Narrator: Listen to part of a lecture in an astronomy class. Professor: Now, we often think of planets as solid, rocky bodies, but that's not always true. Take Jupiter, for example. It's a gas giant, meaning it's mostly hydrogen and helium. But here's an interesting fact: Jupiter emits more energy than it receives from the Sun. Why? Well, as Jupiter slowly contracts under its own gravity, that gravitational energy is converted into heat. This process is called Kelvin-Helmholtz heating. It's similar to how the Sun generates energy, but on a smaller scale. Also, Jupiter has a faint ring system, discovered by the Voyager spacecraft in 1979. These rings are made of dust particles, not ice like Saturn's. The dust likely comes from micrometeorite impacts on Jupiter's small moons. So, Jupiter is far more complex than a simple ball of gas.
❓ คำถาม What does the professor imply about Jupiter's energy emission?
A. A. It is caused by nuclear fusion in the core.
B. B. It results from gravitational contraction.
C. C. It is reflected sunlight from the rings.
D. D. It is produced by chemical reactions in the atmosphere.
✅ คำตอบที่ถูกต้อง
B. It results from gravitational contraction.
TOEFL Listening Tips
Skim the questions first to predict the content
Watch for signal words in lectures and conversations (however, actually, in fact)
For main idea questions, focus on the beginning; for detail questions, focus on examples and data
For attitude questions, pay attention to the speaker's tone and word choice
Take notes on keywords; don't try to write down every word
