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 Sahara desert 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 Shannon number
10^googol		googolplex