Scientists have long sought to explain things like how gravity works or the nature of the Big Bang. But what if gravity worked differently? And why did the Big Bang result in this particular universe?
Such are the questions explored in a set of short, light-hearted videos recently created by Jared Kaplan, associate professor in the Department of Physics and Astronomy in the Johns Hopkins Krieger School of Arts and Sciences. In the first, titled "Did the Universe Have to Be the Way That It Is?" Kaplan considers what would happen if gravity were just a bit stronger (we might live on a Little Prince–sized planet); and if it were just a bit weaker (planets might be shaped like potatoes, instead of orbs).
"So why did the universe end up the way that it is?," Kaplan asks at the end. "We really don't know the answer. But one possibility, or at least food for thought, is that maybe the universe is the way it is because if it were different, we wouldn't be here to talk about it."
A theoretical physicist, Kaplan received a 2015 CAREER grant from the National Science Foundation for his research on quantum theories. The grant, which supports early-career faculty who serve as academic role models and leaders, requires an outreach component to encourage people to pursue science. Kaplan got the idea of making a film to fulfill the requirement from his colleague David Kaplan (no relation), a professor in the same department who created the documentary "Particle Fever" about the physicists and experiments at the Large Hadron Collider.
Kaplan reached out to Emily Driscoll, a science video producer at Quanta Magazine, whom he'd met several years ago when he consulted with the publication for a film they made about holography in the context of quantum gravity. With Driscoll providing the direction and contacts, and Kaplan providing the science and narration, the duo created the three videos with the help of an animator, photographers, and Driscoll's artist stepmother's New York studio as the location. Scientific American published the videos, which are available on YouTube.
"I wanted to cover topics a little bit different from what is usually discussed, and I wanted them to be fun and somewhat whimsical," Kaplan says.
The second video, "How the Big Bang Governs the Texture of Our Universe," explores why the universe isn't just empty, and also why matter is distributed in clumps separated by large voids, rather than being evenly scattered. "To understand this curious composition and how it changed over the history of the universe, it's helpful to think about the matter in the universe as a herd of animals," Kaplan intones in the video's opening.
Viewers go on to learn that the universe's texture reveals clues about how it was formed. "These issues are not commonly discussed, but they're an important feature of how we understand the Big Bang," Kaplan says.
The third installment, "Why Is Gravity Different?", considers why gravity is different from other natural features, and what makes quantum gravity more different still. This line of research most closely reflects Kaplan's usual scholarly pursuits, in which he poses questions about our place in the universe and the universe's place in something bigger. Kaplan's days are filled with mind-bending ideas like fundamental numerical constants that take on different values in other, theoretical universes, and how it is that we happen to live in a universe where structure and life are possible.
"Understanding how other universes would be different tells you about whether other universes are possible," he says.
With their quirky, down-to-earth (no pun intended) style, the films are intended to appeal to a general audience with an interest in science. "I want people to be intrigued and entertained," Kaplan says, "and get a slightly more nuanced and humanized idea of what scientists are doing and how they're thinking about things, and to understand that science is a human enterprise like any other."