W5, a star-forming region in the Cassiopeia constellation, 7,000 light years away. here, clouds of gas and dust are formed into pillars by radiation and winds from hot, massive stars. infrared false-colour image captured by the Spitzer space telescope. Courtesy of NASA/JPL-Caltech/Lori Allan and Joseph Hora,
Jaymie Mark Matthews’ feet are on Fourth Avenue, but his head is light years away. His cheap brown boots are planted near a tall green lamppost; his thick, meaty fingers are raised skyward, as if cradling the glass globe of the streetlight overhead. He’s explaining why astronomers have yet to locate another small, rocky planet like Earth. “It’s like trying to see a mosquito buzzing around a streetlight,” he says. “The mosquito is very small. The light is very bright. And in this case they’re both very, very far away.” For all the light that would reach us here in Vancouver, he explains, “the streetlight might as well be in Saskatchewan.”
It was only a decade ago that astronomers confirmed that there are planets around other stars. Since then, nearly two hundred extra-solar planets—or exoplanets—have been identified. Most are giant balls of gas, like Jupiter, that would not support life as we know it. But within the next decade, Matthews predicts, “we will find an Earth-like planet.” That discovery will likely be made using a method he and his team are pioneering at the University of British Columbia. “To point to a star and say, “That star has a planet around it that is about the mass of the Earth and is in an orbit at which liquid water could exist,’” he says, lowering his index finger to his face. “You only need to find one of those.”
Matthews’ bus arrives and the stocky planet hunter squeezes aboard among the throng of clerks, students, and other commuters. Sporting a black T-shirt and blue jeans, he looks more like an aging roadie than a rocket scientist. But Matthews is leading the only team in the world currently capable of discovering an Earth-like planet. His crew operates a small satellite telescope launched by the Canadian Space Agency in 2003. In just three years, the tiny spacecraft—dubbed
most (Microvariability and Oscillations of STars)—has overturned much of what astronomers thought they knew about stars and solar systems.
most is about to get some competition. In October, a French-led consortium plans to deploy a similar satellite telescope called corot. And the Americans intend to launch a much larger planet-hunting spacecraft called Kepler in the fall of 2008. These are just the first among a half-dozen serious planet-hunting missions in the works, part of an international adventure the likes of which this planet has not witnessed since the era of Magellan and Drake: a race to determine whether or not we are alone in the universe.
“And so there are innumerable suns, and likewise an infinite number of earths circling about those suns, just like the seven near to us which we see circling about the sun.” —Giordano Bruno, De l’infinito universo et Mondi (1584)
Four centuries ago, attempts to expand our knowledge of the universe could be met with charges of heresy. Astronomer and philosopher Giordano Bruno, an advocate of the Copernican solar system, was burned at the stake by the Roman Inquisition, for example. But by the time Matthews launched most, a Life magazine poll had found that 54 percent of respondents believed intelligent life exists on other planets, 30 percent thought aliens had already visited Earth, and 1 percent claimed to have met an extraterrestrial. “A good fragment of the population believes The X-Files was a documentary series,” Matthews chuckles.
The bus lurches into traffic. Its windows are so splattered with mud and grime that streetlights are difficult to see clearly—mosquitoes would be impossibly so. Likewise, the Earth’s rich atmosphere, which makes this little blue planet so hospitable, makes it impossible for Earth-based astronomers to “see” planets outside this solar system. But while exoplanets cannot be seen, they can be detected indirectly. Because stars are affected by the gravity of other objects, they will wobble if a planet is nearby. Measure the wobble accurately, and you can infer the mass of the planet, as well as the size and shape of its orbit.
Astronomers began looking for wobbles in the mid-twentieth century, attaching cameras to the first generation of large refracting telescopes and arduously plotting the small movements of nearby stars. In 1963, prominent American astronomer Peter van de Kamp announced that he’d discovered a planet orbiting Barnard’s Star. Van de Kamp’s claim appeared credible, and his discovery was hailed in the media. But later scrutiny found problems with his results, and his peers concluded that it was not yet possible to track star position with sufficient precision to find planets.
