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Black Holes Trigger Stars to Self-Destruct
Scientists have long understood that supermassive black holes weighing millions or billions of suns can tear apart stars that come too close. The black hotels gravity pulls harder on the nearest part of the star, an imbalance that pulls the star apart over a period of minutes or hours, once it gets close enough.
Scientists say this Uneven pulling is not the only hazard facing the star. The strain of these unbalanced forces can also trigger a nuclear explosion powerful enough to destroy the star from within. Matthieu Brassart and Jean-Pierre Luminet of the Observatoire de Paris in Meudon, France, carried out computer simulations of the final moments of such an unfortunate star's life,as it veered towards a supermassive black hole.
When the star gets close enough, the uneven forces flatten it into a pancake shape. Some previous studies had suggested this flattening would increase the density and temperature inside the star enough to trigger intense nuclear reactions that would tear it apart. But other studies had suggested that the picture would be complicated by shock waves generated during the flattening process and that no nuclear explosion should occur.
The new simulations investigated the effects of shock waves in detail,and found that even when their effects are included,the conditions favor a nuclear explosion. "There will be an explosion of the star-it will be completely destroyed," Brassart says. Although the explosion obliterates the star, it saves some of the star's matter from being devoured by the black hole. The explosion is powerful enough to hurl much of the star's matter out of the black hole's reach, he says.
The devouring of stars by black holes may already have been observed, although at a much later stage. It is thought that several months after the event that rips the star apart,its matter starts swirling into the hole itself. It heats up as it does so, releasing ultraviolet light and X-rays.
If stars disrupted near black holes really do explode, then they could in principle allow these events to be detected at a much earlier stage, says Jules Hatpern of Columbia University in New York, US. "It may make it possible to see the disruption of that star immediately if it gets hot enough," he says.
Brassart agrees. "Perhaps it can be observed in the X-rays and gamma rays, but it's something that needs to be more studied," he says. Supernova researcher Chris Fryer of the Los Alamos National Laboratory in Los Alamos, New Mexico, US, says the deaths of these stars are difficult to simulate, and he is not sure whether the researchers have proven their case that they explode in the process.
文章(36~40)
Something destructive could happen to a star that gets too close to a black hole. Which of the following destructive statements is NOT mentioned in the passage?
Scientists have long understood that supermassive black holes weighing millions or billions of suns can tear apart stars that come too close. The black hotels gravity pulls harder on the nearest part of the star, an imbalance that pulls the star apart over a period of minutes or hours, once it gets close enough.
Scientists say this Uneven pulling is not the only hazard facing the star. The strain of these unbalanced forces can also trigger a nuclear explosion powerful enough to destroy the star from within. Matthieu Brassart and Jean-Pierre Luminet of the Observatoire de Paris in Meudon, France, carried out computer simulations of the final moments of such an unfortunate star's life,as it veered towards a supermassive black hole.
When the star gets close enough, the uneven forces flatten it into a pancake shape. Some previous studies had suggested this flattening would increase the density and temperature inside the star enough to trigger intense nuclear reactions that would tear it apart. But other studies had suggested that the picture would be complicated by shock waves generated during the flattening process and that no nuclear explosion should occur.
The new simulations investigated the effects of shock waves in detail,and found that even when their effects are included,the conditions favor a nuclear explosion. "There will be an explosion of the star-it will be completely destroyed," Brassart says. Although the explosion obliterates the star, it saves some of the star's matter from being devoured by the black hole. The explosion is powerful enough to hurl much of the star's matter out of the black hole's reach, he says.
The devouring of stars by black holes may already have been observed, although at a much later stage. It is thought that several months after the event that rips the star apart,its matter starts swirling into the hole itself. It heats up as it does so, releasing ultraviolet light and X-rays.
If stars disrupted near black holes really do explode, then they could in principle allow these events to be detected at a much earlier stage, says Jules Hatpern of Columbia University in New York, US. "It may make it possible to see the disruption of that star immediately if it gets hot enough," he says.
Brassart agrees. "Perhaps it can be observed in the X-rays and gamma rays, but it's something that needs to be more studied," he says. Supernova researcher Chris Fryer of the Los Alamos National Laboratory in Los Alamos, New Mexico, US, says the deaths of these stars are difficult to simulate, and he is not sure whether the researchers have proven their case that they explode in the process.
