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??”