A new approach emerged in the 1970s. As a star wobbles toward or away from its observer, the light it emits shifts slightly to the blue and red ends of the spectrum, respectively. Armed with this knowledge, Canadian astronomers Bruce Campbell and Gordon Walker fitted a telescope with a tube of hydrogen fluoride gas (used to measure tiny changes in wavelengths), creating an interstellar spectrometer. In 1982, after tests at the Dominion Observatory in Victoria, they took their big tube of poisonous gas to the Canada-France-Hawaii Telescope on the summit of the Mauna Kea volcano. There they began monitoring twenty-three nearby stars.
Campbell and Walker’s technique “called the precision radial-velocity method” soon detected what appeared to be several large planets. But within a few years, the astronmers realized that the stars they were observing were far more turbulent than the sun. They were simply detecting movement within the stars themselves. By 1992, the only star they were still fairly certain was under the sway of a planet was Gamma Cephei, relatively close by at only 52 light years away. Seeking to avoid the kind of embarrassment that befell van de Kamp, Campbell and Walker published a paper in the fall of 1992 with the circumspect title, “Gamma Cephei: rotation or planetary companion”
Three years later, a team of Swiss astronomers led by Michel Mayor and Didier Queloz scooped the Canadians, announcing the detection of a planet with the same mass as Jupiter orbiting the star 51 Pegasi. One hundred ninety-nine exoplanets have been discovered since, all but a handful using variations on the precision radial-velocity technique. One of these planets orbits Gamma Cephei, just as Campbell and Walker suspected. “Everyone in the field recognizes that Campbell and Walker were the first ones to see evidence for a planet around a sun-like star in 1992,” Matthews says. “Bruce and Gordon could legitimately have gone out and told everybody they’d found a planet, and the history books might look a little bit different.” He sighs. “But being good scientists—and maybe being conservative Canadians—they didn’t make the proclamation that it was definitely a planet.”
Matthews, who was a post-doctoral fellow during the Campbell-Walker study, falls uncharacteristically silent. “To be honest,” he says at last, “it was me who pointed out that the star had this independent signal that was the same as the radial-velocity signal.” He was uncertain whether they were looking at a star with a planet around it or the star’s natural turbulence. “I am probably the one to blame for them not making a more definitive announcement.”
“The next thing I observed is the essence, or substance, of the Milky Way. With a telescope this can be perceived so palpably that all the disputes that have tormented philosophers for so many centuries are quashed by sheer ocular proof, and we are released from all those wordy arguments.” —Galileo Galilei, Sidereus Nuncius (1610)
Matthews regains his verbal momentum as he walks across campus. He moves like a truck, belly out front like a grille. After marching up the steps of the dirty white stucco building that houses the ubc astronomy department, he is hailed by everyone in the most office.
The idea for
most was born in the summer of 1996. Matthews was at the annual meeting of the Canadian Astronomical Society when he noticed a science fair—style poster about a Mississauga company that had developed a way to stabilize very small satellites. The company, Dynacon, was seeking a way to prove its new technology.
That night, he and the poster’s author, Slavek Rucinski of the University of Toronto, debated the prospects of a suitcase-sized observatory that would measure the microvariability and oscillations of stars from orbit—sidestepping the problem of peering through the Earth’s grimy “windows” by essentially lifting the telescope off the bus. Together with Dr. Tony Moffat of l’Université de Montréal, Matthews and Rucinski drafted a proposal to the Canadian Space Agency and won the right to launch Canada’s first science satellite in more than thirty years.
The satellite was built to carry a telescope with a 15-centimetre aperture backed by a camera with two
ccd (charge-coupled device) image sensors. Matthews flew to Russia and negotiated a launch at a cut-rate price aboard a refurbished intercontinental ballistic missile ( icbm), and on June 30, 2003, the tiny 60 cm x 60 cm x 30 cm satellite was launched from the formerly top-secret Plesetsk Cosmodrome, about 800 kilometres north of Moscow. The icbm carried most up to an altitude of 820 kilometres and released it into a polar orbit.
The satellite travels at about 27,000 kilometres per hour, circling the planet every hundred minutes. Whereas terrestrial telescopes can observe only from sundown to sunrise,
most can observe a target star continuously for up to sixty days before the Earth’s horizon gets in the way. The observatory then radios its data to modest ground stations in Vancouver, Toronto, and Vienna. The Vancouver outpost is nothing more than two desktop computers connected to a single rack of electronic components, served by a 2.5-metre satellite dish on the roof of the ubc physics and astronomy building.