文章(36~40)
Something destructive could happen to a star that gets too close to a black hole. Which of the following destructive statements is NOT mentioned in the passage?
A. The black hole could tear apart the star.
B. The black hole could trigger a nuclear explosion in the star.
C. The black hole could dwindle its size considerably.
D. The black hole could devour the star.
B. The black hole could trigger a nuclear explosion in the star.
C. The black hole could dwindle its size considerably.
D. The black hole could devour the star.
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参考解析
解析：
更多 “Black Holes Trigger Stars to Self-Destruct Scientists have long understood that supermassive black holes weighing millions or billions of suns can tear apart stars that come too close. The black hotels gravity pulls harder on the nearest part of the star, an imbalance that pulls the star apart over a period of minutes or hours, once it gets close enough. Scientists say this Uneven pulling is not the only hazard facing the star. The strain of these unbalanced forces can also trigger a nuclear explosion powerful enough to destroy the star from within. Matthieu Brassart and Jean-Pierre Luminet of the Observatoire de Paris in Meudon, France, carried out computer simulations of the final moments of such an unfortunate star's life,as it veered towards a supermassive black hole. When the star gets close enough, the uneven forces flatten it into a pancake shape. Some previous studies had suggested this flattening would increase the density and temperature inside the star enough to trigger intense nuclear reactions that would tear it apart. But other studies had suggested that the picture would be complicated by shock waves generated during the flattening process and that no nuclear explosion should occur. The new simulations investigated the effects of shock waves in detail,and found that even when their effects are included,the conditions favor a nuclear explosion. "There will be an explosion of the star-it will be completely destroyed," Brassart says. Although the explosion obliterates the star, it saves some of the star's matter from being devoured by the black hole. The explosion is powerful enough to hurl much of the star's matter out of the black hole's reach, he says. The devouring of stars by black holes may already have been observed, although at a much later stage. It is thought that several months after the event that rips the star apart,its matter starts swirling into the hole itself. It heats up as it does so, releasing ultraviolet light and X-rays. If stars disrupted near black holes really do explode, then they could in principle allow these events to be detected at a much earlier stage, says Jules Hatpern of Columbia University in New York, US. "It may make it possible to see the disruption of that star immediately if it gets hot enough," he says. Brassart agrees. "Perhaps it can be observed in the X-rays and gamma rays, but it's something that needs to be more studied," he says. Supernova researcher Chris Fryer of the Los Alamos National Laboratory in Los Alamos, New Mexico, US, says the deaths of these stars are difficult to simulate, and he is not sure whether the researchers have proven their case that they explode in the process. 文章(36~40) Something destructive could happen to a star that gets too close to a black hole. Which of the following destructive statements is NOT mentioned in the passage?A. The black hole could tear apart the star. B. The black hole could trigger a nuclear explosion in the star. C. The black hole could dwindle its size considerably. D. The black hole could devour the star.” 相关考题
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B1i'k Holes1 Black holes can be best described as a sort of vacuum,sucking up everything in space. Scientists have discovered that black holes come from an explosion of huge stars. Stars that are near death can no longer burn due to loss of fuel , and because its temperature can no longer control the gravitational（重力的）force, hydrogen ends up putting pressure onto the star' s surface until it suddenly explodes then collapses.2 Black holes come from stars that are made of hydrogen,other gases and a few metals. When these explode it can turn into a stellar-mass ( 恒星质量）black hole , which can only occur if the star is large enough (should be bigger than the sun) for the explosion to break it into pieces,and the gravity starts to compact every piece into the tiniest particle. Try to see and compare:if a star that' s ten times the size of the sun endsup being a black hole that' s no longer than 70 kilometers ,then the Earth would become a black hole that' sonly"fraction of an inch! 3 Objects that get sucked in a black hie will always remain there,never to brsak fren. But rememberthat black holes can only gobble up（吞噬）objects within a specific distance to it It' s possible for a largestar near the sun to become a black hole,but the sun will continue to stay in place. Orbits (轨道）do notchange because the newly formed black hole, contains exactly the same amount of mass as when it was a star,only this time its mass is totally contracted that it can end up as on biggeer tnan a state. 4 So far, astronomers have figured out that black holes exist because of Albert Einstenin's theory of relativity. In the end,through numerous studies ,they have discovered that black holes truly exist. Since blackholes trap light and do not give off light,it is nearly impossible to detect black goles via a telescope. Butastronomers continue to study galaxies (银河系）,space and the solar system to understand how black holes misht evolve. It is possible that black holes can exist for millions of years,and later contribute to a biggerprocess in galaxies ,which can eventually lead to creation of new entities（实体）.Scientists also credit blackholes as helpful in learning how galaxies began to form. Paragraph 2_____________A:What Happens to the Objects Around a Black Hole?B:Is There Proof That Black Holes Really Exist? C:How Were Black Holes Named? D:What Are Different Types of Black Holes?E:What Are Black Holes Made of?F:How Are Black Holes Formed?
