What is important in popular science?

It’s almost always entertaining, but you can’t count on all three.

Years ago one of our consultants was a teaching assistant for a popular professor, one whose basic astronomy course was preferred by many non-science majors.  He was very entertaining, with attention-getting demonstrations and a lively lecturing style.  Unfortunately, student interest and good course evaluations did not translate into a significantly higher level of learning, as measured by test results.  Our consultant concluded that popular science (meaning presenting science to non-scientists) needed to have three attributes: it must be entertaining, clear and correct.  In the years since we have seen a great deal of the genre, in several forms; and unfortunately much of it fails to meet his criteria.

The requirement to be entertaining is obvious.  With all the noisy competition for people’s attention these days, a book or podcast or whatever has to stand out as generating interest.  To some degree the subject matter generates its own interest.  Thinking of our own specialties, there are things to be found in physics and astronomy that go beyond anyone’s imagination, and much more that simply stretches the mind.  Even in the more sedate world of the nineteenth century, one could count on audiences to be wondering about the nature of and distances to stars.  We’ve seen very little popular science that fails to be entertaining, probably because any such efforts would sink without a trace.

Clarity is much, much harder.  Because the results of science often use mathematics beyond the grasp of the general population and always require a background they do not have, some form of translation is required.  Here is where the skills of the expositor shine.  Somehow, by simile or analogy or metaphor, the behavior of an equation has to be made clear; or the interaction of a complicated set of processes laid out.  It is not always successful.  On our Bookshelf of Bad Examples is an attempt to describe the mathematics of how planets in the Solar System interact by gravity.  The metaphors are complicated in themselves, and together are often contradictory, so the result is complete confusion for the reader.  A more subtle trap is often found in expositions of mathematics: the reader, comprehending a metaphor, comes away with the illusion of understanding the math.

We are particularly concerned about the last quality, correctness, which we think gets much less attention than the first two.  An incorrect understanding is easy enough to come by through simply pushing a metaphor too far.  Yes, gravity can be pictured as the curvature of a rubber sheet, where masses make dimples in it; the mathematics of both are the same (making allowance for the fact that the first is four-dimensional, the second two-dimensional).  But the cosmological “expansion of space” is not just like a rubber sheet being stretched.  You can’t plant a flag at some point in space and watch how it’s being moved by the sheet.

Then there are the explanations that are simply wrong.  If you can go faster than light, yes you can catch up to the light-rays showing what you did yesterday, and so in a way go back in time.  But (in a process that would take too long to describe) in an entirely different way faster-than-light travel would allow you to visit your own past, not just see it.  You could shake your own hand.  Or do other things.

Unfortunately, while anyone in the audience can judge whether a bit of popular science is entertaining and clear, whether it’s correct requires a scientist.