The universe made a scheduled stop at a pastry cafe last week. About 50 people filled up on general relativity, black holes and coffee cake. Our Earth was compared to a basketball, a pinhead and a piece of candy.
“You can eat one if you want,” said Jocelyn Read, as she passed the candy around the room. “They’re great.”
Read, 31, freely distributed food for thought for about an hour during the second meeting of the Oxford Science Cafe. She’s a post-doctoral research associate at the University of Mississippi Department of Physics and Astronomy. She’s also an expert on neutron stars, black holes and gravitational fields. Read took a deliberate step back from the cutting edge of physics to share some of the wonders of the universe that float through her mind every day.
“One of my favorite things to do is to try to think about things in four dimensions,” she said before the lecture. “It’s hard, but it’s trippy.”
Any fan of the PBS television show, “NOVA,” would’ve been able to follow Read’s talk. She said the production values of her lecture weren’t up to TV’s standards. Then again, you seldom get to ask the TV questions.
“I love it,” said Jack Barbera, 66, of Oxford. “I have all these questions for Brian Greene (on ‘NOVA’) and I can’t ask them. I can actually ask them here.”
Marco Cavaglia, 43, started the Oxford Science Cafe as an outreach program to the community. The overall goal is to encourage young people to pursue careers in science, technology, engineering and mathematics.
But the secondary goal is almost as important, and that’s to engage a lay audience that’s eager to learn more about how things work.
“I went to North Carolina, and they had a science cafe there. They asked me to give a talk,” said Cavaglia, associate professor of physics and astronomy at UM. “At first, I was perplexed about why they would do this. Then I was surprised. The pub was full. They paid attention and asked questions. I was surprised there were a lot of people interested in science.”
He came back to Oxford with a plan. The university pays for pastries and drinks at Lusa Pastry Cafe, and anyone who’s interested is welcome to listen to a free lecture, then pepper the presenter with questions.
“They ask a lot of questions,” Cavaglia said. “That’s great. That’s what we want. Science is about questions.”
Basketballs and stars
In October, Josh Gladden delivered the Oxford Science Cafe lecture on “Airplanes to Turbulence to Dark Energy.”
Read’s talk was titled “The Intense Life of Stars After Death.” She took it slow and gave the audience a sense of the scales involved.
“If the Earth is a basketball, the sun is the size of a house,” she said. “If the sun is a basketball, the earth is the head of a pin.” That’s when she handed out the tiny candy, and explained if the sun was the size of a pinhead, the next star would be 11 miles away. “We’re kind of in the boonies of the Milky Way,” she said.
In our sun, hydrogen atoms keep slamming together, and their fusion creates 99 percent of the energy that the star releases.
Mary Queyja, 76, of Oxford, answered Read’s next question: What happens when a star runs out fuel?
“The fire goes out,” Queyja said.
Not exactly, but close.
A star the size of the sun would become a white dwarf, and it’s expected to cool and die peacefully. For a star that’s 1.5 times to nearly 5 times bigger than the sun, gravitational forces cause the star to collapse into a “super hot, very dim and very small” neutron star, Read said.
“Everything that was in the house fits into the basketball,” she said.
A much larger star would collapse into a black hole, where the gravitational forces are so strong nothing can escape, not even light. Read provided three different models that resembled paper funnels. From a star to a neutron star and to a black hole, the funnels stretched farther to show how gravitational effects increase.
“I listen to all types of podcasts about science, but I still learned something from Dr. Read here,” said Carlos Pruitt, 48, of Oxford. “I really liked her description of the cross sections of stars and black holes, just the way they curve space. I never saw it put that way.”
If the preceding descriptions confused you, blame it on the reporter because Read definitely made the information accessible, as she flowed from one interstellar topic to the next. No one left the Oxford Science Cafe ready to get a Ph.D. in physics, but people pooled together and discussed what they’d learned long after the talk ended. The heavens seemed a touch more approachable, even from the boonies of the Milky Way. Read got something from the exchange, too. She was clearly jazzed as audience members came up to her and shared their interpretations of what they’d just heard.
“This is why I did this,” she said with a smile, “because it’s so awesome.”
Courtesy of NEMS360.com by M. Scott Morris