L2
讲座
1. What is the main purpose of the lecture?
To explain the features of an exoplanet orbiting a star remarkably similar to our Sun
To explain how the theory of the habitable zone originated
To show how astronomers resolved a controversy about a star’s effect on one of its planets
To describe an exoplanet that might have conditions capable of supporting life
2. Why does the professor mention the planet Venus?
To emphasize the difference between our solar system and that of Gliese 581
To give an example of a planet that is too small to support an atmosphere
To illustrate the features of a planet at the inner limits of a habitable zone
To explain the stabilizing effect of water vapor on an atmosphere
3. According to the professor, what factors suggest that Gliese 581d might be habitable?（多选题）
Its gravity is strong due to its large mass
It is located in the middle of a habitable zone
Its atmosphere probably has a high carbon dioxide content
Its speed of rotation is almost equal to Earth’s
4. What does the professor say about the light of the star Gliese 581?
The amount of light that the star emits continues to diminish rapidly
Most of the light reaches the surface of the planet Gliese 581d
The light would appear blue from the surface of the planet Gliese 581d
The light’s red color makes the planet Gliese 581d difficult to detect
5. What does the professor imply when he discusses the distance between Earth and Gliese 581d?
He looks forward to advances in technology revealing better information about Gliese 581d.
He thinks travel to Gliese 518d may become possible sooner than many researchers believe.
He doubts that the most important questions about Gliese 581d can ever be answered.
He expects that astronomers will someday disprove current assumptions about Gliese 581d.
6. What does the professor mean when he says this about Gliese 581d?
The dark side of the planet would most likely be permanently frozen.
Temperature extremes would be reduced by atmospheric movement.
Changes in the temperature of a gas depend on its density.
Extreme cold can cause a planet’s atmosphere to collapse.
