|Yale professor Meg Urry explained black holes to her audience in Scarsdale. YWAA treasurer Rich Fabbro '76 (top, L) introduced her before the presentation, Dec. 9 (YWAA photos)|
Urry, a professor of astronomy and physics, is Chair of Yale's physics department, head of the American Astronomical Society, and a leading researcher in black holes. At the Scarsdale Library in front of an audience of about 90, she was afforded a chance to expound passionately on something she knows and cares about in a way that allowed her listeners to follow her step by step, equation by equation with dark, colorful images on a lit screen behind her.
First, let's define black holes in the way NASA describes them: "A black hole is a place in space where gravity pulls so much that even light cannot get out. The gravity is so strong because matter has been squeezed into a tiny space. This can happen when a star is dying."
|After her presentation, Urry speaks to audience members about the mass of supermassive black holes. (YWAA photos)|
No one present doubted her passion. Most wondered how she would explain the phenomena of black holes, concepts of "space-time," and theories of special and general relativity to a group with a familiarity of calculus from nothing to basic to advanced.
Somehow she succeeded with a display of cartoons, drawings, and even movie excerpts from "The Wizard of Oz." She used the piano on stage to explain how galaxies expand. (And she amused all by pointing out an egregious math error in the "Oz" movie when the scarecrow receives his brain and rambles on about isosceles triangles.)
She exploited numbers, statistics, and familiar expressions. She explained, "The Milky Way is the galaxy that is our hometown." From end to end, it's about 100,000 light-years across. "It would be hard to have a conversation with our neighbors on the other end," she said.
Urry kept it simple and logical. She started with basic principles of Issac Newton and gravity and explained with hand-and-fist gestures the difficulties Albert Einstein had with Newton's notions of gravity. Describing gravity and the concept of escape velocity helped her explain black holes and the challenges scientists have in calculating the mass of black holes.
"All galaxies have a supermassive black hole in their center," she said and showed with graphics. "Galaxies send matter into black holes," she added, "while black holes send out energy." Someone asked: What happens if black holes suck in all matter within a galaxy? She paused, envisioned and described such a scenario without resorting to equations and arcane jargon.
She reminded her audience a few times that the galaxy is 13 billion years old. One member of the audience asked her what should we expect in the next 13 billion years. Glad to address that question, Urry relished having to contemplate a universe 13-billion years hence.
A sudden wrinkle has interrupted our understanding and study of the universe, she said. The discovery and importance of dark energy (and dark matter, too) over the past 15 years mean scientists now have to incorporate something that has proven to be too prevalent to ignore in the universe. "Another topic for another time," she said as time wound down.
During a question-and-answer period, responding to a query about why there might be inadequate numbers of physicists and astronomers, Urry said, "Physics isn't always taught right. Scientists use too much jargon." Moments later, she added, "It's really simple stuff. (Physics) can explain everything."
After an hour or so of explaining gravity, black holes, and galaxies in dramatic, lively and vivid ways, she summarized her enthusiasm. "No person on earth can't learn physics, if I'm given enough time," she wrapped up in a light-hearted way. Her audience applauded, chuckled, and generally agreed with her.