The Future of Humanity

by Michio Kaku

  In any event, if we are to explore the planets and stars, we will have to modify and enhance ourselves to survive the journey. And, since there is a limit to how far we can terraform a distant planet, we will need to adjust ourselves to different atmospheres, temperatures, and gravity. So genetic and mechanical enhancements will be necessary.

  But so far, we have only discussed the possibilities of enhancing humanity. What happens when we explore outer space and encounter intelligent life-forms that are completely different from us? Moreover, what happens if we meet civilizations that are millions of years ahead of us in technology?

  And if we do not encounter advanced civilizations in outer space, how might we become one ourselves? Although it is impossible to predict the culture, politics, and society of an advanced civilization, there is one thing that even alien civilizations will have to obey, and that is the laws of physics. So what does physics tell us about such advanced civilizations?

  Originally, you were clay. From being mineral, you became vegetable. From vegetable, you became animal, and from animal, man…And you have to go through a hundred different worlds yet. There are a thousand forms of mind.

  —RUMI

  If you threaten to extend your violence, this Earth of yours will be reduced to a burnt-out cinder. Your choice is simple: Join us and live in peace or pursue your present course and face obliteration. We shall be waiting for your answer. The decision rests with you.

  —KLAATU, ALIEN FROM THE DAY THE EARTH STOOD STILL

  12 SEARCH FOR EXTRATERRESTRIAL LIFE

  One day, the aliens arrived.

  They came from distant lands no one had ever heard of, in strange, wondrous ships, using a technology that one could only dream of. They came with armor and shields stronger than anything ever seen before. They spoke an unknown language and brought with them strange beasts.

  Everyone was wondering, Who are they? Where do they come from?

  Some said they were messengers from the stars.

  Others whispered that they were like gods from heaven.

  Unfortunately, they were all wrong.

  The fateful year was 1519 when Montezuma met Hernán Cortés and the Aztec and the Spanish Empires collided. Cortés and his conquistadors were not messengers from the gods but cutthroats lusting after gold and whatever they could plunder. It took thousands of years for the Aztec civilization to rise from the forest, but, armed with only Bronze Age technology, it was overwhelmed and destroyed by Spanish soldiers in a matter of months.

  As we move into outer space, one lesson we can learn from this tragic example is that we should be cautious. The Aztecs, after all, were perhaps only a few centuries behind the Spanish conquistadors in their technology. If we encounter other civilizations in space, they might be so far ahead of us that we can only imagine the power they possess. If we were to enter a war with such an advanced civilization, it might be like King Kong meets Alvin the Chipmunk.

  Physicist Stephen Hawking has warned, “We only have to look at ourselves to see how intelligent life might develop into something we wouldn’t want to meet.” Referring to the consequence of Christopher Columbus meeting Native Americans, he concludes, “That didn’t turn out so well.” Or, as astrobiologist David Grinspoon says, “If you live in a jungle that might be full of hungry lions, do you jump down from your tree and go, ‘Yoo hoo’?”

  Hollywood movies, however, have brainwashed us into thinking that we can defeat the alien invaders if they are a few decades or centuries ahead of us in technology. Hollywood assumes that we can win by using some primitive, clever trick. In Independence Day, all we have to do is inject a simple computer virus into their operating system to bring them to their knees, as if the aliens use Microsoft Windows.

  Even scientists make this mistake, scoffing at the idea that an alien civilization living many light-years away could even visit us. But that assumes that alien civilizations are only a few centuries ahead of us in technology. What happens if they are millions of years ahead of us? A million years is nothing but the blink of an eye in cosmic terms. New laws of physics and new technologies would open up when contemplating these incredible time scales.

  Personally, I believe that any advanced civilization in space will be peaceful. They might be aeons ahead of us, which is plenty of time for them to resolve ancient sectarian, tribal, racial, and fundamentalist conflicts. But we must be prepared if they are not. Rather than reaching out and sending radio signals into space to announce our existence to any alien civilization, it might be more prudent to study them first.

  I believe we will make contact with an extraterrestrial civilization, perhaps sometime in this century. Instead of being merciless conquerors, they might be benevolent and willing to share their technology with us. This would then be one of the most important turning points in history, comparable to the discovery of fire. It could determine the course of human civilization for centuries into the future.

  SETI

  Some physicists have actively tried to settle this issue by harnessing modern technology to scan the heavens for signs of advanced civilizations in space. This is called SETI (search for extraterrestrial intelligence) and involves scanning the heavens with the most powerful radio telescopes we possess to listen for transmissions from alien civilizations.

  At present, thanks to generous contributions from Paul Allen, cofounder of Microsoft, and others, the SETI Institute is constructing 42 state-of-the-art radio telescopes at Hat Creek, California, about three hundred miles northeast of San Francisco, to scan a million stars. Eventually, the Hat Creek facility may have 350 radio telescopes scanning radio frequencies between one and ten gigahertz.

  But working on the SETI project is often a thankless task, begging wealthy donors and wary contributors to fund this project. The U.S. Congress has shown only halfhearted interest, and they finally withdrew all financing in 1993, calling it a waste of taxpayer money. (In 1978, Senator William Proxmire ridiculed it by awarding it his infamous Golden Fleece Award.)

