Space Age
Epilogue
(The Shape of Things To Come)
" The essential wildness of science as a manifestation of human behavior is not generally perceived."
-- Lewis Thomas
For aeons life was Earthbound. Now, in the form of the human race, it has found a way to leave the planet and expand its frontiers into space. Never before did we have more than a world to explore, today we have an entire cosmos. Not entirely by design, the knowledge and experience gathered during the Space Age has made us more capable of resolving the fundamental questions that initiated it in the first place: where do we fit in, how did we come to be, what forces power the universe, are we alone?
Searching for the answers to questions this fundamental is bound to lead to unknown territory. Contact, for example. In the 17th century Christiaan Huygens, a phycisist of ferocius intelligence and impeccable credentials, and his more famous contemporary, Isaac Newton, both speculated on the likelihood of life on other worlds. Huygens wrote in his book on cosmology entitled Cosmotheoros, "A man that is of Copernicus's opinion, [that theSun not Eartth is the center of the universe] ... cannot but sometimes think that it's not improbable that the rest of the Planets have their Dress and Furniture, and perhaps their Inhabitants too as well as this Earth of ours." Newton speculated that just as the microscope had found all kinds of strange life in everthing from water to blood, "so may the heavens above be replenished with beings whose nature we do not understand." Tsiolkovsky wrote a book of science fiction entitled Dreams of Earth and Sky , that speculated on alien life. Being a social species, we seem reluctant to be alone,. the idea of extraterrestrial life was once considered material for pulp science fiction and bad B-movies, but today scientists take the possibility very seriously. As big as the universe is, with an estimated one hundred billion galaxies, and three hundred billion stars in the Milky Way alone, our chances for finding company look promising. The processes that brought life into existence are not likely to be unique to our small world in a physics experiment as vast as the universe. We may find that life is as common in cosmic evolution as brains and eyes are in evolution of life on Earth. Scientists do not yet have any hard evidence, but there are indications that many of the stars we see each evening in the sky are surrounded by planets just as our own sun is, places where life could have only recently arisen, or others where races have been evolving a billion years longer than the human race, busily colonizing their galaxy.
Many scientists believe that the best chance we have for discovering these other civilizations is to listen for them using radio telescopes which are planted like flowers all around the world now. It is possible that just as our television signals are strong enough to drift out into space, an alien civilization is leaking bits of its culture too. Or perhaps they are as curious to know if they are alone as we are, actively sweeping the cosmos with a radio beacon the way a New England lighthouse sweeps the sea. If so, we have our ears cupped, our radio satellite dishes tuned in, systematically searching the sky for the call of other beings far away.
But there is a lot to listen to out there: the universe resounds with radio noise. Everything from stars to hydrogen molecules emit a message in thousands of frequencies which together they make a sound like wind. (The universal channel selector is considerably larger than the ones in our cars.) On rare occassions astronomers have found signals that disturb these interstellar breezes, occurances so strange that those listening have allowed themselves to think for a single astonishing moment that they had actually stumbled across another version of life. But when they re-aim their telescopes to the origin of the signal, it has disappeared, only a stellar or molecular aberration in the normal whoosh of the universe, perhaps.
Princeton physcisist Freeman Dyson believes we can vastly reduce the territory radio telescopes are scanning for radio signals by first searching not for a message, but for heat. In his book Disturbing the Universe the writes that finding evidence of a civilization on our own level of advancement, one which is moving toward successfully managing the resources of their planet, there would be few apparent clues across intergalactic distances. We would, however, have a chance of finding evidence of what he calls a type 2 civilization, aliens that have harnessed the power of their sun. "There is one kind of emmission a type 2 civilization cannot avoid making. According to the second law of thermodynamics, a civilization that exploits the total energy output of a star must radiate away a large portion of this energy in the form of waste heat...as infrared radiation, which astronomers on Earth can detect."
Instead of these approaches, some scientists have suggested we should send probes in search of extraterrestrial life. Robert L. Forward, a respected engineer at Hughes Research Laboratories, who, like Tsiolkovsky before him, puzzles on the problems of spaceflight and dabbles in science fiction, believes that we should design ships that can cover interstellar distances in reasonable times to carry robotic probes to other star systems.
Star travel, he admits, is a monumental undertaking. "It is difficult to go to the stars. They are far away and the speed of light limits us to a slow crawl along the starlanes." Although, Hollywood has conveniently outmaneuvered the speed of light, in the real world where the laws of physics apply, the cosmic speed limit is set at 186,300 miles per second, and despite the determined efforts of many scientists, no immediate methods for skirting the regulations have been found.
