☆江咪★的部落格

An artist's drawing shows a large black hole pulling gas away from a nearby star. Image Credit: NASA E/PO, Sonoma State University, Aurore Simonnet
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A black hole is a place in space where gravity pulls so much that even light can not 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. They are invisible. 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 than other stars. 


How Big Are Black Holes?

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 "stuff," in an object. 

Another kind of black hole is called "stellar." Its mass can be up to 20 times more than the mass of the sun. There may be many, many stellar mass black holes in Earth's galaxy. Earth's galaxy is called the Milky Way. 

An artist's drawing shows the current view of the Milky Way galaxy. Scientific evidence shows that in the middle of the Milky Way is a supermassive black hole. Image Credit: NASA/JPL-Caltech
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The largest black holes are called "supermassive." These black holes have masses that are more than 1 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 is called Sagittarius A. It has a mass equal to about 4 million suns and would fit inside a very large ball that could hold a few million Earths. 


How Do Black Holes Form?

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 collapses. When this happens, it causes a supernova. A supernova is an exploding star that blasts part of the star into space. 

Scientists think supermassive black holes were made at the same time as the galaxy they are in. 

This image of the center of the Milky Way galaxy was taken by the Chandra X-ray Observatory. Image Credit: NASA/CXC/MIT/F.K. Baganoff et al.
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If Black Holes Are "Black," How Do Scientists Know They Are There?

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 can not be seen with human eyes. Scientists use satellites and telescopes in space to see the high-energy light. 


Could a Black Hole Destroy Earth?

Black holes do not go around in space eating stars, moons and planets. Earth will not fall into a black hole because no black hole is close enough to the solar system for Earth to do that. 

This artist's drawing shows a supermassive black hole in the center of a galaxy. The black hole is surrounded by a cloud of material that is spiraling into it. Image Credit: NASA E/PO, Sonoma State University, Aurore Simonnet
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Even if a black hole the same mass as the sun were to take the place of the sun, Earth still would not fall in. The black hole would have the same gravity as the sun. Earth and the other planets would orbit the black hole as they orbit the sun now. 

The sun will never turn into a black hole. The sun is not a big enough star to make a black hole. 


How Is NASA Studying Black Holes?

NASA is using satellites and telescopes that are traveling in space to learn more about black holes. These spacecraft help scientists answer questions about the universe. 

 

 

 

 

 

 

 

一個藝術家的繪畫顯示了一個大黑洞拉氣體遠離附近的明星。圖片來源：NASA E / PO，索諾瑪州立大學，奧羅爾 Simonnet
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黑洞是一個地方的空間，引力拉這麼多，連光也無法脫身。重力是如此的強烈，因為此事已經被擠壓到一個狹小的空間。這可能發生在一個明星是奄奄一息。 

因為沒有光可以脫身，人們無法看到黑洞。他們是看不見的。空間望遠鏡有特殊工具可以幫助找到黑洞。特殊工具可以看到恆星非常接近黑洞的行為不同於其他明星。 


黑洞有多大？

黑洞可大或小。科學家認為黑洞是最小的小到只有一個原子。這些黑洞是非常微小的，但有質量的大山。質量是量的問題，或“東西”，在一個對象。 

另一種類型的黑洞被稱為“恆星”。其質量可達到 20倍以上的大規模的太陽。可能有很多很多的恆星質量黑洞在地球的星系。地球的星系被稱為銀河系。 

一個藝術家的繪畫顯示當前視圖的銀河系。科學證據表明，在中間的銀河系是一個黑洞。圖片來源：NASA / JPL -加州理工學院
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最大的黑洞被稱為“超大”。這些黑洞的質量都超過 100萬個太陽在一起。科學家發現證明，每一個大星系包含一個黑洞在它的中心。該黑洞在銀河系中心被稱為人馬座星系A.它有一個質量大約相當於 400萬個太陽，將裝進一個非常大的球，可以容納幾百萬地球。 


如何黑洞表格？

科學家認為，最小的黑洞，宇宙開始時形成。 

黑洞是由恆星時中心的一個非常大明星愛上自己時，或倒塌。當發生這種情況，它會導致超新星。超新星是恆星爆炸的恆星爆炸部分進入太空。 

科學家認為，超大質量黑洞是在同一時間，因為他們所在的星系 

此圖片為中心的銀河系是由錢德拉 X射線天文台。圖片來源：NASA / CXC / MIT / FK Baganoff等。
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如果黑洞“黑”，科學家怎樣知道自己有哪些？

黑洞不能被看見，因為強大的引力拉所有的光進中間的黑洞。但是，科學家們可以看到強大的引力影響周圍的恆星和氣體的黑洞。科學家可以研究恆星看看他們是到處亂飛，或繞行，一個黑洞。 

當一個黑洞和恆星距離很近，高能量的光而成。這種光線不能被看作與人的眼睛。科學家利用衛星和望遠鏡在太空中看到的高能量的光。 


請問黑洞毀滅地球？

黑洞周圍不走在太空吃星星，月亮和行星。地球不會落入黑洞黑洞是因為沒有足夠接近太陽系地球這樣做。 

這位藝術家的繪畫顯示了一個黑洞在星系的中心。該黑洞周圍有雲的材料，螺旋進去。圖片來源：NASA E / PO，索諾瑪州立大學，奧羅爾 Simonnet
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即使相同的質量黑洞，太陽的地方要採取的太陽，地球仍然不會裡鑽的黑洞會擁有相同的重力的太陽。地球和其他行星軌道的黑洞會，因為他們現在太陽軌道。 

太陽永遠不會變成一個黑洞。太陽是不是足夠大明星做一個黑洞。 


如何是美國宇航局研究黑洞？

美國宇航局正在利用衛星和望遠鏡在太空旅行是更多地了解黑洞。這些航天器幫助科學家解答：宇宙。