🔥Theories of Planet Formation Questioned: Đề thi thật IELTS READING (IELTS Reading Recent Actual Test) - Làm bài online format computer-based, kèm giải thích từ vựng

READING PASSAGE 3

You should spend about 20 minutes on Questions 27-40, which are based on Reading Passage 3 on pages 10 and 11.

Theories of Planet Formation Questioned

A. The traditional view of astronomy has been that planets form slowly as material congeals within the disk of gas, dust, and ice known to surround young stars. First, gravity gathers together bits of dust that merge to form boulder-sized bodies, which themselves coalesce into bigger and bigger objects. In about a million years, these form rocky planets like Earth and Mars. Over the next few million years, gas from the disk settles around some of these solid bodies, and they grow far larger, becoming giants like gaseous Saturn and Jupiter. This theory of planet formation is known as the core-accretion model. However, several astronomers now say that this model for making planets may not be entirely correct.

B. These astronomers have devised an alternative theory in which planets as massive as Jupiter, whether orbiting our sun or a distant star, would form completely within a few hundred years, rather than millions of years as previously believed. Both theories for planet formation start with the same reservoir of planet-making materials. The spinning cloud of gas, dust, and ice rapidly fattens into disk-like shapes known as proto-planetary disks; and, as time goes by, gravity causes material in these disks to clump into planet-sized objects. However, it is the speed of the clustering, and the size of the initial clumps, that provide the disparity in the two models for planet formation.>> Form đăng kí giải đề thi thật IELTS 4 kĩ năng kèm bài giải bộ đề 100 đề PART 2 IELTS SPEAKING quý đang thi (update hàng tuần) từ IELTS TUTOR

C. According to the core-accretion model, the making of Jupiter required the initial formation of a solid core five to ten times Earth’s mass. It would have taken about a million years to achieve this. Most astronomers believe that the large core then had enough gravity to attract a huge amount of gas from the proto-planetary disk to create a planet of the massive proportions of Jupiter. In this core-accretion model, these 'gas giants' may take as long as ten million years to form.

D. That is several million years too long in the opinion of Lucio Mayer of Zurich University. Direct telescope sightings suggest that the proto-planetary disks do not last more than about seven million years, and studies of the environment in which stars form suggest that many disks may evaporate in much less time. Mayer asserts that most stars in the Milky Way form in dense clouds of gas, dust, and ice. Their temperatures are very intense, and the ultraviolet light they send into space can evaporate a proto-planetary disk in less than 100,000 years. In the core-accretion model, that is not enough time for a Jupiter-like planet to form.

E. Recent computer simulations show that when individual stars form, the gravitational pull between them can result in the outer gaseous parts of the proto-planetary disks being destroyed in 100,000 years or less. Thus, Thomas Quinn of the University of Washington concludes that if a gas giant planet cannot form quickly, it will probably never form. He also asserts that if the core-accretion model is correct, gas giant planets like Jupiter should be rare. However, since 1995, astronomers have found more than one hundred planets as large as Jupiter outside our solar system.

F. Quinn and his colleagues recently analyzed the standard core-accretion model of planet formation and investigated whether giant planets could form quickly. They looked at the work of Gerard Kuiper, who, in the 1950s, proposed that they could. Alan P Boss of the Carnegie Institute did more extensive work on the subject in the late 1980s. Using computer simulations, he was surprised to find that gravity could cause a proto-planetary disk, after a few orbits of its parent star, to break into clumps as big as an average-sized planet. The clumps would continue to pull in gas, ice, and dust. This is called the gravitational-instability model of planet formation.

G. Recent calculations have suggested that many of the solid bodies that might be the rocky core for Jupiter-size planets in the traditional theory would pin into the parent star before the massive planet could form. Moreover, further analysis has shown that other effects could also cause a proto-planetary disk to become unstable and split into large fragments. For instance, within the disk, electrically charged material might accumulate, leading to fragmentation of the disk. Or a powerful gravitational disturbance, such as the pull of a star passing nearby, could produce instability in the proto-planetary disk.

H. Nevertheless, the gravitational-instability model has problems of its own, as it is mathematically complicated and requires sophisticated computer use. Therefore, no one has studied the simulations long enough to establish conclusively that the model allows for the formation of massive planets.

I. In response, Mayer says that he and his team have described the results of an extensive simulation based on the gravitational-instability model. They spent two years refining calculations to track what would happen to a proto-planetary disk over one thousand years, which is more than any other simulation had done. In addition, over a decade previously, Mayer and his team had made simulations of the formation and evolution of galaxies. In doing this, they had already developed a fast computer code that could run in parallel on machines with hundreds of processors, and this knowledge assisted them in investigating their gravitational-instability theory.

Questions 27-32
Reading Passage 3 has nine paragraphs, A-I.
Which paragraph contains the following information?
Write the correct letter, A-I, in boxes 27-32 on your answer sheet.

