A black hole is a place in space where gravity pulls so much that even light cannot get out. The gravity is so strong because matter has been squeezed into a tiny space. This can happen when a star is dying.
Because no light can get out, people can’t see black holes. Space telescopes with special tools can help find black holes. The special tools can see how stars that are very close to black holes act differently from other ones.
Black holes can be big or small. Scientists think the smallest black holes are as small as just one atom. These black holes are very tiny but have the mass of a large mountain. Mass is the amount of matter, or “staff”, in an object.
Another kind of black hole is called “stellar”(星球黑洞). Its mass can be up to 20 times more than the mass of the sun. There may be many stellar mass black holes in Earth’s galaxy. Earth’s galaxy is called the Milky Way.
The largest black holes are called “supermassive”(超大质量黑洞). These black holes have masses that are more than one million suns together. Scientists have found proof that every large galaxy contains a supermassive black hole at its center. The supermassive black hole at the center of the Milky Way galaxy has a mass equal to about four million suns and would fit inside a very large ball that could hold a few million Earths.
Scientists think the smallest black holes formed when the universe began. Stellar black holes are made when the center of a very big star falls in upon itself, or falls apart. When this happens, it exploded part of the star into space. Scientists think supermassive black holes were made at the same time as the galaxy they are in.
A black hole can not be seen because strong gravity pulls all of the light into the middle of the black hole. But scientists can see how the strong gravity affects the stars and gas around the black hole. Scientists can study stars to find out if they are flying around, or orbiting a black hole.
When a black hole and a star are close together, high-energy light is made. This kind of light cannot be seen with human eyes. Scientists use satellites and telescopes in space to see the high-energy light.
【小题1】The gravity of a black hole may bee so strong that light cannot get out when .A．the star is going to dieB．special tools are used on itC．other stars e close to itD．it is seen from the space telescopes【小题2】According to the passage, which of the following is NOT true?A．A black hole can be very tiny but extremely heavy.B．The gravity of a black hole holds all light in its center.C．Scientists observe high-energy light through their own eyes.D．Some small black holes came into being as early as the universe.【小题3】The underlined word “galaxy” in Paragraph 5 means .A．a black holeB．the Milky WayC．a series of starsD．a planet near the earth【小题4】What does the last sentence in Paragraph 5 suggest?A．Neither the sun nor the earth is as heavy as a black hole.B．There is a supermassive black hole at the center of the Milky Way.C．The supermassive black hole had existed before the Milky Way was formed.D．There is a reason why the large black holes are called “supermassive”.【小题5】The last two paragraph mainly focus on the question of .A．what a black hole isB．how black holes formC．how big black holes areD．how scientists know about black holesA
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(答案→)A
解析：文章介绍黑洞的形成，它的特点以及科学家探索研究黑洞的方法。
【小题1】细节题：根据文章第一段中“This can happen when a star is dying.”可知恒星的死亡可能会形成黑洞。故选A。
【小题2】细节题：根据第三段中“These black holes are very tiny but have the mass of a large mountain”这些黑洞可能会非常小，但是有一座山一样的质量，可知A正确；根据倒数第二段中“A black hole can not be seen because strong gravity pulls all of the light into the middle of the black hole.”黑洞不可见是因为强大的引力将所有的光线吸进黑洞的中间，可知B项正确；根据最后一句“Scientists use satellites and telescopes in space to see the high-energy light.”科学家们使用卫星和太空望远镜查看高能光，可知科学家不是用自己的眼睛，因此C错误；根据第六段中“Scientists think the smallest black holes formed when the universe began.”科学家认为最小的黑洞在宇宙开始时形成，可知D项正确。故选C。
【小题3】推理题：根据第四段中“Earth’s galaxy is called the Milky Way”地球所在的星系叫银河系，常理可知星系是有很多星星组成的。故选C。
【小题4】推理题：根据第五段最后一句“The supermassive black hole at the center of the Milky Way galaxy has a mass equal to about four million suns and would fit inside a very large ball that could hold a few million Earths.”在银河系中心的超大质量黑洞的质量相当于四百万个太阳,是一个可以容纳几百万地球在内的巨大的球，由此可知这是在解释什么叫做“超大质量黑洞”。故选D。
【小题5】推理题：阅读最后两段内容可知是在介绍科学家是如何找到黑洞的。故选D。