object

milky way central black hole

The supermassive black hole Sagittarius A* at the Galactic Center.
69 related articles

Description

Sagittarius A* (Sgr A*) is the supermassive black hole at the center of our Milky Way galaxy. With a mass about four million times that of the Sun, it anchors the orbits of stars in the galactic core. While it is relatively quiet compared to black holes in other galaxies, it occasionally flares in X-rays and infrared, and its gravitational influence shapes the motion of gas and stars in the central region.

History

The existence of a massive compact object at the galactic center was proposed in the 1970s, and the name Sagittarius A* was coined in 1982. The Nobel Prize in Physics 2020 was awarded for the discovery that Sgr A* is a supermassive black hole.

How it works

Sgr A* is so massive that its gravity dominates a region of space about the size of our solar system. Stars orbiting it, like the famous star S2, follow paths that can be precisely measured to test Einstein's theory of general relativity. The black hole itself is invisible, but its presence is revealed by the motion of these stars and by the radiation emitted from gas that heats up as it spirals inward.

In practice

Sgr A* serves as a natural laboratory for testing general relativity in a strong gravitational field and for studying how supermassive black holes grow and interact with their host galaxies.

Fun fact

If you were to stand at the event horizon of Sgr A*, you would experience tidal forces so strong that you would be stretched into a thin stream of atoms, a process astronomers call 'spaghettification'.

