Laser Tests Offer Clue to Magnetic Field Mystery

A shock wave is the only thing needed to create a magnetic field, lab experiments show. An experiment using powerful lasers demonstrated what could happen when a star explodes. The test showed how an exploding star could lead to the creation of magnetic fields.

Gravity may be the master of the universe, but it has had a key assistant in shaping the cosmos -- magnetism. Exactly how that force, which comes from the motion of electric charges, got its start however, has been a mystery -- until now.

A new experiment shows that a relatively simple system that's not initially magnetized can generate magnetic fields out of nothing, said University of Michigan astrophysicist Paul Drake.

"From the standard theories of the Big Bang, you don't start with a strong magnetic field. It has to arise out of what the universe does," Drake told Discovery News.

Working in a laboratory in France, scientists fired high-energy lasers that pulse in a billionth of a second with a trillion times the intensity of sunlight into a helium-filled chamber. The lasers are made of carbon rods, similar to what is found in ordinary pencil lead.

When they pulse, some of the carbon atoms are ripped apart and explode, creating a blast wave that moves out into the gas and generates a magnetic field.

ANALYSIS: Stars Caught in Fiery Merger

The process is similar to what happens when a star explodes. It shows one mechanism by which the universe formed and evolved.

Gravity gets the process started, eventually giving rise to collapsing objects that send out shock waves.

"Shocks are the driving force for the formation of magnetic field, and all this precedes galaxy formation," lead researcher Gianluca Gregori, with Oxford University in the United Kingdom, told Discovery News.

Once magnetic fields are established, turbulence takes over, making them larger and sustaining them over the eons.

"It's been rather mysterious that the universe is as magnetized as it," Drake said. "When you do simple calculations, any magnetic field formed in the early phases of the universe one would think should have vanished by now."

Magnetic fields are found everywhere in the universe, even in places where they seemingly shouldn't exist, such as the voids between clusters of galaxies.

NEWS: Mysterious 'Dark Flow' May Be Tug of Other Universe

Gravitation is the driving force for the formation of shocks and shocks are the driving force for the formation of magnetic field, and all this precedes galaxy formation," Gregori explained.

Gregori plans to repeat his experiment using the world's largest laser at the Lawrence Livermore National Laboratory in California. It has 10,000 times as much energy as the lasers used in his study.

"If we can use a bigger laser we can drive this shock wave even more powerfully," Gregori said.

"The process that we're investigating now is one possibility (for the origin of magnetic fields), but people have come up with different ideas. The experiments are a tool to guide you to what could be the answer," he said.

The research appears in this week's journal, Nature.

View the original article here

Book Review: Fool Me Twice

Politicians often make decisions that have an impact on science, but because they usually lack basic scientific literacy, they really don't have an understanding of the scope involved in these decisions. In his new book, Fool Me Twice: Fighting the Assault on Science in America, filmmaker and science advocate Shawn Lawrence Otto argues that scientists need to become more engaged in the political realm and politicians need to have a better scientific understanding in order to make more informed decisions.

Among at least one Republican candidates for president, there is some concern about whether this science antagonism is good for their party, let alone the country as a whole. In his book, Otto explains how scientific ignorance on both the left and right ends of the political spectrum are leading to decisions which are based more on ideology than on fact-based evidence. In order to solve the significant challenges our country will face in the years ahead, we must invoke a solid understanding of science.

Otto's argument goes beyond mere pragmatism, though, making the case that the anti-authoritarian nature of scientific thinking is fundamentally and ideologically tied into the character of American democracy.?This book is a critical values check and should be required reading for every American politician ... and citizen.

You can find out more about the book by reading our full review.

View the original article here

Infants Grasp Gravity with Innate Sense of Physics

Infants already have an intuitive understanding of certain physical laws by 2 months of age. As infants grow and learn they gain vast amounts of information about the laws governing the world around them.

Infants as young as 2 months old already have basic knowledge of "intuitive physics," researchers report in a new study.

Most studies into infant cognition employ eye-tracking technology - psychologists can tease out what an infant is thinking and what she considers to be unexpected by following her gaze in different scenarios. This method, called violation of expectation, involves showing babies photos, videos or events that proceed as expected, followed by others that break everyday rules. If the infant understands the implicit rules, he or she will show little interest in an expected situation, but will stare at images of a surprising event.

