Exploring the Terrestrial Planets

What evidence supports the theory that Venus once had water on its surface?

• The presence of large oceans

• High levels of atmospheric oxygen

• Deuterium to hydrogen ratio in the atmosphere

• Extensive river networks

Answer explanation

The deuterium to hydrogen ratio in Venus's atmosphere suggests that it lost a significant amount of water. A higher ratio indicates that water was once abundant, supporting the theory that Venus had water on its surface.

Which geological process is primarily responsible for the formation of the Moon's maria?

• Tectonic activity

• Volcanic eruptions

• Impact cratering

• Erosion by wind

Answer explanation

The Moon's maria were formed primarily by volcanic eruptions that filled large impact basins with basaltic lava, creating the dark, flat plains we see today. This process is distinct from impact cratering and erosion.

Which geological process is most responsible for shaping the surface of Mercury?

• Erosion by wind

• Volcanic activity

• Impact cratering

• Tectonic plate movement

Answer explanation

Impact cratering is the primary geological process on Mercury, as the planet's surface is heavily marked by craters from collisions with asteroids and comets, rather than being shaped by erosion, volcanic activity, or tectonic movements.

Which of the following is a key factor in determining the habitability of a planet?

• The planet's size

• The presence of a magnetic field

• The planet's color

• The distance from the nearest star

Answer explanation

The distance from the nearest star is crucial for habitability, as it affects a planet's temperature and potential for liquid water. Too far means it's too cold, while too close can lead to extreme heat.

Compare the orbital period of Earth to that of Mars.

• Mars has a shorter orbital period than Earth

• Mars has a longer orbital period than Earth

• Mars and Earth have the same orbital period

• Mars' orbital period is twice that of Earth

Answer explanation

Mars has a longer orbital period than Earth, taking about 687 Earth days to complete one orbit around the Sun, compared to Earth's 365 days. This makes Mars' year nearly twice as long as that of Earth.

Analyze the significance of the discovery of water ice on the Moon.

• It suggests the Moon was once part of Earth

• It indicates the potential for future lunar bases

• It proves the Moon has an atmosphere

• It confirms the presence of life on the Moon

Answer explanation

The discovery of water ice on the Moon is significant as it indicates the potential for future lunar bases. Water can support human life and be used for fuel, making sustained lunar exploration and habitation more feasible.

Synthesize data from past missions to determine the primary component of Mars' atmosphere.

• Oxygen

• Nitrogen

• Carbon dioxide

• Methane

Answer explanation

Mars' atmosphere is primarily composed of carbon dioxide, making up about 95.3% of its atmosphere. This is supported by data from various missions, confirming that oxygen, nitrogen, and methane are present in much smaller amounts.

Which of the following factors is most important when analyzing the atmosphere of a terrestrial planet?

• The planet's distance from the Sun

• The composition of the planet's core

• The presence of greenhouse gases

• The planet's magnetic field

Answer explanation

The presence of greenhouse gases is crucial as they trap heat, influencing a planet's temperature and climate. This factor directly affects the atmosphere's ability to support life and maintain stable conditions.

Analyze the role of Earth's magnetic field in protecting its atmosphere.

• It deflects solar wind particles

• It increases atmospheric pressure

• It enhances greenhouse gas effects

• It stabilizes the planet's orbit

Answer explanation

Earth's magnetic field plays a crucial role by deflecting solar wind particles, which helps protect the atmosphere from being stripped away. This is essential for maintaining the conditions necessary for life on the planet.

Evaluate the geological processes that have shaped the surface of Venus.

• Plate tectonics similar to Earth

• Extensive volcanic activity

• Erosion by liquid water

• Impact cratering

Answer explanation

Venus's surface is primarily shaped by extensive volcanic activity, which has created vast lava plains and numerous volcanoes. Unlike Earth, Venus lacks plate tectonics, and erosion by liquid water is minimal due to its harsh environment.