Where Is Everyone? by Eric Dosier

WHERE IS EVERYONE?

iii

WHERE IS EVERYONE?

Copyright ÂŠ 2015 by Eric Dosier All rights reserved. This book or any portion thereof may not be reproduced or used in any manner whatsoever without the express written permission of the publisher except for the use of brief quotations in a book review. Printed in the United States of America First Printing, 2015 ISBN 0-9000000-0-0 Eric Dosier Publishing 1967 32nd Ave. San Francisco, Ca. 94116 www.FallingAnvilBooks.com

This book is dedicated to the brilliant minds of Carl Sagan, Stephen Hawking, Neil deGrasse Tyson, and others, who were unafraid to think that humans are alone in the vast universe...

TABLE OF CONTENTS 1

Is There Anybody Out There?

Fermi’s Paradox

The Earth Is A Typical Planet

The Sun Is An Ordinary Star

Civilizations May Develop Interstellar Travel

The Galaxy Can Be Colonized In A Few Tens of Millions of Years

Is It Me You’re Looking For?

Neil Tyson DeGrasse on Alien Life

Drake Equation

Planetary Habitability

3 Can You Hear Me Major Tom?

Stephen Hawking On Intelligent Life

Hubble Telescope

Kepler Telescope.

Habitable Systems Infographic

Kepler 186

Why Won’t They Talk To Me?

Terry Bisson - They’re Made Out of Meat?

Crab Nebula

Milky Way Galaxy

Bibliography

The Fermi Paradox is the contradictory and counter-intuitive observation that we have yet to see any evidence for the existence of ETIâ&#x20AC;&#x2122;s. The size and age of the Universe suggests that many technologically advanced ETIâ&#x20AC;&#x2122;s ought to exist. However, this hypothesis seems inconsistent with the lack of observational evidence to support it.

FERMI’S PARADOX It’s been a hundred years since Fermi, an icon of physics, was born (and nearly a half-century since he died). He’s best remembered for building a working atomic reactor in a squash court. But in 1950, Fermi made a seemingly innocuous lunchtime remark that has caught and held the attention of every SETI researcher since. (How many luncheon quips have you made with similar consequence?) The remark came while Fermi was discussing with his mealtime mates the possibility that many sophisticated societies populate the Galaxy. They thought it reasonable to assume that we have a lot of cosmic company. But somewhere between one sentence and the next, Fermi’s supple brain realized that if this was true, it implied something profound. If there are really a lot of alien societies, then some of them might have spread out. Fermi realized that any civilization with a modest amount of rocket technology and an immodest amount of imperial incentive could rapidly colonize the entire Galaxy. Within ten million years, every star system could be brought under the wing of empire. Ten million years may sound long, but in fact it’s quite short compared with the age of the Galaxy, which is roughly ten thousand million years. Colonization of the Milky Way should be a quick exercise.

So what Fermi immediately realized was that the aliens have had more than enough time to pepper the Galaxy with their presence. But looking around, he didn’t see any clear indication that they’re out and about. This prompted Fermi to ask what was (to him) an obvious question: “where is everybody?” This sounds a bit silly at first. The fact that aliens don’t seem to be walking our planet apparently implies that there are no extraterrestrials anywhere among the vast tracts of the Galaxy. Many researchers consider this to be a radical conclusion to draw from such a simple observation. Surely there is a straightforward explanation for what has become known as the Fermi Paradox. There must be some way to account for our apparent loneliness in a galaxy that we assume is filled with other clever beings.

foundly shorter than the age of the Galaxy. It’s like having a heated discussion about whether Spanish ships of the 16th century could heave along at two knots or twenty. Either way they could speedily colonize the Americas. Consequently, scientists in and out of the SETI community have conjured up other arguments to deal with the conflict between the idea that aliens should be everywhere and our failure (so far) to find them. In the 1980s, dozens of papers were published to address the Fermi Paradox. They considered technical and sociological arguments for why the aliens weren’t hanging out nearby. Some even insisted that there was no paradox at all: the reason we don’t see evidence of extraterrestrials is because there aren’t any.

A lot of folks have given this thought. The first thing they note is that the Fermi Paradox is a remarkably strong argument. You can quibble about the speed of alien spacecraft, and whether they can move at 1 percent of the speed of light or 10 percent of the speed of light. It doesn’t matter. You can argue about how long it would take for a new star colony to spawn colonies of its own. It still doesn’t matter. Any halfway reasonable assumption about how fast colonization could take place still ends up with time scales that are pro-

THE EARTH IS A TYPICAL PLANET The first aspect of the paradox, “the argument by scale”, is a function of the raw numbers involved: there are an estimated 200–400 billion (2–4 ×1011) stars in the Milky Way and 70 sextillion (7×1022) in the visible universe. Even if intelligent life occurs on only a minuscule percentage of planets around these stars, there might still be a great number of civilizations extant in the Milky Way galaxy alone. This argument also assumes the mediocrity principle, which is an argument from probability that we should not expect the Earth to be special, but merely a typical planet, subject to the same laws, effects, and likely outcomes as any other world.