But at what point in their development do babies begin to understand how the physical world works?

NEWS: Mom's Diet Can Shape Baby's Brain

"We believe that infants are born with expectations about the objects around them, even though that knowledge is a skill that's never been taught," Kristy vanMarle, an assistant professor of psychological sciences at the University of Missouri, said in a statement. "As the child develops, this knowledge is refined and eventually leads to the abilities we use as adults."

To come to this conclusion, vanMarle and her colleague, Susan Hespos, a psychologist at Northwestern University, reviewed infant cognition research conducted over the last 30 years. They found that infants already have an intuitive understanding of certain physical laws by 2 months of age, when they start to track moving objects with both eyes consistently and can be tested with eye-tracking technology.

For instance, at this age they understand that unsupported objects will fall (gravity) and hidden objects don't cease to exist. In one test, researchers placed an object inside of a container and moved the container; 2-month-old infants knew that the hidden object moved with the container.

BRIEF: No TV for the Baby, Doctors' Group Urges

This innate "physics" knowledge only grows as the infants experience their surroundings and interact more with the world. By 5 months of age, babies understand that solid objects have different properties than noncohesive substances, such as water, the researchers found.

In a 2009 study, a research team (which included Hespos) habituated 5-month-old infants to either a blue solid or a blue liquid in a glass cup, which appeared to be the same when at rest. They tipped the glasses left and right, and poured the contents into other glasses, allowing the infants to form ideas about how the substances worked. Infants habituated to the liquid (but not the solid) weren't surprised that straws could penetrate it, but were confused when straws couldn't penetrate the blue solid. The opposite happened with infants habituated to the solid.

Hespos and vanMarle also learned that babies have rudimentary math abilities: Six-month-old infants can discriminate between numbers of dots (if one set held twice as many dots as the other), and 10-month-old infants can pick out which of two cups holds more liquid (if one cup held four times as much liquid as the other). Also at 10 months of age, babies will consistently choose larger amounts of food - such as crackers - in cups, though only if there are no more than three items in any cup.

While infants appear to be born with intuitive physics knowledge, the researchers believe that parents can further assist their children in developing expectations about the world through normal interactions, such as talking, playing peek-a-boo or letting them handle various safe objects.

NEWS: Humans Age at the Same Rate as Chimps, Gorillas 

"Natural interaction with the parent and objects in the world gives the child all the input that evolution has prepared the child to seek, accept and use to develop intuitive physics," vanMarle said.

The study was published in the January issue of the journal WIREs Cognitive Science.

Related LiveScience Stories

Copyright 2011 LiveScience, a TechMediaNetwork company. All rights reserved. This material may not be published, broadcast, rewritten or redistributed.

View the original article here

Black Holes: Facts, Theory & Definition

Black holes are some of the strangest and most fascinating objects found in outer space. They are objects of extreme density, with such strong gravitational attraction that even light cannot escape from their grasp if it comes near enough.

Stellar black holes — small but deadly

When a star burns through the last of its fuel, it may find itself collapsing. For smaller stars, up to about three times the sun's mass, the new core will be a neutron star or a white dwarf. But when a larger star collapses, it continues to fall in on itself to create a stellar black hole.

Black holes formed by the collapse of individual stars are (relatively) small, but incredibly dense. Such an object packs three times or more the mass of the sun into a city-sized range. This leads to a crazy amount of gravitational force pulling on objects around it. Black holes consume the dust and gas from the galaxy around them, growing in size.

This artist's conception of Cygnus X-1 shows the black hole drawing material from companion star (right) into a hot, swirling disk.
CREDIT: Chandra X-Ray Observatory, NASA

View full size image

Supermassive black holes — the birth of giants

Small black holes populate the universe, but their cousins, supermassive black holes, dominate. Supermassive black holes are millions or even billions of times as massive as the sun, but have a radius similar to that of Earth's closest star. Such black holes are thought to lie at the center of pretty much every galaxy, including the Milky Way.

