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If the neutron star is very large(much bigger than our sun)the process of shrinking may be so intense that a black hole______(result).
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更多 “ If the neutron star is very large(much bigger than our sun)the process of shrinking may be so intense that a black hole______(result). ” 相关考题
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Ten years ago the population of our vilage was () that of theirs.
A、as twice as large asB、twice as large asC、twice as much asD、as twice much as
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We very much appreciate your efforts________
A.our production costs must be no more than 15 percent.B.has done damage to our reputationC.to negotiate with youD.to make this product possible
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There are books in our school library than in yours.
A.so manyB.much moreC.many moreD.such many
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Passage FourMillions of stars are traveling about in space. A few form. groups which journey together, but most of them travel alone. And they travel through a universe so large that one star seldom comes near to another.We believe, however, that some two thousand million years ago, another star wandering through space, happened to come near our sun. Just as the sun and the moon raise tides on the earth, so this star must have raised tides on the surface of the sun. But they were very different from the small tides that are raised in our oceans; a large tidal wave' must have travelled over the surface of the sun, at last forming a mountain so high that we cannot imagine it. As the cause of the disturbance (动荡) came nearer, so the mountain rose higher and higher. And before the star began to move away again, its tidal pull had become so powerful that this mountain was torn to pieces and threw off small parts of itself into space. These small pieces have been going round the sun ever since. They are the planets (行星).46. Millions of stars are______.A. following a regular path in spaceB. always travelling togetherC. seldom wandering about in the universeD. moving about without a fixed course
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Some two thousand million years ago, the mountain on the sun was raised probably because______.A. the star moved away from the sunB. another star happened to come near the sunC. fhe sun and the moon raised the tides on the earthD. a large tidal wave of a star travelled over the surface of the sun
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AWhen you look at the sky at night,the moon looks bigger than the stars. In fact,the moon is much smaller than the stars.It is much smaller than the earth. But the moon is much closer to us than any star. That is why it looks so big. If you hold a coin close.to your eye,it looks big.If you look at it across the room,it looks small.The moon moves around the earth. It makes one trip in about four weeks. The moon looks flat(扁的)to us. But it is a round ball,like the earth.People once thought the moon had fire(火) on it. They thought the fire made it bright.Now we know the moon is like a mirror( 镜子 ). It gets its light from the sun Our sunlight comes from the sun,too: What is the sun? The sun is star. The stars we can see have their own light. There are many big stars we can-t see. Their light has burned out. Others are still bright,but they are so far away that we can-t see them. The sun looks bigger and much brighter than other stars because it is the nearest of all stars. The sun and the other stars we see are very hot,but the air around us saves us from(使------免于) the heat(热量) of the sun.The sun gives us light and warmth.It makes plants grow and leaves turn green. It makes life possible on our earth.It is a life-giving star.( )21. The moon looks bigger because__________ .A. some stars are smaller than itB.it is between the sun and the earthC.it is the closest to the earthD.it is very bright
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24. The passage tells us __________.A. the sun is not the biggest starB. the sun is bigger than any other starC. only the sun can shineD. the sun is one of the farthest stars from us
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My uncle’s house in the downtown area is much smaller than ours, but it is twice _______ expensive.A. as B. so C. too D. very
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Our stocks include a wide range of first-class electrical typewriters at very competitive prices.They have the correcting and automatically storing system. From the catalogues enclosed, you will find that our prices are much lower than those in the market.(英译中)
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Now the air in our city is _______ than it used to be. Something must be done to stop it.A.very good B.much better C.rather bad D.even worse
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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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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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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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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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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. 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 explosion of huge starsE: a fraction of an inchF: the tiniest narticle
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Mercury’s( )is so much greater than the Earth’s that it completes more than four revolutions around the Sun in the time it takes the Earth to complete one.A.velocity
B.orbit
C.weight
D.diameter
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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.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 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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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.
考题
According to the fourth paragraph, which of the following is NOT true?A. No nuclear explosion would be triggered inside the star.
B. The star would be destroyed completely.
C. Much of the star's matter thrown by the explosion would be beyond the black hole's reach.
D. The black hole would completely devour the star.
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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 powerful 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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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 powerful 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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单选题Because our work is very busy, so we need to relax at midday.A
We are very busy,B
Our work being busy,C
Our work so very busy,D
Because our work so very busy,
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单选题Our car is a much older _____ than yours and so we paid less than you.A
modelB
manufactureC
formD
pattern
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