  Some scientists, frustrated by the lack of funding, have asked the public to participate directly in order to broaden this search. At the University of California, Berkeley, astronomers created SETI@home, an effort to enlist millions of amateurs online to participate in the search. Anyone can take part. You just download the software from their website. Then at night, while you sleep, your computer searches through the mountain of data they’ve collected, hoping to find that needle in the haystack.

  Dr. Seth Shostak of the SETI Institute in Mountain View, California, whom I have interviewed on a number of occasions, believes that we will make contact with an alien civilization before 2025. I asked him how can he be so sure. After all, decades of hard work have not led to a single verified signal from an alien civilization. Furthermore, using radio telescopes to listen in on alien conversations is a bit of a gamble; maybe the aliens do not use radio. Maybe they use entirely different frequencies, or use laser beams, or an entirely unexpected mode of communication that we haven’t thought of. All of these are possible, he admitted. But he was confident that soon we will make contact with alien life. He had the Drake equation on his side.

  In 1961, astronomer Frank Drake, not satisfied with all the wild speculation about aliens in space, tried to calculate the odds of finding such a civilization. For example, one can start with the number of stars in the Milky Way galaxy (about one hundred billion) and then reduce that number by the fraction that have planets around them, then by the fraction of the planets that have life on them, then the fraction that have intelligent life, and so on. By multiplying a string of these fractions, one gets a ballpark figure of the possible number of advanced civilizations in the galaxy.

  When Frank Drake first proposed this formula, there were so many unknowns that the final results were sheer speculation. Estimates of the number of civilizations in the galaxy ranged from tens of thousands to millions.

  Now, however, with the flood of exoplanets found in space, one can make a much mor
e realistic estimate. The good news is that every year, astronomers narrow down the various components of the Drake equation. We now know that at least one out of every five sun-like stars in the Milky Way galaxy has Earth-like planets circling it. According to the equation, we have more than twenty billion such Earth-like planets in our galaxy.

  Many more corrections have been made to the Drake equation. The original equation was too naïve. As we have seen, we now know that Earth-like planets have to be accompanied by Jupiter-sized planets in circular orbits in order to clean out the asteroids and debris that can destroy life. So we have to reduce the number of Earth-like planets to only those that have Jupiter-sized neighbors. Earth-like planets also have to be accompanied by large moons in order to stabilize their spin, or else they will eventually wobble and even flip over after millions of years. (If the moon were tiny, like an asteroid, then small perturbations in the Earth’s spin would gradually build up over the aeons, according to Newton’s laws, and the Earth might eventually flip over. This would be disastrous for life, since there would be giant earthquakes, monstrous tsunamis, and horrendous volcanic eruptions as the crust of the Earth began to crack. Our moon is large enough so that these perturbations do not build up. But Mars, with tiny moons, may actually have flipped over in the distant past.)

  Modern science has given us an ocean of concrete data on how many planets capable of spawning life are out there, but it has also found many more ways in which that life can be extinguished through natural disasters and accidents. There have been many times in the Earth’s history when intelligent life was almost extinguished through natural disasters (such as asteroid collisions, planet-wide ice ages, volcanic eruptions). A fundamental question is what percentage of planets that meet these criteria actually have life and what percentage of those have escaped planetary disasters and spawned intelligent life. So we still are a long way from an accurate assessment of the number of intelligent civilizations in our galaxy.

  FIRST CONTACT

  I asked Dr. Shostak what happens if the aliens come to Earth. Does the president summon an emergency meeting of the Joint Chiefs of Staff? Does the U.N. draft an announcement welcoming the aliens? What is the protocol when we make first contact?

  His answer was rather surprising: basically, there are no protocols. Scientists have conferences in which they discuss this matter, but they only make informal suggestions that have no official weight. No government takes this issue seriously.

  In any event, first contact will likely be a one-way conversation, with a detector on Earth picking up a stray message from a distant planet. But this does not mean that we can establish communication with them. Such a signal may come from a star system that is, for example, fifty light-years from Earth, so it will take one hundred years for a message to be sent to that star and a return message sent back to Earth. This means that communication with an ET in space would be extremely difficult.

  Assuming that one day they can reach the Earth, a more practical question is, How do we talk to them? What kind of language will they speak?

  In the movie Arrival, the aliens send huge starships that hover ominously over many nations. When earthlings enter these starships, they are met by aliens who look like gigantic squids. Attempts to interact with them are difficult, since they communicate by scribbling strange characters on a screen, which linguists struggle to translate. A crisis occurs when the aliens scribble a word that can be read either as “tool” or “weapon.” Confused by this ambiguity, the nuclear powers put their weapons on high alert. It seems that an interplanetary war is about to break out, all because of a simple linguistic mistake.

  (In reality, any species advanced enough to send starships to Earth would probably have been monitoring our TV and radio signals and deciphered our language ahead of time, so they would not have to depend on linguists from Earth. But in any case, it would be unwise to start an interplanetary war with aliens that are perhaps millennia more advanced than we are.)