Scientists aren't certain how such large black holes spawn. Once they've formed, they can easily gather mass from the dust and gas around them, material that is plentiful in the center of galaxies, allowing them to grow to enormous sizes. [Photos: Black Holes of the Universe]

Supermassive may be the result of hundreds or thousands of tiny black holes that merge together. Large gas clouds could also be responsible, collapsing together and rapidly accreting mass. A third option is the collapse of a stellar cluster, a group of stars all falling together. [Images: The Big Bang & Early Universe]

Intermediate black holes – stuck in the middle

Scientists once thought black holes came in only small and large sizes, but recent research has revealed the possibility for the existence of midsize, or intermediate, black holes. Such bodies could form when stars in a cluster collide in a chain reaction. Several of these forming in the same region could eventually fall together in the center of a galaxy and create a supermassive black hole. [What's at the Center of Black Holes?]

Black hole theory — how they tick

Black holes are incredibly massive, but cover only a small region. Because of the relationship between mass and gravity, this means they have an extremely powerful gravitational force. Virtually nothing can escape from them — under classical physics, even light is trapped by a black hole.

Simulated view of a black hole in front of the Large Magellanic Cloud.
CREDIT: Alain R. | Wikimedia Commons

View full size image

Such a strong pull creates an observational problem when it comes to black holes — scientists can't "see" them the way they can see stars and other objects in space. Instead, scientists must rely on the radiation that is emitted as dust and gas are drawn into the dense creatures. Supermassive black holes, lying in the center of a galaxy, may find themselves shrouded by the dust and gas thick around them, which can block the tell-tale emissions.

Sometimes as matter is drawn toward a black hole, it ricochets off of the event horizon and is hurled outward, rather than being tugged into the maw. Bright jets of material traveling at near-relativistic speeds are created. Although the black hole itself remains unseen, these powerful jets can be viewed from great distances.

Black holes have three "layers" — the outer and inner event horizon and the singularity.

The event horizon of a black hole is the boundary around the mouth of the black hole where light loses its ability to escape. Once a particle crosses the event horizon, it cannot leave. Gravity is constant across the event horizon.

The inner region of a black hole, where its mass lies, is known as its singularity, the single point in space-time where the mass of the black hole is concentrated.

Under the classical mechanics of physics, nothing can escape from a black hole. However, things shift slightly when quantum mechanics are added to the equation. Under quantum mechanics, for every particle, there is an antiparticle, a particle with the same mass and opposite electric charge. When they meet, particle-antiparticle pairs can annihilate one another.

If a particle-antiparticle pair is created just beyond the reach of the event horizon of a black hole, it is possible to have one drawn into the black hole itself while the other is ejected. The result is that the event horizon of the black hole has been reduced and black holes can decay, a process that is rejected under classical mechanics.

Scientists are still working to understand the equations by which black holes function.

Artist's concept of the huge black hole at the heart of the galaxy M87, the most massive known black hole to date. Gas swirls around the black hole in an accretion disk. The bright blue jet shooting from the region of the black hole is created by gas that never made it into the hole itself but was instead funneled into an energetic jet.
CREDIT: Gemini Observatory/AURA illustration by Lynette Cook

View full size image

Interesting facts about black holes

• If you fell into a black hole, gravity would stretch you out like spaghetti. Don't worry; your death would come before you reached singularity.

• Black holes do not "suck." Suction is caused by pulling something into a vacuum, which the massive black hole definitely is not. Instead, objects fall into them.

• Albert Einstein first predicted black holes in 1916 with his general theory of relativity.

• The term "black hole" was coined in 1967 by American astronomer John Wheeler.

• The first object considered to be a black hole is Cygnus X-1. Rockets carrying Geiger counters discovered eight new x-ray sources. In 1971, scientists detected radio emission coming from Cygnus X-1, and a massive hidden companion was found and identified as a black hole.

• Cygnus X-1 was the subject of a 1974 friendly wager between Stephen Hawking and a fellow physicistKip Thorne, with Hawking betting that the source was not a black hole. In 1990, he conceded defeat.

• Miniature black holes may have formed immediately after the Big Bang. Rapidly expanding space may have squeezed some regions into tiny, dense black holes less massive than the sun.

• If a star passes too close to a black hole, it can be torn apart.

• Astronomers estimate there are anywhere from ten million to a billion stellar black holes, with masses roughly thrice that of the sun, in the Milky Way.

• The interesting relationship between string theory and black holes give rise to more types of massive giants than found under conventional classical mechanics.

