coronal mass ejection

In a pot on the stove, water starts to churn from the bottom long before the whole thing boils. Bubbles of steam rise from the base even though the burner itself hasn't heated up yet.

When a star explodes, its material flies into space. In the supernova remnant SNR 0509-67.5, this material did not spread into a smooth cloud but gathered into separate clumps, like lumps in batter that is quickly stirred. The MUSE telescope in Chile saw these clumps in the faint glow of forbidden iron and calcium lines.

In the solar corona, it rains from time to time — only not water, but plasma. The hot gas cools, clumps into blobs, and rushes downward along magnetic loops, like drops running down invisible gutters.

Two galaxies (our Milky Way and its satellite, the Large Magellanic Cloud) slowly circle each other. Their gravitational pull stirs the distant outskirts of the Milky Way, like a pebble thrown into a pond makes the water ripple.

In the summer of 2021, comet 7P/Pons-Winnecke put on quite a show. A network of telescopes, the Las Cumbres Observatory, tracked it for nearly three months and counted eight sudden outbursts.

The Universe at 700 million years old was a noisy construction site, just beginning to light up. Telescopes caught a signal from that distant epoch: the galaxy REBELS-25, massive and full of stellar fuel.

A sunspot cools, and above it a dark filament, a prominence, hangs for weeks. Inside it, like a compressed spring, hides the magnetic field. It can be laid out in neat arches, or it can be twisted into a tight rope.

When a massive star dies, its core collapses, and a supernova explosion occurs. The cataclysm births streams of particles — like ripples from a thrown stone. The first to arrive are swift neutrinos, which pierce the Earth, hardly interacting. Then, hours later, ghost particles with a tiny charge appear.

In the dense gaseous cocoon around a young massive star, streams of matter collide as if in a giant chemical flask. One stream moves relative to us at about 11 kilometers per second, the other at about 5. The telescope at Onsala (Sweden) caught their radio voices and resolved them into hundreds of spectral lines — molecular fingerprints.

In the scorching solar corona, where temperatures soar past a million degrees, float cold, dense clouds — solar prominences. They hang for weeks, neither falling nor dissolving, like icebergs in a boiling ocean. How they got there is a question that has puzzled astronomers for decades.

A stream of scorching gas races away from a star, and suddenly stalls, as if it hit an invisible wall. That's exactly what researchers saw when they tried to reproduce a stellar eruption on a laboratory scale. They used a laser to create a plasma jet and shot it through a magnetic field — first weak, then strong, like that of many stars.

A radio signal travels from Mars to Earth, but on the way it has to push through the invisible "wind" of charged particles blowing from the Sun. This wind, like ripples on water, slightly distorts radio waves.

A crowd pours out of a narrow passage. Some run in a tight group in one direction, like jetty events in nuclear collisions. Others scatter evenly in all directions, like isotropic events. The shape of particle debris, which physicists call transverse sphericity, turned out to be a handy tool for hunting a rare phenomenon.

Interstellar space is not empty: it is filled with tenuous gas, which is warm in some places and cold in others. The boundaries between such regions resemble the walls between soap bubbles.

In the first moments after the Big Bang, the universe was not empty and quiet but filled with hot plasma, particles, and magnetic fields. Among the particles, there may have been axions — light, nearly elusive dark matter candidates.

The Sun sometimes produces giant clouds of plasma that try to escape into space. But often they fail: an invisible magnetic cage keeps them near the surface. Such failed eruptions are called "trapped." Scientists built a computer model to understand exactly how this cage works.

In its youth, Earth resembled a beehive: it grew by sticking together from countless rocky chunks. When the main construction was over, a late swarm of meteorites rained down on the young planet — the so-called late veneer. These impacts, scientists thought, brought platinum, gold, and other rare metals to Earth's upper layers.

A distant galaxy, similar to our Milky Way, is blowing gas into space like a hair dryer blowing dust off a table. Seven beams of light from an even more distant object pierced this gas cloud, and astronomers saw that the gas flow is narrow, like a jet from a hose, not wide like a fan.

The Sun's surface boils like water in a pot. Hot gas rises, cools, and sinks: that's convection. Magnetic fields churn around, tearing and reconnecting. In this frenzy, spicules are born: narrow plasma jets that shoot thousands of kilometers upward.

