雅思阅读 041 · Giant Black Holes May Be the Universe's Best Planet Makers

改编自 Scientific American（Phil Plait, 2026）。题型：段落信息匹配 + T/F/NG + 填空。难度：中等偏上（Passage 2，约 800 词）。

---

🎧 课文朗读音频（约 1 分钟）

正文 Passage

A. The first exoplanets

With about 6,300 exoplanets discovered so far and more than 10,000 candidates awaiting confirmation, it's easy to forget the ones that started it all: the very first exoplanets discovered and announced in 1992. These worlds were not orbiting stars like the sun. Instead they circled a pulsar, the dead remains of an exploded star. This is one of the last places in the universe astronomers expected to find planets.

Clearly nature excels at making planets, even under extremely hostile conditions.

B. Planets around black holes

Planets like those in our solar system form from whirling disks of gas and dust around baby stars, but disks are common around another kind of astrophysical object, too: black holes. Could planets be born there as well?

The answer, astonishingly, is "maybe," though it depends on what kind of black hole we're talking about.

For stellar-mass black holes — which, like pulsars, are forged in the collapsing core of an exploding massive star — there are some caveats. When a massive star goes supernova, a majority of its matter is flung out into space. If enough matter is lost, the star's gravity will be sufficiently weakened so that it can't hold on to any extant planets.

C. Supermassive black holes

But there also exist far, far larger beasts: supermassive black holes. These lurk in the centres of all big galaxies and play a critical role in galactic birth and growth.

The one in the centre of our Milky Way galaxy, called Sagittarius A*, is four million solar masses, which actually makes it a relative lightweight; other supermassive black holes can contain billions of solar masses.

It's conceivable that planets circle some of these supermassive black holes. We know many stars orbit Sgr A*, and we know from statistics that most stars host planets.

D. How planets could form

Stranger still, it's possible that planets could actually form around supermassive black holes.

A galaxy's central supermassive black hole is often accompanied by a colossal accretion disk consisting of huge quantities of infalling material. Surrounding this disk is a doughnut-shaped cloud of dark, cold dust called a torus. Vast quantities of dust also exist in the disk's cooler outer regions, which are hundreds of billions of kilometres away from the black hole.

Dust can be raw material for planets, which can be built bit by bit via minuscule particles glomming together. Small grains aggregate into pebbles, then boulders, then upward and onward until planetary-mass objects emerge.

E. The findings

In their study, the astronomers found that a supermassive black hole's outer disk and torus could foster this cumulative growth with remarkable efficiency. In fact, their work suggests this process can churn out a broad range of objects: anything from Earth-mass planets to hefty, full-fledged stars with 300 times our sun's mass.

Moreover, the scientists found that a typical disk and torus should contain so much material that tens of millions of planetary-mass objects could form there.

If true, galactic cores with actively feeding black holes may, on average, be the most fecund places for planets in the universe!

F. Habitability

The paper doesn't cover whether such worlds could be habitable, but we can still speculate. Leaving aside any nastiness from the nearby black hole itself, if such planets were much bigger than Earth, they would probably make it difficult for life because of their cell-crushing, intensely powerful surface gravity.

It's harder to gauge life's prospects on approximately Earth-size worlds around a supermassive black hole. The probable lack of a gaseous atmosphere would be a huge hindrance to life as we know it.

Still, the universe itself is telling us this sort of thing seems to be possible, so stretching our minds is in order.

---

题目 Questions

Questions 1-5: Which paragraph mentions the following?

1. the first exoplanets discovered in 1992

2. Sagittarius A* being four million solar masses

3. dust aggregating into pebbles and boulders

4. tens of millions of planetary-mass objects forming

5. surface gravity making life difficult

Questions 6-9: T/F/NG

6. The first exoplanets orbited a star like the sun.

7. Supermassive black holes lurk in the centres of all big galaxies.

8. Planets around supermassive black holes would be made mostly of gas.

9. The study confirms such planets are habitable.

Questions 10-13: Complete the notes. Choose NO MORE THAN TWO WORDS.

• The first exoplanets circled a (10) ____________.
• Supermassive black holes in galaxy centres are surrounded by an accretion disk and a (11) ____________.
• The process can produce objects from Earth-mass planets to stars (12) ____________ times our sun's mass.
• The doughnut-shaped cloud of cold dust is called a (13) ____________.

---

答案 Answers

题号	答案
1	A
2	C
3	D
4	E
5	F
6	FALSE (orbited a pulsar)
7	TRUE
8	FALSE (completely made of rock)
9	FALSE (doesn't cover habitability)
10	pulsar
11	torus
12	300
13	torus

---

核心词汇

black hole / exoplanet / pulsar / supernova / accretion disk / supermassive / galaxy / Milky Way / Sagittarius A* / torus / dust / planet formation / habitability