L2
讲座
1. What is the lecture mainly about?
Reasons why exoplanets tend to have retrograde orbits
Different methods used to discover giant gas exoplanets
A new discovery about the formation of distant stars and planets
The detection of an exoplanet and its unusual characteristics
2. Why does the professor point out that stars and planets form from swirling gas clouds?
To help explain how planetary orbits are initially established
To help students remember a theory about gas giant planets
To emphasize the indirect nature of astronomical research
To suggest an explanation for the thick clouds on WASP-17b
3. According to the professor, what are two weaknesses of the method of using a star’s wobble to detect exoplanets?（多选题）
Equipment used to observe stars is more sensitive to blue shifts than to red shifts.
It is impossible to detect a wobble created by low-mass objects in orbit
The method is useful only when the star’s distance from Earth is affected
Some stars wobble without the influence of an orbiting object.
4. What does the professor suggest about the analogy of the spinning top?
It helps explain an important aspect of the red-blue starlight shift.
It provides only a basic illustration of the process that could change a planet’s orbit
It overstates the impact that gravity has on the motion of distant stars
It demonstrates why retrograde orbits tend to be less stable than regular orbits.
5. What does the professor say contributes to WASP-17b’s large diameter?
WASP-17b’s gas composition allows it to expand easily when heated.
WASP-17b’s retrograde orbit causes it to expand
WASP-17b’s strong gravitational force continually pulls in new material.
WASP-17b collided with many other planets early in its formation
6. What is the professor’s opinion regarding WASP-17b’s internal heat?
It will probably destroy the planet’s atmosphere eventually.
It indicates that WASP-17b is closer to its star than originally thought.
It is likely to decrease as WASP-17b continues to expand in size.
It is probably the result of two independent processes.