October 10, 2024. The Sun hurled a cloud of magnetized plasma toward Earth, and four spacecraft, stationed at a single point between the Sun and Earth, simultaneously recorded how that cloud churned. The distance between the outermost probes was just 80 Earth radii, about half a million kilometers.

A solar flare is like a giant spring that gets twisted and twisted, and then suddenly snaps. The energy stored in the magnetic field is unleashed into space within minutes, heating plasma to millions of degrees.

The Sun regularly produces explosions that hurl huge clouds of charged particles into space. Such a cloud travels toward Earth and can knock out satellites, disrupt radio communications, and even leave cities without electricity.

The Sun occasionally hurls enormous clouds of plasma into space — coronal mass ejections. Often tangled within these clouds are prominences: cooler, denser clumps of material. These contain plenty of neutral atoms that shine brightly in specific spectral lines.

A solar flare is like a tightly coiled spring suddenly uncoiling. In the Sun's corona, energy accumulates in the twisted magnetic field, and then it is abruptly released, accelerating particles and heating plasma.

A solar flare is like an explosion in a star's atmosphere: in minutes, it releases energy comparable to billions of nuclear bombs. On May 4, 2022, the RT-7.5 radio telescope in Moscow was watching an M5.7-class flare. The instrument was catching millimeter radio waves: those shorter than a centimeter and invisible to the eye.

The Sun frequently launches narrow plasma jets, coronal jets, that resemble fountains of superheated gas erupting from the star's atmosphere. One such eruption, which occurred on November 10, 2022, caught scientists' attention: it was accompanied by a C1.1-class flare and had an unusually wide cone.

On December 31, 2023, the Sun unleashed a flare of the highest class — one that releases the energy of billions of atomic bombs in just a few minutes. Along with it, a huge prominence, a cloud of superheated gas, tore away from the surface and shot outward at nearly 3000 kilometers per second.

A solar flare is like an explosion in the atmosphere: bright, fast, with different 'voices.' X-rays come from electrons that have been accelerated and then abruptly slowed down, losing energy. But in 2017, detectors on the Fermi satellite caught a different signal — gamma rays that didn't fit this picture.

On March 30, 2022, two spacecraft — BepiColombo and STEREO-A — simultaneously felt a shockwave from the Sun. The first was at 0.6 times the Earth-Sun distance, the second at exactly one such distance.

In the binary system 4U 1624-49, a neutron star pulls gas from its companion star. This gas spirals into a glowing disk, like water in a funnel. And from the edge of this funnel, a hot stream tears away — hydrogen and other elements fly off at speeds up to 320 kilometers per second.

The Sun constantly emits a stream of charged particles, mostly hydrogen — the solar wind. Sometimes the Sun ejects dense blobs of magnetized gas, inside which calm usually reigns. But in 2000, scientists noticed two regions inside one such cloud where the gas was churning.

A total solar eclipse offers rare minutes when the Moon blocks the Sun's bright disk, revealing its outer atmosphere — the corona. In white light, the corona extends tens of solar radii, and images show fine structures: vortex rings, waves like ripples on water, and huge plasma ejections.

The red dwarf V374 Pegasi is a star one-third the size of the Sun, but with the temperament of a volcano. Every few hours, giant clumps of plasma tear away from its surface, like steam bubbles from a boiling cauldron. These ejections, called prominences, fly off into space and generate bursts of radio waves.

Cosmic rays are like a downpour pelting from all sides. But when the wind blows, the droplets change direction. In the same way, a solar storm, a cloud of magnetized gas from the Sun, bends the paths of these particles that normally rain down on Earth evenly. Cosmic rays are invisible messengers from distant galaxies.

On the night of March 9–10, 2024, a cloud of plasma ejected by the Sun raced away from the star. It had already passed a distance of five solar radii when a ground-based array of 352 antennas in California's Owens Valley caught a brief radio signal from it.

The ARCADE2 radiometer on a high-altitude balloon detected an excess radio emission, while the ground-based EDGES experiment found an anomalously deep trough in the hydrogen spectrum at 21 cm. Both signals do not fit the standard cosmological model and point to an unknown source of soft photons.