What is a black hole? The universe's dark, mysterious monsters

Black holes are elusive and powerful regions of space. They have inspired sci-fi writers, scientists and space fans to peer into the deepest mysteries of the universe. 

Nothing, not even light, can escape from a black hole's strong gravitational field. Stellar black holes can be traced to the deaths of massive stars that collapse in on themselves, but scientists are also studying supermassive black holes, mind-boggling giants that can be found lurking at the centers of big galaxies, including our Milky Way.

We have wondered and speculated what black holes might look like, and we now have a better idea than ever before. Most of our pictures of what black holes look like come from artist concepts, like this one released by NASA in 2015. This image is communicating the idea of black holes blasting out radiation and high-speed winds. This artwork is based on an image of the Pinwheel Galaxy snapped by the Hubble Space Telescope.

This gallery was originally published June 24, 2019 and will be updated with new black hole discoveries.

The Large Millimeter Telescope Alfonso Serrano in Mexico was one of eight that collaborated to deliver the first ever black hole image as part of the Event Horizon Telescope project. The collaboration essentially created an array as wide as the Earth.

The group also looked at Sagittarius A*, the black hole at the center of the Milky Way galaxy, but hasn't produced an image of it.

This is it. The real deal. Scientists and artists have created many visualizations of black holes, but on April 10, 2019, the Event Horizon Telescope project unveiled the first direct visual evidence of a supermassive black hole and its shadow.

The black hole resides at the center of Messier 87, a massive galaxy in the nearby Virgo galaxy cluster.

The first black hole image wowed the internet and sparked both jokes and tributes. Google celebrated by unveiling an animation of the black hole in action, sucking down the Google letters.

How many telescopes does it take to get to the center of the Milky Way? NASA used its Chandra X-ray Observatory to capture this image of the middle of our galaxy. There's a supermassive black hole called Sagittarius A* lurking there.

Scientists long suspected a black hole is hiding out in the middle of our very own Milky Way galaxy. In late 2018, they finally confirmed it. A group of European scientists observed flares of radiation coming from Sagittarius A*.

This illustration shows what the supermassive black hole might look like.

Cygnus X-1 is a stellar-mass black hole located in the Milky Way that was likely created from the collapse of a massive star. This illustration depicts the black hole pulling material from its companion star.

"This material forms a disk (shown in red and orange) that rotates around the black hole before falling into it or being redirected away from the black hole in the form of powerful jets," NASA said in 2011.

The European Southern Observatory put together this visualization of Sagittarius A* using "data from simulations of orbital motions of gas swirling around at about 30% of the speed of light on a circular orbit around the black hole."

Astronomers used NASA space telescopes to learn more about how black holes flare. The telescopes detected a supermassive black hole erupting with X-ray light. This NASA artist's illustration depicts an eye-catching view of a black hole.

"The results suggest that supermassive black holes send out beams of X-rays when their surrounding coronas -- sources of extremely energetic particles -- shoot, or launch, away from the black holes," NASA reported in 2015.

This teacup-shaped formation appears in a galaxy where NASA said a "storm is raging." The stormy source is a supermassive black hole.

"As matter in the central regions of the galaxy is pulled toward the black hole, it is energized by the strong gravity and magnetic fields near the black hole," said NASA. "The infalling material produces more radiation than all the stars in the host galaxy."

The Milky Way's own supermassive black hole Sagittarius A* has a ring of gases around it. The ALMA observatory was able to image the cool, nebulous gases and shared the view in June 2019.

The red areas show hydrogen gas moving away relative to Earth, while the blue portion represents gas moving toward us. The crosshair is the black hole's location.

"This information will provide new insights into the ways that black holes devour matter and the complex interplay between a black hole and its galactic neighborhood," the National Radio Astronomy Observatory said.

The V404 Cygni black hole is an oddball. Scientists revealed in early 2019 this black hole is spitting out bright jet beams of matter into space at different angles. The jets seem to be rotating, giving the black hole a wobble like a spinning top. This artist's impression shows the V404 Cygni system and the accretion disk around the black hole.

The European Space Agency's Hubble Space Telescope site shared this doozy of an illustration in late 2016, saying, "The artist's impression depicts a Sun-like star close to a rapidly spinning supermassive black hole, with a mass of about 100 million times the mass of the Sun, in the center of a distant galaxy." The gravitational pull of the black hole is shredding the star.

This colorful image shows how a supercomputer looked at a black hole through a simulation. Researchers unveiled the results of the simulation in June 2019. It was aimed at investigating a theory that says the inner-most region of a spinning black hole would eventually align with the hole's equatorial plane.

In this image, the accretion disk (red) aligns along the equatorial plane of the black hole (white center circle). The researchers called this the most-detailed simulation of a black hole to date.

Data from NASA's Chandra X-ray Observatory and other telescopes sent astronomers on a 2017 hunt for a supermassive black hole that may be moving. NASA described it as a "renegade black hole" that may have been formed by two smaller black holes colliding and merging.

This illustration hints at what this black hole might look like.

Black holes are usually found at the center of galaxies, so what happens to the monster space beasts when two galaxies collide? They merge.

Recent evidence suggests that this process results in the formation of a "cold quasar" which blows out all the gas and dust in the galaxy, but remains ringed by an area of star-forming debris. The black hole is responsible for "quenching" the galaxies star-forming abilities, so cold quasars are actually regions in space on the brink of death.

Say hello to the closest known black hole to Earth. It's located in the HR 6819 system at about 1,000 light-years away. A team led by astronomers from the European Southern Observatory announced the black hole's discovery in May 2020, highlighting how the star system can be spotted with the unaided eye from our planet's southern hemisphere.

This artist's impression shows the orbit of the two stars in the HR 6819 system. The black hole orbit appears in red with its nearby companion star in blue. The wider blue arc represents another star in the system.

This artist's image shows black hole LB-1 and its companion star (in blue). Researchers from the Chinese Academy of Sciences discovered this unreal monster of a black hole that "should not even exist in our galaxy." The scientists estimate its size at 70 billion times the mass of our sun. 

"LB-1 is twice as massive as what we thought possible. Now theorists will have to take up the challenge of explaining its formation," said astronomer Liu Jifeng from the National Astronomical Observatory of China in 2019.

Far, far away from Earth, a supermassive black hole in the OJ 287 galaxy is locked in a dance with a smaller partner. On a 12-year cycle, the daintier black hole crashes through the debris disk of the OJ 287 galaxy and creates a flare brighter than 1 trillion stars. 

NASA's Spitzer space telescope caught sight of one of these flares in 2019 and a NASA artist created this version of what the event might have looked like had somone been closer to witness it.

In late 2019, an instrument on NASA's Osiris-Rex spacecraft spotted an outburst from a newly discovered black hole located 30,000 light-years away. It was a happy accident since Osiris-Rex is focused on studying the asteroid Bennu. 

The X-ray outburst can be seen in this image from the Regolith X-Ray Imaging Spectrometer instrument. This sort of flare-up can happen when a black hole pulls in matter from a companion star. 

Galaxy NGC 6240 was born when two galaxies collided. It's a messy, irregular galaxy with a surprise inside. Astronomers originally thought NGC 6240 had two supermassive black holes at its center. New research shared in 2019 pointed to a whopping three black holes hiding out in the galaxy.