AST101: The Sun and its Neighbours - Class 16: Asteroids, Comets, and Dwarf Planets

These flashcards cover key concepts about asteroids, comets, and dwarf planets as discussed in the AST101 lecture.

What are asteroids primarily made of?

Asteroids are made mainly of rock and metal.

How many asteroids are larger than 100m in diameter?

There are 25 million asteroids larger than 100m in diameter.

What effect does Jupiter have on asteroids?

Jupiter affects the orbit of asteroids; orbits in exact resonance with Jupiter get displaced.

What is the largest object in the asteroid belt?

Ceres is the largest object in the asteroid belt.

Why is Ceres classified as a dwarf planet?

Ceres is classified as a dwarf planet because it orbits the sun, is massive enough to be roughly spherical, and does not clear its orbit.

What distinguishes a comet's tail from an asteroid?

A comet's tail points away from the sun due to gas and dust, while asteroids typically do not have tails.

How did Vesta differ from Ceres in terms of shape?

Vesta is not round enough to be classified as a dwarf planet.

What was the main goal of the OSIRIS-REx mission?

The OSIRIS-REx mission aimed to collect and return samples from the asteroid Bennu.

What is the Oort Cloud?

The Oort Cloud is a huge spherical cloud of comets that formed near Jupiter and were subsequently displaced.

How long is Pluto's orbital period?

Pluto's orbital period is 248 years.

What is one reason why comets can outgas when getting close to the sun?

Comets outgas as their ices melt and boil away when heated by the sun.

What is the primary difference between a meteoroid and a meteorite?

A meteoroid is an object in space, while a meteorite is a meteoroid that has struck the Earth's surface.

What significant event is related to an asteroid strike 66 million years ago?

The Cretaceous-Paleogene extinction event, which corresponds with the extinction of most dinosaurs.

What type of objects are located in the Kuiper Belt?

The Kuiper Belt contains several known dwarf planets, including Pluto.

What recent spacecraft studied the tail of Comet Wild 2?

The Stardust spacecraft successfully returned a sample from the tail of Comet Wild 2.