1. Galaxies are vast groups of stars in space.
Warm-Up # 11 – What is a galaxy?
Galaxies are vast groups of stars in space.
Warm-Up # 12 – What galaxy is Earth in??
The Milky Way

2. Warm-Up # 13 – How are galaxies?
Galaxies are classified based on shape.
Warm-Up # 14 – How do galaxies appear to the naked eye??
They appear as points of light in the night sky, a lot like stars.

3. Universe, Milky Way, Solar System, the Sun, Earth, U.S., NJ, EHMS
Warm-Up # 15 – Put in order from largest to smallest: Earth, EHMS, Universe, Solar System, NJ, Milky Way, the Sun, U.S.
Universe, Milky Way, Solar System,
the Sun, Earth, U.S., NJ, EHMS
Warm-Up # 16 – How many stars are in a galaxy?
Around 200 billion stars are in a galaxy.

4. Warm-Up # 17 – How many galaxies are in the universe?
Billions
Warm-Up # 18 – What force keeps the planets and stars from flying out into space?
Gravity

5. There are more stars in the center of a galaxy.
# 19 Why does the galaxy appear much brighter at its center?
There are more stars in the center of a galaxy.
# 20 Do stars move?
Stars in a galaxy rotate around its center. IT takes the sun more than 200 million years to revolve around the center of the Milky Way.

6. The Challenges of Getting to Mars
Chapter 1 Landing Site Selectionb
Chapter 2 Transporting a Mars Rover
Chapter 3 Getting a Rover Ready for Launch
Chapter 4 Launching a Mars Rover
Chapter 5 The Cruise to Mars
Landing Day