1. Components of the Universe Note Section

2. The Solar System- One star and everything that orbits it.

3. Planets: the larger bodies orbiting the Sun (or any other star)

4. The planets of our Solar System [& Pluto]

5. The biggest planet is…. -- but the biggest object in the Solar System, by far, is …..

6. Surface of Sun – Gas bubbles

7. Solar Flare – an explosive event on the Sun’s surface

8. Galaxy- Billions of stars bunched together. The Sun is a star in the Milky Way Galaxy.

9. A spiral Galaxy seen Edge-on -the actual 3D-shaped is like a pancake with a lump in the center

10. How big is a galaxy? # of stars:about a billion or so (smallest) - up to 100’s of billions for large galaxies Diameter: Very large: what units of distance should be used? -- using miles gives awkwardly numbers. -- a larger unit is needed. -- for example…..

12. Light-Travel-Time from the Earth TO TIMEDISTANCE a.the moon1.25 sec1.25 light-seconds b.the sun8.5 minutes8.5 light-minutes c.Pluto~6 hours d.Alpha Cen4.3 yrs4.3 LY e.North Star650 years650 LY f.M312.5 million yrs2.5 M. LY..so just keep in mind that all of those units of length are based on the speed of light; - for example: 1 light-minute = the distance that light travels in one minute

13. The “Milky Way” galaxy is a spiral galaxy. The Sun is in a spiral arm half-way out from the center.

14. Map of Milky Way Our Sun(yellow dot) is in a spiral arm, ½-way out

15. Galaxies contain more than just stars. The irregular-looking blobs are either hot (pink) or cold (dark) interstellar clouds

16. Galaxies occur in galaxy clusters. This is M31 (the Andromeda Galaxy)… …. and friends (2 smaller neighboring galaxies) - sort of a “triple galaxy”

17.  LMC  SMC  comet

18. The Universe is Everything- All the Galaxies

19. Distance = 500 million LY

20. What can you see with the naked eye? [outside of the Solar System] - Milky Way stars! (meaning only stars in our own galaxy) i.e., you cannot see any individual stars in any other galaxy;-- they’re just too far and too faint Note: Every star visible to your eye is part of the Milky Way!