186,300 miles per second seems incredibly fast, until you consider the distances involved. The Moon, for example, is a quarter of a million miles away and takes three days to reach in a chemical rocket. Neptune, the eighth planet from the sun is ten thousand times farther away than the Moon, and with great difficulty, after more than a decade, Voyager managed to arrive in 1989. But these distances are piddling compared with the territory that lies between Earth and even the nearest star, Proxima Centauri, which is 4.3 light years away, ten thousand times farther than Neptune, one hundred million times farther than the Moon! Pioneer 10 , the swiftest object humans beings have ever built has now cleared our solar system and is hurtling into interstellar space at 25 miles a second -- 90,000 miles an hour. But that's still 7500 times slower than the speed of light. It would take Pioneer 33,000 years to reach Proxima Centauri, and 15 billion years, the present age of the universe, to reach the nearest galaxy! We are a long way off from even a "slow crawl."
But assuming that we could invent ships that could attain even one third the speed of light, we would then be capable of traveling to 17 star systems inside of 40 years, well within the span of a single human lifetime. According to Robert Forward the technologies that could make this possible are not too far off -- nuclear pulse engines driven by hydrogen bombs, fusion rockets, even ships fueled by anti-matter. As unreal as its name sounds, anti-matter, when combined with an equal amount of matter releases 200 percent of its mass as energy. We have already manufactured anti-matter, but so far only in vanishingly small amounts, a few subatomic particles at a time. Anti-protons are produced and stored at the the European Centre for Nuclear Research (CERN) in Switzerland. Difficult to make, and even more difficult to store, anti-matter has to be slowed, cooled and trapped by lasers or magnetic fields which suspend it, like a trussed-up prisoner. Furthermore the estimated cost of producing it in the 21st century is $10 million a milligram -- $9.1 quadrillion a ton.
On the other hand, it wouldn't take much anti-matter to power a spaceship. Once developed, such vessels will be able to sail from one end of the solar system to the other in days or weeks, rather than years, making a journey to Mars hardly longer than a cruise to Europe. Sending one-way probes to the nearest star systems this way would could reduce travel times from millennia to a mere twelve or thirteen years.
However, as with all fuels, anti-matter has its shortcomings. The laws of relativity hold that as an object approaches light speed, its mass likewise approaches infinity. Truly high speeds, therefore, require enormous amounts of fuel to move the ever-increasing weight. If an anti-matter driven space shuttle could be built that travelled, say, 99 percent of the speed of light, it would require a half million tons of anti-matter. The solution to this problem is to invent a ship that doesn't need to carry along its own fuel, one that grazes the galaxy for atoms as it travels. In 1960 physicist and consultant R.W. Bussard designed just such a vessel. He called it an interstellar ramjet, a ship that looks something like a plunger with an enormous saucer at its nose. This saucer would scoop up hydrogen atoms floating in space, accelerate them into a fusion reactor which would then propel the ship at speeds approaching light. The scoop would have to be hundreds of miles across because in interstellar space, matter is rare -- about one atom every 10 cubic centimeters. Grazing the wide open spaces between stars would require a very large mouth.
To say that Bussard designed the ship isn't quite accurate because that would imply it could be built, but it can't be. It would work theoretically, but the technology needed to assemble such leviathan and sophisticated machine is beyond anything science can tackle right now or is likely to be able to tackle anytime soon. The design is really a thought experiment, more than a blueprint, and raises some interesting issues about high speed travel because if Bussard's ramjet could be built, it would be a true time machine. A crew who boarded it , and travelled from Earth toward the center of the Milky Way at close to the speed of light, would arrive 21 years later according to their onboard clock, but the laws of relativity stipulate that 30,000 years will have passed on Earth. Following a return trip, a total of 60,000 years would have passed on Earth, but the crew would debark their ramjet only 42 years older. The planet they return to would be an unimaginably different world and the human race, assuming it had survived, thoroughly changed. (To provide an idea of how much can change within 60,000, anthropologists still debate whether or not true human beings even existed on Earth that far in the past years ago.)
If we do make contact, who or what, might we find? Physical appearances are a wide open question. In his 1895 science fiction fantasy Dreams of Earth and Sky , Konstantin Tsiolkovsky imagined creatures with glassy airtight bodies and winglike appendages that ennabled them to live in a vacuum and use sunlight to manufacture food. (It's interesting to note that Tsiolkovsky, who was deaf, had the creatures communicate in this vacuum with brightly colored images that constantly changed beneath their transparent skin.) Robert Forward has written a science fiction book in which jelley-fish-like aliens lived on a water planet. Some scientist have imagined creatures that have no solid bodies, but exist as pure thought, as patterns of magnetism.
