Five Billion Years of Solitude (34 page)

Winding down his presentation, Marcy made it plain his faith in NASA had been so shaken by the failure of TPF that he now wondered whether portions of the agency’s overlarge portfolio shouldn’t be entirely outsourced to the more agile private sector. Besides TPF, he did dream of one other great and worthy task for the agency in the next half century, one he articulated in a Tsiolkovskian appeal directly to President Obama. “Stand up and make the following announcement,”
Marcy implored. “Say that before this century is out, we will launch a probe to Alpha Centauri, the triple star system, and return pictures of its planets, comets, and asteroids as soon as possible, even if it takes a few hundred years or a thousand years to get there. . . . It would be a great mission, to go to Alpha Centauri. It would engage the K-through-twelve children, it would engage every sector of our society, Congress, and so on. It would jolt NASA back to life, if we’re really lucky. . . . And of course any such mission should be an international one involving Japan, China, India, and Europe. . . . A mission to Alpha Centauri would bring the diplomatic coherence in the world that we need, as well as scientific progress.”

A few audience members laughed again, this time with bitter cynicism. Politically, the country was hyperpolarized, and financially it was mired knee-deep in debt. To think that any U.S. politician, let alone the president, would choose to expend one shred of political capital pursuing a voyage to the stars against such heavy headwinds smacked of the same wishful thinking that had years ago tipped the TPF project into calamity.

Moments later, Seager stood again before the crowd. She was scheduled to deliver a prepared talk but had discarded most of her presentation in light of the debate sparked by Charbonneau’s and Marcy’s remarks.

“We want to go out and map the very nearest stars,” Seager reiterated, establishing the common ground on which everyone could agree. “Thousands of years from now, when people are embarking on their interstellar journey, they will look back and remember us as the people who found the planets like Earth around the very nearest stars. . . . I want to say I love NASA; NASA has helped my career tremendously. But I also see that NASA probably can’t do the Terrestrial Planet Finder within the next forty years. That has become more and more clear to me, and everybody in this room knows that I am one of the biggest, ardent supporters of any terrestrial planet–type mission. That’s what I want to do. I want a TPF in my lifetime. . . . And until now I never
really worried about that.” For a fraction of a second, her gaze and voice betrayed a sudden hint of sadness.

Seager noted that her position as a tenured MIT professor gave her tremendous security, which offered an opportunity—almost an obligation—to pursue high-risk, high-reward research. With flagging confidence that NASA could achieve TPF within her lifetime, she had been forced to consider other paths, new developments. One in particular looked promising: the recent debut of a new generation of commercial spaceflight providers, a select group of high-tech start-ups that were building rockets and spaceports with an eye toward at last overcoming the crippling paradigm of high launch costs. The companies had names such as SpaceX, Blue Origin, and XCOR, and multimillionaire CEOs who had made their fortunes with companies like PayPal, Amazon, and Intel. Seager thought the new companies might finally bring the profitable, sustainable human expansion into space that NASA had failed to deliver. They could be a powerful means to an elusive end, kicking off the next wave of synergies astronomers needed to lower the costs and accelerate the launches of TPF-style space telescopes, bringing the light of other living worlds into the lives and careers of all those assembled before her in the room. She had summoned her friends and colleagues to the meeting not only to discuss the field’s future, but also to bid it a temporary farewell. Her work on exoplanets would continue, but it would compete against a new, overarching emphasis on aiding the emergence of a self-sustaining commercial spaceflight industry. The surprise announcement set off whispering reverberations through the crowd.

“That’s what I’m going to be doing now,” Seager explained with firm determination. “Most of you haven’t seen me at meetings lately; you won’t see me a lot in the future, because I’m investing in this. And if you see me working on asteroids and Mars, you’ll know that I’m not really interested in those that much. I’m interested in getting the commercial spaceflight world whatever I can to help them.” She cited estimates for launch costs: reaching orbit on one of NASA’s space shuttles had cost some $100 million, while a ride on a simpler Russian Soyuz
rocket was only $10 million. Commercial providers could perhaps drop launch costs by another order of magnitude. “We need them to succeed if we want to do Terrestrial Planet Finder, because we’re never going to be able to do it at the ten-billion-dollar price tag. If we get that down by helping them, it will happen.”

