Beyond: Our Future in Space (26 page)

The Drake equation is quite a mouthful, but it’s proved to be a durable way to encapsulate SETI. The first three factors are now measured by astronomers. However, the last four terms are unknown, and estimates range over orders of magnitude. Unfortunately,
N
is as uncertain as its most uncertain factor. Even Frank Drake agrees that his brainchild is more of a container for ignorance than a useful tool (
Figure 44
).

Uncertainty, however, has not deterred SETI researchers. Congress squashed NASA’s funding for SETI on the grounds that it was a frivolous use of taxpayers’ money, but many groups around the world are continuing the search. At the epicenter of the effort is the SETI Institute, founded in 1984 as a California nonprofit organization. It is building the Allen Telescope Array, an array of 350 antennas northeast of San Francisco, partially funded by Paul Allen, cofounder of Microsoft. SETI faces a classic “needle in a haystack” problem—that is, if these particular needles even exist. The haystack incorporates millions of potential targets, billions of potential frequencies, and many possible ways of filtering and detecting a signal. After more than half a century of failure, it seems quixotic to continue looking, but SETI researchers point out that they are riding the wave of exponentially increasing computer power and detector bandwidth. In its first few months online, the fully built Allen Telescope Array will eclipse the sum of all previous searches.
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It will be easier to decide that a radio signal is artificial in origin than to decode the meaning in the signal. If you doubt that, recall that we can’t communicate with primates that share 99 percent of our DNA. Now imagine that we’re trying to communicate with aliens who might not even have DNA, aliens of unknown function and form. We assume that if they send radio signals, they must be intelligent. In other words, the choice of a means of communication is very telling. The medium is the message.

The main approach to SETI continues to be radio astronomy. But the power of modern lasers suggests an alternative. If a civilization on a planet was using rapidly pulsed lasers to send signals rather than radio transmitters, the pulses might stand out against the steady light of the nearby star. Optical SETI can be done with small telescopes if the stars are nearby. Pulsed lasers are now powerful enough to match the Sun’s energy—but only for radiation traveling in one direction and only for a billionth of a second.

Another strategy is to look for energy used by a civilization in the form of heat “waste.” Infrared telescopes can look for an excess of cool or low energy radiation, above what would be produced naturally by a star and its surrounding planets. This offers the prospect of detecting civilizations even if they are making no active attempt to communicate.

SETI is more accurately called a search for extraterrestrial technology, since it’s possible to have intelligence without technology. Consider the orca. Often called killer whales, orcas are actually relatives of dolphins. They grow up to 30 feet long, weigh up to 11 tons, and can live as long as humans. Lori Marino at Emory University has analyzed an orca brain with magnetic resonance imaging (MRI), finding that their brains are large and extremely well wired for analyzing their three-dimensional environment.
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Orcas have a complex language with dialects that vary regionally; they have dynamic social groups; they spend a lot of time socializing their young; and they seem to have hunting methods that pass from generation to generation. This ability to transmit cultural information puts them in an elite category, one previously thought to include just us. With no natural enemies but man, they’re perfectly adapted to their aquatic environment and have no need to evolve fingers and opposable thumbs. Orcas will never do SETI, and SETI will never find creatures like orcas elsewhere.

Even though light is fleet-footed, space is vast. The nearest Earth-like planet is likely to be dozens of light years away. And if technological civilizations are rare outcomes of biological evolution, our nearest “pen pals” might be hundreds or thousands of light years away. A civilization might have decayed or died by the time we received its signals. As we contemplate leaving our home planet, we must prepare for the fact that space might be a very lonely place.

Given the dichotomy between being “alone” and “not alone” in the galaxy, each possibility affects our rationale for exploring deep space. If we’re alone, the only reasons to venture beyond the Solar System are curiosity or a desire to propagate our civilization beyond the home planet. If we’re not alone, interstellar travel is an attempt to be part of something much larger than our planet and our species.

11

Living Off-Earth

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Biosphere 3.0

It seemed like a science fiction reality show on steroids. In 1991, eight men and women were sealed into a three-acre glass-and-steel complex in the Arizona desert called Biosphere 2 (
Figure 45
). Their mission was to live in a self-sustaining environment for two years, as a prototype of how humans might one day live on Mars, or in space.
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Texas billionaire Ed Bass sank $150 million into the project, and it was variously characterized in the press as a utopian dream or a rich man’s folly. The occupants wore jumpsuits out of
Star Trek
—which, depending on your point of view, made them look like either consummate professionals or inmates at a county jail. Few had serious scientific credentials. The soaring architecture was inspired by Buckminster Fuller’s geodesic domes, but there was also a darker backstory associated with founder John Allen, who ran a commune in New Mexico that had the trappings of a cult. Allen was a metallurgist and Harvard MBA who experimented with peyote and spent the late 1960s lecturing in San Francisco’s Haight-Ashbury district. In 1974, when young Yale dropout Ed Bass arrived at Allen’s Synergia Ranch, the two men instantly hit it off, based on their shared interest in the environment. Allen had big ideas and Bass was heir to an oil fortune, so they built an 82-foot sailboat and traveled around the world studying ecosystems and sustainable development. Allen became obsessed with space colonization.
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As the project unraveled, former Biospherians claimed that Allen had exercised oppressive control over them, creating paranoia and low morale. Early on, Jane Poynter sliced off the tip of her finger and had to leave to get medical attention. She returned with two mysterious duffel bags that critics claimed were full of supplies. Over the first year, the occupants lost 10 percent of their body weight and had to use imported food. A carbon dioxide scrubber was installed to stop the gas from rising to dangerous levels. There were rumors of squabbling and warring factions.
³

