Lost world: How Canada missed its moment of glory
SEPTEMBER 26, 2009
THE GLOBE AND MAIL
In June 2007, the Nobel Foundation sponsored a symposium in Stockholm, Sweden on the physics of exoplanets, planets that orbit stars other than the Sun. For the world-leading astrophysicists in attendance, the event was a nudge-nudge, wink-wink indication from the secretive Nobel folks that one of its annual prizes in physics would be awarded, perhaps as early as this October, for one of the greatest accomplishments of 20th century astrophysics—the discovery of the first exoplanet. That much is certain. What’s uncertain is who will get the prize.
Will the committee take the obvious route and award the duo of Swiss astronomers who announced the global headline-making discovery of exoplanet 51-Pegasus in 1995? Or, will they side with the American astronomer whose university press releases claim he discovered the first exoplanet three years earlier?
Or will the committee members have an empathetic eye for the vagaries of scientific fate and award the prize, at least in part, to the dark horses in this Nobel race: Canadian astronomers Gordon Walker and Bruce Campbell. After all, the pair of British Columbia-based astronomers’ pioneered the world’s most succesful exoplanet search technique. In the 1970s and 80s they devoted the core of their careers to a quest that many of their colleagues thought was akin to UFO-ology. They even published the first scientific paper that accurately reported the detection of an exoplanet.
But, on this last point it’s certain that a Nobel-committee member will point-out the odd twist to this scientific paper and its history making claim. In a case of scientific self-doubt, Professor Walker retracted the exoplanet claim. But only after his colleague Campbell quit astronomy in frustration and professional heartbreak.
In this the 2009 International Year of Astronomy as we stand on the historic brink of the possible discovery of the first alien Earth, Campbell and Walker’s story is emerging as the centerpiece of the other space race of the past half-century, the search for other worlds.
“Gordon Walker and Bruce Campbell were the real true pioneers of (exoplanet) detection,” says Alan Boss, an astrophysicist at the Carnegie Institution in Washington, D.C. and author of the new book The Crowded Universe: The Search for Living Planets, which recounts the history of the modern search for exoplanets.
But to many, theirs is an untold Canadian story of enormous promise, near victory and eventual heartbreak. As compelling a tale of the physical and psychological challenges of the scientific journey as any in history. A story of reaching into the vast unknown of space to behold a magical star, but be uncertain of its true message.
“Bruce Campbell is the father of all of the exoplanet work that is happening in the world right now,” says University of California at Berkeley astronomer Geoff Marcy, the world’s leading exoplanet hunter. “There are several thousand people working on exoplanets, and it all goes back to Bruce Campbell.”
Marcy has co-discovered 170 of the approximately 360 exoplanets found to date. Most importantly, he’s done it using a technique pioneered by Campbell and Walker.
“(They) invented the technique that we stole,” says Marcy, who in the cast of characters involved in the exoplanet search plays the role of a central witness, having worked in the field since 1982. “If it wasn’t for Bruce Campbell, you wouldn’t be talking to me.”
On the August evening I speak with him by phone, he’s at the UC Berkeley campus remotely directing the giant 10-metre Keck Telescope, atop Hawaii’s dormant Mauna Kea volcano. He’s trying to verify new exoplanet sightings as a member of NASA’s Kepler space telescope mission.
Kepler, launched this past March, is the first telescope capable to spotting Earth-sized rocky planets around stars like our Sun. In mid-August, the Kepler team announced that the telescope is working perfectly and is on-target to reach its ambitious goal: conducting a census of possible nearby Earth-sized planets, due to be completed by 2012. To do this it’s staring at approximately 100,000 stars in the Milky Way, watching for planetary transits. A transit occurs when a planet passes in front of its star resulting in a mini-eclipse, a temporary dimming of the star’s light as seen from Earth.
“Kepler will not find ET, it’s hoping to find ET’s home,” said Bill Borucki, the NASA visionary leading the Kepler mission, on the occasion of Kepler’s launch. “Whether we show that there are lots of Earth-like planets, or very, very few, we’ll answer a question that has been asked by mankind for millennia: Are there other worlds, or are we alone? We should get that answer.”
