Planetary Science Basics

What is planetary science?

• The study of stars and galaxies

• The study of planetary systems, moons, stars, and other objects in space

• The study of Earth's atmosphere

• The study of ocean currents.

A planet is a celestial body that meets which of the following criteria?

• Is in orbit around a star (Sun)

• Has sufficient mass for its self-gravity to overcome rigid forces and maintain a nearly round shape

• Is big enough that its gravity clears away any objects of a similar size near its orbit

• All of the above.

Fill in the blank: The solar system is a collection of ___ planets and their moons in orbit around the Sun.

• 5

• 8

• 10

• 12

Which of the following is NOT a criterion for a celestial body to be considered a planet?

• It must be in orbit around a star

• It must have a ring system

• It must have sufficient mass for its self-gravity to maintain a nearly round shape

• It must clear its orbit of other objects.

What does the solar system consist of besides planets and their moons?

• Only stars

• Only comets

• Other objects

• Only asteroids.

Fill in the blank: Planetary science is the branch of science that studies ___.

• ocean currents

• planetary systems, moons, stars, and other objects in space

• Earth's atmosphere

• animal behavior

Which of the following statements is true about a planet?

• It must be in orbit around a moon

• It must have a solid surface

• It must be big enough that its gravity clears away any objects of a similar size near its orbit

• It must be the largest object in its orbit.