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Black HolesMost scientists agree that black holes exist but are nearly impossible to locate.A black hole in the universe is not a solid object,like a planet,but it is shaped like a sphere（球体）. Astronomers（天文学家）think that at the center of a black hole there is a single point in space with infinite（无限的）density（稠密）.This single point is called a singularity（奇点）. If the singularity theory is correct,it means that when a massive star collapses,all the material in it disappears into the singularity.The center of a black hole would not really be a hole at all,but an infinitely dense point.Anything that crosses the black hole is pulled in by its great gravity.Although black holes do exist,they are difficult to observe.These are the reasons.No light or anything else comes out of black holes.As a result,they are invisible to a telescope.In astronomical terms,black holes are truly tiny.For example,a black hole formed by the collapse of a giant star would have an event horizon（视界）only 18 miles across.The nearest black holes would be dozens of light years away from Earth.One light year is about 6 trillion（万亿）miles. Even the most powerlul telescopes could not pick out an object so small at such a great distance.In 1994 the Hubble Space Telescope provided evidence that black holes exist.There are still answers to be found,however,so black holes remain one of the mysteries of the universe.The nearest black holes are hundreds of light years away from us.A:Right B:Wrong C:Not mentioned
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共用题干
B1i'k Holes1 Black holes can be best described as a sort of vacuum,sucking up everything in space. Scientists have discovered that black holes come from an explosion of huge stars. Stars that are near death can no longer burn due to loss of fuel , and because its temperature can no longer control the gravitational（重力的）force, hydrogen ends up putting pressure onto the star' s surface until it suddenly explodes then collapses.2 Black holes come from stars that are made of hydrogen,other gases and a few metals. When these explode it can turn into a stellar-mass ( 恒星质量）black hole , which can only occur if the star is large enough (should be bigger than the sun) for the explosion to break it into pieces,and the gravity starts to compact every piece into the tiniest particle. Try to see and compare:if a star that' s ten times the size of the sun endsup being a black hole that' s no longer than 70 kilometers ,then the Earth would become a black hole that' sonly"fraction of an inch! 3 Objects that get sucked in a black hie will always remain there,never to brsak fren. But rememberthat black holes can only gobble up（吞噬）objects within a specific distance to it It' s possible for a largestar near the sun to become a black hole,but the sun will continue to stay in place. Orbits (轨道）do notchange because the newly formed black hole, contains exactly the same amount of mass as when it was a star,only this time its mass is totally contracted that it can end up as on biggeer tnan a state. 4 So far, astronomers have figured out that black holes exist because of Albert Einstenin's theory of relativity. In the end,through numerous studies ,they have discovered that black holes truly exist. Since blackholes trap light and do not give off light,it is nearly impossible to detect black goles via a telescope. Butastronomers continue to study galaxies (银河系）,space and the solar system to understand how black holes misht evolve. It is possible that black holes can exist for millions of years,and later contribute to a biggerprocess in galaxies ,which can eventually lead to creation of new entities（实体）.Scientists also credit blackholes as helpful in learning how galaxies began to form. Black holes are formed after_____________. A: the existence of black holesB: the creation of new entitiesC: the same amount of massD: an explosion of huge starsE: a fraction of an inchF: the tiniest narticle
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共用题干
Black HolesMost scientists agree that black holes exist but are nearly impossible to locate.A black hole in the universe is not a solid object,like a planet,but it is shaped like a sphere（球体）. Astronomers（天文学家）think that at the center of a black hole there is a single point in space with infinite（无限的）density（稠密）.This single point is called a singularity（奇点）. If the singularity theory is correct,it means that when a massive star collapses,all the material in it disappears into the singularity.The center of a black hole would not really be a hole at all,but an infinitely dense point.Anything that crosses the black hole is pulled in by its great gravity.Although black holes do exist,they are difficult to observe.These are the reasons.No light or anything else comes out of black holes.As a result,they are invisible to a telescope.In astronomical terms,black holes are truly tiny.For example,a black hole formed by the collapse of a giant star would have an event horizon（视界）only 18 miles across.The nearest black holes would be dozens of light years away from Earth.One light year is about 6 trillion（万亿）miles. Even the most powerlul telescopes could not pick out an object so small at such a great distance.In 1994 the Hubble Space Telescope provided evidence that black holes exist.There are still answers to be found,however,so black holes remain one of the mysteries of the universe.The sun is the heaviest star in the universe.A:Right B:Wrong C:Not mentioned
