2. STARS BALL OF GASES, MOSTLY HYDROGEN AND HELIUM Are all stars the same color? NO! Color- determined by surface temperature.

3. 1. Blue- young and hottest Ex. Rigel (above 30,000 degrees Celsius 2. White - usually old and hot Ex. Sirius (10,000 o C) 3. Yellow – Average (5000-6000 o C ) temperature and middle age Ex. The sun

4. 4 – Red- coolest and growing old Ex. Betelgeuse less than 3,500 o C

5. All radiant energy that travels the speed of light in waves Electromagnetic Spectrum shortestlongest Infrared Ultraviolet ^

6. Longest to shortest wavelength

7. Spectroscope Attaches to an optical telescope –Analyzes light from the stars Bright line spectrum

8. Separates visible light by its different wavelengths Each element is then identified by its own spectrum Shows direction, movement and composition Spectrum___

9. DOPPLER EFFECT **THE APPARENT SHIFT IN WAVELENGTH DUE TO A MOVING OBJECT Red shift- moving away Blue shift- moving toward

10. DISTANCE LIGHT TRAVELS IN ONE YEAR 6,000,000,000,000 MILES (186,000 mi/sec) or 300,000 km/s AU: Astronomical unit Distance from Earth to Sun 149,597,870,700 m or just 1 AU

11. Distance is measured by using PARALLAX- THE APPARENT SHIFT IN MOTION over time Ex. Hold out one arm and give a thumbs up Close one eye and cover the Red Star Now switch eyes That apparent change is parallax!

15. 2. Apparent Brightness (Magnitude) –A. The brightness we see from earth –B. Depends on size, distance and surface temperature.

16. C. Star’s Brightness 1. Luminosity or absolute magnitude. –A. Actual brightness of the star –B. found by using the distance and apparent magnitude.

19. OPTICAL TELESCOPES 1. REFRACTING TELESCOPE **uses lenses to bend light to a focus point person

20. 2. Reflecting Telescope –Uses mirrors –Concave mirror reflects light to a flat mirror –Ex. Hubble Space Telescope Hale telescope

21. 3. Catadioptric Telescope –Uses mirrors –AND Lenses –Ex. Celestron 8

22. Problems with Optical telescopes Light pollution

23. EM (electromagnetic) spectrum

25. Jansky 1905-1950 Discovered radio waves in space 1931

26. Reber- 1911-2002 Built the first radio telescope (1937) Collects radio waves from space Can be used at anytime or weather

28. VLA in New Mexico

30. ASTRONOMICAL INSTRUMENTS

31. Radio Telescopes Operate in the radio frequency portion of the EM spectrum where they can detect and collect data on radio sources. Used anytime, no light pollution or weather problems

32. Scientific Terms a (testable) proposed explanation for a phenomenon a well-confirmed type of explanation of nature, made in a way consistent with scientific method "Big Bang theory" Alvarez hypothesis “Meteor-impact” describes some aspects of the universe or phenomenon “gravity”

33. D. Classification 1. H. R. diagram (Hertzsprung – Russell) 2. Classifies by surface temperature and absolute magnitude. 3. Main sequence stars- stars of similar composition and size –A. “average” stars

34. 4. Outside of main sequence –A. Red super giants and red giants –B. Blue Giants. –C. White Dwarfs Betelgeuse

35. Rigel Betelgeuse Sirius Sun

36. E. Life Cycle Of Stars STEP 1. Begins as a nebula- a cloud of dust and gas. (mostly H and He)

37. STEP 2. Protostar - gravity forms a ball- shaped pocket and temperature increases.

38. STEP 3. Nuclear fusion 4 hydrogen fuse to make helium plus energy Occurs in the core Must be 10 mil –degrees C

39. STEP 4. Main Sequence Star Must have enough mass to have nuclear fusion for its energy

40. STEP 5. RED GIANTS a) Size of giants depends on the initial mass b) Could be a super red giant like Betelgeuse c)No more H(very little), He turns into C More energy H  He and He  C, gravity cant hold on ahhh!

41. STEP 6. Supernova or white dwarf a) white dwarf- small, hot, older star no shell, only core left to cool – 1. Ex. Sirius or the Sun (some day) b) supernova- gigantic explosion of a large mass star like Betelgeuse Chinese recorded one in 1054 AD

42. Supernova Feb.24, 1987 170,000LY

43. c)NEUTRON STAR 1. Extremely dense; like the mass of our sun into a 8 mi diameter

44. d) Black hole- 1. An object so dense that not even light can escape its surface

47. Pulsars- –a neutron star that spins rapidly and sends out radio waves Quasars- Very powerful source of energy most distant objects in space

48. GALAXIES

49. 3 TYPES SPIRAL- 2-4 arms –EX. ANDROMEDA IRREGULAR – –EX. MAGELLANIC CLOUDS ELLIPTICAL