AST101: The Sun and its Neighbours - Class 13: Terrestrial Planets Part 1

This set of flashcards is designed to help review key concepts on terrestrial planets and their formation, the nature of seismic waves, planetary differentiation, and cooling mechanisms.

What forms when tiny small objects stick together during planet formation?

Planetesimals are formed.

What is the primary difference in the formation of planetesimals inside and outside the frostline?

Inside the frostline, only metal and rock can form planetesimals, while outside, metal, rock, and hydrogen compounds can form planetesimals.

What are the two types of earthquake waves mentioned?

P Waves (compression) and S Waves (side to side).

Why do we believe there is a liquid layer in the Earth's core?

S-waves don’t travel through liquids, indicating a liquid layer must exist.

What process leads to differentiation in planetary interiors?

Lighter materials float to the surface while heavier materials sink to the core.

What are the dominant sources of heat in a planet today?

Radioactive decay is the dominant source of heat today.

How do planets cool through convection?

Hot rock rises due to being less dense than cooler rock, which sinks.

What happens to a planet's heat when it radiates more light than it receives from the Sun?

The planet cools.

What effect does planet size have on cooling, according to the notes?

Smaller planets cool faster due to their greater surface area-to-volume ratio.

What are craters on Mercury and the Moon a result of?

They are formed when planetesimals strike the surface, creating explosions and leaving craters.