After Seager’s talk, the audience filed out of the auditorium into the hallway, clumping into loose pockets of caffeinated conversation. I listened as a biochemist explained to an astrophysicist how the quest for a life-finding space telescope resembled the race during the 1990s to sequence the human genome. “There were all these different groups with the technologies to do it just trashing each other,” said the biochemist. “Then you had the government agencies and the academic institutions and the pharmaceutical companies all separately decide to try to sequence it for their own ends. That mix of state and commercial competition pushed everyone toward the goal. . . . You guys need to figure out how to make China decide to go find the first habitable planets and name them all in Chinese.”

Over by the coffee and tea tables, an engineer told a scientist that it would be straightforward to send a robotic probe at 10 percent of light-speed to Alpha Centauri: all he needed was a nuclear reactor from a Virginia-class submarine hooked up to a high-impulse electric propulsion system. “We could do it with today’s technology!” the engineer exclaimed. “We’d probably be alive to see the pictures it sent back!” The scientist’s only response was a polite nod, as if the engineer had forgotten to factor in a few important variables in his mental calculations.

That evening, after the conference’s official end, a handful of the participants migrated from the Media Lab to Seager’s office on the seventeenth floor of MIT’s Building 54, the Green Building, the tallest high-rise in Cambridge. At Seager’s invitation, some of us climbed up to the rooftop, which was dotted with antennae and white radar domes, to gaze down at the twinkling lights of Boston’s skyline and at sailboats plying the calm waters of the Charles River. Mountain, Seager, and
Grunsfeld chatted quietly, admiring the view. Traub stood silent for a time, watching the sunset. Marcy clambered up to pose for a few pictures beneath the immense radar dome, then descended. He mostly made small talk, but, when pressed, would dive again into discussing NASA’s plight.

“NASA’s in big trouble,” he told me later. “It seems like even with all its infrastructure and expertise, it can’t outdo the private sector. It’s unable to overcome its own bureaucracy. How could NASA turn its back on TPF? I don’t want to blame NASA per se; maybe it’s not really NASA’s fault. Maybe it’s just that we have challenges when we try to organize ourselves to do great things. Rome falls. People are imperfect. We make incredibly tragic mistakes. . . . It’s just our nature, it seems.” He raised an empty hand, with thumb and forefinger angled like chopsticks grasping a single grain of rice. “We are just this far above the ants. That’s how I see it. We function in some ways like a bee colony. It’s natural. But, you know, there is something called colony collapse disorder, too.”

Back inside the Green Building, the discussions continued, and a drift of people buzzed around Seager, the queen bee of this transitory hive. Standing at its fringes, I overheard her muse again about interstellar travel. “I don’t know if we’ll ever leave the solar system,” she said. “All I know is, it would be nice to have the option.”

Into the Barren Lands

A
n expanding shell of light surrounds our solar system, with our Sun as its source. The shell is not perfectly spherical, but instead tapered like an hourglass at its midsection, where some light is extinguished by thick lanes of gas and dust within the Milky Way’s spiraling galactic plane. Above and below the galactic plane, relatively free of occluding debris, the Sun’s photonic shell ripples outward in twin lobes, ever expanding at the speed of light. Though the shell’s boundaries sweep three hundred thousand kilometers farther away from us every second, their expansion through the great intergalactic voids is so glacial that their position can be pegged at 4.6 billion light-years away. The shell’s edges are composed of photons first erupted in the flash of thermonuclear
ignition that announced our star’s birth. Each unfolding moment of our solar system’s history follows behind, encoded in planetary reflections, refractions, and occultations of starlight. In all probability, the beginning of the end for this photonic broadcast will occur some six billion years from now, when our Sun, long since swollen into a pulsating red giant, finally burns through its last stores of hydrogen and helium. It will leave behind scorched planets, an evanescent nebula of ionized gas, and a stellar remnant, a white-hot ember of carbon and oxygen ash. Slowly cooling over the eons, the remnant’s faint light will finally fade to black, switching off the solar transmission as surely as scissors cutting a thread, leaving only the light of ancient days to echo through eternity.

