Astronomy must be the most baffling of all sciences.
In what other discipline do researchers freely admit they don’t yet understand 96 percent of their subject? According to astronomers’ best calculations, only 4 percent of the universe is made up of matter that is recognizable to us — the rest is mysterious stuff called dark matter (23 percent) and dark energy (73 percent).
And even this is hypothetical. Dark matter is an invisible element in the universe that does not emit or reflect electromagnetic radiation, but astronomers can detect its gravitational pull on stars and galaxies. Its existence was first postulated in 1934 by Swiss astronomer Fritz Zwicky to account for discrepancies in scientists’ measurements of distant galaxies. Dark energy, which fills the empty spots of outer space, was identified only in 1998 when astronomers discovered that the universe was expanding at an accelerating rate rather than slowing down as was previously thought. Another big discovery, however, could challenge the existence of both dark energy and dark matter, setting research back to square one.
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Yet for Notre Dame astrophysicist Peter Garnavich — who played a key role in discovering dark energy — the almost maddening complexity of the subject is the appeal. “I’ve always liked to understand how things work, even when I was a kid. And when you’re that kind of person, you don’t want the easy stuff. You want to understand what no one understands.”
This is what inspires him, his colleagues on the Notre Dame astrophysics faculty and astronomers everywhere to devote their careers probing what happens light years away in places they will never experience as anything more than specks on a telescope. “Patience is very important in this work,” notes Garnavich, 52. “We’ve been waiting 300 years to see a supernova go off near us in the universe. I myself have been waiting since 4th grade.”
As baffling as it is, astronomy stirs a keen sense of adventure. Astronomers are grappling with questions so immense it makes your head spin. What is the nature of the universe? How far does it extend? How did it begin? Will it ever end?
“This kind of research gives us a different perspective on things,” Garnavich explains. “I marvel about how small the Earth really is. When I look at faraway images on the telescope I realize that each of these dots could contain many planets with people who are looking at us right now. I’d be crazy not to think about other forms of life in the universe because there are just so many possibilities out there.”
Making a trek last winter to the Large Binocular Telescope (LBT) observatory in southeastern Arizona, I discovered that astronomy’s spirit of adventure is not all theoretical. Notre Dame owns a small share of the LBT (along with a consortium of German and Italian research institutes and six other U.S. universities), which is the world’s largest optical telescope with 10 times the clarity of the Hubble Space Telescope. It’s located at the peak of 10,700-foot Mount Graham alongside the Vatican Observatory, where Garnavich also conducts frequent research (see sidebar).
While distances like a billion light years can feel hopelessly abstract, I have a new appreciation for just how far 10,000 feet actually is after driving up the mountain through five ecological zones ranging from Sonoran desert where I started my ascent to spruce and Douglas fir at the top, where traces of snow could be seen on the ground. It felt like I covered at least half the distance to the stars.
I had been skeptical when Garnavich told me it would take an hour-and-a-half to cover the last 25 miles to the observatory, but it ended up taking me two-and-a-half. I climbed 7,200 vertical feet on a road consisting of one hairpin turn after another where the white line at the edge of the pavement was often no more than a few inches from a sheer cliff. But this wasn’t the most-nerve racking part of the drive. That came at the very end when I turned up a steep gravel road and was required to announce my presence through a hand-held radio given to me in the base camp at the foot of the mountain. They warned me the road was too narrow for two vehicles to meet, so I must wait at the bottom if I hear word of anyone coming down. My radio, however, did not seem to be working so I crept along the gravel with white knuckles gripping the steering wheel.
Nonetheless, I was enraptured by the magnificent vistas and ever-changing scenery out the windshield. This landscape is sacred to the San Carlos Apache and White Mountain Apache people, and I can certainly understand why.
Upon finally reaching the top, the observatory reminded me of a hideout in a James Bond movie — a hulking industrial facility in a remote location sheathed in white metal atop a huge concrete slab where a diabolical villain hatches his evil plans. Adding to the intrigue was a small fence cordoning off the whole area, which I later learned was part of an effort to keep humans from interfering with the habitat of a rare species of red squirrel found only on Mount Graham. Construction of the observatory was vigorously opposed by both native peoples and wildlife conservationists, so strict measures are enforced to protect the surrounding landscape.
