Our Solar System

In the sun's core, nuclear fusion involves

Planets closer to the sun tend to be

The outer planets are made up of mostly what?

The shape of a planet's orbit is

Which astronomer realized the orbits of the planets did NOT have to be perfect circles?

Scientific theory says that planets began as tinier bodies known as

Distances in our solar system are measured using

The northern lights are

The colored layer of the sun's atmosphere is the

The solid layer of the sun is located

The model of the solar system with the Earth at the center is the

Which astronomer modified the geocentric model by adding smaller circles to the planets' orbits

The model of the solar system with the sun at the center is known as the