 Objective 1 Compare the size and distance of objects within systems in the universe.  Use the speed of light as a measuring standard to describe the relative distances to objects in the universe (e.g., 4.4 light years to star Alpha Centauri; light years to the sun).  Compare distances between objects in the solar system.  Compare the size of the Solar System to the size of the Milky Way galaxy.  Compare the size of the Milky Way galaxy to the size of the known universe.  Objective 2 Describe the appearance and apparent motion of groups of stars in the night sky relative to Earth and how various cultures have understood and used them.  Locate and identify stars that are grouped in patterns in the night sky.  Identify ways people have historically grouped stars in the night sky.  Recognize that stars in a constellation are not all the same distance from Earth.  Relate the seasonal change in the appearance of the night sky to Earth's position.  Describe ways that familiar groups of stars may be used for navigation and calendars. Standard 4

Students will understand the scale of size, distance between objects, movement, and apparent motion (due to Earth's rotation) of objects in the universe and how cultures have understood, related to and used these objects in the night sky. The BIG Idea

How Far is Far?

Average of 238,000 Miles Earth to Moon Distance

93,000,000 Miles 1 Astronomical Unit (AU) Sun to Earth Distance

BodyAU Mercury.39 Venus.72 Earth 1.0 Mars 1.5 Jupiter 5.2 Saturn 9.5 Uranus 19.2 Neptune 30.1 Pluto 39.5

Solar System Model Diameter Orbital Radius Model Diameter Scaled Radius Body in Miles in Miles in Inches in Feet Sun 865,000 9 Mercury 3,032 36,000, Venus 7,521 67,000, Earth 7,926 93,000, Mars 4, ,000, Jupiter 88, ,000, Saturn 74, ,000, Uranus 31,763 1,782,000, ,546 Neptune 30,775 2,794,000, ,425 Pluto 1,423 3,666,000, ,186

Calculating Distance Viewpoint B Viewpoint A Viewpoint B Parallax

Viewpoint B Viewpoint A

Proxima Centauri Alpha Centauri A & B Our Nearest Neighbors 4.2 Light-Years 5 Light-Years

100,000 Light-Years The Size of Galaxies

The Galactic Neighborhood 2 Million Light-Years

 Light travels at a speed of 186,000 miles per second.  Nothing can travel faster than light. The Speed of Light

If the Sun is 93,000,000 miles away from Earth, how long does it take light to travel from the Sun to Earth’s surface? Think About It

A spaceship flying from the Earth to the Sun would take about a year, yet light takes just eight minutes to cross the same vast distance. In one year how many miles can light travel? Think About It

 We call this distance a light year.  The farther away a star or galaxy is from Earth, the longer its light takes to reach us.  The nearest star after our the Sun is more than 4 light years away - Proxima Centauri  The nearest galaxy to our own is 2 million light years away – Andromeda Galaxy A Light Year

186,000 miles/second The Light-Year X 60 minutes/hour X 24 hours/day X 365 days/year X 60 seconds/minute 5,865,696,000,000 miles/year

 A galaxy is a family of billions of stars held together in space by the pull of gravity.  Galaxies are not evenly spread out through the universe.  Arranged in great sheets, strings, and groups.  Large families are called clusters.  Many clusters of galaxies are grouped into even larger families, called super-clusters.  Galaxy shapes – spiral, barred spiral, and elliptical galaxies. Galaxies

Classifying Galaxies

 Our home, a spiral galaxy.  100 billion stars.  Belongs to a cluster of about 30 galaxies scattered across 3 million light years. The Milky Way

Hubble Deep Field Image

 Imaginary star pictures  Named for animals or mythological characters  Astronomers recognize 88 constellations  Different constellations are visible in the night sky at different times of the year. Why? Constellations

Winter

Summer

 Polaris (a.k.a. the North Star)  Found in the constellation Ursa Minor (the little bear).  Ursa Minor is also known as the Little Dipper.  The last star in the handle. Which way is north?

 Astronomers use constellations as a kind of map to find their location on Earth – navigation.  Also used as a map of the sky.  Can tell us what season it is.  For entertainment. Why do we need constellations?