1. The Universe
EQ:

2. What is The Universe?
The universe is HUGE!!! It is made up of stars, galaxies, planets, moons, comets, meteoroids, gas, and dust (but it’s mostly made of empty space). The universe formed about 14 billion years ago.

3. The Hierarchy of organization
Moving from left to right!
Hierarchy of Organization
smallest
largest
meteoroids
universe
planets
solar systems
moons
galaxies
stars

4. We are Here

5. GALAXIES
A collection of billions of stars held together by gravity.

6. Galaxies
Classified by shape: spiral, elliptical and irregular.

7. Galaxies
Earth is in a spiral galaxy called the Milky Way.

8. We are Here

9. Solar System
A collection of large and small bodies that orbit a central star.

10. Solar Systems
Consists of at least one star, planets, moons, asteroids, dwarf planets, and comets.

11. Stars
Huge spheres of ionized gas held together by gravity.

12. Stars
Creates and gives off heat and light.
Classified by size.

13. We are here

14. Planet A round, celestial object that orbits around a star.
There are eight planets in our solar system.

15. Terrestrial Planets Small, dense, rocky planets with a metal core
Thin atmosphere
Mercury, Venus,
Earth, Mars

16. Gas Giant Planets Large, gaseous, low density with a rocky core
Thick atmosphere
Jupiter, Saturn,
Uranus, Neptune

17. Kilometers (Km) 1Km = 1000 meters
Useful when measuring the distance between a planet and its moon.

18. Astronomical Units (AU)
1 AU = 149,597,871 Km
Equal to the average distance between Earth and the Sun.
Useful to measure the distance between planets.

19. Light Year (ly) 1 ly = 9.46 trillion Km
Equal to the distance that light can travel in one year in a vacuum.
Useful to describe the distance between stars.

20. Parsec (pc)
1pc = 3.26 ly
Used to measure enormous distances like the distance between galaxies.