Looks aside are aliens likely to be sinister like H.G. Well's Martians or wise and peaceful like Percival Lowell's? Some scientists believe any truly advanced civilization must be wise and benign, otherwise they would very likely have wiped themselves out, just as we might yet do. Long progress would probably mean they have overcome not only the desire to annihilate themselves, but the desire to spread annihilation around the universe. War is costly, it might not be possible to slaughter one another and develop the advanced technologies that ennable travel to other solar systems. In our case, the cold war may have catapulted us into the Space Age, but it also damaged it, channeling vast amounts of money and human talent in the United States and the old Soviet Union into developing multi-billion dollar weapon systems. On the surface it may seem that evolution has tended to favor predators, creatures that are fast, flexible, and aggressive, but the larger tendency of living things ultimately seems to be to cooperate and build. Life on Earth has made the planet a monumental construction project carried out by millions of species -- symbiosis on a planetary scale. Seen this way, predation might only be smaller part of the general process of cooperation; rampant and perfectly efficient predators would have left only one kind on the planet with nothing else to eat, except for each other.
If cooperation of this sort is common throughout the universe, any aliens we might contact may well be . But establishing lines of communications with extraterrestial isn't likely to be easy no matter how wise and happy they are to share their knowledge and experience. How , after all, can expect to communicate with creatures whose reality might be as different from ours as ours is from a termite? We already know that dolphins and certain whales have large, complex brains, but we haven't yet found a way to bring our minds together with their's except on the most basic level. Could we even find a common language with another race from far away?
Astronomer Carl Sagan believes that mathematics is our best
shot at a cross-cosmos lingua franca, that a knowledge of prime numbers,
for example, could help establish a system of communication. In his book
The Lives of a Cell, Lewis Thomas, on the other hand, has suggested, a
little more whimsically that the best way to explain ourselves to extraterrestrials
might be in the music of Bach. "We would be bragging of course,"
he writes, "but it is surely excusable for us to put the best possible
face on at the beginning of such an acquaintance."
Even if we found a way to communicate, what would we talk about? Since
they are so advanced, we might ask whether they have solved any extraordinarily
hard questions that we haven't. Is there a way to excced the speed
of light? Have you seen God? Are children a universal joy? Is there sadness
on your world? Astronomer Frank Drake, now a professor the University
of California at Santa Cruz, and a man who pioneered the radio telescope
approach to extraterrestrial searches, feels that even a rudimentary exchange
could be of immeasurable benefit. A simple yes or no to the question,
"Will fusion power work?" would save the human race billions
of dollars and years of effort.
Beyond all of these concerns, simply making contact would
rattle the foundations of every culture on Earth, and remind us once again
that we are not the center of the universe. Wholesale reassessments of
science, religion, and philosphy would be in order; a situation which
might leave us temporarily speechless. But at the outset, maybe silence
will be best..
"After all," Lewis Thomas writes, "the main question
will be the opener: Hello? Are you there? If the reply should turn out
to be Yes, hello, we might want to stop there and think about that, for
quite a long time."
Of course there is the possibility that we are alone in the universe, in which case the Space Age, rather than producing a means for making contact, is more likely to focus on spreading human life around the universe the way Tsiolkovsky imagined nearly a hundred years ago. We could set out for other galaxies in states of suspended animation, reduced to the "granular state," that Goddard imagined in "The Ultimate Migration," his quirky view of the far future. Or, to defeat the obstacle of long intergalactic journeys we might digitally download our minds into a futurstic computer which will not run down like a biological body and brain and might even allow us to beam ourselves in the form a laser from one galaxy to another.
We are beginning the work of this kind of settlement already
as we study the possibilities of permanently inhabiting the Moon and Mars,
except that now we are content to build shelters or outposts on these
worlds, burying ourselves beneath their surfaces like seeds. Not far in
the future we might begin to terraform these places, rendering them Earthlike.
Mars is the most probable candidate for planetary metamorphosis since
at one time it may have been warm, volcanic, and watery. Today it is altogether
different -- frozen and nearly airless, barren and pocked, but the old,
basic constituents for life may well be locked in Mars' rusty rock. Looking
at it this way, says Mars expert Chris McKay at NASA's Ames Research Center,
"[T]erraforming could be viewed as a restoration project."
