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24.1 The Study of Light

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. Light. Comes in “packets” called photons Is both a waves and a particle

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24.1 The Study of Light

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  1. 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

  2. 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

  3. Spectra • Continuous spectrum • A continuous band of color

  4. Spectra 2. Absorption spectrum • Dark lines running through it

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

  6. 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

  7. A red shift • A blue shift

  8. 24.2 Tools to Study Space • Refracting Telescope • Reflecting Telescope • Radio Telescopes • Hubble Space Telescope • Others

  9. 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

  10. 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

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

  12. 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

  13. 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

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

  15. 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

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

  17. 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!

  18. 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

  19. Chromosphere • Thin atmosphere layer • Oh boy

  20. 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

  21. 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

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