What would be the most efficient way to power a spaceship carrying hundreds of thousands of passengers? According to some newly-published calculations, the best option would be to use the passengers themselves—by harnessing the power of exercise.

The paper, "Can We Power A Spaceship?" is one of the offerings in the most recent issue of the *Journal of Interdisciplinary Science Topics*. The journal is published by the University of Leicester, where students apply their knowledge to various pop culture conundrums, such as whether the transformation of a frog into a prince violates the laws of conservation of mass and energy.

Or, in this case, how best to power the Axiom spaceship featured in the film *Wall-E*.

According to the students:

We know that there is a population of 600,000 and if each person does 2 hours of exercise a day:

3379.2 J hr-1 x 2 hr x 600,000 = 4.06x109 Joules

The exercise would not necessarily have to be done in one go, as this could possibly cause major health issues. Instead, it should be sufficient to assume that the 2 hours of exercise is completed over the course of one day. In addition, the humans would need to sustain their bodies, and hence they would be required to consume enough calories, using the resources available on the Axiom, to maintain their body mass.

Assuming relativistic effects do not take place, it will take 720,000 years for the Axiom to reach the speed of light.

Hey, whatever works.

## DISCUSSION

This is just silly; remember, today is April Fools Day. All human energy comes from the food we eat, so all things being equal, the ship would have to carry that much more food. Plus extra to accelerate that mass, etc, if the ship uses a reaction engine. And, humans are only about 25% efficient at converting food to energy, so it's that much worse. You'd be a whole lot better off with a tank of deuterium or something.