The Big Picture

By Chad Galts / July / August 1998
November 30th, 2007
On a warm spring night in late April, twenty-odd students from Physics 22, Beginning Astronomy, crowd onto the deck of Ladd Observatory on Hope Street. They have come to peer through the sixteen-foot-long telescope that hangs from a single point at the apex of the dome. Installed when the building went up in 1891, this twelve-inch refracting scope still has to be pointed and focused manually; in order to open or rotate the building's thirty-foot-wide copper-and-steel roof, either David Targan '78 or one of his teaching assistants must pull a series of chains that tie into an elaborate system of pulleys.

"It's a teaching tool," Targan says of the Ladd telescope as he watches an assistant dangle from a chain to grind the dome into place above them. "It's kind of nice to know we're using it in the same way it was being used over a hundred years ago."

Officially, Targan is an associate dean of the College, an adjunct assistant professor of physics, and director of the Ladd Observatory. Unofficially, he's a kind of astronomical Pied Piper. Whether he's coordinating the observational lab sessions for Beginning Astronomy at Ladd, setting up a mobile telescope during a frosty January evening on northeastern Rhode Island's Jerimoth Hill, or looking at the sun through an elaborate set of eye-protecting filters at high noon on the roof of Barus and Holley, Targan's objective is always the same: he wants to provide students with the wow factor of a face-to-face encounter with the heavens.

Teaching this kind of astronomy comes easily to Targan, a smallish, friendly forty-two-year-old with bright hazel eyes and a neatly trimmed beard. A close observer of heavenly phenomena since childhood, he joined the physics department in 1988 with a Ph.D. in astronomy and science education from the University of Minnesota. Tonight, Targan starts by focusing on the moon's Sea of Crises, which, he explains, is "about 200 miles from the [first] Apollo landing site." He then sets up for a look at Algieba, a binary star in the constellation Leo. Once his teaching assistant has cranked the dome around to just the right place, Targan grabs hold of the telescope, swings it around, and unscrews the eyepiece. He reaches into a wooden box, finds a lens with a higher magnification, sets it in place, and focuses. Then he calls in the students.

As a relic of nineteenth-century astronomy, the Ladd Observatory contains no computers; the main observing room lacks even a power outlet. Modern observatories, which use automated devices to find their celestial marks, are normally crammed with computer workstations, high-resolution monitors, and ultrasensitive digital spectrographs. "We have a spectrograph," Targan deadpans. "It dates back to 1891. It's a very nice antique."

Ladd's simplicity, which the University steadfastly preserved in a recent renovation, serves at least two important functions. In addition to introducing astronomy to a range of students, it provides an opportunity one evening a week for its Providence neighbors to see what's above them in the light-polluted night sky. Ladd may not be collecting data on astronomy's most burning questions, Targan says, but the observatory, with its simple, fir-plank deck, remains a persuasive teaching tool, a place for directing attention upward.

For example, three nights after a lunchtime lab on the roof of Barus and Holley, during which Targan and a group of students watched the third-largest solar flare ever observed, the group abandoned their work pointing the Ladd telescope and simply walked outside. They didn't need extra magnifying power to see the spectacular light show as particles from the flare entered the Earth's upper atmosphere. "We all just stood there," Targan says. "Everybody was silent. The aurora display was so bright that it outshone the city lights. The whole sky was curtains of red and green. It was spectacular."

If the Ladd sessions are a facet of astronomy that hasn't changed since Galileo, it's Professor of Physics David Cutts's job to introduce the students of Beginning Astronomy to the science as practiced in 1998. The day after Targan's lab, Cutts is putting the class's observations into a big-picture perspective in Barus and Holley 168. "There is some controversy as to how old the universe actually is," he says. "Thirteen billion years is a good guess." Cutts is tall and angular, with long sideburns, a gentle voice, and large, square glasses. He stands behind a waist-high desk at the front of room. The 139-seat auditorium pitches up steeply before him, supporting a firmament of students who sit in small, constellation-like groupings.