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共用题干
Black HolesMost scientists agree that black holes exist but are nearly impossible to locate.A black hole in the universe is not a solid object,like a planet,but it is shaped like a sphere（球体）. Astronomers（天文学家）think that at the center of a black hole there is a single point in space with infinite（无限的）density（稠密）.This single point is called a singularity（奇点）. If the singularity theory is correct,it means that when a massive star collapses,all the material in it disappears into the singularity.The center of a black hole would not really be a hole at all,but an infinitely dense point.Anything that crosses the black hole is pulled in by its great gravity.Although black holes do exist,they are difficult to observe.These are the reasons.No light or anything else comes out of black holes.As a result,they are invisible to a telescope.In astronomical terms,black holes are truly tiny.For example,a black hole formed by the collapse of a giant star would have an event horizon（视界）only 18 miles across.The nearest black holes would be dozens of light years away from Earth.One light year is about 6 trillion（万亿）miles. Even the most powerlul telescopes could not pick out an object so small at such a great distance.In 1994 the Hubble Space Telescope provided evidence that black holes exist.There are still answers to be found,however,so black holes remain one of the mysteries of the universe.The center of a black hole is empty.A:Right B:Wrong C:Not mentioned
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共用题干
B1i'k Holes1 Black holes can be best described as a sort of vacuum,sucking up everything in space. Scientists have discovered that black holes come from an explosion of huge stars. Stars that are near death can no longer burn due to loss of fuel , and because its temperature can no longer control the gravitational（重力的）force, hydrogen ends up putting pressure onto the star' s surface until it suddenly explodes then collapses.2 Black holes come from stars that are made of hydrogen,other gases and a few metals. When these explode it can turn into a stellar-mass ( 恒星质量）black hole , which can only occur if the star is large enough (should be bigger than the sun) for the explosion to break it into pieces,and the gravity starts to compact every piece into the tiniest particle. Try to see and compare:if a star that' s ten times the size of the sun endsup being a black hole that' s no longer than 70 kilometers ,then the Earth would become a black hole that' sonly"fraction of an inch! 3 Objects that get sucked in a black hie will always remain there,never to brsak fren. But rememberthat black holes can only gobble up（吞噬）objects within a specific distance to it It' s possible for a largestar near the sun to become a black hole,but the sun will continue to stay in place. Orbits (轨道）do notchange because the newly formed black hole, contains exactly the same amount of mass as when it was a star,only this time its mass is totally contracted that it can end up as on biggeer tnan a state. 4 So far, astronomers have figured out that black holes exist because of Albert Einstenin's theory of relativity. In the end,through numerous studies ,they have discovered that black holes truly exist. Since blackholes trap light and do not give off light,it is nearly impossible to detect black goles via a telescope. Butastronomers continue to study galaxies (银河系）,space and the solar system to understand how black holes misht evolve. It is possible that black holes can exist for millions of years,and later contribute to a biggerprocess in galaxies ,which can eventually lead to creation of new entities（实体）.Scientists also credit blackholes as helpful in learning how galaxies began to form. Albert Einstein's theory of relativity helps to prove____________.A: the existence of black holesB: the creation of new entitiesC: the same amount of massD: an explosion of huge starsE: a fraction of an inchF: the tiniest narticle
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共用题干
Black HolesMost scientists agree that black holes exist but are nearly impossible to locate.A black hole in the universe is not a solid object,like a planet,but it is shaped like a sphere（球体）. Astronomers（天文学家）think that at the center of a black hole there is a single point in space with infinite（无限的）density（稠密）.This single point is called a singularity（奇点）. If the singularity theory is correct,it means that when a massive star collapses,all the material in it disappears into the singularity.The center of a black hole would not really be a hole at all,but an infinitely dense point.Anything that crosses the black hole is pulled in by its great gravity.Although black holes do exist,they are difficult to observe.These are the reasons.No light or anything else comes out of black holes.As a result,they are invisible to a telescope.In astronomical terms,black holes are truly tiny.For example,a black hole formed by the collapse of a giant star would have an event horizon（视界）only 18 miles across.The nearest black holes would be dozens of light years away from Earth.One light year is about 6 trillion（万亿）miles. Even the most powerlul telescopes could not pick out an object so small at such a great distance.In 1994 the Hubble Space Telescope provided evidence that black holes exist.There are still answers to be found,however,so black holes remain one of the mysteries of the universe.The attraction of two large stars leads to gravity.A:Right B:Wrong C:Not mentioned
