The first image of Sagittarius A*—the supermassive black hole at the center of the Milky Way Galaxy—was revealed in 2022, almost 50 years after its discovery.

Invisible to direct observation, scientists determined the object at the center of the Milky Way—Sagittarius A*—was a supermassive black hole based on the orbits of fast-moving stars in the area.

Released in 2024, the polarized image of Sagittarius A* shows that the supermassive black hole at the center of the Milky Way exhibits powerful, spiraling magnetic fields.

The first image of a black hole was created from an international telescope network

The Event Horizon Telescope united radio observatories worldwide to image the supermassive black hole at the center of the Milky Way, known as Sagittarius A*. The team couldn’t transmit their massive dataset online, so they physically flew hundreds of terabytes of data to MIT aboard airplanes.

The first-ever image of a black hole

The Black Hole at the center of galaxy M87 is ready for its close-up, becoming the first black hole to have its image directly captured. The Event Horizon Telescope caught the distant yet massive object—it's more than 55 million light years away—recording its gravity's effect on nearby hot gases.

More than 40 quintillion black holes are estimated to exist in the universe, including about 100 million in the Milky Way, each with masses up to hundreds of times that of the sun.

The first image of a black hole was captured by creating an Earth-sized virtual observatory from a network of eight radio telescopes.

Black holes 101

At the center of our galaxy, a supermassive black hole churns. Learn about the types of black holes, how they form, and how scientists discovered these invisible, yet extraordinary objects in our universe. This three-minute video from National Geographic tutors the viewer on the basics regarding the universe's most mysterious residents.

Nearly 50 years before the first observational evidence, a soldier fighting on the Eastern Front in World War I found a mathematical solution to Einstein's equations that suggested the existence of black holes.

TON 618, the largest black hole ever detected, has the mass of 66 billion suns

The supermassive black hole is 18 billion light-years away and emits radiation with the brightness of 100 trillion stars. It is so massive that light would take an entire week to travel from its edge to its center.

Black holes can disrupt the formation of galaxies

A team of astronomers in Munich detected a gas cloud being stretched and torn apart by the supermassive black hole at the center of the Milky Way, preventing matter from coalescing into new stars. Energy released from siphoned gas produced warm winds that may also prevent surrounding gas from coalescing.

Cygnus X-1 helped scientists confirm black holes are real and measurable phenomena

The 1964 discovery of Cygnus X-1 provided the first strong candidate, but it took decades—and a famous bet between Stephen Hawking and Kip Thorne—before scientists were certain it was a black hole. Hawking's thumbprinted concession was delivered after breaking into Thorne's office.

Explaining 'impossible' black holes

When stars collapse, the black holes they form can have the mass of either 50 suns or over 120—but current models claim strongly that no black hole should have a mass that falls in between that range. But in 2019, gravitational wave observatories detected two within it: one at 66 solar masses, the other at 85. The discovery disrupted established science and left researchers questioning the Standard Model of physics.

Research suggests that about 1% of all matter in the universe is locked inside black holes, millions of which are likely to lurk undetected near us in space.

Black holes are formed from massive stars collapsing under their own gravity

This creates a region where spacetime curves infinitely, known as a singularity. Black holes' intense mass and energy allow them to trap light, distort time and space, and present challenges with reconciling Einstein's theory with quantum mechanics.

What lies inside a black hole remains one of the universe's greatest mysteries

At the center of black holes is a theoretical point of infinite density called a singularity. Alternatively, one theory suggests a black hole's core could form a Planck star—a mind-bogglingly tiny object just a trillionth trillionth trillionth of a meter in size.

The most mysterious (known) star in the universe

Something massive, with roughly 1,000 times the area of Earth, is blocking the light coming from a distant star known as KIC 8462852. One of astronomers' more intriguing theories: Alien technology. Discovered via NASA's Kepler space telescope and a...

Mapping the universe's 1.3 million quasars

Quasars form the core of active galaxies where supermassive black holes devour unimaginable amounts of matter. You can see a map of all 1.3 million of these objects with this 3D map. It was assembled with data from the Gaia spacecraft and shows how the spread of dark matter across space matches that described by the Cosmic Microwave Background.

Quasars are extremely luminous cores of distant galaxies, powered by supermassive black holes that consume as much as 100 Earth masses of gas and dust per minute.

