Five Billion Years of Solitude (11 page)

“Just finding any planet around another star isn’t as newsworthy or appealing as it used to be,” Laughlin told me one afternoon in Santa Cruz. “That alone won’t get you a flashy press conference and the front pages of newspapers and lurid artist’s renditions like it would have ten, twenty years ago. Ten, twenty years from now, just finding an Earth-mass planet in the habitable zone of a Sun-like star probably won’t be a big deal, either. Historians may look back and shake their heads at this period, when astronomers were regularly claiming to have found
the ‘first habitable planet,’ but only in comparison to the last, previous ‘first habitable planet.’ It’s my sense they’ll remember this time as when the Heroic Age of extrasolar planet discovery came to a close.”

“The real story,” Marcy once remarked to me, “isn’t the validity or the timing of discovery of any particular Earth-size, Earth-mass planet. Simply detecting one of these things does not overturn astrophysics or planetary science. The real story here is the amazing plausibility of detecting them at all, the fact that from our perch upon this speck of dust, we have come to the point where we are on the threshold of these sorts of discoveries. It’s as surprising as an ant, living its life among other ants on an anthill, somehow calculating the size of the solar system. All we do is collect photons from the stars, and from that we can deduce the existence of planets and the scale and structure and future of the whole shooting match. It’s crazy.”

When, after repeated setbacks and delays, the APF at Lick Observatory finally became fully operational in 2013, observing time was evenly divided between the Marcy and Butler-Vogt teams. The break had been complete, and seemed irreversible: Butler and Marcy had not spoken since 2007, and perhaps never would again. And yet on nights when the sky above Mount Hamilton was dark and clear, they could be found virtually side by side, as their shared robotic telescope slewed between separate, distant points, building fractured empires among the stars.

The Worth of a World

B
ack in 2009, less than a week after a Delta II rocket launched Kepler into planet-hunting history, Laughlin had quietly posted a strange, half-whimsical equation on his blog
systemic,
at oklo.org. In a series of subsequent posts, he explained how the long string of obscure variables and weighted functions could be used to crudely quantify the value of any terrestrial exoplanets that Kepler and the handful of other leading surveys might soon discover. It was, he said, an attempt to judge whether any particular “Earth-like” world was worthy of legitimate scientific excitement, independent of media hype. After plugging in a few key parameters—such as a planet’s mass, its estimated temperature, and the age and type of its star—Laughlin’s equation would generate a value, in
U.S. dollars, that could be assigned to that particular world. Small, rocky worlds in clement orbits around middle-aged, middle-of-the-road stars similar to the Sun merited the highest values, as those planets presumably offered the best chance for harboring complex biospheres that could eventually be detected by future space telescopes. For a planet to be worthy of wide attention, Laughlin opined, it would need to at least break the million-dollar mark.

Laughlin drew his economic baselines from simple math, dividing Kepler’s federally funded $600 million price tag by 100, a conservative estimate of how many terrestrial planets the space telescope would discover during its lifetime. If such planets could be considered commodities, the math suggested that the 2009 market price, as determined by U.S. taxpayers, could be set at $6 million per world—a value that could drop over time if small rocky planets began to overflow astronomers’ coffers. If, however, Kepler found a terrestrial world in the middle of a Sun-like star’s habitable zone, Laughlin’s test runs suggested such a planet’s value could exceed $30 million in his equation. Zarmina’s World, if it existed, garnered a value of around $60,000. GJ 667Cc was worth even less. According to Laughlin’s calculations, Kepler’s first million-dollar candidates appeared in February 2012. Several more would follow, bearing names such as Kepler-62f and Kepler-69c, until the Kepler spacecraft suffered a crippling malfunction in May of 2013 that all but ended its primary mission.

