1. The Structure of the Universe

2. Standards
SC.8.E.5.3 Distinguish the hierarchical relationships between planets and other astronomical bodies relative to solar system, galaxy, and universe, including distance, size, and composition.
SC.8.E Recognize that there are enormous distances between objects in space and apply our knowledge of light and space travel to understand this distance.
SC.8.E.5.2 Recognize that the universe contains many billions of galaxies and that each galaxy contains many billions of stars.

3. The Universe
Consists of everything that exists, including all matter and energy, the planets, stars, galaxies, and the contents of intergalactic space.
Each of those little dots aren't stars… They're galaxies (billions of stars in each)

4. Light-Years
A light-year is a unit of distance. It is the distance that light can travel in one year. (About 6 trillion miles) Used to measure distances OUTSIDE of our solar system.
We use light-years when discussing distances within intergalactic space.

5. Astronomical Units
In astronomy, an astronomical unit is defined as the average distance from the Sun to the Earth, or about 93 million miles. Used to measure distances inside our solar system. You can abbreviate astronomical unit as AU.
We use AU when discussing distances from the planets to the sun.

6. What is a “galaxy”?
A galaxy consists of billions of stars , planets, and other celestial bodies held together by gravity.
Information at
NOVEMBER 29, 2007: Resembling festive lights on a holiday wreath, this NASA/ESA Hubble Space Telescope image of the nearby spiral galaxy M74 is an iconic reminder of the impending season. Bright knots of glowing gas light up the spiral arms, indicating a rich environment of star formation. M74 is located roughly 32 million light-years away in the direction of the constellation Pisces, the Fish. The image is a composite of Advanced Camera for Surveys data taken in 2003 and 2005.

7. Nebulas and Stars Nebulas are clouds of dust and gas where stars form
Stars are giant balls of flaming gases

8. Our Galaxy: The Milky Way
The Milky Way is our galaxy which contains the Solar System.

9. Our Solar System
The solar system contains the sun , which is the star. In addition, eight major planets and their moons, “dwarf” planets, and countless asteroids, meteoroids, comets.

10. The Sun
The sun is our star at the center of our solar system.

11. The Planets The Rules to be considered a planet:
A planet must be shaped like a sphere.
It must orbit the sun.
It must have enough gravity to keep it from being pulled into another planet’s orbit.
It must have enough gravity to pull in rocks and other space “junk” orbiting around it.

12. Dwarf Planets
A celestial body orbiting the Sun that is massive enough to be a spheres a result of its own gravity but has not cleared its neighboring region.

13. Moon
Natural satellites revolve around planets in our Solar System.

14. Asteroids
Asteroids are pieces of rock that are smaller than planets but bigger than meteoroids. Most of the asteroids orbit the sun in a region between Mars and Jupiter known as the Asteroid Belt.

15. ***Usually in the outer solar system
Comets
A comet is a relatively small object, made of dirty ice, that orbits or moves around the sun
***Usually in the outer solar system