Black Holes Most scientists agree that black holes exist but are nearly impossible to loca - 试题答案网问答

第1题

请根据短文内容，回答题。 Black HolesMost scientists agree that black holes exist but are nea

请根据短文内容，回答题。

Black Holes

Most 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.＜br＞

Anything that crosses the black hole is pulled in by its great gravity.＜br＞

Although black holes do exist, they are difficult to observe. These are the reasons.＜br＞

No light or anything else comes out of black holes. As a result, they are invisible to a telescope.＜br＞

In astronomical terms, black holes are truly. For example, a black hole formed by the collapse of a giant star would have an event horizon (视界) only 18 miles across.＜br＞

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.＜br＞

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.＜

Black holes are part of space. 查看材料

A.Right

B.Wrong

C.Not mentioned

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第2题

根据下面材料，回答题。 Black HolesMost scientists agree that black holes exist but are nea

根据下面材料，回答题。

Black Holes

Most 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. 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.

Black holes are part of space. 查看材料

A.Right

B.Wrong

C.Not mentioned

点击查看答案

第3题

根据下列文章,请回答 31～35 题。 Black Holes What is a black hole？ Well, it's difficult

根据下列文章,请回答 31～35 题。

Black Holes

What is a black hole？ Well, it's difficult to answer this question, since the terms we normally use to describe a scientific phenomenon are inadequate here. Astronomers and scientists think that a black hole is a region of space (not a thing) into which matter has fallen and from which nothing can escape -- not even light. So we can't see a black hole. A black hole exerts (施加) a strong gravitational (重力的) pull and yet it has no matter. It is only space -- or so we think. How can this happen？

The theory is that some stars explode ,when their density increases to a particular point; they "collapse" and sometimes a supernova (超新星) occurs. The collapse of a star may produce a "White Dwarf (白矮星) " or a "neutron star"-- a star whose matter is so dense that it continually shrinks by the force of its own gravity. But if the star is very large this process of shrinking may be so intense that a black hole results. Imagine the earth reduced to the size of a marble, but still having the same mass and a stronger gravitational pull, and you have some idea of the force of a black hole. Any matter near the black hole is sucked in. It is impossible to say what happens inside a black hole.

Our space and time laws don't seem to apply to objects in the area of a black hole. Einstein's relativity theory is the only one that can explain such phenomena. Einstein claimed that matter and energy are interchangeable, so that there is no "absolute" time and space. There are no constants at all, and measurements of time and space depend on the position of the observer -- they are relative. Einstein's theory provided a basis for the idea of black holes before astronomers started to find some evidence for their existence. It is only recently that astronomers have begun specific research into black holes.

The most convincing evidence of black holes comes from research into binary (由两部分组成的) star systems. In some binary star systems, astronomers have shown that there is an invisible companion star, a "partner" to the one which we can see in the sky. There is one star, called by its catalogue number HDE 226868, which must have a partner. This partner star, it seems, has a mass ten or twenty times greater than the sun-- yet we can't see it. Matter from HDE 226868 is being dragged towards this companion star. Could this invisible star, which exerts such a great force, be a black hole？ Astronomers have evidence of a few other stars too, which might have black holes as companions.

第 31 题 Which of the following does NOT fit the definition of the black hole？

A．The black hole is a region of space.

B．The black hole sucks in any object that passes by it.

C．The black hole is visible through an infrared telescope.

D．The black hole has no matter.

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第4题

Black HolesWhat is a black hole？ Well, it's difficult to answer this question, since the t

Black Holes

What is a black hole？ Well, it's difficult to answer this question, since the terms we normally use to describe a scientific phenomenon are inadequate here, Astronomers and scientists think that a black hole is a region of space (not a thing) into which matter has fallen and from which nothing can escape—not even light. So we can't see a black hole. A black hole exerts (施加) a strong gravitational (重力的) pull and yet it has no matter. It is only space—or so we think. How can this happen？

The theory is that some stars explode when their density increases to a particular point; they "collapse" and sometimes a supernova (超新星) occurs. The collapse of a star may produce a "White Dwarf (白矮星) "or a "neutron star"—a star whose matter is so dense that it continually shrinks by the force of its own gravity. But if the star is very large this process of shrinking may be so intense that a black hole results. Imagine the earth reduced to the size of a marble, but still having the same mass and a stronger gravitational pull, and you have some idea of the force of a black hole. Any matter near the black hole Is sucked in. It is impossible to say what happens Inside a black hole.