Peter Garnavich greets me at the door of the towering facility (my radio worked after all!) wearing jeans and a blue “Notre Dame Physics” sweatshirt. Once inside, I notice a preponderance of oxygen tanks. “Some people get altitude sickness at this height,” he explains, adding ominously, “It’s not a pretty sight.”
He’s just out of bed after an all-nighter scanning the heavens but is game to give me a tour of the observatory, which opened in 2005 and continually adds state-of-the-art equipment. The telescope itself reinforces my James Bond fantasy. It’s four stories tall, looking like a gigantic modern sculpture with thick silver tubes sprouting out of red metal hubs. It’s precisely the spot where 007 and the villain would engage in an extended shoot-out near the end of the movie, both of them narrowly averting numerous plunges to their death.
At the heart of the telescope are two mirrors, each 8.4-meters in diameter (about 9 yards), which are large enough to easily park a Humvee on but only 1.6 millimeters thick (6/100 of an inch). At dusk when a section of the ceiling opens to the stars, this huge apparatus swivels back and forth tracking distant targets chosen by the team of astronomers upstairs.
The rest of the facility consists of a spacious kitchen with a wall of refrigerators stuffed with provisions to last a team of astronomers a week — equally proportioned between healthy choices and junk food; a recreation room outfitted with a pool table (a tradition in observatories around the world, Garnavich tells me) and a big-screen TV tuned to a sports channel; sleeping quarters that look positively monastic; and the observation room where the astronomers get down to work once the sun sets.
Think of Peter Garnavich as the lucky kid who grew up to be what he always dreamed — like many who imagined becoming baseball pitchers or ballerinas. Born into a military family, he had seen a lot of the world before landing in Bowie, Maryland, outside Washington, when he was 7. But he continued to explore new places from the vantage point of his backyard — the heavens.
While in high school he hooked up a 35mm camera to his telescope and captured an image of an exploding nova that was studied by Harvard researchers and written up in Sky & Telescope magazine (which is to astronomers what Rolling Stone is to rock musicians). That hooked him on astronomy for good.
“Sometimes I wonder what I would have done if I had not become an astronomer,” Garnavich muses. “I can’t imagine. This is even better than being a baseball player because you keep doing it after age 35.”
He majored in the subject at the University of Maryland, earned a master’s degree in physics at MIT, a Ph.D. in astronomy at the University of Washington and a post-doctoral fellowship at the Dominion Astrophysical Observatory in Victoria, British Columbia, where he met his wife, Lara Arielle Phillips, who is also on the Notre Dame astrophysics faculty.
Along the way he also branched out to become a cosmologist — the study of the nature of the universe, which was once part of metaphysics but now is a subset of astronomy. Although Garnavich admits, “There’s still a lot of philosophy involved.” He developed research specialties in supernovae (stellar explosions) and gamma-ray bursts (brilliant flashes of light produced by explosions in distant galaxies).
His next post was at Harvard, where in 1994 he helped assemble the High-Z team, a collaboration of 20 astrophysicists around the world studying supernovae as a way to measure the expansion of the universe, a concept established in the work of Albert Einstein and Edwin Hubble. “We had no idea we were studying dark energy when we started,” Garnavich confesses.
For decades scientists thought the universe was expanding at a decelerating rate, a belief so strongly held that Albert Einstein repudiated his own theory of the cosmological constant because it contradicted this prevailing view. But data collected by the High-Z team over several years tells a different story. Their study of far distant supernovae found that explosions were less bright than could be explained by the theory of decelerating expansion.
At first, as Garnavich pored over data from the Hubble Space Telescope, he thought there was a mistake. “It’s like you a threw a ball into the air expecting it to come back down, and instead it kept going. But when I sat down with my collaborators we saw the findings were right.”
When a competing team of scientists, the Supernova Cosmology Project, arrived at the same conclusion, it became clear to everyone that the rate of expansion in the universe was speeding up, not slowing down. This means that over the course of millions of centuries, distant galaxies will move farther and farther away from us.
In 1998, Garnavich was lead author of one of three articles that announced these shocking astronomical findings in the Astrophysical Journal. Their research points to the existence of some sort of mass energy in the vast empty stretches that comprise three-fourths of outer space, which was called dark energy.
