9. 24.1 The Study of Light
Visible light from sun is only a small part of what’s emitted
Electromagnetic waves
Radio waves, IR, light, UV, X-rays
Wavelength is the difference
ROYGBIV
186,000 miles/hr…all waves

12. Light Comes in “packets” called photons Is both a waves and a particle
Radiation pressure is the “push” of the particle of light
Spectroscopy = the study of light’s properties

13. Spectra
Continuous spectrum
A continuous band of color

14. Spectra
2. Absorption spectrum
Dark lines running through it

15. Spectra 3. Emission spectrum Bright lines emitted
A star’s spectra = its fingerprint…tells what elements are in the star.

16. Doppler Effect
The change in frequency, either higher or lower, when wave source is moving.
The pith gets higher or lower for sound.
Applies to any wave
Higher (blue shift) – moving to us
Lower (red shift) – moving away

17. A red shift
A blue shift

18. 24.2 Tools to Study Space Refracting Telescope Reflecting Telescope
Radio Telescopes
Hubble Space Telescope
Others

19. Refracting Telescope Uses a big lens to focus light Upside down image
Blue and red light don’t focus at the same place!
Lens is heavy and can distort images
Not the “big” telescopes of today

21. Reflecting Telescope Uses a big mirror to collect light
+ doesn’t sag (weighs less)
+ cheaper glass
+ can be bigger/stronger
the second mirror is in the way of the light

24. Optical Telescope Properties
Light gathering power
Amount of light it can get
Resolving power
Finer detail ability
Magnification power
Magnifies it

25. Radio Telescopes “Sees” radio waves Satellite dishes are good enough
Weak signals so the telescopes are huge!
Poor resolution so they “hook up” with other radio telescopes
VLA = very large array

26. Radio Telescopes Less affected by weather 24/7 viewing
See through interstellar dust
No observatory = cheaper
Detect cool objects (no light seen)
Detect human radio signals

31. HST In orbit above earth NO air interference Launched 1990
8 foot mirror
10 billion times stronger than the human eye!!!

39. 24.3 The Sun Just 1 of 10,000,000,000 stars in Milky Way
Joe average star
Only close star for study
109 earths wide
1.25 million earth’s volume

40. Sun Facts IT’S A GAS…it doesn’t have a solid surface! 4 parts Interior
Photosphere
Chromosphere
Corona

41. Interior Nuclear fusion provides energy
4 hydrogen make 1 helium & energy
Mass is lost in reaction… E = mc2!
4 million tons of hydrogen are lost each second …
Can still last for 10 billion yrs!
Internal temp = 15 million degrees!

42. Photosphere A 300 mile thick surface covering Looks grainy on surface
From rising/sinking hot gas
Convection currents
90% hydrogen, 10% Helium (sun)
6000 degrees

43. Chromosphere
Thin atmosphere layer
Oh boy

44. Corona Another thin layer of hot gases Extends 600,000 miles out
Hot gas “blows” out from sun = solar winds, at 500 miles/sec
Causes the Northern Lights
1,000,000 degrees

45. The Active Sun Spins on axis like planets
25 days at eq, 33 days near top/bot
Sunspots = dark regions
On an 11 year cycle
Prominences – ejected material
Solar flares – bright sunspots that eject material and high energy
Aurora Borealis – form solar flares

51. A radio image of the sun