Origin of the Solar System & Anatomy of Earth (Lecture 2)

12 practice questions covering key concepts from Origin of the Solar System and the Anatomy of the Earth.

What is the origin of the Solar System?

Began from hot gases and dust in a nebula, remnants of dead stars.

What are Steps A–C in solar system formation?

A protoplanetary nebula forms; the densest region collapses into a protosun; B gas forms a protoplanetary disc around the center of mass; C dust condenses into particles and grows into planetary embryos by accretion.

What is accretion in planetary formation?

Growth by random collisions and gravitational attraction with smaller objects, leading to planetary embryos and eventual planets.

When did Earth form in the solar system?

Earth emerged about 4.56 billion years ago.

State Newton's law of gravity as used in the lecture.

Gravitational force is proportional to the product of masses and inversely proportional to the square of the distance between them (F ∝ m1 m2 / r^2).

What are planetesimals?

Small bodies ranging from a few centimeters up to 10 kilometers; not yet round.

What are protoplanets?

Larger embryonic bodies hundreds of kilometers in size, starting to become round (e.g., Vesta).

What are dwarf planets?

Late-stage embryos about 1000 km in size; examples include Pluto and Ceres.

What happens during magma ocean differentiation?

Dense elements sink while less dense elements float, forming core, mantle, and crust.

Which elements are the common rock-forming elements on Earth?

O, Si, Al, Na, K, Ca, Fe, Mg; their distribution among crust, mantle, and core is controlled by density and bonding (SiO2 silicates).

What is a mantle xenolith?

A piece of mantle rock carried to the surface by volcanic rocks; a chunk of upper mantle.

How is Earth's interior classified?

Chemistry-based: core, mantle, crust; Physical-state-based: lithosphere (rigid), asthenosphere (plastic), mesosphere (solid), outer core (liquid), inner core (solid).