The current excitement over the search for alien worlds belies a huge shift in our view of the cosmos. While by 1980 movie goers were accustomed to a Star Wars menagerie of fictional other worlds, from desert Tatooine to icy Hoth, astronomers counted only nine real planets in the entire cosmos—those of our solar system.
“It is quite hard nowadays to realize the atmosphere of skepticism and indifference in the 1980s to proposed searches for exoplanets,” writes Gordon Walker in a recent scientific article chronicling his exoplanet search.
The skepticism was fuelled by almost a half-century of amazing exoplanet false alarms, as recounted in the new book Pluto Confidential: An insider account of the ongoing battles over the status of Pluto. (It was the discovery of hundreds of exoplanets that reshaped astronomers thinking about the nature of planets and demoted Pluto to dwarf planet status.)
The grand challenge in finding exoplanets is that the planet is hidden in the glare of its star. It’s still only possible to detect an exoplanet indirectly by looking for the minute ways it changes the light coming from its star.
In 1967, a seeming exoplanet discovery around Barnard’s star famously made it into astronomy text books, only to ingloriously fade-out in 1973 when it was shown to be not a planet, but a telescope problem. In another case of mistaken exoplanet identity, a venerable American astronomer arrived at what was planned to be the announcement of an alien world he’d found, only to announce that what he thought was a planet was in truth a mathematical error. (He was none-the-less hailed by his colleagues for having been brave enough to break the news himself.)
“There was literally a gravesite with lots of tombstones of planets that had come to life erroneously and then laid to rest over the decades as false planets,” says Berkeley’s Geoff Marcy.
If other world’s were out there, astronomers knew they were devilishly hard to detect, maybe impossible. Into this astronomical minefield walked Campbell and Walker.
The two astronomers met forty years ago this month, when Campbell, a 21-year-old third year engineering student at the University of British Columbia walked into his first astronomy class. At the front of the lecture hall was Gordon Walker, a Cambridge-trained, 33-year-old recent immigrant from Scotland in his first year as a professor.
It was little more than a month after Neil Armstrong put humanity’s first step on another world, and the cosmos suddenly seemed a little more accessible, that humans were capable of reaching further into the stars than most had imagined.
However, unlike the Apollo program, Walker and Campbell didn’t initially deliberately set-out on the first dedicated search for alien worlds. They were astronomy tech geeks—Campbell scored top marks in Walker’s class, ‘Astronomical Measurements’—drawn together by a love and fascination for building better, faster telescopic equipment.
And in astronomy, the better you see, the more you see. Just as Galileo’s radical insights were based on a better telescope, Campbell and Walker knew they were onto something when they created a radically better way of studying starlight.
“I heard myself say (to Bruce), We could start looking for planets,” said
Walker from his home in Victoria, BC, where at 73 he’s still very active in astronomy as an adjunct professor at the University of Victoria. “I don’t know where the idea came from. That’s how these things happen in science, suddenly a light turns on. It’s the art of the possible.”
What they developed was an amazingly more accurate way of clocking a star’s movement, or speed.
While we’re used to thinking of stars as fixed points of light in the night sky, stars in fact move. A lot. They expand and contract due to their thermonuclear nature. A star rotates on its axis, just like Earth’s rotation that gives us day and night. And just like a planet, a star has an orbit. Although we think of planets orbiting a stationary star, the star and any planets actually orbit a common centre of mass. It’s like a large adult and small child on a teeter-totter—to make it work, the adult gets very close to the centre of mass, the child far away. The ‘parent’ star is very close to the centre of mass, giving it an orbit not much larger than its own diameter.
Measuring a star’s speed around this orbit depends on a 150-year-old standard of astronomy, the doppler method. The doppler method is based on the same fundamental physics we experience when we hear changes in the pitch of an ambulance siren as it speeds towards us and then away.
In the case of stars, astronomers look for changes in the pitch, or frequency, of starlight to measure a star’s speed towards or away from us. The technique is called the ‘wobble method’ because seen on a graph, the star’s speed creates a wave, or wobble, as it appears to move faster when approaching Earth, and slower when moving away. The bigger the wobble, the bigger or closer the planet.
Astronomers had long known that the accuracy of the doppler method depends on the ability to tease apart light into its various colours, or wavelengths, a technique called spectroscopy.
