L3：
讲座
1. What is the main purpose of the lecture?
To explore the possibility that life may have once existed on Titan
To show how evidence of water on Titan was detected
To discuss recent findings about precipitation on Titan
To explain how the moons of Earth and Saturn have evolved similarly
2. Why does the professor mention the discovery of a large dark spot on the surface of Titan?
To identify one reason scientists now think that it rains on Titan
To point out the difficulty in distinguishing surface and atmospheric features onTitan
To emphasize that surface winds have changed the landscape
To show how lakes are detected on Titan
3. According to the professor, how does Titan’s ITCZ differ from that of Earth?
Titan’s ITCZ does not result from the convergence of surface winds
Titan’s ITCZ remains at the north pole most of the time
The position of Titan’s ITCZ ensures that tropical precipitation occurs all year round
The position of Titan’s ITCZ shifts from one polar region to the other
4. According to the professor, why are the atmospheric circulation patterns on Titan simpler than those found on Earth?
Titan’s ITCZ keeps these patterns from becoming move com
Titan rotate more slowly than Earth does
Titan is a moon rather than a planet
Titan’s hydrologic cycle involves methane rather than water
5. What does the professor say are likely results of the very low temperatures on Titan?（多选题）
Lakes of liquid methane can exist there.
There is no possibility of life there
Precipitation evaporates quickly there
The ITCZ migrates widely there
6. What is the professor’s opinion regarding future research on Titan?
Astronomers should concentrate for now on interpreting the data they have already
gathered
Future research may provide a different interpretation of Titan’s atmospheric properties
It will probably be difficult to obtain funding for additional research missions to
Saturn
Future research will add to our understanding of conditions on Earth before life appeared
