Figure 1-13: Examples of Powers-of-Ten Notation This scale gives the sizes of objects in meters, ranging from subatomic particles at the left to the entire observable universe at the right. The protons and neutrons in the illustration on the left form the nucleus of an atom; the electrons orbit around a hundred thousand times farther out. Second from left is the cell wall of a single-celled aquatic organism called a diatom, 10−4 meter (0.1 millimeter) in size. At the center is the Taj Mahal, about 60 meters tall and within reach of our unaided senses. On the right is the planet Earth, about 107 meters in diameter. At the far right is a galaxy, 1021 meters (100,000 light-years) in diameter.
(Andrzej Wojcicki/Science Photo Library/Getty Images; Steve Gschmeissner/Science Photo Library/Getty; iStockphoto/Thinkstock; NASA/JPL; 2004–2013 R. Jay GaBany, Cosmotography.com)