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Honors PhysicsPreview for the Year
Mr. FinnFall, 2013
Take TWO slips of paper
Are We Alone?
1. Is the Earth the only planet in the Milky Way galaxy harboring life?
2. Is the Earth the only planet with life in the entire Universe?
Milky Way
Ultra-Deep Hubble Field
Write TWO answers on separate slips of paper:Yes, No, or Maybe
Drake Equation
N = # planets with advanced civilizations
N* = # stars in galaxy
fP = fraction of stars with planets
ne = # “earth-like” planets orbiting stars with
planets
fL = fraction of “earth-like” planets with life
fI = fraction of planets developing “intelligent”
life
fC = faction of planets developing “advanced
civilizations”
L = life time of “advanced civilizations”
T = age of galaxy
How can we find values?
Values in Drake Equation
N = ____________________
N* = ____________________
fP = ____________________
ne = ____________________
fL = ____________________
fI = ____________________
fC = ____________________
L = ____________________
T = ____________________
Fermi Paradox
Any “modestly” advanced civilization could colonize the Galaxy in ~10 million yr?!– space ships v 10% c (speed of light)– colonies sent out more colonies every 100 yr– 10 106 << 13 109 (age of Galaxy)– conclusion insensitive to assumption
“Where is EVERYBODY??”