Our space and time laws don't seem to apply to objects in the area of a black hole. Einstein's relativity theory is the only one that can explain such phenomena. Einstein claimed that matter and energy are interchangeable, so that there is no "absolute" time and space, There are no constants at all, and measurements of time and space depend on the position of the observer— they are relative. Einstein's theory provided a basis for the idea of black holes before astronomers started to find some evidence for their existence. It is only recently that astronomers have begun specific research into black holes.

The most convincing evidence of black holes comes from research into binary (由两部分组成的) star systems. In some binary star systems, astronomers have shown that there is an invisible companion star, a "partner" to the one which we can see in the sky. There is one star, called by its catalogue number HDE 226868, which must have a Partner. This partner star, it seems, has a mass ten or twenty times greater than the sun—yet we can't see it. Matter from HDE 226868 is being dragged towards this companion star. Could this invisible star, which exerts such a great force, be a black hole？ Astronomers have evidence of a few other stars too, which might have black holes as companions.

Which of the following does NOT fit the definition of the black hole？

A．The black hole is a region of space.

B．The black hole sucks in any object that passes by it.

C．The black hole is visible through an infrared telescope.

D．The black hole has no matter.

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第5题

听力原文：Rats are the enemy of human beings. They eat or spoil crops of grain and rice bef

听力原文： Rats are the enemy of human beings. They eat or spoil crops of grain and rice before they can be harvested, or while they are in storage. In India, where millions of people go hungry, there are ten times as many rats as people. Rats devour half of the available food. Rats will also attack birds and animals, from frogs and chicks to geese and young calves. They have even destroyed dams and buildings by making holes through or under them, and have started fires by chewing on electrical wiring.

The most terrible destruction caused by rats, however, has come from the diseases they carry. In the fourteenth century, rats caused the death of one-third of the world's population by transmitting the dreadful Black Plague that mined Europe.

Ironically, it is in fighting diseases that rats have been most useful to humanity. Thousands of specially bred rats are used in research laboratories every year to test medicines which can possibly be used to prolong and improve human life. Some laboratory rats are even used to test new methods of eliminating their cousins, the wild rats.

(23)

A．The Black Plague.

B．Enemy of Humanity.

C．Common Animal pests.

D．Causes of World Hunger.

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第6题

Paragraph 2 __________ 查看材料A.Is there proof that bl

Paragraph 2 __________ 查看材料

A.Is there proof that black holes really exist？

B.What are different types of black holes？

C.How are black holes formed？

D.How were black holes named？

E.What happens to the objects around a black hole？

F.What are black holes made of ？

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第7题

Paragraph 3 __________ 查看材料A.Is there proof that bl

Paragraph 3 __________ 查看材料

A.Is there proof that black holes really exist？

B.What are different types of black holes？

C.How are black holes formed？

D.How were black holes named？

E.What happens to the objects around a black hole？

F.What are black holes made of ？

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第8题

Black holes exist but are difficult to observe.

Black holes exist but are difficult to observe. 请帮

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第9题

Black holes are formed after__________ 查看材料A.the cr

Black holes are formed after__________ 查看材料

A.the creation of new entities

B.an explosion of huge stars

C.the tiniest particle

D.the same amount of mass

E.the existence of black holes

F.a fraction of an inch

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第10题

The nearest black holes are hundreds of light years away from us.A．RightB．WrongC．Not menti

The nearest black holes are hundreds of light years away from us.

A．Right

B．Wrong

C．Not mentioned

点击查看答案