“(Walker) was the Jedi knight of spectroscopy,” says current UBC astronomer Jaymie Matthews, who initially came to UBC in to conduct research with Walker.
Campbell was his Luke Skywalker, an “audacious, young astronomer,” says Marcy, who brought their star-speed tracking up to exoplanet-finding speed. Campbell who’d graduated UBC in 1971, but returned to work with Walker as a post-doctoral researcher in 1976 after earning a PhD at the University of Toronto. With Walker, he developed a spectroscopy technique that was a spectacular 100 times more sensitive to the movement of stars.
“They were measuring the velocities of stars, for the first time in history, to plus or minus ten metres a second,” says Marcy, who began his own exoplanet search after hearing a talk about the technique by Campbell in the early 1980s. “The best that anybody at any observatory in the world had done was plus or minus one kilometre per second.”
They could use a telescope like a police speed radar gun to clock a distant star’s velocity to within the accuracy of the speed of an Olympic sprinter. It was the magic number for planet-hunting. Astronomers knew that massive Jupiter causes our Sun to wobble at about 12 meters per second. Thus, Campbell and Walker’s technique would be able to spot the wobble’s induced by Jupiter-sized exoplanet’s on their stars elsewhere in the Milky Way.
If they were out there.
After a trial run with their system on the telescope at the Dominion Astrophysical Observatory in Saanich, north of Victoria, in 1980 Campbell installed their star speed system on the new, much larger Canada-France-Hawaii Telescope atop Mauna Kea in Hawaii, where he was now on staff.
Their exoplanet hunt plan was straightforward: assuming that other solar systems existed and were like ours, Jupiter-like exoplanets would take about 12 years to orbit their star, just as Jupiter does. So Walker and Campbell began a decadal search of 26 stars looking for Jupiter-sized exoplanets, ones large enough, they reasoned to tug at their stars to a degree visible with their telescope.
“Out of two dozen stars, and if you observed for a decade or longer, it seemed that it was a sure thing that you’d find something like Jupiter,” says UBC’s Matthews.
Three or four times a year Campbell, Walker, or University of Victoria astronomer Stephenson Yang the other long-term member of the team, would spend several nights atop Hawaii’s Mauna Kea summit, 14 000 feet above the Pacific, searching for other worlds. They’d start just after dusk and work through the night in winter parkas, enduring high-altitude induced headaches, until dawn’s light drowned-out the stars.
“It was deadly,” says Walker, of the psychological challenge of searching for exoplanets no-one knew existed, or could even be found. “Of course, you never knew from one night to the next if you were observing anything. You could only tell when the data were reduced about once a year, whether we were seeing trends.”
But by 1987, they believed they were seeing something no Earthling had ever seen before—stellar wobbles caused by orbiting planets.
That summer, at a press conference at the annual meeting of the American Astronomical Society in Vancouver, Campbell announced their preliminary results: they showed a half-dozen stellar wobbles indicative of possible exoplanets, but one star’s motion was particularly intriguing: gamma Cephei.
It was a fitting star for the Canadian planet hunters. A bright star 45-light years away gamma Cephei is always visible from Canada in the night sky shining near Polaris, the pole star. Campbell described how from their detailed measurements they’d seen that gamma Cephei had a periodic 2.5 year-long wobble. As viewed from Earth the star moves towards us and then away over a two-and-a-half year cycle—evidence, they thought, of an exoplanet gravitationally tugging at the star.
“I presided over Campbell’s press conference and remember to this day the charged atmosphere and excitement that greeted his announcement,” says Steve Maran co-author of the book Pluto Confidential, who retired recently as the long-time press officer for the American Astronomical Society.
The New York Times headline read Planets Outside Solar System Hinted. “They were calling us planet hunters. We were on the track, “ says Campbell, from Victoria where he now lives.
His professional colleagues weren’t as impressed. In an arena of super-charged skepticism, their tentative announcement generated more doubt than accolade. An astronomer in the NYT’s article said: I probably won’t call it a planet until I can get out and walk on the surface of it. No researchers attempted to confirm the results.
Walker says the press conference, ironically, was more the beginning of the end, rather than a high point, increasing the pressure to deliver results from a project that was by its nature deeply long-term.
Two years later, Campbell, Walker and Yang still had nothing conclusive, and worse, Campbell didn’t have a secure job.