Black Holes: Facts, Theory & Definition

Black holes are some of the strangest and most fascinating objects found in outer space. They are objects of extreme density, with such strong gravitational attraction that even light cannot escape from their grasp if it comes near enough.

Stellar black holes — small but deadly

When a star burns through the last of its fuel, it may find itself collapsing. For smaller stars, up to about three times the sun's mass, the new core will be a neutron star or a white dwarf. But when a larger star collapses, it continues to fall in on itself to create a stellar black hole.

Black holes formed by the collapse of individual stars are (relatively) small, but incredibly dense. Such an object packs three times or more the mass of the sun into a city-sized range. This leads to a crazy amount of gravitational force pulling on objects around it. Black holes consume the dust and gas from the galaxy around them, growing in size.

This artist's conception of Cygnus X-1 shows the black hole drawing material from companion star (right) into a hot, swirling disk.
CREDIT: Chandra X-Ray Observatory, NASA

View full size image

Supermassive black holes — the birth of giants

Small black holes populate the universe, but their cousins, supermassive black holes, dominate. Supermassive black holes are millions or even billions of times as massive as the sun, but have a radius similar to that of Earth's closest star. Such black holes are thought to lie at the center of pretty much every galaxy, including the Milky Way.

Scientists aren't certain how such large black holes spawn. Once they've formed, they can easily gather mass from the dust and gas around them, material that is plentiful in the center of galaxies, allowing them to grow to enormous sizes. [Photos: Black Holes of the Universe]

Supermassive may be the result of hundreds or thousands of tiny black holes that merge together. Large gas clouds could also be responsible, collapsing together and rapidly accreting mass. A third option is the collapse of a stellar cluster, a group of stars all falling together. [Images: The Big Bang & Early Universe]

Intermediate black holes – stuck in the middle

Scientists once thought black holes came in only small and large sizes, but recent research has revealed the possibility for the existence of midsize, or intermediate, black holes. Such bodies could form when stars in a cluster collide in a chain reaction. Several of these forming in the same region could eventually fall together in the center of a galaxy and create a supermassive black hole. [What's at the Center of Black Holes?]

Black hole theory — how they tick

Black holes are incredibly massive, but cover only a small region. Because of the relationship between mass and gravity, this means they have an extremely powerful gravitational force. Virtually nothing can escape from them — under classical physics, even light is trapped by a black hole.

Simulated view of a black hole in front of the Large Magellanic Cloud.
CREDIT: Alain R. | Wikimedia Commons

View full size image

Such a strong pull creates an observational problem when it comes to black holes — scientists can't "see" them the way they can see stars and other objects in space. Instead, scientists must rely on the radiation that is emitted as dust and gas are drawn into the dense creatures. Supermassive black holes, lying in the center of a galaxy, may find themselves shrouded by the dust and gas thick around them, which can block the tell-tale emissions.

Sometimes as matter is drawn toward a black hole, it ricochets off of the event horizon and is hurled outward, rather than being tugged into the maw. Bright jets of material traveling at near-relativistic speeds are created. Although the black hole itself remains unseen, these powerful jets can be viewed from great distances.

Black holes have three "layers" — the outer and inner event horizon and the singularity.

The event horizon of a black hole is the boundary around the mouth of the black hole where light loses its ability to escape. Once a particle crosses the event horizon, it cannot leave. Gravity is constant across the event horizon.

The inner region of a black hole, where its mass lies, is known as its singularity, the single point in space-time where the mass of the black hole is concentrated.

Under the classical mechanics of physics, nothing can escape from a black hole. However, things shift slightly when quantum mechanics are added to the equation. Under quantum mechanics, for every particle, there is an antiparticle, a particle with the same mass and opposite electric charge. When they meet, particle-antiparticle pairs can annihilate one another.

If a particle-antiparticle pair is created just beyond the reach of the event horizon of a black hole, it is possible to have one drawn into the black hole itself while the other is ejected. The result is that the event horizon of the black hole has been reduced and black holes can decay, a process that is rejected under classical mechanics.

Scientists are still working to understand the equations by which black holes function.

Artist's concept of the huge black hole at the heart of the galaxy M87, the most massive known black hole to date. Gas swirls around the black hole in an accretion disk. The bright blue jet shooting from the region of the black hole is created by gas that never made it into the hole itself but was instead funneled into an energetic jet.
CREDIT: Gemini Observatory/AURA illustration by Lynette Cook

View full size image

Interesting facts about black holes

• If you fell into a black hole, gravity would stretch you out like spaghetti. Don't worry; your death would come before you reached singularity.

