Part 4 — The Rumpus-to-Weight Ratio

As soon as you have checked in at the hotel, and have learned the local surface speed, it would be wise to calculate the planet's rumpus. Aside from giving you an idea of what to expect at the new year's celebration, you may wish to know the rumpus because any planet's weight is proportional to it. A planet where the speed is 10 cents has a rumpus which is 10 thousand quartic cents, and must weigh 100 million tons. Sometimes in bars the locals will ask a visitor what he or she thinks their planet weighs and it is a sign of good manners to know. One of these things where if you don't know it you should probably buy everybody a round of drinks.

The ratio of a planet's rumpus to its weight is the same for every planet but how the ratio looks when you write it down depends on what units are used to measure speed and force. The ratio is officially called G and we already know what it looks like when speed and force are measured in cents and tons:

G = 10^-4 cent⁴ per ton

However you look at it, it is a ratio built into nature and intrinsic to the way gravity works. In case you are curious, here what the same ratio looks like in metric terms:
G = 6.673×10^-11 (m/s)⁴ per newton.
In metric terms the unit of force is newton and the unit of speed is meter per second (m/s). G still works as the ratio of any planet's rumpus to its weight. The determining choices for the metric system were made around 1790 in France during the Reign of Terror.

Cent speed is about 2/3 miles per hour. One way to imagine walking at that speed, if you really want to, is to think of taking foot-long steps once a second. If your shoes are roughly a foot long then think of snapping your fingers twice a second and taking a heel-toe step with every other snap. It's apt to look silly, partly because of the finger snapping but mainly because it is such a slow walk. Silly or not, that is the surface-skimming orbit speed on a planet that weighs ten thousand tons.

We can use the G ratio to weigh the sun. Earth's orbit speed is 10⁵ cents. If we plug that in for the speed, the rumpus number is 10²⁰ and the force that goes with that is 10²⁴ tons. This is what a copy of the sun would weigh if placed the same distance we are from the sun. In my dialect, 10¹² is a trillion, so this weight is a trillion trillion tons.