"Galaxies are found in clusters," Cutts continues, pulling on a cord to bring down a slide-projection screen. "We happen to be in a rather insignificant one." Cutts, who teaches the lecture portion of Beginning Astronomy, keeps his students visually stimulated. Today he will show slides of spiral galaxies, do a complicated explanation of Hubble's law on an overhead transparency, run a short video clip of a NASA press conference about the discovery of what appears to be a black hole, and use a big-screen projection from the course's Web page - all in an effort to explain physicists' current best guess as to the ultimate fate of all known matter.

While the lab sections try to give students a closer look at individual objects in the heavens, Beginning Astronomy lectures are designed to make them understand how all of it works. Many of Cutts's slides, for example, are images from the Hubble Space Telescope (HST), a 2.4-meter reflecting telescope orbiting 600 kilometers above the Earth. It has no screw-in eyepieces; deployed in 1990, HST is completely controlled by computers. The images gathered by HST are vastly superior to anything visible through a terrestrial telescope; the light it collects is not filtered and refracted through the atmosphere. The orbiting telescope is so powerful, in fact, that it is helping collect data to answer questions astronomers never even dreamed of asking ten years ago.

"Will the universe keep getting bigger and more diffuse?" Cutts asks students in Beginning Astronomy. "Or will it eventually collapse back in on itself?" Such questions are difficult to imagine on a human scale.

"Will the universe keep getting bigger and more diffuse?" Cutts asks the class. "Will it reach a steady state? Or will it eventually collapse back in on itself?" Such questions are difficult to imagine on a human scale. Some of the galaxies that Cutts discusses, for example, are so far away that their light is just now visible to humans even though those objects are older than the entire Milky Way galaxy, let alone the Earth. "Recent data suggest that the most distant things in the universe are still moving apart - even speeding up," Cutts says. "It looks like the universe is growing."

During the semester, Cutts takes the class to the farthest reaches of space and time. Beginning with a discussion of how stars form and evolve, Cutts steers the students into the dynamics of the Milky Way. Soon he is piloting them to other galaxies, galaxy clusters, and galactic nebulae; they swing past black holes, pulsars, quasars, neutron stars, and into clouds of dark matter. Helping students understand such objects and phenomena as black holes or dark matter comes with an added challenge, Cutts says: "They are, by definition, unseeable." The gravitational force of a black hole is so strong that not even light can escape its grasp to be collected in a telescope. Dark matter is (or might be) made up of neutrinos and other fragments of subatomic matter that physicists believe pervade the entire universe.

Cutts, whose specialty is particle physics, has been searching for bits of subatomic matter ever since joining the Brown faculty in 1973. While teaching the course, he often spends two days a week at Fermilab, a national research laboratory in Batavia, Illinois, that is home to the world's most powerful particle accelerator. Though Cutts's own work is conducted on an infinitesimally small scale - on the level of individual protons or electrons - he says his research has many astronomical applications. "Studying the fundamental constituents of nature and looking at galaxies have a lot in common," he says to the class. "A lot of things that one does in the lab to calculate the properties of nature's smallest particles can be of use when you're studying something like the Big Bang."

Many of Cutts's more complex concerns about the fundamental nature of matter need to get checked at the door of Beginning Astronomy, but the professor doesn't mind. "You can talk a little bit about modern physics, and they can relate it to how a star produces energy," he says. "It's really a nice opportunity to bring in topics from the forefront of scientific research and give them to students who listen and even appreciate what it is you're trying to do."

Cutts, a Providence native, traces his own interest in astronomy to a boyhood trip he took with his parents to Ladd Observatory. There Cutts found Charles Smiley, a Brown professor and keeper of the Ladd telescope from 1930 until he retired in 1969. Smiley "delighted in talking to kids and showing them things in the telescope," Cutts says. "He gave me the idea that science was fun and respectable and exciting." With his own students, Cutts begins at precisely that point, and shows them how science can be nothing less than a way of life.

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July / August 1998