultra-dense remnants of dead stars spin at tremendous speeds and emit precise radio pulses.

A glowing cloud in a telescope looks like a wisp of fog about to dissipate. Planetary nebulae are gas shells cast off by dying stars. Young nebulae are bright and compact, but as they age, they expand, cool, and become increasingly transparent until they vanish into the interstellar medium.

At night, a distant streetlamp seems motionless, but if you walk closer and look carefully, you might notice it swaying slightly in the wind. That's roughly how astronomers hunt for planets around other stars: they measure how a star shifts ever so slightly under the gravitational tug of its invisible companions.

Around distant icy bodies the size of a city, circling beyond Neptune, rings of dust and ice have been found. Small moons often whirl nearby. Mathematical analysis shows that a moon's gravity rocks the ring like a swing, making it tilt.

Massive stars end their lives in a colossal explosion, which Fritz Zwicky called a supernova. The core crushes down into a black hole or a neutron star.

A planet hugging its star is like an ice cube forgotten on a scorching skillet. The ice melts and evaporates, except instead of water, it's hydrogen and helium from the planet's upper layers.

Astronomers nicknamed them 'little red dots' — distant galaxies where a giant black hole hides at the center, wrapped in a thick layer of hydrogen. This packaging isn't just camouflage; it's a natural cannon. The black hole sucks in matter, but some of it is spat back out in narrow jets.

Thanks to gravitational lens — an effect predicted by Fritz Zwicky, where a galaxy cluster acts like a magnifying glass — the James Webb Space Telescope spotted two red dots in a galaxy 800 million years after the Big Bang.

Picture a star waltzing with an invisible partner: its rhythmic wobble, caused by the gravitational pull of a companion, is picked up by instruments, yet the partner itself eludes detection. Usually, such wobbles are the result of a Doppler shift, a change in the frequency of light due to the star's motion, that betrays the presence of a planet.

The planet's gravity rhythmically squeezes and kneads the moon like dough: from this constant 'kneading', the interior heats up, and oceans of water can persist under the icy crust for ages. In the Galaxy, there are plenty of rogue planets, thrown out by supernova explosions.

Many planets around other stars — exoplanets — have elongated orbits. With each close approach, the star’s gravity squeezes and stretches them, like kneading dough. Friction heats up the interior to the point where rock melts, creating underground oceans of magma.