Far from finding a sky filled with stars like the sun,
most has revealed a strikingly diverse universe in which there may be no two stars that are exactly alike. Matthews smirks as he notes that it looks as though the project’s lifespan will extend to “a five-year mission to seek out new life and new civilizations….” He interrupts himself to hum the Star Trek theme.
Perhaps the most astounding thing about
most is its price tag. While the costs of other “low-budget” space missions are typically counted in the hundreds of millions, the total for the most mission is a mere $10 million—about the price of a waterfront home near ubc. “When I talk to American colleagues and people at the Space Telescope Science Institute at nasa, they can’t get their heads around the fact that we did a mission for essentially [what was then] $7 million US,” Matthews says. In a poke at nasa’s $3-billion Hubble Space Telescope, he calls most the “Humble Space Telescope.
” If there are globes in the heaven similar to our earth, do we vie with them over who occupies the better portion of the universe For if their globes are nobler, we are not the noblest of rational creatures. Then how can all things be for man’s sake How can we be the masters of God’s handiwork” —Johannes Kepler, in a letter to Galileo (1610)
Matthews’ office is as chaotic as the ground station is spartan. The room bristles with trinkets. An X-Files trivia map hangs alongside posters for scientific conferences. A cardboard cut-out of the Lost in Space robot stands over a pile of scientific papers. Glow-in-the-dark alien heads rest atop classified reports about space missions. One is tempted to conclude that Canada’s premier space-science mission is being managed from the bedroom of a precocious child.
most telescope is not much larger than the cheap “Tasco special” Matthews grew up using in Chatham, Ontario. The self-described “über-geeky junior-egghead nerd” would lug his white plastic telescope into the nearby Maple Leaf Cemetery to stargaze. “I’d be at the cemetery at midnight,” Matthews recalls, “and police would come by, doing their cruise. They’d see this silhouette. They’d find me, age eleven, and so of course they’d take me home.” As he laughs, Matthews’ head bobs beneath a large banner that reads “Mars Customs & Immigration: Please Have Your Ticket Ready.”
Rather than watching for wobbles,
most detects what astronomers call “transits.” Just as a mosquito passing in front of a streetlight blocks the light ever so slightly, a planet passing between its star and Earth dims the amount of light reaching most. By measuring this minuscule reduction in light, the most team can estimate the size of the transiting planet, which in turn suggests whether it is terrestrial or not (larger planets tend to be gaseous, smaller planets rocky). most can also detect the amount of starlight that reflects off the planet. “If we can figure out how much light the planet is reflecting, we know what kind of atmosphere it has: does it have thick cloud cover or is it fairly clear” Matthews explains. “It really does astound me. We’re making measurements telling us what the clouds are like on a planet that we can’t even see, around a star 160 light years away.”
most was designed to monitor only one star at a time, Rainer Kuschnig, the team’s instrument scientist, has figured out how to track up to twenty nearby stars during each two-month pointing. Together with the extended mission, this will boost the number of stars the team studies into the hundreds. “If we were looking at the right star at the right time, we would be able to see a transit of an Earth-sized planet,” Matthews says. “The odds are not in our favour.” But for another couple months, at least, “We have the best chance. We’re it.”
” Let man consider what he is in comparison with all existence; let him regard himself as lost in this remote corner of nature; and from the little cell in which he finds himself lodged, I mean the universe, let him estimate at their true value the earth, kingdoms, cities, and himself.” —Blaise Pascal (c. 1647)
In the heart of the City of Light, with stone foundations 27 metres deep, stands L’Observatoire de Paris. Founded in 1667, the Observatoire’s claims to fame include mapping the moon, early calculations of the speed of light, and hanging Foucault’s pendulum (the first easily observable proof that the Earth rotated). In 1876, the Observatoire moved its major observation equipment out to an old royal estate at Meudon. Today, it is planning a very different move—this time to space.
In October, the French will launch an international mission called
corot, an acronym for COnvection, ROtation, and planetary Transits (not to mention the name of a renowned Parisian painter regarded as a forerunner of impressionism). corot is akin to most, but larger. The 600-kilogram satellite carries a telescope backed by four ccds, double the number borne by most. Rather than pointing at small groups of stars for two months at a time, the $225-million mission will survey a region of the sky for five months, tracking up to twelve thousand stars per pointing. During the two-and-a-half-year mission, corot will observe more than a hundred thousand stars.
