The Earth, Sun and Energy:

1. The Earth, Sun and Energy:

2. Sun Jupiter Saturn Neptune Uranus Pluto Missoula Mercury Venus Earth Mars

3. Comparing the Sun and Earth Size: • The radius of the Earth is R = 6371 km. R 2) The radius of the Sun is R = 7x105 km.

4. If the Sun weighed as much as the aircraft carrier independence……… The Earth would only weigh as much as two members of its crew…. Comparing the Sun and Earth Mass: • The mass of the Sun is M = 2 x 1030 kg 2) The mass of the Earth is M = 6 x 1024 kg 3) The ratio of Sun to Earth = 3.3 x 105

5. 1 paperclip weighs about 1 Gram (g) 1 cubic centimeter (cm-3) is about the size of a Sugar Cube Comparing the Sun and Earth Density: • The Density of the Sun is D = 1.4 g cm-3 2) The Density of the Earth is D = 5.5 g cm-3 Water has a density of 1 g cm-3 while Lead is 10.8g cm-3 3) The Earth is the densest planet in the solar system. Why????

6. Composition: Earth (Full) 34.6% Iron 29.5% Oxygen 15.2% Silicon 12.7% Magnesium 2.4% Nickel 1.9% Sulfur Earth (Air) 78% Nitrogen 21% Oxygen 0-4% Water 1% Argon 0.035% CO2 0.0017% Methane • Sun • 92.1% Hydrogen • 7.8% Helium • 0.1% Carbon/Oxygen • 0.001% Iron Comparing the Sun and Earth

7. Comparing the Sun and Earth Temperature: Earth Surface 300K (average ground) Atmosphere 300-1000K (ground to top) Interior 3000-5000K Sun Surface 5000-104K (visible) Atmosphere 2 x 106 K (Corona) Core 1.5 x 107K °K = 273 + (°F - 32)/1.8 273°K = 32°F and 373°K = 212°F

8. Pop Question! True or False?Deep mine shafts become very hot because of warmth diffusing from the Earth’s interior through the crust. False!!!! Most heating in the crust is from radioactive decay! The crust itself is a very good insulator. If not, the core would have already cooled.

9. Comparing the Sun and Earth Time and Evolution: The Earth 100-10000 sec. Electrical Disturbances/Storms 104-105 sec. Day-Night cycle - Tides 107 sec. Seasons 1011 - 1012 sec. Ice Ages/Climate Shifts 1015 - 1016 sec. Continent Drift/Magnetic Field/Life 1017 sec. Age of Earth (4.5 billion years) The most significant changes to surface conditions on the Earth were brought about by loss of atmospheric constituents and the emergence of life.

10. Changes in the Earth’s Atmosphere Time and Evolution: • The Early Earth • Atmosphere similar to Solar Composition • 100x thicker than today • Hydrogen-Helium • 4.5-3.5 billion years • The Young Earth • Hydrogen/Helium Lost • Oceans form/ CO2 from Volcanic Activity • CO2 dissolved in Oceans • 3.5-0.5 billion years ago • The Living Earth (0.5 byr-Present) • Nitrogen Dominates as CO2 is lost, leading to its modern concentration. • Plants evolve photosynthesis-Oxygen Balloons-Feedback with Sun’s evolution. • Animals adapt to O2 metabolism-move to land. • O2 in atmosphere: life’s smoking gun/Impossible without.

11. Comparing the Sun and Earth Time and Evolution: The Sun 10000 sec. Convection at visible surface 105 - 106 sec. Flares-Solar Events-Oscillations 2x106 sec. Solar Rotation 107 - 108 sec. Magnetic Cycle 1015 - 1016 sec. Energy Transport- Changes in Core 1017 sec. Age of Sun (4.5 billion years) 2x1017 sec. Sun a Red Giant/Stellar Death

12. Energy Production from the Sun: The Sun dominates the energy ‘budget’ of the solar system • How much energy does the Sun produce? • How does the energy reach us? • How does it produce that energy?

13. Energy Production How Much? A typical power bill in the Seattle area will be for about 1200 kilowatt hours (KWH) in one month (Mn), or about 400 KWH per person. The USA as a whole uses 400KWH x 12Mn x 2.5 x 108people = 1.2 x 1012 KWH How does that compare with the Sun?

14. Energy Production How Much? The Solar Energy Output is 4 x 1026 Watts!!! How much of that hits us? Consider that the Sun’s energy must be spread over the entire sphere of space that is 1 AU away. 1 AU is R=1.5x1011 m and the area of a sphere is A=4R2 We can show then that the fraction of the Sun’s energy that hits the Earth is….

15. Energy Production How Much? How much is 2 billionths? (or 1.8 x 10-9) When the Sun is directly over head, it delivers the equivalent of 2 65 Watt light bulbs over each square ft (ft2) of ground!!! This amount, 1340 W m-2, is known as the Solar Constant How is solar energy delivered from the Sun to the Earth? As Light!!!!

16. Energy Production Using Light: There are many ways to transfer energy from one place to another. Convection: Direct movement of material of one temperature to another location. Conduction: Energy transport by direct contact. Radiation: Energy transported by electromagnetic radiation. While energy inside the Sun is transferred in several ways, the primary method the Sun uses to get energy into space is light. Light itself is a bundle of energy that follows very specific rules. We call a single one of these ‘bundles’ a photon.

17. Photons: A photon is really an oscillating combination of electric and magnetic fields. All photons move through space at the same speed, 3x105 km s-1. Nothing can move faster than light!

18. Photons: Since a photon is a carrier of energy and it’s velocity is fixed, then how is the amount of energy in a photon manifest? Photons are characterized by the spacing of wave peaks (wavelength l) and the number of oscillations per second (frequency n) The amount of energy is directly proportional to frequency and inversely to wavelength. or E  n and E  l-1

19. The Electromagnetic Spectrum: How is a difference in the frequency or wavelength of light observed? As Color So why does the Sun emit light and what ‘colors’ of light does it emit?