Concept graph →

Related articles · 69

The Galactic Center Ridge: A Break in the Gamma-Ray Spectrum
At the center of the Milky Way, where the supermassive black hole Sagittarius A* churns gas clouds like a millstone, astronomers have caught an irregular pulse. Gamma-ray emission, the most energetic light in the universe, arrives not as a smooth wave but with a break, as if the Galaxy's heart beats with arrhythmia.
Immortal Stars with Black Holes Inside: How Gas Accelerates Mergers in Galactic Centers
At the center of a galaxy, where a supermassive black hole spins a disk of scorching gas around itself, giant stars sometimes form. They are unlike ordinary stars: the disk continuously feeds them with matter, and a star can grow to hundreds of solar masses, staying bright as long as the gas flow lasts.
A Puzzle with No Picture on the Box
A network of radio telescopes scattered across the planet catches the whisper of a distant black hole. Each antenna records a signal, but how do you combine these recordings if the clocks at the stations tick at different rates and the atmosphere distorts incoming waves?
Cosmology2026-08-122 minarXiv:2608.12042
Radio Echo at the Cluster's Edge: MeerKAT Catches a Ghostly Glow
The galaxy cluster RXC J0528.9−3927 is like a city shrouded in fog: at its center, a radio halo shines brightly, but farther out, beyond the usual boundaries, astronomers have spotted a barely visible glow. It stretches for two million light-years — three times farther than the halo itself.
Galaxies2026-08-111 minarXiv:2608.10577express
Measuring the Milky Way Through Dusty Stars
Red giants in the center of the Milky Way resemble distant lighthouses that brighten and dim. Their light pierces through dense dust, but standard distance-measuring methods fail here: the stars are too bright and unstable, and dust distorts the picture. Astronomers found a workaround.
Galaxies2026-08-102 minarXiv:2608.10088express
The Andromeda Nebula: What Does Its Hot Halo Hide?
The Andromeda galaxy is our nearest large neighbor, and like the Milky Way, it has an invisible gaseous shroud. This shroud of extremely hot, rarefied gas extends for hundreds of thousands of light-years. Seeing it directly is nearly impossible — the gas is too faint.
General Relativity2026-08-072 minarXiv:2608.07229express
A Black Hole in a Fur Hat
A dance floor where couples whirl. At the center, an invisible master of ceremonies sets the rhythm. This is the supermassive black hole at the heart of the Milky Way, and the couples are stars whose orbits astronomers have tracked for years. But what if the master himself is wrapped in a fluffy fur coat of tenuous matter?
High Energy2026-08-072 minarXiv:2608.07391express
Gravitational Echoes of Dying Stars
The calm surface of a lake suddenly ripples — somewhere in the depths, an underwater cliff has collapsed. The water trembles almost imperceptibly, and the circles spread wider and wider until they reach a bobber near the shore.
Galaxies2026-07-242 minarXiv:2607.22517
Stellar Fossils: S301 — The Lost Twin?
1799 kilometers per second — that's the speed at which star S5-HVS1 is permanently leaving the galaxy. 4.8 million years ago, it was ejected from the center of the Milky Way during a close encounter with the supermassive black hole Sgr A*.
Cosmic Graininess: Finsler Gravity Extends the Mass Limit of Neutron Stars
In August 2019, the LIGO and Virgo detectors picked up gravitational waves from the merger of two compact objects in a binary star. One weighed 23 solar masses — a standard black hole. The other came in at 2.5–2.67 M⊙.
Galaxies2026-07-064 minarXiv:2607.04942
Stellar Nurseries in the Jet's Shadow: JWST Explores Centaurus A
The cosmic spectacle unfolds on the stage of Galaxy галактики Centaurus A. In the lead role: a supermassive сверхмассивная чёрная дыра with a powerful jet that pierces space for hundreds of thousands of light-years.
Gravitational Slingshot: How Black Holes Accelerate Dark Matter
In 1933, Fritz Zwicky first spoke of an invisible mass holding galaxy clusters together. Decades later, Vera Rubin mapped galactic rotation, revealing the ghostly presence of dark matter. Today we know it pervades the cosmos, but its particle nature remains elusive.
The Collapsar's Gravitational Boomerang: Cracking the GW190814 Anomaly
LIGO and Virgo detectors catch ripples in spacetime, but some signals force us to rewrite the scripts of stellar death. GW190814 — the merger of a black hole of 23 solar masses with a compact object of 2.6 solar masses — is a discordant chord in the symphony of standard models.
Galaxies2026-06-211 minarXiv:2606.22559express
Invisible Conductors of Galactic Disks
At the heart of nearly every large galaxy shines an active nucleus — a supermassive black hole surrounded by a flat, rotating disk of incandescent gas. The disk itself flickers, but astrophysicists suspect that within it lurks a whole swarm of small, stellar-mass black holes.
Cosmology2026-06-061 minarXiv:2606.08097express
X-ray Snapshot of a Sleeping Giant
A giant city of thousands of galaxies is shrouded in an invisible cloud of scorching gas. This gas is like the air in a room: it can be calm, or it can churn with drafts. Astronomers aimed the latest X-ray "thermometer" at such a city — the cluster Abell 1795—and measured how fast the gas moves there.
Galaxies2026-06-043 minarXiv:2606.06620
Roots of the Cosmic Banyan: How Black Holes Feed
Cosmic black holes at the centers of galaxies are like giant banyan trees: their aerial root‑filaments stretch for kiloparsecs to harvest nourishing matter. For decades astronomers have debated: how does cooling gas from cluster atmospheres fall into the sphere of influence of a supermassive hole?
General Relativity2026-05-211 minarXiv:2605.22210express
A Star Dances with Dark Matter Near a Black Hole
At the heart of our stellar metropolis — the Galaxy — lurks the supermassive black hole Sagittarius A*. Around it, star S2 whirls in a swift dance. But its movements reveal more than just the hole's pull: an invisible partner joins the dance — dark matter.
Galaxies2026-05-202 minarXiv:2605.21212express
Cosmic Lens Reveals Invisible Clump of Dark Matter
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.
High Energy2026-05-162 minarXiv:2605.16766express
An X-ray Snowstorm Around a Black Hole
The XRISM X-ray telescope spent 170,000 seconds staring at the core of galaxy Cygnus A — one of the most powerful radio sources in the sky. At its center lurks a supermassive black hole that sucks in matter and heats it until it glows in X-rays. The instrument caught light from iron atoms that had lost electrons.
High Energy2026-05-132 minarXiv:2605.13962express
X-ray Flares from the Black Hole at the Center of the Milky Way
