CATCHING WAVES
LSU scientists, students play major role in groundbreaking gravitational wave research

Some 24 miles from the LSU campus, in a location that could be called "off the beaten path," the sprawling facility known as the Laser Interferometer Gravitational-Wave Observatory, or LIGO, sits on a massive tract of land, hidden by acres of dense forest.

In this unlikely location, researchers and technicians from a group called the LIGO Scientific Collaboration spend their days on the cutting edge of scientific discovery, monitoring parts of the universe that are unquestionably "off the beaten path." Using lasers rather than telescopes, the staff of this unusual observatory "listens" to the heavens, waiting to "hear" something that will set the scientific world on its ear - gravitational waves.

Produced by violent events in the distant universe, gravitational waves are "ripples" in the fabric of space and time. Though the concept may sound like something from Star Trek, it actually comes from the mind of Albert Einstein, who predicted the existence of these waves in the early 20th century as part of his theory of general relativity.

According to current scientific thought, the waves are the product of massive cosmic events, such as the collision of black holes or shockwaves from the center of supernova explosions. Like waves in a gigantic pond, these ripples in space-time fabric travel toward Earth, carrying information on the very nature of gravity.

"The places in the universe where gravitational waves are emitted, are the most 'wild' and interesting," says Joseph Giaime, LSU associate professor of physics and astronomy and Chief Scientist at LIGO. "Gravity is so strong there that it is twisting spacetime around and things don't behave in the way we are used to or taught. Thus, Einstein's theories become necessary (for understanding the phenomena)."

Nevertheless, despite a large amount of scientific evidence supporting their existence, no one has ever actually detected one of these gravitational waves. That is where the LIGO team comes in, working not only to unravel the mysteries of space, but also, in effect, prove a crucial part of Einstein's theory.

"It's absolutely exciting science," says Giaime. "It's right here in our backyard and LSU students, faculty, and employees are fully involved."

LSU has been a key player in the LIGO research project for some time, and much of the credit goes to Physics and Astronomy Professor Warren Johnson and Physics Professor Emeritus William Hamilton. Long before the construction of LIGO began, Hamilton and Johnson began developing a wave-detection device of their own. That device is a two-ton, gravity-wave bar antenna known as ALLEGRO, which is one of only five such gravitational-wave detectors in the world and is still located on LSU's campus. While they worked to develop the ALLEGRO device, they also became involved in the early stages of the LIGO project, which is the brainchild of researchers from the California Institute of Technology and the Massachusetts Institute of Technology.

LIGO carried out its first observational run in 2002. Since then, there have been three additional observational runs, with the last, multi-month run being completed recently. Thus far, the efforts have not resulted in the detection of a gravitational wave. Next fall, LIGO will crank up its technology again and kick off a fifth observational run. This time, however, the goal is to observe for a six-month period. After that, Giaime says, there will be continuous observation for the next several years.

Ultimately, none of the scientists know if they will ever actually detect a gravitational wave, but it doesn't dampen their enthusiasm. The potential reward for their work is simply too great.

ON THE WEB:
LSU Department of Physics and Astronomy
LIGO Livingston Parish
LSU Center for Computational Technology

from Spring 2005