1. STAR SYSTEMS AND GALAXIES SPACE SCIENCE

3. Star Systems and Planets  Our solar system has a medium sized star, the sun.  More than half of all stars are members of groups of two or more stars, called star systems.  Stars systems with 2 stars are called binary stars.  Alpha Centauri A and Alpha Centauri B  Proxima Centauri is a triple star system close to our sun.  To see a planet directly, astronomers will have to shield their view from the glare of the star that the planet revolves around.

4. Galaxies  Our solar system is located in the Milky Way Galaxy  A galaxy contains single and double stars, star systems, and lots of gas and dust.  The dark blotches in the Milky Way are clouds of dust that block light coming from stars behind them  Astronomers have classified most galaxies into 3 main categories: spiral, elliptical and irregular Milky Way

5. Spiral Galaxies Appear to have arms that spiral outward, like pinwheels Milky Way galaxy is a spiral galaxy The center of our galaxy is about 25,000 light- years from the sun The center is hidden from our view by massive clouds of stars, gas, and dust between the sun and the center.

6. Elliptical Galaxies  Appear like flattened balls.  Contain billions of stars but have little gas and dust between the stars  New stars cannot form in elliptical galaxies because of the lack of gas and dust

7. Irregular Galaxies Some galaxies do not have regular shapes The Large Magellanic Cloud is an irregular galaxy about 160,000 light-years away from our galaxy.

9. Exit Ticket Describe the three main types of galaxies.