Facts and approximate Values for generating Fermi problems

Mass:				Density:	    				

Earth 6 x 10^24 Kg		Water: 1 g/cm^3	    
Sun	10^30 Kg		rock:  2g/cm^3      

Hydrogen atom	10^-27 Kg	air:  .018 g/cm^3

Proton:  10^-27 Kg		

Electron  10^-31 Kg



DISTANCES:						RATES: 	
Est. dist. across universe: 15x10^9 Light Yrs.         Solar Energy flux at 	
							Earth's surf.: 2 cal/cm^2-min.       
# of galaxies in universe:  50x10^9
diameter of Milky Way: 1x10^5 LY			 Sound in air: 340 m/s  

Diam. of Sun: 1.5x10^6Km                                 Speed of light in vacuum 3x10^8m/s
Earth radius: 6x10^6m                                    
Atmosphere thickness: 60 mi.                             tectonic drift: 2cm/ year
Avg. ocean depth: 2 mi.
% of earth sruface under water: 70%
Atom diameter:   10^-10 m
Red blood cell diam:  5x10^-6m
Human hair diam: 70x106-6 m
# of transistors on a Pentuim chip: 2x10^6