What are terrestrial planets?
Small, dense, rocky planets with layered interiors (Mercury, Venus, Earth, Mars).
What is differentiation in terrestrial planets?
The separation of a planet into layers (crust, mantle, core) based on density.
How do atmospheres vary among terrestrial planets?
Venus has a thick atmosphere, Earth moderate, Mars thin, Mercury and Moon almost none.
What are the three main layers of a terrestrial planet?
Crust (low-density surface), mantle (dense rock), core (metallic, high density).
What does heavy cratering indicate about a planetary surface?
It is old and has experienced little geological activity.
hy do small terrestrial planets become geologically inactive faster?
They lose heat more quickly due to their smaller size.
What are the main sources of internal heat in planets?
Leftover heat from formation and radioactive decay.
How is Earth’s internal structure studied?
Using seismic waves from earthquakes.
What is plate tectonics?
The movement of Earth’s lithospheric plates over the mantle due to convection currents.
What generates Earth’s magnetic field?
The liquid outer core through the dynamo effect.
What are the three types of plate boundaries?
Divergent (move apart), convergent (collide/subduction), transform (slide past).
What is a spreading zone?
A divergent boundary where new crust is created.
What is a subduction zone?
A convergent boundary where one plate is forced beneath another.
What is continental drift?
The idea that continents move over time, now explained by plate tectonics.
What is Pangaea?
A supercontinent that existed about 200 million years ago.
What role do volcanoes play in Earth’s atmosphere?
Release gases (CO₂, water vapor) that help form and maintain the atmosphere.
What is outgassing?
The release of gases from a planet’s interior, contributing to atmosphere formation.
What was Earth’s primary atmosphere composed of?
Carbon dioxide, nitrogen, and water vapor.
What is the greenhouse effect?
The trapping of heat by gases like CO₂ in a planet’s atmosphere.
What is causing modern global warming on Earth?
Increased CO₂ from burning fossil fuels.
How did oxygen accumulate in Earth’s atmosphere?
Through photosynthesis by early life forms.
What is the role of ozone (O₃)?
It protects Earth from harmful ultraviolet radiation.
What are maria on the Moon?
Dark, smooth plains formed by ancient lava flows.
What are lunar highlands?
Bright, heavily cratered, older regions of the Moon.
