Globe

Babson Geophysical Globe. U.S. Merchant Marine Academy. Schuyler Otis Bland Memorial Library. Kings Point, New York.

I have a globe. It is slightly larger than normal with a diameter of 16 inches. It is nowhere near as large as the Babson Globe shown above, but I like it. I'm thinking I should make some kind of mounting for it, and I got to thinking that maybe I should fill it with concrete so as to give it a more realistic feel. Set something like that to spinning on good bearings and it might be days before it came to a stop.

    Then I got to wondering just how much a scale globe should weigh, so I did some checking. Here's what I found:

• density of granite:   170 pounds per cubic foot
• density of steel:     500 pounds per cubic foot
• density of the Earth: 345 pounds per cubic foot

So the density of the Earth is midway between that of granite and steel. That makes a certain amount of sense. So how much would a scale model globe weigh with the same density as the Earth?

• typical 12" globe:                   180 pounds
• my extra large 16" globe:            425 pounds
• Babson globe (7' 6" in diameter): 76,000 pounds

Then I got to thinking about the biosphere, the portion of the Earth where there is life, and I realize it's like the skin of a balloon, pretty damn thin, and fairly insubstantial. There are also some fairly sizable holes in it, like deserts, high mountain ranges and the polar regions. Our small size gives us a limited view, and gravity keeps us glued to the surface. Even though some of us have our eyes on the stars we are really all flatlanders.