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Black holes exist but are difficult to observe.A．RightB．WrongC．Not mentioned
Black holes exist but are difficult to observe.
A．Right
B．Wrong
C．Not mentioned
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题目内容
（请给出正确答案）
Black holes exist but are difficult to observe.
A．Right
B．Wrong
C．Not mentioned
答案
更多“Black holes exist but are difficult to observe.A．RightB．WrongC．Not mentioned”相关的问题
第2题
Black holes exist but are difficult to observe.
A．Right
B．Wrong
C．Not mentioned
第4题
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 ？
第5题
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 ？
第6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.
A．Right
B．Wrong
C．Not mentioned
第7题
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
第8题
Paragraph 4 __________ 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 ？
第9题
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
第10题
Black Holes
1 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 end up being a black hole that’s no longer than 70 kilometers, then the Earth would become 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. But 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 its mass is totally contracted that it can end up as no bigger than a state.
4 So far, astronomers have figured out that black holes exist because of Albert Einstein’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 not possible to detect black holes via a telescope. But astronomers continue to explore galaxies(银河系), space and the solar system to understand how black holes. It is possible that black holes can exist for millions of years, and later contribute further process in galaxies, which can eventually lead to creation of new entities. Scientists also credit black holes as helpful in learning how galaxies began to form.
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 happened to the objects around a black hole？
F What are black holes made of？
23 Paragraph 1________
