Some Numbers...

Speed of light: C = 2.998 X 10⁸ m/s
Light year: LY = 9.46 X 10¹⁵ m
Absolute Zero temperature: T_o = -273°C
Mass of Earth: M_e = 6.0 X 10²⁴ kg
Diameter of Earth: D_e = 1.3 X 10⁷ m
Mass of Sun: M_s = 2.0 X 10³⁰ kg
Diameter of Sun: D_s = 1.4 X 10⁹ m
Age of Universe: T_u = 13 X 10⁹ years
Number of cells in adult human: = 60 X 10¹² cells
Number of atoms in one cell: = 120 X 10¹² atoms
Number of atoms in one cm³ of air we breathe: = 10¹⁹ atoms
Number of atoms in one cm³ of interstellar gas of the Galaxy: = 1 atom
Number of atoms in one m³ of intergalactic space: = 1 atom
Number of electrons (or protons) in the universe = 10⁸⁰ electrons
Number of photons in the universe: = 10⁸⁹ photons