Terraforming suits Mars in other ways: it tilts at almost precisely the same angle on its axis as Earth does, has frozen water and plenty of carbon and oxygen, though possibly not enough nitrogen, and the length of both planets's days are nearly identical. The ultimate terraformation of Mars, however, would need the ingredient that most thoroughly wrought the terraformation of our own planet. "The only known mechanism that can change a planetary atmosphere is life," says McKay. "At a very early stage we might release on Mars specially engineered microorganisms that could adapt to the extreme cold. As the planet warms and the atmosphere thickens, hardy species of grasses and shrubs might be introduced, followed by flowering plants, trees and food crops." This aspect of the plan takes a page out of Lynn Margulis' theories. Given a basic environment and life's habit of filling whatever niches it can, microbes would take over the job on Mars just as they did on Earth more than three and a half billion years ago.
Prompting the propagation of Earths in this way will also change the human beings that live upon these new worlds. Like the varieties of finches Darwin noticed on the Galapagos Islands, over time the settlement of other planets and moons will breed variations on us. Within a few generations, Mars would beget Martians not humans, creatures branching off an Earthbound evolutionary line, as surely as human ancestors branched from the same line that also gave rise to the chimpanzee and great ape. By extending this process to other worlds, the solar system might someday become a cosmic rain forest, brimming with new species of plants and animals and intelligent beings, all springing from common terrestrial ancestors.
Not all of the central quests of the next age look to the future of life, some look back. The nature of our origins also lie hidden among the wild percolations that produced the universe; phenomena completely unknown before we developed the ability to leave Earth. As scientists begin to understand celestial manifestations like pulsars, quasars, and the formation of galaxies, they are inching closer to uncovering nature's ultimate secrets: how space, time, matter and life come into existence.
The Space Age lead to the discovery of the x-ray universe and many of the other universes that lie along the electro-magnetic spectrum, and orbiting observatories like the Cosmic Background Explorer (COBE) and the Hubble Telescope are joining the minds of scientists with instruments in space and to further pull back the curtain on the universe and the forces within it. These instruments belie the perfection, and absolute celestial order that Aristotle said he saw when he looked into the sky. Modern astronomers and astrophysicist know today that the universe is anything but serene. Beyond the Milky Way, for example, a swarm of thousands of galaxies amounting to trillions of trillions of stars, are hurtling across the universe at 700 miles per second, beckoned by some siren center of gravity. Astronomer Alan Dressler of the Carnegie Institution of Washington calls it the Great Attractor. "A structure so gargantuan deserved an equally good name," he says. The best guess is that the Great Attractor is an immense collection of galaxies 100 million light years thick and 200 million light years wide. It's mass may equal the mass of 10,000 trillion suns. Some surmise that the universe is perforated with holes that are black and invisible, so dense that the unimaginable power of their gravity swallows everything around them -- light, matter, all evidence of being. Where they exist, the pressures and forces at work may be so crushing that the laws of the universe -- what we normally call reality -- cease to apply. The "here" of a black hole, in other words, is nowhere, and literally anything is possible. Elsewhere astronomers have found galaxies colliding, igniting stars like fireworks, and quasars where the bodies of entire suns explode as they are shredded and sucked wholesale into black holes. Within the universe there are walls of galaxies woven into latices hundred of millions of lights years long, and out in the endless night may be unknown dimensions, cosmic strings which have warped the structure of the universe from the beginning of time; and wormholes, passages to gardens where whole parallel universes may be in bloom. We may live, in other words, not simply within one universe but among an infinitude of infinite universes.
These are the very forces that create suns and planets which in turn have brought forth the human race. In the stars are also the ingredients of life. We are, it has been said, a star's way of understanding itself. Our comprehension of the universe, however, is in its very earliest stages. Nevertheless, the Space Age does represent a new level in our effort. Why do we build rockets and search for life on other worlds, and launch observatories that cost billions of dollars to gaze deep and wide-eyed into the sky? Why should such outlandish undertakings so thoroughly engage our wonder? Because we are congenitally curious, a trait that has proven invaluable to us over the long haul, keeping us moving and cross-pollinated with new knowledge. Without this talent for wanderlust, without our ability to dream, we might still be sitting in damp, cold caves without even a fire to warm us, or a rock in hand out of which to strike a tool.
Now, having found frontiers beyond Earth it is difficult to say precisely where we are headed. We are at a branch point in our evolution, like the first lung fish that crawled up out of the sea onto land. We may not be able to explain why we are departing the familiar surroundings of one environment for the dangers and mysteries of another, but we have taken the step and such adventures inevitably foreshadow momentous change. The results are likely to be surprising and far beyond anything we can imagine right now. After all, of the creatures that first slithered tentatively from the sea, which of them could have foreseen a dinosaur, an ape, or a human, much less a rocket, a robot or a computer?