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共用题干
B1i'k Holes1 Black holes can be best described as a sort of vacuum,sucking up everything in space. Scientists have discovered that black holes come from an explosion of huge stars. Stars that are near death can no longer burn due to loss of fuel , and because its temperature can no longer control the gravitational（重力的）force, hydrogen ends up putting pressure onto the star' s surface until it suddenly explodes then collapses.2 Black holes come from stars that are made of hydrogen,other gases and a few metals. When these explode it can turn into a stellar-mass ( 恒星质量）black hole , which can only occur if the star is large enough (should be bigger than the sun) for the explosion to break it into pieces,and the gravity starts to compact every piece into the tiniest particle. Try to see and compare:if a star that' s ten times the size of the sun endsup being a black hole that' s no longer than 70 kilometers ,then the Earth would become a black hole that' sonly"fraction of an inch! 3 Objects that get sucked in a black hie will always remain there,never to brsak fren. But rememberthat black holes can only gobble up（吞噬）objects within a specific distance to it It' s possible for a largestar near the sun to become a black hole,but the sun will continue to stay in place. Orbits (轨道）do notchange because the newly formed black hole, contains exactly the same amount of mass as when it was a star,only this time its mass is totally contracted that it can end up as on biggeer tnan a state. 4 So far, astronomers have figured out that black holes exist because of Albert Einstenin's theory of relativity. In the end,through numerous studies ,they have discovered that black holes truly exist. Since blackholes trap light and do not give off light,it is nearly impossible to detect black goles via a telescope. Butastronomers continue to study galaxies (银河系）,space and the solar system to understand how black holes misht evolve. It is possible that black holes can exist for millions of years,and later contribute to a biggerprocess in galaxies ,which can eventually lead to creation of new entities（实体）.Scientists also credit blackholes as helpful in learning how galaxies began to form. A newly formed black hole and the star it comes from are of____________.A: the existence of black holesB: the creation of new entitiesC: the same amount of massD: an explosion of huge starsE: a fraction of an inchF: the tiniest narticle
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Black Holes1 Black holes can be best described as a sort of vacuum,sucking up everything in space.Scientists have discovered that black holes come from an explosion of huge stars.Stars that are near death can no longer burn due to loss of fuel , and because its temperature can no longer control the gravitational（重力的）force,hydrogen ends up putting pressure onto the star's surface until it suddenly explodes then collapses.2 Black holes come from stars ihat are made of hydrogen,other gases and a few metals.When these explode it can turn into a stellar-mass（恒星质量) black hole , which can only occur if the star is large enough (should be bigger than the sun)for the explosion to break it into pieces,and the gravity starts to compact every piece into the tiniest particle.Try to see and compare:if a star that's ten times the size of the sun ends up being a black hole that's no longer than 70 kilometers,then the Earth would become a black hole that'S only a fraction of an inch!3 Objects that get sucked in a black hole will always remain there,never to break free.i1it remember that black holes can only gobble up（吞噬）objects within a specific distance to it.It's possible for a large star near the sun to become a black hole,but the sun will continue to stay in place.Orbits（轨道）do not change because the newly formed black hole contains exactly the same amount of mass as when it was a star, only this time its mass is totally contracted that it can end up as no bigger than a state.4 Sofar,astronomers have figured out that black holes exist because of Albert Einstcin's theory of relativity.In the end,through numerous studies,they have discovered that black holes truly exist.Since black holes trap light and do not give off light,it is nearly impossible to detect black holes via a telescope.But astronomers continue to study galaxies（银河系）, space and the solar system to understand how black holes might evolve.It is possible that black holes can exist for millions of years,and later contribute to a bigger process in galaxies,which can eventually lead to creation of new entities（实体）.Scientists also credit black holes as helpful in learning how galaxies began to form.When a large star explodes,the gravity compacts every piece into______.A:the existence of black holesB:the creation of new entitiesC:the same amount of massD:an fraction of an inchE:a fraction of an inchF:the tiniest particle
