Back Hole

Back Hole

Browse

Search

Entertainment & Pop Culture
Geography & Travel
Health & Medicine
Lifestyles & Social Issues
Literature
Philosophy & Religion
Politics, Law & Government
Science
Sports & Recreation
Technology
Visual Arts
World History

On This Day in History
Quizzes
Podcasts
Dictionary
Biographies
Summaries
Top Questions
Week In Review
Infographics
Demystified
Lists
#WTFact
Companions
Image Galleries
Spotlight
The Forum
One Good Fact

Entertainment & Pop Culture
Geography & Travel
Health & Medicine
Lifestyles & Social Issues
Literature
Philosophy & Religion
Politics, Law & Government
Science
Sports & Recreation
Technology
Visual Arts
World History

Britannica Classics Check out these retro videos from Encyclopedia Britannica’s archives.
Britannica Explains In these videos, Britannica explains a variety of topics and answers frequently asked questions.
Demystified Videos In Demystified, Britannica has all the answers to your burning questions.
#WTFact Videos In #WTFact Britannica shares some of the most bizarre facts we can find.
This Time in History In these videos, find out what happened this month (or any month!) in history.

Student Portal Britannica is the ultimate student resource for key school subjects like history, government, literature, and more.
COVID-19 Portal While this global health crisis continues to evolve, it can be useful to look to past pandemics to better understand how to respond today.
100 Women Britannica celebrates the centennial of the Nineteenth Amendment, highlighting suffragists and history-making politicians.
Britannica Beyond We’ve created a new place where questions are at the center of learning. Go ahead. Ask. We won’t mind.
Saving Earth Britannica Presents Earth’s To-Do List for the 21st Century. Learn about the major environmental problems facing our planet and what can be done about them!
SpaceNext50 Britannica presents SpaceNext50, From the race to the Moon to space stewardship, we explore a wide range of subjects that feed our curiosity about space!

While every effort has been made to follow citation style rules, there may be some discrepancies.
Please refer to the appropriate style manual or other sources if you have any questions.

Corrections? Updates? Omissions? Let us know if you have suggestions to improve this article (requires login).

Feedback Type

Select a type (Required)
Factual Correction
Spelling/Grammar Correction
Link Correction
Additional Information
Other

Articles from Britannica Encyclopedias for elementary and high school students.

While every effort has been made to follow citation style rules, there may be some discrepancies.
Please refer to the appropriate style manual or other sources if you have any questions.

Corrections? Updates? Omissions? Let us know if you have suggestions to improve this article (requires login).

Feedback Type

Select a type (Required)
Factual Correction
Spelling/Grammar Correction
Link Correction
Additional Information
Other

Articles from Britannica Encyclopedias for elementary and high school students.

By

The Editors of Encyclopaedia Britannica

Last Updated:

Aug 24, 2022

Edit History

Key People:

Reinhard Genzel
Kip Thorne
Andrea Ghez
Stephen Hawking
Subrahmanyan Chandrasekhar

... (Show more)

Related Topics:

accretion disk
event horizon
Kerr black hole
singularity
Penrose diagram

... (Show more)

What is the structure of a black hole?
What are some examples of black holes?
Uncover insight into the black hole
Everything in Space in a 25-Minute Quiz
Ever wanted to visit everything in outer space in only 25 minutes? Now you can with this quiz, which will rocket you from planets to black holes to artificial satellites. If you can finish it in less than 15 minutes, you’re a master of the universe!

Get a Britannica Premium subscription and gain access to exclusive content.
Subscribe Now