New model replaces the Milky Way's central black hole with dark matter

A study published in Monthly Notices of the Royal Astronomical Society states that a dense core of fermionic dark matter, rather than a supermassive black hole, could explain both the rapid orbits of stars near the Milky Way's center and the galaxy's large-scale rotation detected in Gaia mission data.

Watch a simulation of a collapsing star becoming a black hole

When a massive star can no longer release enough energy through fusion in its core to fight off gravitational collapse, the dense core collapses first, producing an event horizon that traps light within it, including some light produced within the star at the time of collapse. As more material falls into the growing event horizon, the star will appear to eclipse itself from the inside.

The masses of celestial objects can be determined by analyzing their orbits, observing how they bend light, or measuring their brightness.

Massive objects can significantly bend light to produce gravitational lensing

The theory of general relativity posits that mass and energy bend space and slow down the passage of time. One consequence is that massive objects, such as black holes, curve spacetime to such an extent that light from background sources can loop around them, producing multiple images or ring-like patterns.

Gaia mapped two billion stars in the Milky Way

Using geometric parallax, the European Space Agency mission made position measurements accurate to 2.78 × 10⁻¹⁰ degrees, revealing large-scale galactic structure and dynamics. Remnants of ancient galactic mergers were also identified within the Milky Way.

When they merge, black holes release multiple solar masses of energy

The energy emanates outward in the form of gravitational waves, which can be detected at observatories like LIGO. After merging, it is impossible to determine the characteristics of the two black holes that merged to create it.

Attempts to 'fix' black hole physics have led scientists to theorize new types

Along with their spin and charge, mass is used to categorize black holes as supermassive, intermediate, or stellar-mass. However, ongoing research suggests various additional types may exist, including primordials that formed one second into the universe's birth, fuzzballs—tangles of vibrating strings—and gravastars, which have a shell of dense matter around repulsive vacuum energy.

The event horizon is an inescapable sphere around a black hole singularity

The horizon is often surrounded by an accretion disc of superheated material that orbits the black hole while emitting radiation. Light emitted behind a black hole can be bent around it to create the appearance of a ring of material known as a photon sphere.

Explaining the galaxy-sized gas bubbles hovering around the Milky Way

Depth perception is hard to achieve when looking out into space. For decades, two camps of astrophysicists have disagreed over the nature of the North Polar Spur, a radio-wave emitting arc above the Milky Way galaxy's plane. Was it close and relatively small? Or was it faraway and much more massive? New research utilizing X-ray mapping of the galaxy has helped clarify the existence of both so-called smaller Fermi bubbles and larger X-ray ones.

The mysterious origins of the universe’s biggest black holes

Think you know everything about black holes? You might be surprised. Thought of as massive vacuum cleaners sucking up everything in their cosmic path, black holes actually accrete matter at an incredibly slow pace. Yet, some black holes existed when the universe was only a few billion years young. Learn more in this BBC report.

Watch an artist's impression of two neutron stars merging in a kilonova explosion

Such an event produces enough light to briefly outshine an entire galaxy and to produce characteristic gravitational wave and gamma-ray signals. On August 17, 2017, these signals were captured by the LIGO–Virgo and Fermi/INTEGRAL observatories, respectively, from a kilonova about 130 million light-years away.

View a gallery of Einstein rings

As light from a distant galaxy spreads in all directions, rays that pass around a massive object, such as another galaxy, may be bent around it. If the massive object is positioned between the distant galaxy and our telescopes, we may observe this deflected light forming a ring around it.

LIGO confirmed Stephen Hawking's theorem about black hole surface areas

Black holes are known to grow with increased mass but lose energy during mergers through the emission of gravitational waves. Amid these competing factors, the black hole area theorem—confirmed in 2021 using LIGO data—states that a merged black hole's size cannot be smaller than the combined surface area of its progenitors.

LIGO made the first detection of gravitational waves

On February 11, 2016, scientists at the Laser Interferometer Gravitational-Wave Observatory announced the confirmed detection of ripples in spacetime, which were produced from the collision of two black holes 36 and 29 times the mass of the sun. The detection confirmed that gravitational waves travel at the speed of light, as predicted by Albert Einstein in 1915.