The heliocentric theory places the Sun in the center of the Solar System.

Which two supported the geocentric theory of the Solar System ?

These two early astronomers believed in the heliocentric model of the Solar System.

Kepler and Brahe were the two scientist who theorized that planets orbits were...

Copernicus believed that the Sun was the center of the solar system.

Galileo used a microscope to discover the 4 larger moons of Pluto.

Galileo used his telescope to prove the heliocentric theory by seeing Venus’ phases.

The moon is considered a satellite.

Which of these space vehicles will NOT come back to Earth?

In 1957, the Soviet Union became the first country that placed a satellite in orbit around the Earth.

Alan Shepard was the first man to walk on the moon.

The USA was the first country that put a man on the moon.

Which of these is a manned re-usable space vehicle?

He was the first American in space.

A space probe is an un-manned space vehicle that lands on the moon, another planet, an asteroid and sends information back to Earth.

The International Space Station, because of the cooperation of 16 nations, orbits the Earth. Men and women astronauts do long-term experiments there to support research.

This space tool uses mirrors or radio waves to amplify and make bigger things really far away.

He was the first human in space and to orbit the Earth.

He was the first human to land (and walk) on the surface of the moon.

He was the first American to orbit Earth.

Gravity is...

Inertia is...

There are two things that effect the force of gravity...

Gravity and inertia are forces that keep planets in orbit.

Earth orbits the sun in an elliptical orbit.

This is a “space rock” that is smaller than a planet and has no tail but orbits the sun.

This is a small body moving in the solar system that would become a meteor if it entered the Earth’s atmosphere.

This is an object that has a long orbit around the sun and has a “tail”.

The inner planets are rocky and therefore called...

The outer planets are called...

The inner planets, in order from the sun, are...

The outer planets, in order from the sun, are...

The inner planets are smaller than the outer planets.

The outer planets rotate slower than the inner planets.

A planet usually has an atmosphere of some sort.

The outer planets have fewer moons than the inner planets.

Dwarf planets are not really considered planets because their orbits have other things in their paths around the sun.