• Black holes do not "suck." Suction is caused by pulling something into a vacuum, which the massive black hole definitely is not. Instead, objects fall into them.

• Albert Einstein first predicted black holes in 1916 with his general theory of relativity.

• The term "black hole" was coined in 1967 by American astronomer John Wheeler.

• The first object considered to be a black hole is Cygnus X-1. Rockets carrying Geiger counters discovered eight new x-ray sources. In 1971, scientists detected radio emission coming from Cygnus X-1, and a massive hidden companion was found and identified as a black hole.

• Cygnus X-1 was the subject of a 1974 friendly wager between Stephen Hawking and a fellow physicistKip Thorne, with Hawking betting that the source was not a black hole. In 1990, he conceded defeat.

• Miniature black holes may have formed immediately after the Big Bang. Rapidly expanding space may have squeezed some regions into tiny, dense black holes less massive than the sun.

• If a star passes too close to a black hole, it can be torn apart.

• Astronomers estimate there are anywhere from ten million to a billion stellar black holes, with masses roughly thrice that of the sun, in the Milky Way.

• The interesting relationship between string theory and black holes give rise to more types of massive giants than found under conventional classical mechanics.

Black Holes: Facts, Theory & Definition

Black holes are some of the strangest and most fascinating objects found in outer space. They are objects of extreme density, with such strong gravitational attraction that even light cannot escape from their grasp if it comes near enough.

Stellar black holes — small but deadly

When a star burns through the last of its fuel, it may find itself collapsing. For smaller stars, up to about three times the sun's mass, the new core will be a neutron star or a white dwarf. But when a larger star collapses, it continues to fall in on itself to create a stellar black hole.

Black holes formed by the collapse of individual stars are (relatively) small, but incredibly dense. Such an object packs three times or more the mass of the sun into a city-sized range. This leads to a crazy amount of gravitational force pulling on objects around it. Black holes consume the dust and gas from the galaxy around them, growing in size.

This artist's conception of Cygnus X-1 shows the black hole drawing material from companion star (right) into a hot, swirling disk.
CREDIT: Chandra X-Ray Observatory, NASA

View full size image

Supermassive black holes — the birth of giants

Small black holes populate the universe, but their cousins, supermassive black holes, dominate. Supermassive black holes are millions or even billions of times as massive as the sun, but have a radius similar to that of Earth's closest star. Such black holes are thought to lie at the center of pretty much every galaxy, including the Milky Way.

Scientists aren't certain how such large black holes spawn. Once they've formed, they can easily gather mass from the dust and gas around them, material that is plentiful in the center of galaxies, allowing them to grow to enormous sizes. [Photos: Black Holes of the Universe]

Supermassive may be the result of hundreds or thousands of tiny black holes that merge together. Large gas clouds could also be responsible, collapsing together and rapidly accreting mass. A third option is the collapse of a stellar cluster, a group of stars all falling together. [Images: The Big Bang & Early Universe]

Intermediate black holes – stuck in the middle

Scientists once thought black holes came in only small and large sizes, but recent research has revealed the possibility for the existence of midsize, or intermediate, black holes. Such bodies could form when stars in a cluster collide in a chain reaction. Several of these forming in the same region could eventually fall together in the center of a galaxy and create a supermassive black hole. [What's at the Center of Black Holes?]

Black hole theory — how they tick

Black holes are incredibly massive, but cover only a small region. Because of the relationship between mass and gravity, this means they have an extremely powerful gravitational force. Virtually nothing can escape from them — under classical physics, even light is trapped by a black hole.

Simulated view of a black hole in front of the Large Magellanic Cloud.
CREDIT: Alain R. | Wikimedia Commons

View full size image

Such a strong pull creates an observational problem when it comes to black holes — scientists can't "see" them the way they can see stars and other objects in space. Instead, scientists must rely on the radiation that is emitted as dust and gas are drawn into the dense creatures. Supermassive black holes, lying in the center of a galaxy, may find themselves shrouded by the dust and gas thick around them, which can block the tell-tale emissions.

