1. Electromagnetic Waves with Wavelengths
1 nm = 1 x 10-9 meters

2. What can LIGHT tell us about the objects in space that produce them?
The composition of the gas, by comparing to known gases in the lab
The temperature of the gas, generally the spectral lines of various elements become more prominent at certain temperatures
The motion of the object producing the lines, either towards us or away
from us. This is known as the Doppler Effect

3. There are 3 types of light spectrums that we see in space:
#1) A continuous spectrum
is produced by a HOT glowing solid
(Bright line)
(Dark line)

4. #2) A bright line spectrum or emission spectrum
is produced when a low density gas (like in a nebula)
is HOT and glows
(Bright line)
Each element has its own characteristic bright line spectrum
(Dark line)

5. Emission Spectrum (Bright-line)

6. #3) An absorption spectrum or dark line spectrum
is produced when a gas (in space)
comes between the observer and the source of light
(Bright line)
(Dark line)

7. The Doppler Effect in sound waves

8. Galaxy is moving away from us
Normal line
position

9. Would this be a blue shift or red shift?
So is this galaxy moving towards
or away from us?
Would this be a blue shift or red shift?

10. Would this be a red shift or blue shift?
So is this galaxy moving towards
or away from us?
Would this be a red shift or blue shift?

11. These galaxies all show high red shifts
Farthest look yet into space

12. Why are all galaxies Red Shifted?
Universe began with the Big Bang about billion years ago
The universe is expanding!
Cosmic Background Radiation is the “echo” of the Big Bang
Will the Universe expand forever or collapse in a Big Crunch?
Oscillating Universe?
The expansion of the Universe is speeding up!
Dark Energy?
Dark Matter?
Big Freeze?

13. All stars are contained in galaxies
Our own Milky Way galaxy contains around 200 billion suns
This is what our own galaxy (the Milky Way) might look like if we could get far enough outside of it and view it face on

14. Top view of what Milky Way would look like

15. Spiral Galaxy
(viewed face on)

16. Spiral Galaxy
(viewed edge-on)

17. Elliptical Galaxies – these
galaxies have no spiral arms

18. Irregular Galaxies

19. Stable
main sequence
star

20. Fusion Hydrogen + Hydrogen makes Helium + energy
Fusion is what makes all stars SHINE

21. Luminosity ….Means how BRIGHT a star APPEARS BIG stars appear brighter
CLOSE stars appear brighter
HOT stars appear BLUE

22. Betelgeuse in Orion is a Supergiant (red)
Rigel is BLUE

23. Know this sequence of events in the lives of stars!
Medium size
Large Size
Know this sequence of events
in the lives of stars!

24. H-R Diagram Most stars spend most of their lives on the MAIN SEQUENCE
Dying Stars: Red Giants and Super Giants
Dead Stars: White Dwarfs, Black Dwarfs,
Neutron Stars, Black Holes

25. Dying stars
Young &
Middle aged stars
Dead stars

27. Milky Way: Our Galaxy

31. Pointer Stars point to Polaris

32. Polaris and Circumpolar stars

33. Cassiopeia the Queen

34. Cepheus
the
King

35. Orion the Hunter Left shoulder star is Betelgeuse, red giant,
12th brightest star
Right knee star
is Rigel
(blue-white),
7th brightest star

36. Sagittarius (“teapot”)

37. Where am I?

38. In….Red Hook High School

39. In…Red Hook Village

40. In….Upstate NY

41. In…..Eastern North America

42. On…. Planet Earth

43. In…. The Solar System

44. Nearest Star to the Sun

45. In…. The Solar Neighborhood

46. In… The Milky Way Galaxy

47. Nearest Neighbor Galaxy

48. In… The Local Group of Galaxies

49. In… The Local Supercluster of Galaxies

50. Nearest Neighbor Superclusters

51. In the Universe