1. Sun – Most important star to us on Earth. The sun and all of the heavenly bodies that orbit it make up our solar system.

2. Photosphere – The visible part of the sun.

3. Sunspots – dark patches that are cooler than the granules that surround them.

4. Spicule – Flame like columns of gas that continually erupt from the super granules of the photosphere that make up the sun’s chromosphere

5. The chromosphere is only visible during a solar eclipse, when the photosphere is blocked by the moon.

6. Solar Flare – Tremendous bursts of energy caused by magnetic stress within the sun.

7. Solar Prominences– Streams of dense gas erupting off the chromosphere and returning in looplike fashion.

8. Corona – Huge, hot blanket of vapor that extends hundreds, or thousands of miles from the surface of the sun. Like the chromosphere, only visible during a total eclipse.

9. Solar Wind – A high speed stream of charged particles that beats against the Earth’s upper atmosphere. Caused by holes in the Corona.

10. The sun is 93 million miles away, all other stars are a LOT further away. So far it doesn’t even make sense to talk about the distances in miles. Makes more sense to talk about these distances in light years, which is the distance light travels in one year. Light travels 186,000 miles a second, or 5.9 trillion miles a year.

11. Parallax – The apparent change in the position of an object caused by the actual change in the position of the observer. Parasec - based upon the parallax measurements of star distances. 3.26 light years

12. Apparent Magnitude – The brightness of a star as it appears to an observer on the earth. Depends on actual brightness and distance from earth. The lower the number, the brighter the star.

13. Inverse Square Law– The brightness of a star varies inversely as the square of the distance from the star.

14. Absolute Magnitude – the brightness the star would have to an observer if all stars were equally distant from the Earth.

15. A star’s absolute magnitude depends on its surface temperature and size. Stars that are extremely bright for their surface temperatures and called giants and supergiants because their brightness is due to their size.

16. Average stars are called main sequence or dwarfs. Stars that are dimmer than average stars of the same temperature are called white dwarfs.

17. Binary Star – Stars which are bound together by gravity, one revolves around the other like the moon revolves around the Earth.

18. Optical Double – A pair of stars that appear to form a binary star but do not.

19. Star Clusters – Large stellar groupings.

20. Globular Clusters – Wandering groups of thousands, or millions of stars.

21. Nova – a star that flares up to many times its original brightness.

22. Supernova – the explosion of a star.