This is the second time
corot’s principal investigator, Annie Baglin, has attempted to launch a stellar observatory. A decade ago, she was the principal investigator for a most-sized instrument called Evris, which was designed to hitchhike with the 1996 Russian voyage to Mars, beaming data home throughout the 280-day flight. But after a successful launch, the Russian rocket failed and crashed near Bolivia. “Instead of going out [of the atmosphere], it fell down,” Baglin recalls. “It was terrible,” she says, applying the French pronunciation. “You come back in your office the day after and everything—all the contents of your desk—has lost its meaning.”
But Baglin and her team were already thinking about a next-generation mission—one that would orbit Earth. “The second-generation mission became the first-generation mission,” she says. The project quickly found itself in budget trouble, however. Like
most, the French instrument was designed as an “unsexy” mission focused on studying stars. It was capable of detecting transits, however, so Baglin cunningly added planet hunting to her mission and went “begging in Europe” for funds. The gambit worked. “Without the exoplanets, we would be dead,” she says. “The statement that we will be first, before the Americans, has some weight in France and in Europe in general.”
corot became a French-led multinational mission. Austria built part of the computer. Belgium contributed heavily on the engineering side. Germany developed software. Spain and Brazil will assist with ground-based follow-up. Even Canada is a partner, contributing behind-the-scenes lessons learned from most.
Despite the success of her beat-the-Americans-to-the-next-planet appeal, Baglin remains more interested in science than in what it would mean to discover a planet that could host life. “From a scientific point of view, the most important thing is that we accumulate data to help us understand how planetary systems form,” she says. “We will answer the question of whether there are planets around all stars or only around specific types of stars.”
corot’s upcoming launch, Baglin had a few select vintages of wine prepared. Matthews, who regards Baglin more as a friend than a rival, ordered several bottles.
“For all this furniture and beauty the planets are stocked with seem to have been made in vain, without design or end, unless there were some in them that might at the same time enjoy the fruits and adore the wise Creator of them.” —Christiaan Huygens, Cosmotheoros (1698)
Far from both ubc’s mouldy stucco and L’Observatoire’s ancient stone, sprawled across the southern end of San Francisco Bay, stands nasa’s Ames Research Center. In a corner office sits William Borucki, the principal investigator for nasa’s upcoming Kepler mission. His G-man looks, Capote-like voice, and acrid wit belie a stubborn passion: Borucki is determined to find another Earth. “Mankind’s place in the universe, our understanding of that place, depends on what Kepler finds,” he says.
Borucki figures that the probability of detecting a transit of an Earth-like planet around any given sun-like star is about half a percent. To improve its odds, Kepler will be looking at a
lot of stars. Before launch, nasa will survey ten million stars in order to select more than a hundred thousand sun-like candidates for Kepler to monitor. Then Kepler, which features an array of forty-two ccds, will monitor those stars continuously for at least four years. In order to maintain such a long gaze, Kepler will not orbit the Earth, instead revolving around the sun on its own every 372 days. The mission is expected to cost $500 million (US).
“If I look with my telescope simultaneously at a hundred thousand stars, half a percent is five hundred planets,” Borucki calculates. “If I find five hundred planets, I learn a lot about these planets: how big they are, how close they are, what kind of stars they associate with.” But, he adds, “If I find zero, I can quit. There’s nobody out there.”
Like Matthews, Borucki was the alpha nerd of his (Wisconsin) hometown—he built four-and-a-half-metre-high steel rockets in high school, and the sheriff closed country roads so he could launch them safely. He joined
nasa in 1962 and helped develop heat shields for the Apollo mission. Borucki first studied the concept behind Kepler in 1984, proposing the mission to nasa ten years later only to see it rejected, refined, resubmitted, and re-rejected every two years for nearly another decade afterwards. It was not until exoplanets started to be discovered that the agency took a serious interest. The Kepler mission was approved in 2001 and is presently scheduled to launch in 2008.
Borucki, now sixty-seven, plans to see the mission through. “I’ve been pestering them a long time for money and to support the project,” he laughs. “They can’t make me go away until I get the answer.”
nasa is so optimistic that Earth-like planets exist, it is planning two additional missions: Terrestrial Planet Finder, which will determine whether any potentially habitable planets have oxygen and water vapour in their atmospheres, and Life Finder, which will determine whether those planets actually harbour carbon-based life. “All these missions are stepping stones,” Borucki says. “Our species is on a quest to get these answers. We will not be done in our lifetimes. Probably not in our kids’ lifetimes.”