A Noah’s ark of 3,000 animals entered the dome along with the eight humans. It included thirty-five hens and three roosters, four pygmy goats and one billy goat, two sows and a feral pig, and some tilapia fish. But due to the fluctuating carbon dioxide levels, most of the vertebrates and all of the pollinating insects died. Morning glories choked the rainforest. The cockroach population exploded. Then there were the ants. A species called
Paratrechina longicornis
, or crazy ant, killed off the other ants as well as the grasshoppers and crickets. Relentlessly, they took over the food web. Once, in a frenzy, they overran an ecologist who was one of the occupants in the dome.

It got worse. After sixteen months, the oxygen levels had declined by 25 percent, equivalent to a level available at an altitude of 13,500 feet. So oxygen was injected into the habitat, which removed any remaining pretense that it was a sealed and self-contained environment. As the first wave of occupants emerged and a new wave prepared to enter, simmering conflicts burst into the open. In April 1994, the on-site management team was ousted after being served with a restraining order by federal marshals. A few days later, two members of the first crew, Mark Van Thillo and Abigail Alling, allegedly vandalized the project by breaking panes of glass and opening an air lock and three emergency exits.
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Two members of the second crew had to be replaced. The second mission ended prematurely after only six months.

Two decades later, it’s possible to make a more balanced judgment on Biosphere 2. Anyone reading about it in the popular media would have seen grandiose expectations and hype, followed by damning criticism. The project failed as a prototype for a completely sealed environment, but more than 200 published papers have been based on research done in Biosphere 2.
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It was the largest “closed system” habitat ever built, with five distinct biomes: ocean with coral reef, mangrove wetland, tropical rainforest, savanna grassland, and fog desert. The problems with carbon dioxide and oxygen have been well documented, but the seal system and “lungs” that allowed the system to respond to temperature variations are the best ever constructed. Biosphere leaked about 10 percent of its oxygen per year, whereas the Space Shuttle leaked 2 percent per day. And even though the Biospherians might have smuggled in some snacks, their half-acre of land was the most productive agricultural experiment in history. The occupants got 85 percent of their food from bananas, sweet potatoes, rice, beets, peanuts, and wheat grown in the dome. They lost weight in the first year but gained back much of it in the second year as their bodies adjusted to the low-calorie, nutrient-dense diet. Most of them emerged with improvements in cholesterol level, blood pressure, and immune-system indicators.
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Most of what we now know about the effect of ocean acidification on coral reefs was learned in the Biosphere.
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Wastewater was successfully treated in the artificial wetlands. And even though a few species ran amok for short periods, the overall food web stayed in reasonable balance. Before the Biosphere was built, many ecologists thought the experiment was so complex that it would be a catastrophic failure. In practice, scientists are continuing to learn through tightly controlled variables how earth systems respond to environmental change.

Despite its limitations, Biosphere provided essential lessons for anyone designing a truly sealed and self-contained environment on the Moon or Mars.
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A high-fidelity, end-to-end, full-duration mission simulation is required before sending people off-Earth. The Biospherians could in the end just open the door and go home—Moon and Mars colonists will have very few options. The problems of food production and oxygen loss are not inherent to bioregenerative systems; they were specific to the Biosphere design and can be corrected. Most of the problems encountered were unforeseen and some were unforeseeable. Complex, miniature ecosystems are subject to nonlinear effects that compound over time. Call it the butterfly effect.

Since colonists won’t be able to live exclusively in a bubble, another crucial piece of equipment is a spacesuit. Spacesuits have changed very little since the 1960s; the Americans, Russians, and Chinese all use bulky and clunky suits that offer safety but limited mobility.
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A spacesuit has to deal with vacuum and temperature extremes; it has to protect against micrometeorites and infiltration by dust; it has to provide breathable air; and it has to monitor the occupant’s vital signs. The private space industry is hiring top designers for a new generation of spacesuits; in response, NASA turned to social media by having the public vote among the final designs for its next spacesuit. The winner, called Z-2, has collapsing pleats and electroluminescent blue patches and looks strangely retro.
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