Borne on photons, the echoes of primordial and Precambrian time—the formation of planets, the emergence of life on Earth, the oxygenation of our world’s atmosphere, the invasion of the land—all long ago left the Milky Way to wash over the surrounding galaxies, galactic clusters, and superclusters. An observer somewhere among the trillion stars of Andromeda, our nearest neighboring spiral, would today see the Earth of 2.5 million years ago, when the forerunners of
Homo sapiens
were perfecting the production of crude stone tools in sub-Saharan Africa. Seen from the Large Magellanic Cloud, a dwarf galaxy swooping near the Milky Way, our world would be locked in the glacial advance of 160,000
B.C.
, with our ancestors poised to migrate out of Africa as the ice sheets retreated. Within our own galaxy, the echoes are closer to home. Among the open clusters and blue hypergiant stars of the Carina Nebula, somewhere between 6,500 and 10,000 light-years away, the Earth appears as it was during the rise of agriculture and the Bronze Age civilizations of Mesopotamia, Egypt, and the Indus Valley. Light from the Earth of Thales, Democritus, and other ancient Greeks now washes over the blazing newborn stars and shimmering molecular clouds of the Christmas Tree Cluster, just over 2,500 light-years distant. The Earth in the skies of the giant planets circling the Sun-like star HR 8799 has just begun transmitting in radio and perfecting the internal
combustion engine. The first television transmissions of the 1930s now roll over the ice-blue stars of Regulus, and news of 1969’s
Apollo 11
lunar landing has just reached the aging yellow suns of Capella. Whether any of this has actually found an audience somewhere out there, we cannot yet say. For all we know, the lively broadcast from Earth may be the only one of its kind in the observable universe.

Viewed from the vicinity of the closest stars and compressed into a short time-lapse movie, our solar system’s birth and evolution would present an eerie picture. From a large black cloud of molecular hydrogen, a star forms first, followed by whirling planets. Once settled in their orbits, the outer giant planets remain relatively inert, placid for billions of years beneath their whorls and bands of swirling gas. Even less happens on inmost Mercury after its magma oceans cool and crust over. The other three inner worlds are each a blue-green jewel of cloud, sea, and land, but in a flash Venus bakes beneath a pall of steam, and Mars withers and freezes. For most of the movie’s running time, Earth is the system’s most curiously variable world, a kaleidoscope of wandering continents, pulsing glaciers, erupting mountains, surging tides, and swarming greenery. In the last second before the time-lapse catches up to the present day, the Earth gains electric lattices of nocturnal lights and sparkling haloes of artificial satellites. The transformed planet ejects a handful of spore-like metallic flecks throughout the system. Five of them approach Jupiter and are flung off at solar-escape velocities, destined for parts unknown in the wider galaxy and cosmos. They are humanity’s fledgling interstellar probes, each launched by NASA:
Pioneer
10
and
11
,
Voyager 1
and
2
, and the Pluto-bound
New Horizons
.

On February 14, 1990, the farthest and fastest of those probes,
Voyager 1
, turned its cameras back toward Earth for a final time from a distance of more than six billion kilometers, beyond the orbit of Pluto and high above the solar system’s ecliptic plane. At the insistence of Carl Sagan and other workers on the Voyager missions, the spacecraft sought to reproduce the iconic Apollo “Blue Marble” image, but from a distance one hundred thousand times greater. From so far away, the entire
Earth was almost lost in the Sun’s diffractive radiance, but close inspection revealed our planet as a solitary azure point of light comprising less than a single pixel in
Voyager 1
’s transmitted image.