Our editors will review what you’ve submitted and determine whether to revise the article.
Our editors will review what you’ve submitted and determine whether to revise the article.
A black hole is a cosmic body of extremely intense gravity from which even light cannot escape. Black holes usually cannot be observed directly, but they can be “observed” by the effects of their enormous gravitational fields on nearby matter.
The singularity constitutes the center of a black hole, hidden by the object’s “surface,” the event horizon. Inside the event horizon, the escape velocity exceeds the speed of light so that not even rays of light can escape into space.
A black hole can be formed by the death of a massive star. At the end of a massive star's life, the core becomes unstable and collapses in upon itself, and the star’s outer layers are blown away. The crushing weight of constituent matter falling in from all sides compresses the dying star to a point of zero volume and infinite density called the singularity.
One example of a black hole is can be found in Cygnus X-1, a binary X-ray system consisting of a blue supergiant and an invisible companion 14.8 times the mass of the Sun. Another example is Sagittarius A*, a supermassive black hole that exists at the centre of the Milky Way Galaxy.
black hole , cosmic body of extremely intense gravity from which nothing, not even light , can escape. A black hole can be formed by the death of a massive star . When such a star has exhausted the internal thermonuclear fuels in its core at the end of its life , the core becomes unstable and gravitationally collapses inward upon itself, and the star’s outer layers are blown away. The crushing weight of constituent matter falling in from all sides compresses the dying star to a point of zero volume and infinite density called the singularity .
Details of the structure of a black hole are calculated from Albert Einstein ’s general theory of relativity . The singularity constitutes the centre of a black hole and is hidden by the object’s “surface,” the event horizon . Inside the event horizon the escape velocity (i.e., the velocity required for matter to escape from the gravitational field of a cosmic object) exceeds the speed of light , so that not even rays of light can escape into space. The radius of the event horizon is called the Schwarzschild radius , after the German astronomer Karl Schwarzschild , who in 1916 predicted the existence of collapsed stellar bodies that emit no radiation. The size of the Schwarzschild radius is proportional to the mass of the collapsing star. For a black hole with a mass 10 times as great as that of the Sun , the radius would be 30 km (18.6 miles).
Only the most massive stars—those of more than three solar masses—become black holes at the end of their lives. Stars with a smaller amount of mass evolve into less compressed bodies, either white dwarfs or neutron stars .
Black holes usually cannot be observed directly on account of both their small size and the fact that they emit no light. They can be “observed,” however, by the effects of their enormous gravitational fields on nearby matter. For example, if a black hole is a member of a binary star system, matter flowing into it from its companion becomes intensely heated and then radiates X-rays copiously before entering the event horizon of the black hole and disappearing forever. One of the component stars of the binary X-ray system Cygnus X-1 is a black hole. Discovered in 1971 in the constellation Cygnus, this binary consists of a blue supergiant and an invisible companion 14.8 times the mass of the Sun that revolve about one another in a period of 5.6 days.
Some black holes apparently have nonstellar origins. Various astronomers have speculated that large volumes of interstellar gas collect and collapse into supermassive black holes at the centres of quasars and galaxies . A mass of gas falling rapidly into a black hole is estimated to give off more than 100 times as much energy as is released by the identical amount of mass through nuclear fusion . Accordingly, the collapse of millions or billions of solar masses of interstellar gas under gravitational force into a large black hole would account for the enormous energy output of quasars and certain galactic systems.
One such supermassive black hole, Sagittarius A* , exists at the centre of the Milky Way Galaxy . Observations of stars orbiting the position of Sagittarius A* demonstrate the presence of a black hole with a mass equivalent to more than 4,000,000 Suns. (For these observations, American astronomer Andrea Ghez and German astronomer Reinhard Genzel were awarded the 2020 Nobel Prize for Physics.) Supermassive black holes have been detected in other galaxies as well. In 2017 the Event Horizon Telescope obtained an image of the supermassive black hole at the centre of the M87 galaxy. That black hole has a mass equal to six and a half billion Suns but is only 38 billion km (24 billion miles) across. It was the first black hole to be imaged directly. The existence of even larger black holes, each with a mass equal to 10 billion Suns, can be inferred from the energetic effects on gas swirling at extremely high velocities around the centre of NGC 3842 and NGC 4889, galaxies near the Milky Way.
The existence of another kind of nonstellar black hole was proposed by the British astrophysicist Stephen Hawking . According to Hawking’s theory, numerous tiny primordial black holes, possibly with a mass equal to or less than that of an asteroid , might have been created during the big bang , a state of extremely high temperatures and density in which the universe originated 13.8 billion years ago. These so-called mini black holes , like the more massive variety, lose mass over time through Hawking radiation and disappear. If certain theories of the universe that require extra dimensions are correct, the Large Hadron Collider could produce significant numbers of mini black holes.

Please be respectful of copyright. Unauthorized use is prohibited.
Please be respectful of copyright. Unauthorized use is prohibited.
Please be respectful of copyright. Unauthorized use is prohibited.
Please be respectful of copyright. Unauthorized use is prohibited.
Please be respectful of copyright. Unauthorized use is prohibited.
A view of the central region of the Perseus galaxy cluster, one of the most massive objects in the universe, shows the effects that a relatively small but supermassive black hole can have millions of miles beyond its core. Astronomers studying this photo, taken by the Chandra X-ray Observatory, determined that sound waves emitted by explosive venting around the black hole are heating the surrounding area and inhibiting star growth some 300,000 light-years away. "In relative terms, it is as if a heat source the size of a fingernail affects the behavior of a region the size of Earth," said Andrew Fabian of Cambridge University.