A Vancouver-native, Campbell was determined to stay in the lower mainland. But a decade of effort hadn’t earned Campbell a permanent position at either UBC, UVic, or the National Research Council’s Victoria-based Herzberg Institute for Astrophysics.
“In my view (his not getting a job) had a lot to do with the fact that planet searching was still not above the radar,” says Walker. “It all started to unravel.”
Campbell further alienated those who controlled Canada’s professional astronomy appointments by publicly bemoaning the state of astronomy funding in Canada.
Increasingly frustrated, disheartened and distanced from the academic community, Campbell took a final, renegade approach with the help of an influential supporter, the guru of astronomy popularizing, Carl Sagan.
“I remember telling Carl Sagan we think we’re going to be able to do this,” recounts Campbell, who met Sagan while the two were on a panel about the search for extraterrestrial life together at the University of Toronto in the late 1980s. “He was somewhat incredulous at first, but then I convinced him and he became a great friend and supporter after that.”
Buoyed by Sagan’s endorsement, Campbell raised $125, 000 in private funding to support an endowed planet-hunting chair at UVic. However, the federal government’s university research funding guidelines at the time specified that only tenure-track professors could receive funding, disqualifying Campbell, an adjunct professor, from receiving the necessary matching federal funding for the position.
By 1991, at 42 years old, a salary and family stability were more important to him than the secrets of the stars.
“It had been so frustrating to try to secure some sort of position, and then to try to set up an endowed chair, that, when it all came to naught, I decided to walk away,” says Campbell.
When he did, he went supernova. In a final burst of anger, and a major breach of research etiquette, Campbell erased his computer hard drives deleting a decade’s-worth of compiled and analyzed data.
After the deep uncertainty of looking for other worlds, he turned his back on the stars for good and took-up one of life’s great certainties: taxes.
“It was the advent of electronic filing of tax returns in Canada that got me involved,” says Campbell who started work as a personal tax consultant in 1993 and continues today. “Many accountants were hesitant to get into computers and I pretty much knew how computers worked, so I had the edge there.”
Stunned and bruised by the loss of his younger colleague, it was left to Walker to lead the finalizing of the exoplanet project. It took almost a year of painstaking work for Stephenson Yang, fortunately by then also the University of Victoria’s computer systems manager, and University of Victoria colleague Alan Irwin, to recover the original data and re-analyze it.
In 1992, having re-assessed the data, Walker came to a conclusion about the most promising of the possible exoplanets, the one around gamma Cephei. In a scientific paper, Walker and several co-authors concluded that the star’s 2.5 year ‘wobble’ was probably due to its own cyclical expansion and contraction. As the star expanded, it would appear to move towards Earth, and away as it contracted. There was no invisible exoplanet, just a turbulent star.
“Nobody argued with Gordon Walker at the time that the data did not warrant the proclamation of a planet being detected,” says Berkeley’s Geoff Marcy.
Nobody disputed the conclusion, that is, except Walker himself. In fact he’d quietly agonized over whether the wavy line in their data was in fact a star revealing the presence of another, mysterious world.
“I had written the paper as it being a planet,” revealed Walker, in a recent interview. He was sitting in his office, when the then recently arrived post-doctoral student, now UBC professor Jaymie Mathhews, entered and looked at the data. Mathhews pointed-out that the supposed planet’s 2.5 orbital period coincided with what appeared to be periods of the star’s heightened surface, or chromospheric, activity.
“I think (Jaymie) had a very valid point,” says Walker, who deferred to the dominant view and re-wrote his paper, changing an exoplanet into stellar rumblings.
“Being Canadian we were much more cautious in announcing something like that,” says Stephenson Yang. “Of course, no-one would believe you anyway.”
But Walker had been right. Canada’s planet hunters had found their prize. Yet it wasn’t until 2003, after assessing almost 20-years of data, that exoplanet hunters finally concluded definitively that every 906 days a Jupiter-sized planet completes its orbit around gamma Cephei.
“I feel some responsibility for this,” says Jaymie Matthews. “Had I not piped-up it might have gone forward and gone to a referee who wouldn’t have discussed that and it could have gone forward as the detection of a planet. They could have gone out and had a press conference and said, We think we’ve found a planet. Nobody in the media would have asked if they’d checked the chromospheric activity. The headline would have been ‘Canadians find the first planet’.
