Solar System Unit Test

What percentage of the total mass of the solar system does the Sun make up?

• 50%

• 75%

• 99.8%

• 90%

Which of the following is NOT a characteristic required to be considered a planet?

• Being in orbit around a star

• Having enough mass to be pulled into a stable sphere by gravity

• Dominating its orbit

• Having an atmosphere

Which planets are classified as terrestrial planets in our solar system?

• Mercury, Venus, Earth, Mars

• Jupiter, Saturn, Uranus, Neptune

• Earth, Mars, Jupiter, Saturn

• Venus, Earth, Neptune, Pluto

What is a common characteristic of terrestrial planets?

• They are gas giants.

• They have rings.

• They have hard, rocky surfaces.

• They are predominantly made of ice.

Which of the following planets are considered gas giants?

• Mercury, Venus, Earth, Mars

• Jupiter, Saturn, Uranus, Neptune

• Jupiter, Mars, Venus, Saturn

• Earth, Neptune, Uranus, Pluto

What do scientists believe is present deep under the thick atmospheres of gas giant planets?

• Liquid water oceans

• Rocky cores

• Ice layers

• Metallic hydrogen

How many planets can be seen with the unaided eye from Earth?

• 3

• 5

• 7

• 9

What is the first dwarf planet to be discovered?

• Pluto

• Eris

• Ceres

• Makemake

Why is Pluto not considered the largest object in its orbit?

• Because it is a gas giant

• Because it does not orbit the Sun

• Because its orbit crosses Neptune's orbit

• Because it is smaller than Earth

What are moons considered to be in relation to planets?

• Dwarf planets

• Natural satellites

• Asteroids

• Meteoroids