The cleverest part of Laughlin’s valuation equation was its treatment of a planet’s home star, which allowed his numerical scrutiny to be extended to the worlds in our own solar system. Photons, not dollars, are a planet hunter’s fundamental currency, as they are what allow a planet to be not only detected but also subsequently characterized. Generally speaking, the more photons astronomers can gather from an exoplanetary system, the more they can learn about it. Stars and planets nearer to our solar system are brighter in our skies due to their close proximity, and hence more valuable, providing floods of useful photons where more distant objects would only offer trickles. This facet
was why so many of Kepler’s small planets would struggle to reach a valuation of even a million dollars: the Kepler field stars were far away, and thus very dim. The brightest star visible in the solar system by many orders of magnitude is, of course, the Sun, which has the capacity to send local planetary valuations into truly astronomical territory.

Based on the early-twentieth-century notion of Venus’s clouds as reflective shielding against the potent solar flux, Laughlin’s equation pegged the planet’s value at one and a half quadrillion dollars—$1,500 trillion. Evaluating Venus based on its actual runaway-greenhouse surface temperature gave the planet a value of a trillionth of one cent. Laughlin sometimes compared such discrepancies in planets’ values to the dot-com stock bubble of the mid- to late-1990s, when companies leveraged investors’ irrational exuberance into billion-dollar valuations, only to crater when the bubble collapsed and their true, far lower values were revealed. When he ran his valuation equation for our own planet, Laughlin obtained a value of approximately five quadrillion dollars—roughly one hundred times the global gross domestic product, and, he reckoned, a handy approximation of the economic value of humanity’s accumulated technological infrastructure. Searching for other habitable worlds, it seemed, was rather like speculating in a galactic-scale stock market.

Laughlin had also run his equation on a purely hypothetical Earth-size planet in the habitable zone of one of the two Sun-like stars in the Alpha Centauri system. He obtained a value of $6.5 billion—coincidentally about the same amount of money astronomers often estimate would be needed to build a space telescope capable of seeking signs of life on such a world. If humans actually voyaged there, Laughlin once pointed out to me, the star would become ever brighter, until it was a new Sun in a new sky of a New World. “So in going there, you have this ability to intrinsically increase value. And that’s an exciting thing because it ultimately provides a profit motive for perhaps going out and making a go of it with these planets. This is saying that something that is several billion dollars on Earth could be, if you go there, a quadrillion-dollar payoff.”

Months before our encounter at Tomales Bay, I had interviewed Laughlin about his equation for an article I published on the website BoingBoing.net. The article’s contents made their way into the mainstream media, which focused far more on Laughlin’s musing valuation of our world than on the worth of exoplanets. Stories appeared bearing headlines such as “Earth is worth £3,000 trillion, according to scientist’s new planet valuing formula” (
Daily Mail
, February 28, 2011) and “Wanna buy the Earth? It’ll cost you $5 quadrillion” (
Toronto Sun
, March 1, 2011). Angry e-mails began piling up in Laughlin’s inbox, and television and radio stations called hoping to interview the mad scientist who so arrogantly placed a price on our planet. Laughlin was taken aback—he had emphasized, both in his posts and in his discussions with me, that his equation did not and could not assess the worth of, for instance, a human life or a new idea. Soon the story was churned out of view by the voracious 24/7 news cycle, but the sensational headlines left a lingering impression. Before Laughlin’s talk at the Miller Institute symposium, I overheard one member of the audience jokingly refer to him as “The Man Who Sold the World.”

The day after his presentation, I was in the front passenger seat of Laughlin’s car as he drove us back down to Santa Cruz. In the back seat sat Taylor Ricketts, a World Wildlife Fund ecologist who had given a talk about “natural capital,” the economic benefits of material goods and services provided by Earth’s biosphere. Ricketts was part of a growing interdisciplinary push to study ecology in the context of economics, a field interested in not only the monetary value of, for instance, a pristine forest, but how that value might change if the forest was converted to pasture, or a parking lot.