Sometimes as matter is drawn toward a black hole, it ricochets off of the event horizon and is hurled outward, rather than being tugged into the maw. Bright jets of material traveling at near-relativistic speeds are created. Although the black hole itself remains unseen, these powerful jets can be viewed from great distances.

Black holes have three "layers" — the outer and inner event horizon and the singularity.

The event horizon of a black hole is the boundary around the mouth of the black hole where light loses its ability to escape. Once a particle crosses the event horizon, it cannot leave. Gravity is constant across the event horizon.

The inner region of a black hole, where its mass lies, is known as its singularity, the single point in space-time where the mass of the black hole is concentrated.

Under the classical mechanics of physics, nothing can escape from a black hole. However, things shift slightly when quantum mechanics are added to the equation. Under quantum mechanics, for every particle, there is an antiparticle, a particle with the same mass and opposite electric charge. When they meet, particle-antiparticle pairs can annihilate one another.

If a particle-antiparticle pair is created just beyond the reach of the event horizon of a black hole, it is possible to have one drawn into the black hole itself while the other is ejected. The result is that the event horizon of the black hole has been reduced and black holes can decay, a process that is rejected under classical mechanics.

Scientists are still working to understand the equations by which black holes function.

Artist's concept of the huge black hole at the heart of the galaxy M87, the most massive known black hole to date. Gas swirls around the black hole in an accretion disk. The bright blue jet shooting from the region of the black hole is created by gas that never made it into the hole itself but was instead funneled into an energetic jet.
CREDIT: Gemini Observatory/AURA illustration by Lynette Cook

View full size image

Interesting facts about black holes

• If you fell into a black hole, gravity would stretch you out like spaghetti. Don't worry; your death would come before you reached singularity.

• Black holes do not "suck." Suction is caused by pulling something into a vacuum, which the massive black hole definitely is not. Instead, objects fall into them.

• Albert Einstein first predicted black holes in 1916 with his general theory of relativity.

• The term "black hole" was coined in 1967 by American astronomer John Wheeler.

• The first object considered to be a black hole is Cygnus X-1. Rockets carrying Geiger counters discovered eight new x-ray sources. In 1971, scientists detected radio emission coming from Cygnus X-1, and a massive hidden companion was found and identified as a black hole.

• Cygnus X-1 was the subject of a 1974 friendly wager between Stephen Hawking and a fellow physicistKip Thorne, with Hawking betting that the source was not a black hole. In 1990, he conceded defeat.

• Miniature black holes may have formed immediately after the Big Bang. Rapidly expanding space may have squeezed some regions into tiny, dense black holes less massive than the sun.

• If a star passes too close to a black hole, it can be torn apart.

• Astronomers estimate there are anywhere from ten million to a billion stellar black holes, with masses roughly thrice that of the sun, in the Milky Way.

• The interesting relationship between string theory and black holes give rise to more types of massive giants than found under conventional classical mechanics.

Black Holes: Facts, Theory & Definition

Black holes are some of the strangest and most fascinating objects found in outer space. They are objects of extreme density, with such strong gravitational attraction that even light cannot escape from their grasp if it comes near enough.

Stellar black holes — small but deadly

When a star burns through the last of its fuel, it may find itself collapsing. For smaller stars, up to about three times the sun's mass, the new core will be a neutron star or a white dwarf. But when a larger star collapses, it continues to fall in on itself to create a stellar black hole.

Black holes formed by the collapse of individual stars are (relatively) small, but incredibly dense. Such an object packs three times or more the mass of the sun into a city-sized range. This leads to a crazy amount of gravitational force pulling on objects around it. Black holes consume the dust and gas from the galaxy around them, growing in size.

This artist's conception of Cygnus X-1 shows the black hole drawing material from companion star (right) into a hot, swirling disk.
CREDIT: Chandra X-Ray Observatory, NASA

View full size image

Supermassive black holes — the birth of giants

Small black holes populate the universe, but their cousins, supermassive black holes, dominate. Supermassive black holes are millions or even billions of times as massive as the sun, but have a radius similar to that of Earth's closest star. Such black holes are thought to lie at the center of pretty much every galaxy, including the Milky Way.

