Imagine a spherical cow.

With an opening line like that, one can only imagine the direction this article is going to go. It sounds like the perfect way to begin a discussion of The Far Side comics by Gary Larson or an intro to this article about the use of cows in making zeppelins.

If we are going to be true to the concept of the spherical cow, here is a light-hearted way to describe it:

In physics, a cow once was found,
Whose shape was quite perfectly round.
Its milk, so divine,
Was renowned through the line,
For the creamiest milk to be found!

(Copyright 2024 Commonplace Fun Facts. Movie rights to the above limerick are available for sale to the highest bidder.)

The spherical cow is a bit of physics humor used to illustrate a scientific principle. It starts with this joke:

Milk production at a dairy farm was low, so the farmer wrote to the local university, asking for help from academia. A multidisciplinary team of professors was assembled, headed by a theoretical physicist, and two weeks of intensive on-site investigation took place. The scholars then returned to the university, notebooks crammed with data, where the task of writing the report was left to the team leader. Shortly thereafter the physicist returned to the farm, saying to the farmer, “I have the solution, but it works only in the case of spherical cows in a vacuum.”

Admittedly, it isn’t the sort of joke that puts you in danger of dying from laughter like this guy or this king. For most people, it may not even trigger a snicker. Trust us, though… All the physicists who are reading this are doubling over with belly laughs.

The spherical cow joke illustrates the tendency in physics to develop theoretical models to explain a complex phenomenon and in the process, reduce the solution to something utterly unpractical or unfeasible. An example would be trying to come up with a way to unfold all of the tools in a Swiss Army knife simultaneously and proposing the solution: find a person with thirty arms.

The spherical cow metaphor may be impractical, but it gets high marks from us for having one of the cleverest names in science. Imagining a true spherical cow solution may keep physicists awake at night. The rest of us, however, can happily drift off to sleep, picturing beautiful, round bovines floating through the clouds.

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