At the time, Ricketts was a few months away from becoming director of the University of Vermont’s Gund Institute for Ecological Economics, which he mentioned in passing not long after we crossed over the Golden Gate Bridge and began to drive on Highway 101 through downtown San Francisco. Gund’s previous director, an ecologist named Robert Costanza, had “gotten into trouble” back in 1997 for a
Nature
paper in which he tried to estimate the value of the planet, Ricketts said.

Laughlin’s bushy eyebrows bounced up as he looked back at Ricketts in the rearview mirror. “What was the figure Costanza came up with?”

“Thirty-three trillion dollars per year, for all the world’s ecosystems.”

“I don’t know why you’d get in trouble for that,” Laughlin sighed.

“He made several basic economic mistakes that made his final figure essentially unsupportable,” Ricketts said. “But more fundamentally, his critics just said, ‘Thirty-three trillion dollars is a nice underestimate of infinity.’ The value of the planet to us is infinite, because if all the ecosystems go away, life ends. For all of us. So there’s not really a valid reason to put a number on that. Some people said he was silly for making his estimate, and others called him brave for trying. It’s hard to know how much it has affected his career, but his name is kind of shackled to that paper.”

Minutes passed. We eased into a snarl of afternoon traffic congested by a red stoplight at the crest of a long, high hill.

“So, an interesting counterargument to the ‘infinite’ value of the Earth is the fact that at some point this
will
all go away,” Laughlin said. His eyes darted to sweep over the pedestrians slowly scaling the steep, tree-lined sidewalk, the cars idling their engines in the street, the people wandering in and out of boxy wooden row houses and tall office buildings of glass and steel, before his gaze finally came to rest back in the rearview. “And not because of anything we’re doing, but because the Sun
will
evolve into a red giant and destroy the Earth. I don’t think that’s something for which we just have to sit down and acquiesce. So this becomes a question of where we are willing to begin talking about timescales on which our actions could have some conceivable utility.”

“That’s true,” Ricketts said. “But economics is about how you make decisions under scarcity, right? You can’t do everything, so how do you choose what to do and what not to do? You can’t buy everything, so how
do you choose what to buy and what not to buy? The reason to put value on things is to inform a choice you might have—that’s the fundamental reason for economics to be. To place a value on the Earth . . .” He trailed off for a moment, finding his words. “I don’t understand what the option or choice is there, what we would do with that information. It’s not like we have the option of not being destroyed by the Sun, and that’s probably why economists think a planetary valuation is a bit silly.”

Laughlin shot a smiling glance my way. “But we do have an option. We can move the Earth.”

A pregnant pause. “Move the Earth?”

“Sure.”

“Like, tow it out of the way?”

“Essentially, yeah. We have more than enough time. Just take some large comets or asteroids from the Kuiper Belt and use them to tap and transfer some of Jupiter’s orbital energy and angular momentum to the Earth over a timescale of hundreds of millions of years. Each time one flew by the Earth, you’d get a small kick, and you’d expand the Earth’s orbit very gradually through those repeated close encounters. You’d need on order of a million close passes, one every several thousand years, but you could move the Earth’s orbit out, close to where Mars is now. This is an idea I worked out ten years back with a couple of friends.”

Another pause, as Ricketts pondered Laughlin’s outlandish proposal. “That’s cool. So it’s a cost-benefit analysis: What would it cost us to tow the Earth out of the way, versus what’s at stake on the benefit side?”

“You might destabilize and lose Earth’s Moon,” Laughlin said. “And you would have to be extremely careful to properly time each flyby so your object didn’t collide with and sterilize the planet down to bacteria. But that intervention could net you billions more years for the biosphere, which is a
lot
of economic utility, and the cost is very small in comparison, because most of the energy to move the Earth is actually coming from Jupiter, transferred by the comet. You just have to
have very subtle control of the comet’s trajectory when it’s way out at the slow, far point of its orbit in the outer solar system. It’s a matter of finesse more than brute force, but it’s just rocket science. The point is, we could start doing this practically today, if we wanted.”