College of Liberal Arts

University of Mississippi

A Cosmic Perspective: Oxford Science Cafe Explores the Universe

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 by M. Scott Morris