Astronomy chapter 7

Question 1

What are the three main types of geological features found on Mercury?

Answer 1

• Craters
• Smooth plains
• Cliffs

These features indicate Mercury’s geological history and surface conditions.

Question 2

What are the two main geological features of Venus?

Answer 2

• Volcanoes
• Few craters

The lack of craters suggests a relatively young surface due to volcanic activity.

Question 3

What geological features are observed on Mars?

Answer 3

• Some craters
• Volcanoes
• Riverbeds?

These features suggest past geological activity and possibly the presence of water.

Question 4

What are the geological features of the Moon?

Answer 4

• Craters
• Smooth plains

The Moon’s surface is heavily cratered, indicating a lack of geological activity.

Question 5

What geological features characterize Earth?

Answer 5

• Volcanoes
• Craters
• Mountains
• Riverbeds

Earth is geologically active, with diverse features shaped by various processes.

Question 6

Why is Earth geologically active?

Answer 6

• Retains internal heat
• Drives geological activity
• Core remains molten

The heat from Earth’s interior is crucial for geological processes.

Question 7

What are the three layers of Earth’s interior?

Answer 7

• Core: Highest density; nickel and iron
• Mantle: Moderate density; minerals with silicon, oxygen, etc.
• Crust: Lowest density; granite, basalt, etc.

Each layer has distinct properties and compositions.

Question 8

What is differentiation in planetary geology?

Answer 8

• Gravity pulls high-density material to center
• Lower-density material rises to surface
• Material ends up separated by density

Differentiation is essential for understanding a planet’s internal structure.

Question 9

What is the lithosphere?

Answer 9

A planet’s outer layer of cool, rigid rock

The lithosphere floats on warmer, softer rock beneath it.

Question 10

What drives geological activity on Earth?

Answer 10

• Convection: Hot rock rises, cool rock falls
• Sources of internal heat: Gravitational potential energy, differentiation, radioactivity

These processes contribute to Earth’s dynamic geology.

Question 11

What are the four geological processes that shape Earth’s surface?

Answer 11

• Impact cratering
• Volcanism
• Tectonics
• Erosion

Each process plays a significant role in altering the planet’s landscape.

Question 12

What is the greenhouse effect?

Answer 12

Certain molecules let sunlight through but trap escaping infrared photons

Greenhouse gases include H2O, CO2, and CH4, which warm the planet.

Question 13

What geological evidence suggests that water once flowed on Mars?

Answer 13

The surface of Mars appears to have ancient riverbeds

This indicates that liquid water was present in Mars’ past.

Question 14

What is the Caloris Basin?

Answer 14

The largest impact crater on Mercury

It showcases the geological history of Mercury.

Question 15

True or false: The Moon is currently geologically active.

Answer 15

FALSE

The Moon is considered geologically dead, with no significant activity.

Question 16

What is the role of size in planetary cooling?

Answer 16

Smaller worlds cool off faster and harden earlier

This affects geological activity and surface features.

Question 17

What geological features indicate that water once flowed on Mars?

Answer 17

• Dry riverbeds
• Eroded craters
• Rock-strewn floodplains

These features suggest that Mars had liquid water in its past.

Question 18

Mars has not had widespread surface water for how many years?

Answer 18

3 billion years

This indicates a significant change in Mars’ climate and atmosphere over time.

Question 19

What are the possible reasons for Mars losing its atmosphere?

Answer 19

• Declining magnetic field
• Solar wind stripping atmosphere

The magnetic field may have preserved the early atmosphere before it decreased due to interior cooling.

Question 20

What does the MAVEN spacecraft measure?

Answer 20

Loss of Mars’ atmosphere

MAVEN stands for Mars Atmosphere and Volatile EvolutioN.

Question 21

True or false: Venus has evidence of plate tectonics.

Answer 21

FALSE

Venus does not appear to have plate tectonics, but its surface shows evidence of major volcanism.

Question 22

What keeps the surface temperature of Venus at 470°C?

Answer 22

Greenhouse effect

The thick carbon dioxide atmosphere produces an extremely strong greenhouse effect.

Question 23

What is the main reason Venus is hotter than Earth?

Answer 23

The greenhouse effect is much stronger on Venus than on Earth

Other factors include Venus being closer to the Sun and its reflective atmosphere.

Question 24

What unique features of Earth are important for life?

Answer 24

• Surface liquid water
• Atmospheric oxygen
• Plate tectonics
• Climate stability

These features are interconnected and essential for sustaining life.

Question 25

How does **human activity** change our planet?

Answer 25

* Releases carbon dioxide * Produces greenhouse gases * Drives species to extinction ## Footnote These activities contribute to global warming and environmental degradation.

Question 26

What is the effect of **human-made CFCs** in the atmosphere?

Answer 26

Destroys ozone ## Footnote This reduces protection from UV radiation, impacting ecosystems and human health.

Question 27

What has been the increase in **Earth's average temperature** over the past 50 years?

Answer 27

0.5°C ## Footnote This increase is linked to rising concentrations of greenhouse gases.

Question 28

What is the role of **plate tectonics** in Earth's climate stability?

Answer 28

Creates climate stability ## Footnote Plate tectonics is crucial for the carbon dioxide cycle, which regulates Earth's temperature.

Question 29

What is the significance of **Antarctic air bubbles** in climate studies?

Answer 29

Indicate current CO2 concentration ## Footnote They show that CO2 levels are at their highest in at least 500,000 years.

Question 30

What makes a planet **habitable**?

Answer 30

* Right distance from the Sun * Large enough for geological activity ## Footnote These factors allow for the formation of oceans and retention of an atmosphere.