A giant cauldron that barely smolders most of the time, but occasionally spits out showers of sparks. That is roughly how the supermassive black hole at the center of our galaxy — Sagittarius A*—behaves. It weighs four million times as much as the Sun and lies 26,000 light-years away.
High Energy2026-05-121 minarXiv:2605.12448express
Ancient Black Hole Jet Left a Gamma Trail in the Center of the Galaxy
The center of the Milky Way has long puzzled astronomers: around the supermassive black hole Sagittarius A* there are more gamma rays than expected.
Stellar Mimicry: Boson Stars Pretend to Be Black Holes
The cosmos is full of mimicry. The clearwing moth wears a wasp's mask, a harmless fly buzzes like a bee. And in the world of gravity, the role of impersonator is perhaps played by boson stars — colossal clumps of scalar field, indistinguishable from black holes.
High Energy2026-04-272 minarXiv:2604.24617express
Dust Rings Reveal the Secrets of the Spiral Arms
Imagine a dark room with dust floating in the air. A bright flashlight goes off, and the dust particles light up, revealing their positions. Astronomers have applied a similar trick to our Galaxy. The flashlights were gamma-ray bursts, the most powerful explosions in distant galaxies, and the dust particles were interstellar clouds.
High Energy2026-04-232 minarXiv:2604.21883express
The Invisible Star at the Center of the Galaxy
At the center of the Milky Way lurks something invisible but extremely massive — about four million times heavier than the Sun. It is usually called a black hole and designated Sagittarius A*. But astronomers are not letting their guard down: what if it is not a hole but something more exotic, like a giant ball of ultralight particles — a boson star?
Instrumentation2026-04-202 minarXiv:2604.18825express
Hunting the Mysterious Light at the Galaxy's Center
At the very heart of the Milky Way, something is continuously glowing in gamma rays. This light is special: its energy is exactly 511 thousand electronvolts. Such energy is produced when an electron meets its antimatter counterpart, a positron, and they annihilate, leaving behind a flash of light.
Galaxies2026-04-162 minarXiv:2604.14502express
The Milky Way Swallowed a Neighbor 11 Billion Years Ago
About 11 billion years ago, the Milky Way suffered a head-on collision. Not with an asteroid, but with an entire smaller galaxy. It slammed into ours and was torn apart like a puff of flour hit by a fist. Astronomers call this cosmic scar Gaia-Sausage-Enceladus (after the shape of the orbits of its remaining stars).
High Energy2026-04-132 minarXiv:2604.11874express
Double Echo from Black Hole Not Confirmed
The galaxy MCG+11-11-032 is relatively close to us: its light takes about 150 million years to reach us. At its center, like in most large galaxies, sits a supermassive black hole. But a few years ago, astronomers began to suspect: what if there are two? The clue came from the X-ray spectrum.
Galaxies2026-04-111 minarXiv:2604.10287express
The Heart of the Milky Way Flickers in Polarized Light
At the center of the Milky Way lies the supermassive black hole Sagittarius A*. It is four million times more massive than the Sun, but by cosmic standards it behaves quietly: it only occasionally flares up when it swallows a clump of gas.
High Energy2026-04-102 minarXiv:2604.09761express
A Black Hole's Hot Corona Puffed Up and Flew Away
At the center of the distant galaxy MCG-6-30-15 lies a supermassive black hole. Around it swirls a disk of incandescent gas, and above the disk hangs a cloud of even hotter particles — the corona. In February 2024, three X-ray telescopes (XRISM, NuSTAR, and XMM-Newton) observed this system simultaneously.
Stellar2026-04-101 minarXiv:2604.09901express
Magnetic Fields in the Cores of Red Giants
Eight red giants — bloated old stars like the future Sun — are not behaving by the book. Their surfaces oscillate steadily, like a bell, but within this chime there are glitches: some tones are missing, and the rhythm breaks. Scientists suspected an invisible hand inside — a magnetic field — and tried to calculate its strength.
Galaxies2026-04-082 minarXiv:2604.07440express
A Giant Galaxy from the Young Universe
Through a telescope, you can see a galaxy that looks like a giant glowing pinwheel. Its disk stretches thirty thousand light-years across — a third of the diameter of our Milky Way. But the most astonishing part: this pinwheel already existed just two billion years after the birth of the universe.
High Energy2026-04-082 minarXiv:2604.07588express
An X-ray Tangle at the Heart of the Milky Way
The center of our galaxy is a crowded kitchen where several dishes are simmering at once, and their steam blends into a single cloud. X-rays from the exploded star's remnant, from the stellar wind around the supermassive black hole, and from hot gas between stars all overlap.
Galaxies2026-04-021 minarXiv:2604.01828express
Cosmology2026-03-311 minarXiv:2604.00111express
Mysterious Flashes in Andromeda: Not Black Holes, but Stars
For nearly a century, astronomers have been searching for dark matter — an invisible scaffold that keeps galaxies from flying apart. Fritz Zwicky first proposed it, and Vera Rubin proved its existence by showing that stars on the outskirts of galaxies move too fast.
Galaxies2026-03-261 minarXiv:2603.25600express
The Galaxy's Halo: How to Weigh the Invisible
Every galaxy is wrapped in an invisible shell of hot gas, like steam rising from a pot of boiling water. This gas barely glows in X-rays, making it notoriously difficult to measure. Yet it holds the memory of stellar explosions and the galaxy's growth. The new method uses light from a galaxy's bright center.
Galaxies2026-03-242 minarXiv:2603.23327express
Gas Clouds Dance Around the Galactic Center
In the very center of the Milky Way, hidden behind a thick veil of dust, lies a giant accumulation of gas — the Central Molecular Zone. You can't see it with the naked eye: dust absorbs visible light, much like dense fog hides the lights of a city.
High Energy2026-03-171 minarXiv:2603.17210express
An X-ray Trail at the Center of the Galaxy
At the center of the Milky Way, among dense clouds of gas and dust, lies a region called Sagittarius C. It's like a bustling crossroads: stars are born here, streams of matter collide, and the whole scene is illuminated by X-rays. For a long time, this glow remained a mystery.
Galaxies2026-03-121 minarXiv:2603.12082express
The Shock Wave That Reshapes Galaxies
In the Norma cluster, the nearest rich galaxy cluster to us, astronomers have spotted a shock wave. It arose when one cluster plowed into another, like the bow wave of a ship cutting through water. This wave compressed and heated the gas between the galaxies. Two galaxies sit right behind the wave front.
Stellar2026-03-111 minarXiv:2603.11194express
Seven Stars in One System
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.