Supermassive Black Holes 超大质量黑洞 - 4

This ferocious¹ heart of brilliant hot gas is called a quasar. Scientists thought this whirling mass might be caused by a giant black hole sucking up gas and stars, literally² feeding on the center of a galaxy³.

The idea is that the quasars that we see that look so bright are not the black hole, the supermassive black hole. They are the gas that's just about to fall into the supermassive black hole, that's going around it, shining very brightly just before it disappears down into the black hole.

A giant black hole would have a gravitational pull so overwhelming, it would hurl⁴ gas and stars around it at almost the speed of light. The violent clashing would heat the gas up to over a million degrees.

The gas rubs against itself essentially⁵ and gets extremely hot, and extremely hot gas shines very brightly.

In reality, although a quasar burns brightly, it is actually impossible to see if there's a black hole in the middle. Paradoxically, the black hole is made invisible by the fact that it swallows light. So for years, no one could be certain if supermassive black holes really did exist at the heart of these strange active galaxies⁶. The Nukers have spent the last two decades hunting for these elusive⁷ monsters. The first problem they faced was to prove that supermassive black holes existed at all. What they were to discover would be stranger than most people could have imagined. One of the first of the Nukers to try to find one was Alan Dressler. In 1983 he came to the Palomar Telescope in California convinced that he'd found a way to prove that supermassive black holes exist.

You can't see a black hole directly. That's what makes it a black hole. So what you are looking for is evidence of its gravity. You are ever looking at how it pulls on the stars that are coming nearby.

Dressler knew that although a black hole is invisible, its immense gravity would hurl stars around it at over 500,000 kilometers an hour.

quasar: 类星体 Astronomy a massive and extremely remote celestial object which emits large amounts of energy and typically shows a starlike image

1 ferocious   

adj.凶猛的，残暴的，极度的，十分强烈的

参考例句：

• The ferocious winds seemed about to tear the ship to pieces.狂风仿佛要把船撕成碎片似的。
• The ferocious panther is chasing a rabbit.那只凶猛的豹子正追赶一只兔子。

2 literally   

adv.照字面意义，逐字地；确实

参考例句：

• He translated the passage literally.他逐字逐句地翻译这段文字。
• Sometimes she would not sit down till she was literally faint.有时候，她不走到真正要昏厥了，决不肯坐下来。

3 galaxy   

n.星系；银河系；一群(杰出或著名的人物)

参考例句：

• The earth is one of the planets in the Galaxy.地球是银河系中的星球之一。
• The company has a galaxy of talent.该公司拥有一批优秀的人才。

4 hurl   

vt.猛投，力掷，声叫骂

参考例句：

• The best cure for unhappiness is to hurl yourself into your work.医治愁苦的最好办法就是全身心地投入工作。
• To hurl abuse is no way to fight.谩骂决不是战斗。

5 essentially   

adv.本质上，实质上，基本上

参考例句：

• Really great men are essentially modest.真正的伟人大都很谦虚。
• She is an essentially selfish person.她本质上是个自私自利的人。

6 galaxies   

星系( galaxy的名词复数 )； 银河系； 一群（杰出或著名的人物）

参考例句：

• Quasars are the highly energetic cores of distant galaxies. 类星体是遥远星系的极为活跃的核心体。
• We still don't know how many galaxies there are in the universe. 我们还不知道宇宙中有多少个星系。

7 elusive   

adj.难以表达(捉摸)的；令人困惑的；逃避的

参考例句：

• Try to catch the elusive charm of the original in translation.翻译时设法把握住原文中难以捉摸的风韵。
• Interpol have searched all the corners of the earth for the elusive hijackers.国际刑警组织已在世界各地搜查在逃的飞机劫持者。