  What happens if the aliens have a totally different frame of reference in their language?

  If the aliens descended from a race of intelligent dogs, then their language would reflect smells rather than visual images. If they descended from intelligent birds, their language may be based on complex melodies. If they descended from bats or dolphins, their language may use sonar signals. If they descended from insects, they might signal one another via pheromones.

  Indeed, when we analyze the brains of these animals, we see how much they differ from our own brain. While a large portion of our brain is devoted to eyesight and language, the brains of other animals are devoted to things like smell and sound.

  In other words, when we make first contact with an alien civilization, we cannot assume that they think and communicate like us.

  WHAT DO THEY LOOK LIKE?

  When watching a science fiction movie, the highlight is often when we finally see the aliens. (In fact, one of the disappointing features of the otherwise fine movie Contact was that, after a tremendous buildup, we never see the aliens themselves.) But in the Star Trek series, all the aliens look just like us and talk like us, all speaking perfect American English. The only thing different about them is that they have different types of noses. More imaginative are the aliens in Star Wars, who look like wild animals or fish, but they always come from planets where they breathe air and have a gravity similar to Earth’s.

  At first, one may say that the aliens can look like anything you want, since we have never made contact with them. But there is a certain logic that they are likely to follow. Although we cannot be sure, there is a high probability that life in outer space might begin in the oceans and be composed of carbon-based molecules. Such chemistry is ideally suited to satisfying two vital criteria for life: the ability to store vast amounts of information, because of its complex molecular structure, and the ability to self-replicate. (Carbon has four atomic bonds, which allows it to create long chains of hydrocarbons, which include proteins and DNA. These long carbon DNA chains contain a code in the arrangement of their atoms. These chains occur in two strands, which can unravel and then grab molecules to make a copy of themselves according to this code.)

  A new branch of science has recently been born, called exobiology, to study life on distant worlds with ecosystems different from those found on Earth. So far, exobiologists have had difficulty trying to find a path to creating life-forms that are not based on the carbon chemistry that gives us rich and diverse molecules. Many other possible life-forms have been considered, such as intelligent balloon-like creatures floating in the atmosphere of the gas giants, but it is hard to create a realistic chemistry that makes such creatures possible.

  When I was a child, one of my favorite movies was Forbidden Planet, which taught me a valuable scientific lesson. On a distant world, astronauts are terrorized by a huge monster that is killing crew members. A scientist takes a plaster mold of the tracks it left behind in the soil. He is shocked by what he finds. The monster’s feet, he declares, violate all the laws of evolution. The claws, the toes, bones are all arranged in a way that makes no sense.

  This caught my attention. A monster violating the laws of evolution? This was a new concept to me, that even monsters and aliens have to obey the laws of science. Previously, I thought that monsters just had to be ferocious and ugly. But it made perfect sense that monsters and aliens would have to obey the same natural laws that we do. They do not live in a vacuum.

  For example, when I hear about the Loch Ness monster, I have to ask what would be the breeding population of such a creature? If a dinosaur-like creature could exist in that lake, it must be part of a breeding population of perhaps fifty or so other creatures. In that case, evidence of these creatures (in the form of bones, carcasses of its prey, waste products, et cetera) should be readily found. The fact that no such evidence has been discovered casts doubt on their existence.

  Similarly, one should be able to apply the laws of evolution to aliens in space. It is impo
ssible to tell precisely how an alien civilization might emerge on a distant planet. We can make some inferences, however, based on our own evolution. When we analyze how Homo sapiens developed intelligence, we see at least three components that were essential in our rise from the swamp.

  1. Some Form of Stereo Eyes

  In general, predators are more intelligent than prey. To hunt effectively, one has to be a master of stealth, cunning, strategy, camouflage, and deception. One also has to know the habits of the prey, where they feed, what their weaknesses are, what their defenses are. All this takes some brain power.

  On the other hand, all prey have to do is run.

  This is reflected in their eyes. Hunters, like tigers and foxes, have eyes facing the front of their face, which gives them stereo vision as the brain compares images from the left and right eyes. This allows them to judge distance, which is essential in locating the prey. However, prey do not need stereo vision. All they need is 360-degree vision to scan for the presence of predators, and hence they have eyes on each side of their face, like deer and rabbits.

  In all likelihood, intelligent aliens in space will have descended from predators that hunted for their food. This does not necessarily mean that they will be aggressive, but it does mean that their ancestors long ago might have been predators. We may be well served to be cautious.

  2. Some Form of Opposable Thumb or Grasping Appendage

  One hallmark of a species that could develop an intelligent civilization is the ability to manipulate the environment. Instead of plants, which are at the mercy of changes in their surroundings, intelligent animals can shape their environment to increase their chances of survival. One thing that set humans apart is the opposable thumb, which gives us the ability to use our hands to exploit tools. Previously, the hand was used mainly to swing from tree branches, and the arc created by our index finger and thumb is roughly the size of a tree branch in Africa. (This does not mean that opposable thumbs are the only grasping instrument that could lead to intelligence. Tentacles and claws may also suffice.)