Prof. Janna Levin, Barnard College of Columbia University, explained black holes and theories of uncovering these astrophysical objects at the lecture, “Black Holes, Chaos and Gravitational Waves.” The lecture, which was sponsored by the astronomy department, was held yesterday afternoon in the Space Sciences building.
Levin, an expert in general relativity and black holes, began her discussion by explaining that a black hole is a region in space where nothing can escape. It is formed after the collapse of a star and neither emits nor reflects light.
Levin elaborated on the history of black holes by explaining that they were originally called Schwarzschild Singularities, in honor of Karl Schwarzschild who expounded on Einstein’s Theory of Relativity in 1915.
“It was 50 years until Schwarzschild’s theories were accepted and the term ‘black hole’ was coined,” she said. This is because many, including Einstein himself, rejected the concept of the non-spinning, spherically symmetric region that Schwarzschild presented.
Levin, however, is less interested in the history of black holes and more occupied with detecting binary black holes, which generate gravitational waves.
“We are on the verge of seeing the universe with new eyes and ears,” she said. “Gravitational waves [provide] the ultimate observation.”
“In order to discover these gravitational waves, we need advanced tools,” Levin said. Currently, gravitational wave data is being collected by the detector, LIGO, in Hanover, Wash., and a more technologically advanced detector, LISA, is due to be launched into space in 2015.
“Detection of gravitational waves requires knowledge of dynamics. Yet we only have approximate equations to understand dynamics, and we are not even close to solutions,” she said.
Detection becomes even more complex because of chaos, which describes nonlinear dynamics. Chaos can best be studied through fractal sets.
“Fractals are self-similar structures where a pattern repeats on smaller and smaller scales. They are the signature indicator of chaos in orbits,” Levin said.
Throughout the lecture, Levin emphasized the difficulties in understanding black holes. Yet she is hopeful that new technology, further research and the observation of gravitational waves will eventually be successful in uncovering more information about these mysterious regions of space.
“Black holes populate the universe in remarkably brilliant combinations and [they also] populate the universe in as yet unseen pairs,” Levin concluded.
Levin presented a lecture, which was not only informative but which also appealed to a varied audience, from undergraduates to professors and experts in the field of astronomy.
“This was one of the more enjoyable [lectures] I’ve been to so far. Prof. Levin was good at putting things into layman’s terms,” said Kenny Sauer ’08. He added, “It was just a great introduction to black holes. And I definitely enjoyed learning more about chaos theory and fractals.”
The lecture was a part of The Charles and Barbara Burger Special Colloquium, which is a special of the Fall 2005 Colloquium Series. The series presents a weekly guest lecturer who discusses various topics of astronomy. When speaking in regard to the purpose of the series, Monica Armstrong of the Radiophysics and Space Research Department said: “We’re trying to get different types of people involved [in astronomy].”
The next lecture of the series will be “Probing Neutron Stars with Thermonuclear Flashes.” The lecture will be given by Prof. Andrew Cumming, McGill University, next Thursday afternoon.
Archived article by Jamie Leonard