Power of 10 
Physical Property 
Name or Prefix 
Symbol 
10^{35} 
length in meters where spacetime becomes dominated by quantum effects, the
Planck length 


10^{24 } 

yocto 
y 
10^{21 } 

zepto 
z 
10^{19 } 
charge of one
electron 


10^{18 } 

atto 
a 
10^{15 } 
the radius in meters of one proton
(hydrogen nucleus) 
femto 
f 
10^{12 } 

pico 
p 
10^{10} 
radius in meters of a hydrogen atom 


10^{9 } 
number of seconds it takes light to
travel one foot 
nano 
n 
10^{8} 
period in seconds of an FM radio wave 


10^{7} 
wavelength
in meters of germicidal Ultraviolet
radiation 


10^{6 } 

micro 
m 
10^{3 } 

milli 
m 
10^{2 } 

centi 
c 
10^{1 } 
fraction of stars
that can support life 
deci 
d 
10^{0} 
a) all is one b) density of water in grams per milliliter 
one 
 
10^{1 } 
a) fingers on human hands 
deka 
D 
10^{2 } 
a) human lifespan b) number of stable elements in the
periodic table 
hecto 
h 
10^{3} 
speed of sound
in km/h 
kilo 
k or K ^{**} 
10^{5} 
number of hairs on a human scalp 


10^{6} 

mega 
M 
10^{7} 
number of seconds in a year 


10^{8} 
a) number of people on earth (circa
500BC) b)
number of meters light travels in one second 


10^{9} 
a) number of people on the earth (circa
1800) b) number of heartbeats in a lifetime
for most mammals 
giga 
G 
10^{10} 
number of people on the earth (circa
2050) 


10^{12} 
a) number of cells in the human body b) number of data bits on a
computer hard disk 
tera 
T 
10^{13} 
national debt of USA in
dollars (circa 2008) 


10^{14} 
number of neural
connections in human brain 


10^{15} 
surface area of the earth in square
meters 
peta 
P 
10^{16} 
speed of the fastest computer in FLOPS
(circa 2008) 


10^{17} 
age of the universe in seconds 


10^{18} 
volume of water in the earth’s oceans in
cubic meters 
exa 
E 
10^{19} 
number of possible positions of Rubik’s
cube 


10^{21 } 
volume of the earth in cubic meters 
zetta 
Z 
10^{24 } 
a) number of grains of sand in the b) number of atoms in one
mole (the Avogadro constant) 
yotta 
Y 
10^{28} 
mass of the earth in grams 


10^{33} 
mass of the solar system in grams 


10^{50} 
a) number of atoms in the earth b) number of possible chess
board positions 


10^{66} 
number of atoms in our
Milky Way galaxy 


10^{78} 
volume of the universe in cubic meters 


10^{80} 
number of elementary particles in the
universe 


10^{100} 

googol 

10^{120} 
lower bound on the number
of possible chess games, also called the 


10^{googol} 

googolplex