THE SUN IS AN ORDINARY STAR The second cornerstone of the Fermi paradox is a rejoinder to the argument by scale: given intelligent lifeâ&#x20AC;&#x2122;s ability to overcome scarcity, and its tendency to colonize new habitats, it seems likely that at least some civilizations would be technologically advanced, seek out new resources in space and then colonize first their own star system and subsequently the surrounding star systems. Since there is no conclusive or certifiable evidence on Earth or elsewhere in the known universe of other intelligent life after 13.8 billion years of the universeâ&#x20AC;&#x2122;s history, we have the conflict requiring a resolution. Some examples of possible resolutions are that intelligent life is rarer than we think, that our assumptions about the general development or behavior of intelligent species are flawed, or, more radically, that our current scientific understanding of the nature of the universe or reality itself is seriously incomplete.

CIVILIZATIONS MAY DEVELOP INTERSTELLAR TRAVEL The Fermi paradox can be asked in two ways. The first is, “Why are no aliens or their artifacts physically here?” If interstellar travel is possible, even the “slow” kind nearly within the reach of Earth technology, then it would only take from 5 million to 50 million years to colonize the galaxy. This is a relatively small amount of time on a geological scale, let alone a cosmological one. Since there are many stars older than the Sun, or since intelligent life might have evolved earlier elsewhere, the question then becomes why the galaxy has not been colonized already. Even if colonization is impractical or undesirable to all alien civilizations, large-scale exploration of the galaxy is still possible using various means of exploration and theoretical probes. However, no signs of either colonization or exploration have been generally acknowledged.

THE GALAXY CAN BE COLONIZED IN A FEW TENS OF MILLIONS OF YEARS Travel times may well explain the lack of physical presence on Earth of alien inhabitants of far away galaxies, but a sufficiently advanced civilization could potentially be observable over a significant fraction of the size of the observable universe. Even if such civilizations are rare, the scale argument indicates they should exist somewhere at some point during the history of the universe, and since they could be detected from far away over a considerable period of time, many more potential sites for their origin are within range of our observation. However, no incontrovertible signs of such civilizations have been detected.

For thousands of years, astromers and astrophysicist have been searching for signs of life in our universe. But only recently have we begun to understand how and where to look for these signs of life. New technology and scientific methods are helping us to understand our place in the vastness of space, and have led to the discovery of habitable planets much like our own only a few thousand lightyears away.

“If an alien lands on your front lawn and extends an appendage as a gesture of greeting, before you get friendly, toss it an eightball. If the appendage explodes, then the alien was probably made of antimatter. If not, then you can proceed to take it to your leader.” If the person on next to me on a long airplane flight ever finds out that I am an astrophysicist, nine times out of ten they ask, with wide eyes, about life in the universe. And only later do they ask me about the big bang and black holes. I know of no other discipline that triggers such a consistent and reliable reaction in public sentiment. This phenomenon is not limited to Americans. The time-honored question: “What is our place in the universe” might just be genetically encoded in our species. All known cultures across all of time have attempted to answer that question. Today we ask the same question, but with fewer words: “Are we alone?” Ordinarily, there is no riskier step that a scientist (or anyone) can take than to make sweeping generalizations from just one example. At the moment, life on Earth is the only known life in the universe, but there are compelling arguments to suggest we are not alone. Indeed, most astrophysicists accept a high probability of there being life elsewhere in the universe, if not on other planets or on moons within our

Neil DeGrasse Tyson

own solar system. The numbers are, well, astronomical: If the count of planets in our solar system is not unusual, then there are more planets in the universe than the sum of all sounds and words ever uttered by every human who has ever lived. To declare that Earth must be the only planet in the cosmos with life would be inexcusably egocentric of us. Many generations of thinkers, both religious and scientific, have been led astray by anthropic assumptions, while others were simply led astray by ignorance. In the absence of dogma and data, history tells us that it’s prudent to be guided by the notion that we are not special, which is generally known as the Copernican principle, named for the Polish astronomer Nicholas Copernicus who, in the mid 1500s, put the Sun back in the middle of our solar system where it belongs. In spite of a third century B.C. account of a sun-centered universe proposed by the Greek philosopher Aristarchus, the Earth-centered universe was by far the most popular view for most of the last 2000 years. Codified by the teachings of Aristotle and Ptolemy, and by the preachings of the Roman Catholic Church, people generally accepted Earth as the center of all motion. It was self-evident: the universe not only looked that way, but God surely made it so. The sixteenth century Italian monk Giordano Bruno suggested publicly that an infinite universe was filled with planets that harbor life. For these thoughts he was burned upside down and naked at the stake. Fortunately, today we live in somewhat more tolerant times.