Within months of Walker’s about-face, Polish-American astronomer Alexander Wolszczar announced the discovery of two Earth-sized bodies around a pulsar, the remnant of a supernovae. Completely unexpected—astronomers are still uncertain how planets survive or result from a star’s detonation—they were the first planet-like objects found outside our solar system, earning Wolszczar, in 2002, the honour of a Polish postage stamp with his image.
Then in 1995, Swiss astronomers Michel Mayor and Didier Queloz announced the discovery of 51-Pegasus b. A veteran astronomer, Mayor had led the definitive study of binary stars, those that occur in pairs, and was thus accomplished at studying stellar movements for the wobbles caused by unseen orbiting bodies. After only two weeks of observing 142 stars for exoplanets at the Haute Provence Observatory in France he and his graduate student Queloz scored an exoplanet game winner that stunned astronomers: a Jupiter-sized planet so close to its star that it orbited in only four days.
“Nobody, but nobody, suggested there were going to be Jupiters in few day orbits,” says Walker. “In looking for the familiar you miss the obvious.”
Like a hockey player watching the other team hoist the Stanley Cup after a grueling seven-game series, Gordon Walker was among the first to receive the news—he was one of the scientific referees for Mayor and Queloz’s scientific paper on 51-Pegasus b that appeared in the journal Nature.
In retrospect, says Marcy, Walker, Campbell and Yang were thwarted by too small a sample of stars.
“They’d a technique that would have worked immediately, if only by luck they’d chosen the right stars,” says Marcy. “We now know at least 200 stars that if they’d chosen them as their target stars, any one of them, they would have immediately seen the planet with their existing precision.”
After all this, the final vindication of the detection of gamma Cephei in 2003 “was like a Eureka moment in tortuously slow motion,” Walker recently wrote.
David Charbonneau, an Ottawa-native and now leading exoplanet hunter at the Harvard Smithsonian Center for Astrophysics, says that Walker’s experience is a testament to the excruciating nature of the search to discover new worlds.
“We like to imagine that the scientist looking through the microscope or telescope sees something and then they know that this is the thing they’ve been looking for and it’s just a matter of getting the news out,” says Charbonneau. “But the point is that when you’re actually involved in a true discovery it’s a very uncomfortable process, because you really don’t believe that this is the thing you saw and you want to make absolutely sure you’re not being confused by some spurious signal and you start to question the date yourself.”
In 2000, Charbonneau discovered the first exoplanet that transits its star, setting the stage for the Kepler space telescope mission in search of an alien Earth, of which he’s a team member.
After a half-century of probing the night sky for ever dimmer and more distant as yet unseen truths, Gordon Walker is undeterred, still searching for answers and wondering. He’s a core member of Canada’s MOST space satellite team, a project that includes searching for and studying exoplanets.
“You can’t help but be a little cynical that people (today) can’t get money for big telescopes without mentioning (searching for) exoplanets,” says Walker.
But there’s sadness in his voice when it comes to his old stargazing buddy, Bruce Campbell. Until this past August they lived only several blocks away in the same Victoria, BC neighbourhood, exchanging pleasantries when passing, but not talking of the stars, the emotional pain of an old rupture never fully addressed.
While all agree that Walker and Bruce Campbell’s contribution to the search for exoplanets is significant, will one or both get the nod for a Nobel Prize for leading the way in changing our view of the cosmos?
“In some sense they’re worthy. Walker and Campbell began the field,” says Crowded Universe author Alan Boss. “But my guess is that (the Noble prize) will go to the folks that actually find something in the end. This is a very competitive world. And the Nobel Prizes are as competitive as it gets in science.”
At UC Berkeley, pointing one of the world’s largest telescopes towards the night sky in search of alien worlds, and soon maybe an alien Earth, Geoff Marcy readily acknowledges the giants on whose shoulders he’s standing.
“It’s a real human tragedy, but it’s the way science often goes,” says Marcy. “Somebody has to stick their neck out and try a technique that everybody else thinks is wrong and then interpret the data very carefully, and that other people may not appreciate. You’re not going to break a paradigm, you’re not going to easily make one of the greatest discoveries of the century, the discovery of planets around other stars.”