By Julieta González

Our universe may be just one of many, says William Stoeger, S.J., adjunct professor of astronomy at the University of Arizona, and one of the scientific staff members of the Vatican Observatory.

Stoeger, who has been associated with the Vatican Observatory since 1979, describes his work as primarily theoretical specializing in cosmology and in high energy astrophysics. Early in his research career his work focused on black holes and how they power quasars and active galactic nuclei. Although he still engages in some research in this area, his emphasis now is on cosmology, the physics of the origin and history of the universe, from the Big Bang to the present. Secondarily, he's been heavily involved in the observatory's initiatives and collaborative research relating the natural sciences to theology.

Recent developments in Stoeger's work as a theoretician include the publication of a paper in collaboration with another cosmologist, George Ellis, and one of Ellis' graduate students at the University of Cape Town in South Africa. The paper addresses the question of multiverses. "There are significant theoretical indications that our universe may in fact be but one of billions of other universes," explains Stoeger. "The idea, really, is that there is a collection of many universes that were created and came into existence through the same process."

"This has become an extremely popular idea in theoretical cosmology in attempting to understand how the Big Bang occurred and how our universe came to be the way it is," says Stoeger. "Now it's true that we may never certainly observe these other universes because we can't observe beyond our own. But, the point is that in very clear mathematical and scientific terms the best way to understand the physical nature of our universe may be to consider it as one in a collection of many other universes. This attractive proposal requires a great deal of further scientific and philosophical reflection and study."

Stoeger has also been involved in research related to "Cosmic Micro-Wave Background Radiation." He explains that this is one of the most important cosmological discoveries of the past 100 years. "It's really a bath of micro-wave radiation that pervades the whole universe and that we see coming to us from every direction," says Stoeger. He says that this radiation was first detected as low-level noise in 1965.

"What it turns out to be," says Stoeger "is the after-glow of the Big Bang which strongly reflects the state of the primeval ionized gas, or the plasma, before stars and galaxies formed.

"Because of the finite speed of light, as we look out farther back in time, we eventually reach a point earlier than the first galaxies where we encounter radiation from the nearly smoothly distributed ionized gas about 300,000 years after the Big Bang. This is the cosmic microwave background radiation. There we see the places where that primeval ionized gas was a bit more dense. Those are the places which were the seeds of future galaxies. Those places were still expanding at that time, but more slowly than the surrounding universe. They will have collapsed to form galaxies or clusters of galaxies much later. Our own galaxy, the Milky Way, originated this way."

Stoeger's work in science and theology over the past two decades has enriched the literature in that area and his contribution to the classroom as well. A series of well-known conferences and workshops began in 1987 when the Vatican Observatory was asked by Pope John Paul II to organize a conference on science and theology to mark the 300th anniversary of the publication of Newton's "Principia Mathematica." It was the pope's desire at the time to make a significant statement on science and theology so he also asked the observatory to make suggestions on just what he might say about the topic.

"The Vatican Observatory brought together a world-wide ecumenical group of about 25 people for a conference on the most interesting work in the various areas relating to science and theology," recalls Stoeger. The result was the publication of a volume titled "Physics, Philosophy and Theology: A Common Quest for Understanding." Included in the publication were a series of essays and papers presented at the conference and the pope's letter strongly encouraging the dialogue between science and theology. "One of the principal emphases of his statement," says Stoeger, "was that there can be no conflict between the two if we properly understand each."

This ecumenical group of philosophers, theologians and scientists determined that the success of the first conference merited several more over the following decade. "A crucial aspect of the dialogue between theology and science has been how to understand God's action in the world in light of the conclusions of contemporary science," says Stoeger.

Topics which were brought to bear on "God's action in the world," were quantum creation of the universe and the laws of nature; chaos and complexity; evolutionary and molecular biology; neuroscience and the person and finally the issues of quantum mechanics and quantum theory. The conferences were held at the pope's summer residence in Castel Gandolfo, Italy; at the Graduate Theological Union near the University of California campus at Berkeley, Calif., and at a mountain retreat house near Kradow, Poland.

Stoeger has also been involved with the Center for Theology and the Natural Sciences in Berkeley, Calif., and with the Center of Theological Inquiry in Princeton, N.J. For the past 11 semesters he has team taught a class at the UA on science and theology with associate professor Tom Lindell of the molecular and cellular biology department.