1. The significance of recent discoveries of a large number of massive planets
2. An explanation of the difference between the theories of planet creation
3. The difficulties of proving that the more recent theory of planet creation is correct
4. Reasons why Mayer claims he was able to develop his theory
5. A detailed explanation of the long-held theory of planet creation
6. Description of the destructive effect of heat in space

Questions 33-37
Complete each sentence with the correct ending, A-G, below. Write the correct letter, A-G, in boxes 33-37 on your answer sheet.

Traditionally, astronomers have believed that...

1. LUCIO MAYER physically observed that...
2. THOMAS QUINN believes that...
3. GERARD KUIPER was the first to suggest that...
4. ALAN P. BOSS discovered that...

A. Large planets take millions of years to form.
B. Gaseous planets form before smaller rocky planets.
C. Large planets must form fast or not at all.
D. Large planets had the potential to develop relatively fast.
E. Gravity could cause planet-sized pieces to break off quickly.
F. Hot clumps of gas, dust, and ice were destroyed relatively quickly.
G. Computer studies of planets are too mathematically complex.

Questions 38-40
Complete the summary using the list of words, A-F, below.
Write the correct letter, A-F, in boxes 38-40 on your answer sheet.

The core-accretion model
A hard centre becomes larger, and this produces enough gravity to draw gas from the 38 around it.

The gravitational-instability model
Stars can break up the outer gaseous parts which surround objects in the sky because the attraction of the 39 from stars is very powerful. Heat caused by 40 can also destroy the material surrounding the objects in a relatively short time. Planet-sized segments may split away from the main body following several orbits of the parent star.

A. Gravitational pull
B. Ice
C. Solid core
D. Ultraviolet light
E. Milky Way

• Congeals

  • Vietnamese: Đông lại, đông cứng.
  • IELTS TUTOR xét ví dụ từ bài đọc: "Planets form slowly as material congeals within the disk of gas, dust and ice..."

• Proto-planetary disks

  • Vietnamese: Các đĩa tiền hành tinh.
  • IELTS TUTOR xét ví dụ từ bài đọc: "The spinning cloud of gas, dust and ice rapidly fattens into disk-like shapes known as proto-planetary disks..."

• Coalesce

  • Vietnamese: Kết hợp, hợp nhất.
  • IELTS TUTOR xét ví dụ từ bài đọc: "...bits of dust that merge to form boulder-sized bodies, which themselves coalesce into bigger and bigger objects."

• Clump

  • Vietnamese: Tập hợp lại thành mảng.
  • IELTS TUTOR xét ví dụ từ bài đọc: "Gravity causes material in these disks to clump into planet-sized objects."

• Gravitational pull

  • Vietnamese: Lực hấp dẫn.
  • IELTS TUTOR xét ví dụ từ bài đọc: "In the core-accretion model, the large core then had enough gravity to attract a huge amount of gas..."

• Evaporate

  • Vietnamese: Bay hơi, bốc hơi.
  • IELTS TUTOR xét ví dụ từ bài đọc: "Mayer asserts that most stars in the Milky Way form in dense clouds of gas, dust and ice. Their temperatures are very intense and the ultraviolet light they send into space can evaporate a proto-planetary disk..."

• Simulations

  • Vietnamese: Mô phỏng.
  • IELTS TUTOR xét ví dụ từ bài đọc: "Recent computer simulations show that when individual stars form..."

• Instability

  • Vietnamese: Sự không ổn định.
  • IELTS TUTOR xét ví dụ từ bài đọc: "...other effects could also cause a proto-planetary disk to become unstable and split into large fragments."

• Fragmentation

  • Vietnamese: Sự phân mảnh.
  • IELTS TUTOR xét ví dụ từ bài đọc: "Electricity charged material might accumulate, leading to fragmentation of the disk."

• Disturbance

  • Vietnamese: Sự xáo trộn.
  • IELTS TUTOR xét ví dụ từ bài đọc: "A powerful gravitational disturbance, such as the pull of a star passing nearby, could produce instability..."

• Conclusively

  • Vietnamese: Một cách dứt khoát.
  • IELTS TUTOR xét ví dụ từ bài đọc: "No one has studied the simulations long enough to establish conclusively that the model allows for the formation of massive planets."

• Simulation

  • Vietnamese: Mô phỏng.
  • IELTS TUTOR xét ví dụ từ bài đọc: "Mayer and his team spent two years refining calculations to track what would happen to a proto-planetary disk over one thousand years."

• Processor

  • Vietnamese: Bộ xử lý.
  • IELTS TUTOR xét ví dụ từ bài đọc: "They had already developed a fast computer code that could run in parallel on machines with hundreds of processors..."

• Refining

  • Vietnamese: Tinh chỉnh, cải tiến.
  • IELTS TUTOR xét ví dụ từ bài đọc: "Mayer and his team spent two years refining calculations..."

27 F
28 B
29 H
30 I
31 A
32 D

33 B

34 F
35 C
36 D

37 E

38 F

39 A

40 D