St. Louis, MO. — Sometime within the next two years,
researchers will detect the first signals of gravity waves —
those weak blips from the far edges of the universe passing
through our bodies every second. Predicted by Einstein’s
theory of general relativity, gravity waves are expected to
reveal, ultimately, previously unattainable mysteries of the
universe.

Wai-Mo Suen, Ph.D., professor of physics at Washington
University in St. Louis is collaborating with researchers
nationwide to develop waveform templates to comprehend the
signals to be analyzed. In this manner, researchers will
be able to determine what the data represent — a neutron
star collapsing, for instance, or black holes colliding.

“In the past, whenever we expanded our band width to a
different wavelength region of electromagnetic waves, we
found a very different universe,” said Suen. “But now we
have a completely new kind of wave. It’s like we have been
used to experiencing the world with our eyes and ears and
now we are opening up a completely new sense.”

Suen discussed the observational and theoretical efforts
behind this new branch of astronomy at the 40th annual
New Horizons in Science Briefing, Oct. 27, 2002, at
Washington University in St. Louis. The gathering of
national and international science writers is a function
of the Council for the Advancement of Science Writing.

Gravity waves will provide information about our universe
that is either difficult or impossible to obtain by
traditional means. Our present understanding of the cosmos
is based on the observations of electromagnetic radiation,
emitted by individual electrons, atoms, or molecules,
and are easily absorbed, scattered, and dispersed.
Gravitational waves are produced by the coherent bulk
motion of matter, traveling nearly unscathed through space
and time, and carrying the information of the strong field
space-time regions where they were originally generated,
be it the birth of a black hole or the universe as a
whole.

This new branch of astronomy was born this year. The Laser
Interferometer Gravitational Wave Observatory (LIGO) at
Livingston, Louisiana, was on air for the first time last
March. LIGO, together with its European counterparts,
VIRGO and GEO600, and the outer-space gravitational wave
observatories, LISA and LAGOS, will open in the next few
years a completely new window to the universe.

Supercomputer runs Einstein equation to get templates

Suen and his collaborators are using supercomputing power
from the National Center for Supercomputing Applications
at the University of Illinois, Urbana-Champaign, to do
numerical simulations of Einstein’s equations to simulate
what happens when, say, a neutron star plunges into a
black hole. From these simulations, they get waveform
templates. The templates can be superimposed on actual
gravity wave signals to see if the signal has
coincidences with the waveform.

“When we get a signal, we want to know what is generating
that signal,” Suen explained. “To determine that, we do
a numerical simulation of a system, perhaps a neutron
star collapsing, in a certain configuration, get the
waveform and compare it to what we observe. If it’s not
a match, we change the configuration a little bit, do
the comparison again and repeat the process until we
can identify which configuration is responsible for the
signal that we observe.”

Suen said that intrigue about gravity waves is sky-high
in the astronomy community.

“Think of it: Gravity waves come to us from the edge of
the universe, from the beginning of time, unchanged,” he
said. “They carry completely different information than
electromagnetic waves. Perhaps the most exciting thing
about them is that we may well not know what it is we’re
going to observe. We think black holes, for sure. But
who knows what else we might find?”

Related links:

Wai-Mo Suen’s Web page
http://wugrav.wustl.edu/People/SUEN/HOME.html

Record article on WUSTL Parallel Supercomputing Center
http://wupa.wustl.edu/record/archive/2001/03-23-01/articles/computer.html