L2

讲座

1. What is the lecture mainly about?

How astronomers are using satellite imaging to view a system of canyons on Mars

How similarities between two rocky planets provide astronomers with historical information

Differences between impact craters on Mars and on Earth

Unexpected results from a study comparing two planets

2. What does the professor imply about the surface features of Mars?

They are generally younger than Earth’s surface features are.

They have been altered by meteorite bombardments more than Earth’s features have.

They were formed by the same forces that affect Earth.

Mars has a wider range of types of surface features than Earth does.

3. According to the professor,what are two main factors contributing to the preservation of impact craters on Mars?（多选题）

Distance from the Sun

Climate change

The absence of life forms

The chemical composition of Martian rocks

4. What does the professor imply about the Kasei Valles on Mars?

It was formed by massive flooding.

Its formation continues today.

It is highly mysterious to astronomers.

It formed at about the same time as the Channeled Scablands.

5. What opinion does the professor express about volcanic activity on Mars?

Mars generates more than enough internal heat to produce volcanic activity.

New satellite technology is likely to reveal the presence of active volcanoes.

Measurements of the volume of lava flows on Mars are inconclusive.

There is no direct evidence that Martian volcanoes are currently active.

6. According to the professor,what is true about the present-day surface of Mars?

It is covered by ice in many places.

Its craters contain ash emitted from volcanoes.

Its appearance is significantly affected by wind.

New valleys are continuously being formed on it.