He is concerned about the consequences should Kepler and its successors fail to find habitable exoplanets. “We don’t want to find that we’re alone, that when we come and go it’s the end, there’s just no sentience at all in our galaxy,” he says. “There’s no richness. Astrobiology should be the richness of all these different people and beings communicating with each other, enjoying the universe together, exploring it together.”
“If we indulge a fanciful imagination and build worlds of our own, we must not wonder at our going wide from the path of truth and nature…. On the other hand, if we add observation to observation, without attempting to draw…conjectural views from them, we offend against the very end for which observations ought to be made.” —William Herschel, paper delivered to the Royal Society (1785)
It’s late, nearly midnight. Matthews is crammed into a corner booth at Chivana, an Asian-Cuban jazz joint near his apartment. He’s the last customer of the night and the waiter is dropping hints, but Matthews shows no sign of moving toward the door. Over a leisurely dinner of steak and squid, he has been spinning stories about drinking vodka with Russian rocket scientists, flamenco dancing with Annie Baglin, and chatting with X-Files star David Duchovny. Along the way, two hard facts have repeatedly resurfaced.
One: there are a lot of stars. The total number of stars in the observable universe is estimated to be a numeral with twenty-two zeroes after it.
most will glimpse several hundred of these. corot and Kepler together will gaze at perhaps two hundred thousand. We of this Earth have only begun the hunt for another.
Two: the universe is unfathomably vast. The fastest spacecraft yet launched left for Pluto in January. Travelling at 50,000 kilometres per hour, it will take nine and a half years to reach the frozen fringe of our solar system. That same spacecraft would require seventy thousand years to get to the next closest star, Proxima Centauri. For humankind to reach an extrasolar planet in our lifetimes, we would have had to have launched a spaceship when the Neanderthals were roaming Europe. Radio communication with such far-away destinations is possible, though it would require hundreds of years just to exchange messages. That the Search for Extraterrestrial Intelligence (
seti) has spent decades listening for such signals to no avail is not particularly surprising, considering that Earth has been broadcasting for only a hundred years.
These hard facts have not stopped people from speculating on the possibility—even the necessity—of us contacting other worlds. The urge toward communion seems too powerful to resist even for those well-acquainted with the facts, like turn-of-the-seventeenth-century astronomer Johannes Kepler, who gushed about inhabitants of Jupiter and the moon. Others, such as living physicist Stephen Hawking, argue that dangers such as global warming make the search for a lifeboat planet a matter of urgent necessity.
” Far be it from me to disagree with Professor Hawking,” Matthews says, “but the dangers of global environmental disaster are more immediate than our option of escaping en masse to another Earth-like world. The real reason to discover and study distant stars and planets is to learn more about the true nature of our home star, the sun, and our home world, the Earth. That teaches us to be better caretakers of this planet.” The greenhouse effect, he notes, was first posited by Carl Sagan, who was trying to understand why the planet Venus is so hot.
The Kitsilano restaurant owner finally tosses Matthews out. The planet hunter continues talking as we cross the street. We wind up back on Fourth Avenue, huddled directly beneath the streetlight near the bus stop. Matthews begins musing on the sustainability of human civilization. “Maybe we’ve crawled up to this precipice, and in another hundred years we’ll be gone,” he says. “Or maybe this is the beginning of many millennia of humanity. We have no idea.” Our shadows dance about the sidewalk as the streetlight sways in the night wind. Matthews’ mind remains far away.
” Let’s say we found that first Earth-like planet. If there was any evidence—any evidence whatsoever—of life, what are the implications of that” he asks. “Given the number of stars, and the incalculable expanse of space and time, what are the odds that life would emerge on only two planets The implication to me, and to most scientists, is that life is ubiquitous.”
Matthews smiles, stuffs his hands into his pockets, and walks boldly into the night.
M16, the Eagle Nebula, a star-forming region roughly 7,000 light years from earth. the columns, which are light-
years long, protrude like
stalagmites from a vast cloud of molecular hydrogen.
visible-light false-colour image captured by the Hubble space telescope. / Courtesy of NASA/EAS/STSCI/John J. Hester and Paul Scowen, Arizona State University