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Black Holes1 Black holes can be best described as a sort of vacuum,sucking up everything in space.Scientists have discovered that black holes come from an explosion of huge stars.Stars that are near death can no longer burn due to loss of fuel , and because its temperature can no longer control the gravitational（重力的）force,hydrogen ends up putting pressure onto the star's surface until it suddenly explodes then collapses.2 Black holes come from stars ihat are made of hydrogen,other gases and a few metals.When these explode it can turn into a stellar-mass（恒星质量) black hole , which can only occur if the star is large enough (should be bigger than the sun)for the explosion to break it into pieces,and the gravity starts to compact every piece into the tiniest particle.Try to see and compare:if a star that's ten times the size of the sun ends up being a black hole that's no longer than 70 kilometers,then the Earth would become a black hole that'S only a fraction of an inch!3 Objects that get sucked in a black hole will always remain there,never to break free.i1it remember that black holes can only gobble up（吞噬）objects within a specific distance to it.It's possible for a large star near the sun to become a black hole,but the sun will continue to stay in place.Orbits（轨道）do not change because the newly formed black hole contains exactly the same amount of mass as when it was a star, only this time its mass is totally contracted that it can end up as no bigger than a state.4 Sofar,astronomers have figured out that black holes exist because of Albert Einstcin's theory of relativity.In the end,through numerous studies,they have discovered that black holes truly exist.Since black holes trap light and do not give off light,it is nearly impossible to detect black holes via a telescope.But astronomers continue to study galaxies（银河系）, space and the solar system to understand how black holes might evolve.It is possible that black holes can exist for millions of years,and later contribute to a bigger process in galaxies,which can eventually lead to creation of new entities（实体）.Scientists also credit black holes as helpful in learning how galaxies began to form.Black holes are formed after_________.A:the existence of black holesB:the creation of new entitiesC:the same amount of massD:an fraction of an inchE:a fraction of an inchF:the tiniest particle
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Black Holes1 Black holes can be best described as a sort of vacuum,sucking up everything in space.Scientists have discovered that black holes come from an explosion of huge stars.Stars that are near death can no longer burn due to loss of fuel , and because its temperature can no longer control the gravitational（重力的）force,hydrogen ends up putting pressure onto the star's surface until it suddenly explodes then collapses.2 Black holes come from stars ihat are made of hydrogen,other gases and a few metals.When these explode it can turn into a stellar-mass（恒星质量) black hole , which can only occur if the star is large enough (should be bigger than the sun)for the explosion to break it into pieces,and the gravity starts to compact every piece into the tiniest particle.Try to see and compare:if a star that's ten times the size of the sun ends up being a black hole that's no longer than 70 kilometers,then the Earth would become a black hole that'S only a fraction of an inch!3 Objects that get sucked in a black hole will always remain there,never to break free.i1it remember that black holes can only gobble up（吞噬）objects within a specific distance to it.It's possible for a large star near the sun to become a black hole,but the sun will continue to stay in place.Orbits（轨道）do not change because the newly formed black hole contains exactly the same amount of mass as when it was a star, only this time its mass is totally contracted that it can end up as no bigger than a state.4 Sofar,astronomers have figured out that black holes exist because of Albert Einstcin's theory of relativity.In the end,through numerous studies,they have discovered that black holes truly exist.Since black holes trap light and do not give off light,it is nearly impossible to detect black holes via a telescope.But astronomers continue to study galaxies（银河系）, space and the solar system to understand how black holes might evolve.It is possible that black holes can exist for millions of years,and later contribute to a bigger process in galaxies,which can eventually lead to creation of new entities（实体）.Scientists also credit black holes as helpful in learning how galaxies began to form.A newly formed black hole and the star it comes from are of__________.A:the existence of black holesB:the creation of new entitiesC:the same amount of massD:an fraction of an inchE:a fraction of an inchF:the tiniest particle
