NSF Award Funds Study Of Shape Of Universe

July 22, 1997

It's difficult to image how the universe is shaped. Is it a limitless expanse of stars and dust? A web of soccer balls where one ends and another begins? A cylinder where if you travel far enough in one direction, you eventually return to where you started? Or is its shape something beyond the human imagination?

Glenn Starkman, associate professor of physics at Case Western Reserve University, received a four-year, $200,000 Early Career Development Award from the National Science Foundation to study the shape of the universe by mapping temperature fluctuations throughout space. He also will develop new techniques to detect dark matter (dense matter which gives off no light), which is believed to comprise much of the mass in the universe.

The combined mass of dark matter and ordinary matter -- like stars, gas, and dust -- exerts gravity, impacting how fast the universe expands. "It all ties to the question of whether space is going to expand forever, or one day will it stop and start contracting," says Starkman.

If density of matter in the universe is above some critical factor, the universe will stop expanding. He says finding dark matter is therefore a search for the ultimate fate of the universe.

Starkman said he is particularly interested in what the consequences are when there is not enough mass to stop expansion.

With continued expansion, some interesting things may happen. For example, what astronomers might think is a distant galaxy could actually be the Milky Way seen from a different direction and at a much younger age. He said this is called nontrivial topology.

Starkman theorizes that the universe is very likely to be connected like a cylinder or a mesh of soccer balls, not in the simple way that people have long assumed.

How cosmologists view the model of the universe will change with the launching of the new MAP (microwave anistropy probe) satellite in the next few years.

NASA will launch the satellite to map fluctuations in the temperature of the early universe by measuring the temperature of radiation coming from over 400,000 directions in the sky. An older mapping satellite, called COBE, only mapped 6,000 temperature points.

"Once this satellite goes up, we'll know much more about the universe and have a good handle on the density of the matter," said Starkman. "We should also be able to tell exactly what the topology of the universe is."

The NSF grant is one of several awards which funds his work. He has a $15,000 grant from Jet Propulsion Laboratory run by NASA and Cal Tech to continue his efforts to design a satellite, called IRIS, which will help find planets surrounding nearby stars.

Recently astronomers may have found planets in other solar systems. The gravitation pull of the plants causes the light of the stars to wobble. This makes the light emitted from the stars turn very slightly redder and then bluer as the planet orbits. Astronomers have not directly seen the planets because the stars are brighter than the planets.

Starkman's IRIS satellite will block light from the stars, allowing astronomers to see the dim planets directly.

The satellite also will be useful in measuring the properties of Massive Compact Halo Objects (MACHOs), one type of dark matter which has already been discovered.

According to Starkman, MACHOs are sufficiently massive, having 10-50 percent of the mass of the sun. Their gravity bends passing light rays from stars to act as a lens, temporarily brightening the light from the star.

The IRIS satellite will allow astronomers to make detailed observations of the stars while the dark matter magnifies its brightness. This will reveal much more than currently is known about the nature of MACHOs, said Starkman.

The NSF award, given to promising junior faculty members in the sciences, also enables Starkman to develop teaching initiatives to expand the awareness of physics.

Starkman established a collaboration with the University of Addis Ababa in Ethiopia. This spring, he videotaped the Department of Physics' weekly colloquia and seminars given by visiting physicists, and sent almost 30 hours of lectures on tape to Ethiopia.

He has received a $1,500 Nord grant from CWRU to expand the initiative to more venues and other Third World countries.

Starkman came to CWRU in 1995. From 1993-95, he was a scholar in the cosmology program at the Canadian Institute for Advanced Research.

He earned his B.Sc. (with high honors) in mathematics, physics, astronomy, and astrophysics from the University of Toronto in 1984 and his Ph.D. in physics from Stanford University in 1988. From 1988-91 he was a member of the Institute for Advanced Study in Princeton.

In recognition of his work and scholarship, he has received other honors, including the Gold Medal of the Royal Astronomical Society of Canada and an appointment as an International Associate in the Cosmology Program of the Canadian Institute for Advanced Research.


Toni Searle, amf2@po.cwru.edu
Editor, "Campus News, CWRU
Phone: 216-368-4443
Fax: 216-368-3546

Case Western Reserve University

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