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.
Interbreeding between animals of different lineages is widespread in nature—and may reveal some of the mysteries of evolution.
Following the crop cycles in California and Mexico, generations of Mexican farmworkers have migrated back and forth to provide for their families.
Ancient fortified towns, Roman ruins, and Sahara sands make Africa’s largest country an undiscovered tourism giant hiding in plain sight.
As rivers either rage or fade from climate change-caused extreme weather, the debate is intensifying as to what role dams should or shouldn’t play in managing it.
A glimmer of hope for one of the world's rarest penguins
American bison all have some cattle DNA. Here’s why.
See the year's best wildlife photos
How animals hybrids happen, from ligers to zorses
Why these seabirds stage a rowdy springtime love-in
Tuberculosis is killing this zoo's lemurs—but it hasn't closed
Once devastated, these Pacific reefs have seen an amazing rebirth
Is building more dams the way to save rivers?
4 easy ways to make your holidays more eco-friendly
Melting mountain peaks could kill thousands. Can science help?
Protecting Canada’s wetland wonders
Why this German bunker is full of blood and urine
A German werewolf's 'confessions' horrified 1500s Europe
How Mussolini led Italy to fascism—and why his legacy looms today
Why Diwali is India’s most important holiday
Did these 5 leaders’ legendary achievements happen?
These families lead double lives across the U.S.-Mexico border
The Tower of London has terrified people for nearly 1,000 years
Dinosaur ‘mummy’ reveals a surprisingly hoof-like foot
NASA surprised itself with its asteroid-smashing success
Striking pictures reveal the microscopic world’s hidden wonders
Speakers of rare languages struggled to navigate COVID care
How Fido evolved to have those irresistible puppy-dog eyes
230-million-year-old mystery fossil hints at pterosaurs’ origins
Cruises on the Great Lakes are giving new life to the Rust Belt
Memories are crafted in wool in this tiny Russian republic
Is Algeria the next great travel destination in Africa?
Australia’s newest national parks will be Indigenous-managed
Italy’s last wild steppe is seeing a renaissance
Uncover hidden legends on Ireland’s southern coast
Why are people so dang obsessed with Mars?
The era of greyhound racing in the U.S. is coming to an end
See how people have imagined life on Mars through history
See how NASA’s new Mars rover will explore the red planet
Why are people so dang obsessed with Mars?
The era of greyhound racing in the U.S. is coming to an end
See how people have imagined life on Mars through history
See how NASA’s new Mars rover will explore the red planet
Why are people so dang obsessed with Mars?
The era of greyhound racing in the U.S. is coming to an end
See how people have imagined life on Mars through history
See how NASA’s new Mars rover will explore the red planet
Follow us National Geographic Facebook National Geographic Twitter National Geographic Instagram
A view of the central region of the Perseus galaxy cluster, one of the most massive objects in the universe, shows the effects that a relatively small but supermassive black hole can have millions of miles beyond its core. Astronomers studying this photo, taken by the Chandra X-ray Observatory, determined that sound waves emitted by explosive venting around the black hole are heating the surrounding area and inhibiting star growth some 300,000 light-years away. "In relative terms, it is as if a heat source the size of a fingernail affects the behavior of a region the size of Earth," said Andrew Fabian of Cambridge University.
These infinitely dense points in space will spaghettify anything that ventures too close.
Black holes are points in space that are so dense they create deep gravity sinks. Beyond a certain region, not even light can escape the powerful tug of a black hole's gravity. And anything that ventures too close—be it star, planet, or spacecraft—will be stretched and compressed like putty in a theoretical process aptly known as spaghettification.
There are four types of black holes : stellar, intermediate, supermassive, and miniature. The most commonly known way a black hole forms is by stellar death. As stars reach the ends of their lives, most will inflate, lose mass, and then cool to form white dwarfs . But the largest of these fiery bodies, those at least 10 to 20 times as massive as our own sun, are destined to become either super-dense neutron stars or so-called stellar-mass black holes.
In their final stages, enormous stars go out with a bang in massive explosions known as supernovae. Such a burst flings star matter out into space but leaves behind the stellar core. While the star was alive, nuclear fusion created a constant outward push that balanced the inward pull of gravity from the star's own mass. In the stellar remnants of a supernova, however, there are no longer forces to oppose that gravity, so the star core begins to collapse in on itself.
If its mass collapses into an infinitely small point, a black hole is born. Packing all of that bulk—many times the mass of our own sun—into such a tiny point gives black holes their powerful gravitational pull. Thousands of these stellar-mass black holes may lurk within our own Milky Way galaxy.
Supermassive black holes, predicted by Einstein's general theory of relativity, can have masses equal to billions of suns; these cosmic monsters likely hide at the centers of most galaxies. The Milky Way hosts its own supermassive black hole at its center known as Sagittarius A* (pronounced “ay star”) that is more than four million times as massive as our sun.
The tiniest members of the black hole family are, so far, theoretical. These small vortices of darkness may have swirled to life soon after the universe formed with the big bang, some 13.7 billion years ago, and then quickly evaporated. Astronomers also suspect that a class of objects called intermediate-mass black holes exist in the universe, although evidence for them is so far debatable.
No matter their starting size, black holes can grow throughout their lives, slurping gas and dust from any objects that creep too close. Anything that passes the event horizon, the point at which escape becomes impossible, is in theory destined for spaghettification thanks to a sharp increase in the strength of gravity as you fall into the black hole.
As astrophysicist Neil Degrasse Tyson once described the process: “While you're getting stretched, you're getting squeezed—extruded through the fabric of space like toothpaste through a tube.”
But black holes aren't exactly “ cosmic vacuum cleaners ,” as often depicted in popular media. Objects must creep fairly close to one to lose this gravitational tug-of-war. For example, if our sun was suddenly replaced by a black hole of similar mass, our planetary family would continue to orbit unperturbed, if much less warm and illuminated.
Because black holes swallow all light, astronomers can't spot them directly like they do the many glittery cosmic objects in the sky. But there are a few keys that
French Mature Anal Video
Porno Arthaus Film French
Teen Hard Gagging

Back Hole

Report Page