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Black Holes1 Black holes can be best described as a sort of vacuum,sucking up everything in space.Scientists have discovered that black holes come from an explosion of huge stars.Stars that are near death can no longer burn due to loss of fuel , and because its temperature can no longer control the gravitational（重力的）force,hydrogen ends up putting pressure onto the star's surface until it suddenly explodes then collapses.2 Black holes come from stars ihat are made of hydrogen,other gases and a few metals.When these explode it can turn into a stellar-mass（恒星质量) black hole , which can only occur if the star is large enough (should be bigger than the sun)for the explosion to break it into pieces,and the gravity starts to compact every piece into the tiniest particle.Try to see and compare:if a star that's ten times the size of the sun ends up being a black hole that's no longer than 70 kilometers,then the Earth would become a black hole that'S only a fraction of an inch!3 Objects that get sucked in a black hole will always remain there,never to break free.i1it remember that black holes can only gobble up（吞噬）objects within a specific distance to it.It's possible for a large star near the sun to become a black hole,but the sun will continue to stay in place.Orbits（轨道）do not change because the newly formed black hole contains exactly the same amount of mass as when it was a star, only this time its mass is totally contracted that it can end up as no bigger than a state.4 Sofar,astronomers have figured out that black holes exist because of Albert Einstcin's theory of relativity.In the end,through numerous studies,they have discovered that black holes truly exist.Since black holes trap light and do not give off light,it is nearly impossible to detect black holes via a telescope.But astronomers continue to study galaxies（银河系）, space and the solar system to understand how black holes might evolve.It is possible that black holes can exist for millions of years,and later contribute to a bigger process in galaxies,which can eventually lead to creation of new entities（实体）.Scientists also credit black holes as helpful in learning how galaxies began to form.Paragraph 1________A:What Happens to the Objects Around a Black Hole?B:Is There Proof That Black Holes Really Exist?C:How Were Black Holes Named?D:What Are Different Types of Black Holes?E:What Are Black Holes Made of? F: How Are Black Holes Formed?
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Which of the following are steps to configure destination-based Remote Triggered Black Hole（RTBH）filtering？（）A、Configure OSPF between trigger router and black hole routesB、Configure all edge routers with static （reserved） host route to Null0C、Configure BGP beteen trigger and black hole routersD、Configure on trigger router to advertise victim host route with commumityE、Activate black hole by redistributing route for victim into BGP with next-hop set to the static（reserved）host route configured on edge routers
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What is the requirement of Remote Triggered Black Hole （RTBH ） filtering？（）A、IBGP updates exchange between trigger router and black hole routerB、EBGP updates exchange between trigger router and black hole routerC、OSPF updates exchange between trigger router and black hole routerD、ISIS updates exchange between trigger router and black hole router
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单选题The object of plugging holes below the waterline on a ship should be to（）.A
eliminate all water entering the holeB
only plug holes in machinery or other vital spacesC
reduce the entry of water as much as possibleD
plug the largest holes first
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单选题Jackie Robinson, the first Black American who was to play baseball in the majorleagues, joined the Brooklyn Dodgers in 1947.A
the first and a Black American whoB
was the first Black AmericanC
the first Black AmericanD
the Black American who first
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单选题Engine operating conditions may be indicated by the color of the exhaust smoke.Black smoke could indicate（）A
an insufficient speed droop settingB
an overloaded engineC
clogged drain holes in the oil control ringsD
complete combustion
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单选题We have some white and blue paint, but we （）.A
have black paintB
has black paintC
haven’t black paintD
hasn’t black paint
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多选题TestKing.com uses a SQL Server 2005 database. This database contains a trigger named trg InsertOrders， which fires when order data is inserted into the Orders table. The trigger is responsible for ensuring that a customer exists in the Customers table before data is inserted into the Orders table. You need to configure the trigger to prevent it from firing during the data import process. You must accomplish this goal while using the least amount of administrative effort. Which two Transact-SQL statements can you use to achieve this goal？（）AALTER TABLE OrdersDISABLE TRIGGER trg InsertOrdersBDROP TRIGGER trg InsertOrdersCDISABLE TRIGGER trg InsertOrders ON OrdersDALTER TRIGGER trg InsertOrders ON Orders NOT FOR REPLICATION
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