“This work was absolutely a breakthrough — a real game-changer,” says Ohio State astronomy professor Paul Martini, who frequently shares time at the Mount Graham observatory with Garnavich. In 2007, The Gruber Prize in Cosmology was awarded jointly to the High-Z and the Supernova Cosmology Project teams. It is one of astronomy’s most prestigious awards honoring scientists “whose groundbreaking work provides new models that inspire and enable fundamental shifts in knowledge and culture.”
“Einstein provided the toolbox,” Garnavich says. “This work depended upon him and Hubble. The tools were there, they were just not being used.”
Garnavich, who has taught at Notre Dame since 2000, now explores the meaning of this discovery. In a PowerPoint he presents to his ND classes, he offers six explanations for the existence of dark energy, ranging from gravity leaking from “extra dimensions” to serious flaws in Einstein’s General Theory of Relativity. Another possibility he lists is “something we have not thought of.” So there seems little danger that Garnavich will run out of things to understand.
“The point of science is to test things,” he says, “not just stop when you are satisfied with the results.”
Garnavich reassures us, however, that we needn’t worry about the acceleration of the universe busting the earth apart, as Woody Allen’s neurotic teenage character Alvy Singer did in the film Annie Hall, prompting his exasperated mother to declare: “Brooklyn is not expanding!”
“Woody Allen did not understand astrophysics very well. At least not as a kid,” Garnavich says. “While the universe is expanding, the Earth’s gravitational pull is strong enough to keep Brooklyn safe.” He’s quick to add, “Annie Hall is still one of my favorite movies.”
At the observatory atop Mount Graham, the pace picks up as the last rays of yellow-gold sun stream through the windows. The tapping at keyboards and shuffling of papers, which once sounded random, becomes steady and purposeful.
When blackout shades roll down over the windows around 5:30 on this December day (prime time for viewing because nights are the longest), the observation room is full. There are LBT staff technicians and astronomers from Notre Dame, Ohio State and the University of Arizona, all of whom are co-owners of the telescope, along with visiting grad students from Arizona State and the University of California-Davis — 11 males and one female. The sole woman, Erica Hesselbach, a Notre Dame post-doctoral student, remarks, “It’s not usually this unbalanced. More women have been entering the field.”
Everyone looks dressed for the weekend at a cabin — jeans, cargo pants, hiking boots, running shoes, sweat shirts, fleece jackets, ball caps — which in some ways this place is since the nearest store sits almost two hours away. Garnavich has brought a fresh-made pumpkin pie from a bakery he discovered in the small town of Willcox on the road from Tucson. Through a long career as an astronomer, he has learned that treats immeasurably aid the search for clues about dark matter, dark energy, black holes, white dwarfs, novae, quasars and other phenomenon that comprise our universe. You grow weary scrutinizing tiny images from the telescope projected on a computer screen all night long, he explains, so looking forward to a piece of pie becomes a keen motivator to keep going.
The room itself looks like an office anywhere, decked out with swivel chairs and marker boards but perhaps more computer screens than usual, some mounted overhead like in photos of the trading floor at the New York Stock Exchange. The only decorations are a short string of Christmas lights and a single framed photograph of the Milky Way that shines in green, gray and purple tints. Garnavich wanders off to the kitchen and puts a frozen pizza in the oven, which burns to a crispy brown as he becomes engrossed in conversation with Hesselbach, Ohio State graduate student David Atlee and me.
Discovery doesn’t always come as a flash in the sky, he says, sometimes it’s a flash of insight. “It’s exciting when you see a gamma ray burst but a breakthrough can also come over a period of months sitting at your desk.”
After a couple of tests on the telescope, a technician announces they are ready for the first target. “Get ready!” Garnavich quips. “We’re starting to do some science.”
“Yes, now it will really start to get boring,” responds Ohio State’s Martini.
The astronomers work out the timetable of who uses the telescopes when based on how many hours they are allotted by their share of ownership. Notre Dame owns 3 percent, which means Garnavich and other Notre Dame professors are able to observe a few times a year. (His colleagues Chris Howk and Terrence Rettig will arrive just after Garnavich heads home for South Bend.) He usually books some time at the less powerful Vatican Observatory before or after his LBT slots.
Tonight Garnavich plans to focus on Supernova 2009ig, 20 million light years away. “One important aspect of studying dark energy,” he explains, “is to make supernovae better distance markers. On Earth, we have all sorts of tricks we use to measure what’s far in the distance, like looking at streetlamps — if one streetlight is dimmer than another, we know it is farther away.”
