Order of Magnitude
•The nearest power of ten of a number is called its  Order of Magnitude. Examples from Tipler’s table 1-3:
• Size (m)            Mass (kg)           Time (s)
•Proton 10E-15   Electron 10E-30  Period of
•                                                       visible
•                                                       light 10E-13
•Sun      10E9      Sun 10E30          Age of earth         10E17
•Another illustration: “Zooming in on Tallahassee.”