An image of the birth of a star from NASA's Hubble Telescope. Associate Professor
of Physics Thushara Perera continues the same work as Hubble - looking into the formation
of the universe.
Faculty Member to Take Students into Study
of Dark Energy
February 8, 2010
BLOOMINGTON, Ill. – This fall, an assistant professor
of physics at Illinois Wesleyan University plans to have students help research one
of the biggest questions facing science today: What is dark energy?
According to Assistant Professor of Physics Thushara Perera, studies involving dark
matter and dark energy are showing there is more that is unknown in the universe than
known. “Everything we know about the universe is probably 5 percent of what is really
out there,” he said. “Dark matter is maybe 25 percent, and the other 70 percent is
probably dark energy.”
Highly sensitive cameras, filled with detectors, are set in dry places at high elevation
in an attempt to reveal the nature of dark energy and the history of the universe.
Perera has spent years working on such a camera, known as the Astronomical Thermal
Emission Camera (AzTEC), which was mounted on a telescope in the mountains of Chile.
“The data from AzTEC helps answer fundamental questions about early galaxies and how
they formed,” said Perera from his office at Illinois Wesleyan, where he started teaching
Perera was a research associate for AzTEC at the University of Massachusetts at Amherst
during his recent postdoctoral studies. He is continuing his work with AzTEC by analyzing
data the camera collects, and by building and designing hardware for future cameras.
He plans to have undergraduate students at Illinois Wesleyan help with the data analysis
as well the construction of hardware.
Associate Professor of Physics
Dark matter and dark energy are, in essence, parts of the universe humans cannot see,
and have not yet been able to fully detect, according to Perera. “From our studies
of the universe and an understanding of gravity, we know there is something else out
there,” said Perera, who came to the United States in 1990 from his homeland Sri Lanka
to study astronomy and physics. After graduating from Ohio Wesleyan University in
1994, he earned a master’s degree and doctorate from Case Western Reserve University,
where he began research on dark matter.
Dark energy (nicknamed “anti-gravity”) and dark matter are relatively new concepts
in science. Though theories from Albert Einstein help support the idea, it wasn’t
until the 1980s and 1990s that scientists began significant searches for dark matter
and dark energy after studies showed the expansion of the universe was accelerating,
which contradicted the conventional wisdom of the original Big Bang Theory. “These
experiments showed the universe has been expanding faster than it had been in earlier
times,” said Perera, who noted dark matter is just like other matter in that it pulls
objects into gravitation. “But if it was just dark matter out there, it would be attracting
other things in the universe to it, not this seeming repulsion that causes things
to accelerate away from each other.”
Scientists know something is out there from the evidence of gravitational pull, but
no one is certain what it is. Dark matter itself has not been detected by scientists,
though teams are trying to find ways to do just that. The massive CERN project in
Switzerland is attempting to replicate conditions in which scientists think dark matter
An image from AzTEC
Instruments similar to AzTEC look for dark energy by exploring the patterns around
ancient light. These instruments are sensitive enough to examine light wavelengths
from early in the universe, approximately 300,000 years after the Big Bang, which
scientists believe happened around 13.7 billion years ago. “The aging process of the
universe stretches ancient light, and you have to go through a lot of trouble to see
it,” said Perera. “But that light is critical to understanding the formation of the
Currently, much of the work on dark energy is centered at large, research universities.
Perera hopes the efforts of he and his students will open the doors for dark energy
to be studied at smaller universities. “If students and I are able to make an optical
filter that is useful for instruments being built at several large institutions, that
would be an example of a small university making an important contribution to this
field,” said Perera.
Though Perera’s work in cosmology attempts to understand the origin of the universe,
he said he has no illusion that humans will ever have all the answers. “My research
has been based on finding the missing elements of the universe,” he said. “It is a
search for a deeper understanding, taking me back further in time until maybe the
beginning of the universe. But will we know what happened before the Big Bang, before
time and space began? I don’t think so.”
Perera paused and smiled, “but I don’t want to exclude it either.”
Contact: Rachel Hatch, (309) 556-3960