Supernovae, he says, are the streetlights of outer space, offering a sense of just how distant galaxies actually are.
This particular supernova captured Garnavich’s attention because it is relatively close and was very bright when it exploded a year earlier. “I want to see if the way it fades tells us something about how it exploded. If we know the physics of the explosion we hope to make them even better distance indicators.”
If there’s time he also hopes to explore a newfound research interest — binary stars (two stars located very close together with frequent eclipses, which reveal insights not seen otherwise).
But everyone agrees that Martini goes first to test out some new techniques in studying an enormous cluster of galaxies 12 billion light years away. “This dense region of space is 100 times more dense than usual,” he explains, “and could give us clues on how galaxies form.”
The first image from the telescope pops up on computer monitors about 6:45, and I can see astronomers’ heads bob back and forth between the screen and reams of data flowing across their laptops. But soon there’s a problem with the telescope, and the energy in the room cools down.
“The telescope is so complicated that every night something usually goes wrong — at least for a little while,” Garnavich says.
Checking his email, he announces that an amateur astronomer discovered a new supernova last night in Japan. Amateurs play a surprisingly large role in the field, according to Garnavich. “It’s a big universe out there, and there are a lot of places we aren’t looking.” In fact, he says other scientists envy the enthusiastic support astronomers enjoy from the general public. “You don’t have that in particle physics.”
By 7:45, the telescope is back in action and David Atlee reports, “The viewing is really good after all of this.” It had been cloudy the night before — a relatively rare occurrence in the Arizona desert, which is one reason why major observatories like LBT and Kitt Peak are located here — so everyone is ready to get some work done.
Martini begins scrutinizing faraway galaxies as others occasionally glance over his shoulder. Cooperation trumps competition in the observatory because there is more than enough universe for everyone to study. With new technology it may soon be possible for astronomers to scan the heavens through distant telescopes in the comfort of their offices back home, but Garnavich believes the camaraderie of the observatory is important for swapping ideas, staying up-to-date, fixing glitches and making connections in the field.
By 8:20 the machine is on the fritz again, and the technicians are videoconferencing with colleagues back in Tucson in search of a solution. Yet Garnavich, who has peered through telescopes longer than anybody in the room, remains cheery. As he drinks Earl Grey tea, he gives the impression that even a brief opportunity to gaze out toward distant horizons of outer space is not time wasted.
One by one, everyone abandons their stations and scoots their chairs into one end of the long, narrow room. At first, the assembled group awaits news that the telescope is fixed but eventually a wide-ranging discussion launches covering history, current events, football and so forth. At one point a couple of guys are poring over an Internet map of the 1924 election results (“Hey, Robert LaFollette took Wisconsin”).
When Garnavich mentions he brought a pumpkin pie, a chorus of cheers erupts. The art and science of pie making suddenly becomes the focus of conversation. A surprisingly high percentage of those present baked pumpkin pies for their families’ Thanksgiving feasts the week before, and everyone agrees the secret to success is getting the crust just right. I am especially intrigued by the grad student from UC-Davis, who details how he made his crust out of ginger snaps. This is a long way from investigating the nature of dark energy or the origin of galaxies but the same curiosity, creativity and rigor that drives scholars to study the heavens also fuels their collective passion for pie making.
Around midnight, growing anxious about my morning drive back down the mountain, I say good night and retreat to my room at the Vatican Observatory. About 5 a.m., I hear the visiting students from Arizona State and UC-Davis come in, laughing.
Later, by phone, Garnavich tells me the telescope never worked again that night, but the next “was one of the best nights ever for viewing.” He got a good look at Supernova 2009ig and observed some binary stars about 2 million light years from Earth.
Then he shares something that struck him as he hiked along a national forest trail below the peak that afternoon. “It was a beautiful day, not too cold, and I went up to a firetower to see the view,” he says. “I took a close look at the trees, at the colors, and thought about all the elements it takes to make up the universe. It’s not a simple process that got us here. We are part of a bigger universe, even if we don’t think about it much. When I look at the stars, I see wonder, awe. There is still that unsolved mystery — we don’t know how it all works.”
Jay Walljasper is the author of All That We Share: A Field Guide to the Commons, which features a vision of South Bend in 2035 excerpted on the Notre Dame magazine website. He is editor of OnTheCommons.org and a contributing editor at National Geographic Traveler. His website is JayWalljasper.com.