pierre auger observatory

In the constellation Orion, in the cloud of gas and dust L1641, the young star PR Ori B suddenly flared up like a furnace that someone had thrown fuel into. Its brightness rose fivefold, and astronomers watched for the first time as a fuor was born, a rare event in which a star begins greedily swallowing material from the surrounding disk.

Gamma rays are the most energetic light in the Universe. But one part of them, the medium-energy range, long remained invisible: instruments couldn't catch them, leaving a gaping hole in the sky. Scientists call it the "MeV gap," named after the unit of energy these rays carry. The new camera works like a three-layer detective.

Cosmic rays aren't rays in the usual sense: they're fast particles bombarding Earth from all directions. Mostly they're protons and atomic nuclei. Their energies vary widely, from modest to fantastically huge. When such a particle heads our way and the Moon or Sun gets in its path, it gets absorbed.

Betelgeuse, the red supergiant familiar from Orion's shoulder, keeps surprising us. After the mysterious Great Dimming of 2019–2020, when the star suddenly dimmed, it didn't just recover; it changed its ways.

Empty space is not as empty as it seems. According to quantum theory, the vacuum is filled with particles that constantly pop in and out of existence. In 1976, physicist Bill Unruh showed that if an observer moves with acceleration, this 'quantum soup' turns into a genuinely warm bath for them — the Unruh effect.

In the constellation Aquila, about 40,000 light-years away, one of the most powerful natural accelerators in the Galaxy is at work. It's the microquasar GRS 1915+105—a pair consisting of an ordinary star and a black hole.

Using James Webb, astronomers 'fished out' a third giant planet from the murky dust disk of the star β Pictoris. Two others were already known, but this one was hiding in the bright light, like a fish in muddy water.

Two beams of light race around a closed loop, heading toward each other. Since the speed of light is constant, when the ring turns, one beam has to catch up with a moving finish line, while the other meets it sooner. Their meeting creates a pattern, and from that pattern we can tell how fast the whole system is spinning.

On a dark night over the Uruguayan pampa, a dazzling fireball silently flares up. It streaks for a few seconds, scattering sparks, and fades beyond the horizon. This is a bolide — a large asteroid fragment slamming into the atmosphere. If it survives the fall, a meteorite will land on the ground.

Deep in the Mediterranean Sea, where water presses down with the force of hundreds of atmospheres, a network of light-sensitive spheres waited for a rare guest. And it came — a neutrino that carried through the bulk of the Earth an energy comparable to the impact of a flying brick.

Cosmic rays are particles from deep space, accelerated to colossal energies. Smashing into the atmosphere, they trigger particle showers with radio waves. These waves are fingerprints, revealing the energy and direction of the intruder.

The Oort Cloud is a spherical swarm of trillions of icy bodies at the very edge of the Solar System, about a light-year from the Sun. These objects are almost motionless relative to one another until some gravitational disturbance breaks their calm.

Conventional dark matter detectors are like a soccer goalkeeper waiting for a powerful shot while the ball barely rolls. The invisible particles filling our galaxy often move too slowly to be noticed by sensitive sensors.

Deep in the constellation Aquila lies a nebula that looks like an expanding bubble. It is inflated by a tiny star the size of a city — a pulsar that makes several rotations per second and loses rotational energy. Usually, such bubbles shine exactly as brightly as their pulsar is powerful.

Above Jupiter's poles, auroras blaze as electrons are accelerated by electric fields and slam into the upper atmosphere, making the gas glow. But not all electrons head downward. Some, it turns out, get a kick in the opposite direction — away from the planet, into deep space.

In October 2022, the cosmos put on a fireworks show that every detector on Earth noticed. The explosion, named GRB 221009A, was so bright that it was called the brightest ever observed. It's a gamma-ray burst — a short but incredibly powerful flash that releases as much energy in seconds as the Sun will produce in its entire lifetime.

Every second, invisible particles from space, cosmic rays, strike Earth's atmosphere. Colliding with air molecules, they produce showers of secondary particles, among which muons are especially abundant. A muon is a heavy cousin of the electron that lives only a couple of microseconds but still manages to reach the ground.

In an underground hall at Fermilab, a huge tank holds liquid argon — a transparent fluid at minus 186 degrees. When an invisible neutrino flies into the tank, it occasionally strikes an argon nucleus, and a short track of charged particles flashes.

Neutrinos are ghost particles: predicted by the Standard Model, they barely interact with matter. Catching them is like trying to hear a whisper in the roar of a waterfall.

In 1976, Canadian physicist Bill Unruh asked a simple question: what does an observer see when accelerating through empty space? The answer turned out to be strange: emptiness ceases to be empty. An accelerating observer bathes in thermal radiation with a temperature proportional to the acceleration.

In 2022, the Subaru telescope photographed a point of light 100 astronomical units from the star AB Aurigae. The point was named planet AB Aur b, but debates did not subside: what exactly is glowing, the planet itself or dust around it?

Every second, dozens of particles from space fly through each of us. Most are light protons, but there are also heavier atomic nuclei: carbon, oxygen, iron. They are born in stellar explosions and travel to Earth for millions of years. Their energy can be staggering: a single particle can carry as much as a tennis ball on a serve.

Every clear night, a telescope in the Chilean desert records light from distant stars, and in those recordings, like old ship logs, traces of weather remain. The thin dark bands in the spectrum are imprints of water vapor that hung over the observatory at the moment of observation.