Prof. James Propp Blames Dinosaur Extinction on 'Repulsive Gravity'

Math Prof. James Propp in his office Image by File Photo
Math Prof. James Propp won BAHFest, a silly science contest, for his bogus theory about dinosaur extinction.

By Katharine Webster

Breaking fake news! New theory says a sudden reversal of Earth’s gravity wiped out the dinosaurs! All creatures fell up, then came crashing back down again when gravity returned to normal – and anything larger than 55 pounds either died or failed to survive in large enough numbers to reproduce.

Of course, there’s not a shred of scientific evidence for that idea. But it did win UMass Lowell Math Prof. James Propp top honors this spring at BAHFest – the Festival of Bad Ad Hoc Hypotheses, an MIT-sponsored contest for silly, pseudoscientific theories that’s held on its Cambridge campus.

Like the Bulwer-Lytton Fiction Contest to imagine the best first sentence of the worst novel, BAHFest encourages people to come up with ridiculously bad – but well-explained – scientific theories. Started by cartoonist and comic Zach Weinersmith in 2013, it pitted six contestants against each other before a panel of judges and a live audience. It proved so popular that BAHFests have now been held in England, Australia and around the U.S., and a YouTube channel is dedicated to videos of the performances.

Propp, who currently teaches Discrete Structures I and II, does more serious research in algebraic combinatorics and disc- and sphere-packing. He also blogs about math at and tweets about it @JimPropp.

Q: What is your silly pseudotheory of dinosaur extinction, and how did you come up with it?

A: I had a daydream in which dinosaurs were falling upward and then falling downward. The origin of this notion came about 20 years ago when I learned that Earth’s north and south magnetic poles periodically switch. Once you learn that, it’s fun to imagine, “What would happen if Earth’s gravitational field briefly reversed?” You could speculate in a totally scientifically irresponsible manner that “dark energy” would generate “repulsive gravity,” causing a Gravitational Reversal Event, or GRE.

I’m a mathematician, so part of my job is taking an absurd-seeming premise and seeing what consequences it logically leads to – which is also what a lot of comedians do. In this case, you think, “Animals fall up, animals fall down, animals die.” Then your next thought is, “Small animals can survive a fall better than big animals.” And then you see that there’s a fit between your totally goofy idea and an actual historical event, which is the extinction of the large dinosaurs. 

Math Prof. James Propp explains his theory of dinosaur extinction at BAHFest East 2017.
Q: How did you come to enter BAHFest?

A: First I wrote to Marc Abrahams, who runs the Ig Nobel Prizes – a parody of the Nobel Prizes that highlights research that makes people laugh, but also makes them think about good versus bad science – and asked him if anybody had ever proposed this theory. He said no, so I was planning to submit it to his magazine, The Annals of Improbable Research, but I got caught up in other projects. I’ve got a little bit of professional ADHD.

I found out about BAHFest when it started five years ago, but the first few events were only open to proposals about human evolution – which makes sense, because you can explain almost anything or its opposite with evolution, so it lends itself to pseudoscientific theories. Then this year, the organizer of BAHFest, Zach Weinersmith, just threw it wide open. I submitted my proposal, and it was one of six that was accepted. That was an even bigger high than winning the whole thing.

Q: Then you got up on a stage at MIT and presented it, complete with slides showing equations, real research on falling animals and illustrations of pterodactyls flying upside down and torso-twisting cats falling from the sky.

A: First, Zach coached me on how to make my theory funnier and meatier at the same time. He’s really experienced with how to find the humor, not by going for a laugh, but by digging deeper into the idea.

Q: Where do you get your comic inspiration?

A: One of my favorite musical comedians is Peter Schickele, the creator of P.D.Q. Bach, a fictional child of J.S. Bach. His music makes fun of baroque music and celebrates it at the same time. My theory is kind of P.D.Q. Einstein.

Also, I come from a family of lawyers, so I treated my theory as if I were a courtroom lawyer trying to make a plausible case for a client who doesn’t have justice on his side. For BAHFest, I thought, “What is the strongest possible case I can make? And I’m not allowed to lie, but I’m allowed to distort, and I can use rhetorical tricks, and I’m allowed to try and win my audience over through force of personality.”

The prize for winning BAHFest: a statuette of Hennig Brand boiling his own urine Image by K. Webster
Propp's prize was a statuette of alchemist Hennig Brand boiling his own urine.
Q: What did you win?

A: Bragging rights, $500 and this cool little statuette of Hennig Brand, a 17th century alchemist who collected buckets of urine, let it stand and putrefy until worms were swimming in it, and then boiled it all down into a paste in hopes of finding the philosopher’s stone that would turn base elements into gold. He ended up accidentally discovering the element phosphorus.

Q: Apart from the laughs, are there any lessons to be learned from BAHFest?

A: By thinking about what makes bad science bad, you can also appreciate indirectly what makes good science good. In a time when real science is mistaken for fake science and bad science masquerades as good science, it is so important to make a place in this world for bad science that is honest about the fact that it’s bad science.

Also, like the alchemists, some of my own work resulted from a false guess that led me to look into a topic. And once I got into it, even though I realized that my original hypothesis was completely wrong, I found something unexpected that was actually worth finding. That element of surprise is part of what makes math and science research so much fun.