Overview of lectures in this series
1. Introduction and Motors (Oct. 3)
2. Motors and Generators (Oct. 10)
3. Distribution and use of Electricity (Oct. 17)
4. The Wind (Oct. 24)
5. Thermodynamics (Oct. 31)
6. Heat Engines and Transportation (Nov. 7)
7. Nuclear Fission (Nov. 14)
8. Solar Energy (Nov. 21)
9. Special guest lecture (Dec. 5): “From the Freezer to
the Frying Pan: Trying to Understand the Wackier
Climates of Ancient Earth.” – Dorian Abbot
10. Summary; the future (Dec. 12)
COMPTON LECTURE 8: NOVEMBER 21, 2009
“I’d put my money on the sun and solar energy.
What a source of power! I hope we don’t have to wait
until oil and coal run out before we tackle that.”
—Thomas Edison to Henry Ford and Harvey
Thermonuclear fusion in core out
to ~¼ solar radius, there T ~
14×106 K, density ~ 100x water.
Power radiated: 3.8×1026 W.
Surface temperature 5,780 K.
Distance: 150 million kilometers.
1366 W/m2 in space.
~1 kW/m2 on Earth (AM1.5,
~48 degrees off Zenith).
173,000 TW incident solar
121,000 TW to the Earth’s
Energy used worldwide: ~16 TW
Electricity (world): ~2 TWe.
US ~ 3.4 TW, (~0.4 TWe).
Data: Fundamentals of Renewable Energy Processes (da Rosa) and EIA
Net release: 26.7 MeV
Cf. uranium fission ~ 200 MeV
Let’s face some facts
On the other hand, the 5 Gyr is a significant fraction of the
age of the universe, 13.7 Gyr, and longer than our reserve of