Trivia Thursday - Moony Run

I loath jogging. It really takes a lot to get me running. But I've learned that on the moon, even I might prefer to run. Who would have thought of that when we recall the astronauts walking in their Apollo suits. Even more bizarre is that this was already (unintentionally) explained in the 19th century.

It goes back to William Froude (1810-1879), who was the first to formulate reliable laws for the resistance that water offers to ships and for predicting their stability. Especially, his is remembered in fluid dynamics by the Froude number named after him.

Christopher Carr, a researcher at the Massachusetts Institute of Technology, has recently dicovered that the Fround number explains the counter-intuitive finding, that if you want to conserve energy, on the moon running rather than walking is the best plan:

The Froude number is calculated by squaring a person's walking (or running) speed, and dividing the result by his leg length and (crucially) the strength of the local gravitational field. If the Froude number exceeds 0.5, then it is more efficient to run than to walk. On the moon and Mars, where gravity is weaker than on Earth, that is generally the case.

Now I just have to get around the math to apply this to cycling on the moon.

[Source: The Economist]