Scientists aren't certain how such large black holes spawn. Once they've formed, they can easily gather mass from the dust and gas around them, material that is plentiful in the center of galaxies, allowing them to grow to enormous sizes. [Photos: Black Holes of the Universe]

Supermassive may be the result of hundreds or thousands of tiny black holes that merge together. Large gas clouds could also be responsible, collapsing together and rapidly accreting mass. A third option is the collapse of a stellar cluster, a group of stars all falling together. [Images: The Big Bang & Early Universe]

Intermediate black holes – stuck in the middle

Scientists once thought black holes came in only small and large sizes, but recent research has revealed the possibility for the existence of midsize, or intermediate, black holes. Such bodies could form when stars in a cluster collide in a chain reaction. Several of these forming in the same region could eventually fall together in the center of a galaxy and create a supermassive black hole. [What's at the Center of Black Holes?]

Black hole theory — how they tick

Black holes are incredibly massive, but cover only a small region. Because of the relationship between mass and gravity, this means they have an extremely powerful gravitational force. Virtually nothing can escape from them — under classical physics, even light is trapped by a black hole.

Simulated view of a black hole in front of the Large Magellanic Cloud.
CREDIT: Alain R. | Wikimedia Commons

View full size image

Such a strong pull creates an observational problem when it comes to black holes — scientists can't "see" them the way they can see stars and other objects in space. Instead, scientists must rely on the radiation that is emitted as dust and gas are drawn into the dense creatures. Supermassive black holes, lying in the center of a galaxy, may find themselves shrouded by the dust and gas thick around them, which can block the tell-tale emissions.

Sometimes as matter is drawn toward a black hole, it ricochets off of the event horizon and is hurled outward, rather than being tugged into the maw. Bright jets of material traveling at near-relativistic speeds are created. Although the black hole itself remains unseen, these powerful jets can be viewed from great distances.

Black holes have three "layers" — the outer and inner event horizon and the singularity.

The event horizon of a black hole is the boundary around the mouth of the black hole where light loses its ability to escape. Once a particle crosses the event horizon, it cannot leave. Gravity is constant across the event horizon.

The inner region of a black hole, where its mass lies, is known as its singularity, the single point in space-time where the mass of the black hole is concentrated.

Under the classical mechanics of physics, nothing can escape from a black hole. However, things shift slightly when quantum mechanics are added to the equation. Under quantum mechanics, for every particle, there is an antiparticle, a particle with the same mass and opposite electric charge. When they meet, particle-antiparticle pairs can annihilate one another.

If a particle-antiparticle pair is created just beyond the reach of the event horizon of a black hole, it is possible to have one drawn into the black hole itself while the other is ejected. The result is that the event horizon of the black hole has been reduced and black holes can decay, a process that is rejected under classical mechanics.

Scientists are still working to understand the equations by which black holes function.

Artist's concept of the huge black hole at the heart of the galaxy M87, the most massive known black hole to date. Gas swirls around the black hole in an accretion disk. The bright blue jet shooting from the region of the black hole is created by gas that never made it into the hole itself but was instead funneled into an energetic jet.
CREDIT: Gemini Observatory/AURA illustration by Lynette Cook

View full size image

Interesting facts about black holes

• If you fell into a black hole, gravity would stretch you out like spaghetti. Don't worry; your death would come before you reached singularity.

• Black holes do not "suck." Suction is caused by pulling something into a vacuum, which the massive black hole definitely is not. Instead, objects fall into them.

• Albert Einstein first predicted black holes in 1916 with his general theory of relativity.

• The term "black hole" was coined in 1967 by American astronomer John Wheeler.

• The first object considered to be a black hole is Cygnus X-1. Rockets carrying Geiger counters discovered eight new x-ray sources. In 1971, scientists detected radio emission coming from Cygnus X-1, and a massive hidden companion was found and identified as a black hole.

• Cygnus X-1 was the subject of a 1974 friendly wager between Stephen Hawking and a fellow physicistKip Thorne, with Hawking betting that the source was not a black hole. In 1990, he conceded defeat.

• Miniature black holes may have formed immediately after the Big Bang. Rapidly expanding space may have squeezed some regions into tiny, dense black holes less massive than the sun.

• If a star passes too close to a black hole, it can be torn apart.

• Astronomers estimate there are anywhere from ten million to a billion stellar black holes, with masses roughly thrice that of the sun, in the Milky Way.

• The interesting relationship between string theory and black holes give rise to more types of massive giants than found under conventional classical mechanics.