While there is no guarantee that the Copernican principle will guide us correctly for all scientific discoveries to come, it has humbled our egos with the realization that not only is Earth not in the center of the solar system, but the solar system is not in the center of the Milky Way galaxy, and the Milky Way galaxy is not in the center of the universe. And in case you are one of those people who thinks that the edge may be a special place, then we are not at the edge of anything either. A wise contemporary posture would be to assume that life on Earth is not immune to the Copernican principle. If so, then how can the appearance or the chemistry of life on Earth provide clues to what life might be like elsewhere in the universe?

N = N* The Number of stars in the Milky Way Galaxy

How can we estimate the number of technological civilizations that might exist among the stars? While working as a radio astronomer at the National Radio Astronomy Observatory in Green Bank, West Virginia, Dr. Frank Drake conceived an approach to bound the terms involved in estimating the number of technological civilizations that may exist in our galaxy. The Drake Equation, as it has become known, was first presented by Drake in 1961 and identifies specific factors thought to play a role in the development of such civilizations. Although there is no unique solution to this equation, it is a generally accepted tool used by the scientific community to examine these factors.

The number of advanced technological civilizations in the Milky Way Galaxy

DR AK Eâ&#x20AC;&#x2122;S EQUATION

The fraction of the life of a planet that a technological civilization survives

The fraction of those planets with intelligent life that develop a technilogical civilization

The fraction of those planets with life on which intelligent life appears

The fraction of those planets on which life actually arises

The average number of planets in a given planetary system that are suitable for the development of life

The fraction of those stars that have planetary systems around them

f n f f f f * c

PLANETARY HABITABILY Planetary habitability is the measure of a planet’s or a natural satellite’s potential to develop and sustain life. Life may develop directly on a planet or satellite or be transferred to it from another body, a theoretical process known as panspermia. As the existence of life beyond Earth is unknown, planetary habitability is largely an extrapolation of conditions on Earth and the characteristics of the Sun and Solar System which appear favourable to life’s flourishing— in particular those factors that have sustained complex, multicellular organisms and not just simpler, unicellular creatures. Research and theory in this regard is a component of planetary science and the emerging discipline of astrobiology. An absolute requirement for life is an energy source, and the notion of planetary habitability implies that many other geophysical,

geochemical, and astrophysical criteria must be met before an astronomical body can support life. In its astrobiology roadmap, NASA has defined the principal habitability criteria as “extended regions of liquid water, conditions favourable for the assembly of complex organic molecules, and energy sources to sustain metabolism.” In determining the habitability potential of a body, studies focus on its bulk composition, orbital properties, atmosphere, and potential chemical interactions. Stellar characteristics of importance include mass and luminosity, stable variability, and high metallicity. Rocky, terrestrial-type planets and moons with the potential for Earth-like chemistry are a primary focus of astrobiological research, although more speculative habitability theories occasionally examine alternative biochemistries and other types of astronomical bodies.

HABITABLE ZONE

MASS OF STAR RELATIVE TO SUN

The idea that planets beyond Earth might host life is an ancient one, though historically it was framed by philosophy as much as physical science.[a] The late 20th century saw two breakthroughs in the field. The observation and robotic spacecraft exploration of other planets and moons within the Solar System has provided critical information on defining habitability criteria and allowed for substantial geophysical comparisons between the Earth and other bodies. The discovery of extrasolar planets, beginning in the early 1990s and accelerating thereafter, has provided further information for the study of possible extraterrestrial life. These findings confirm that the Sun is not unique among stars in hosting planets and expands the habitability research horizon beyond the Solar System.

Mars Earth Venus 0.5

0.1

RADIUS OF ORBIT RELATIVE TO EARTH’S

? ?

The SETI Institute is a not-for-profit organization whose mission is to “explore, understand and explain the origin, nature and prevalence of life in the universe”. SETI stands for the “search for extraterrestrial intelligence”. One program is the use of both radio and optical telescopes to search for deliberate signals from extraterrestrial intelligence. Other research, pursued within the Carl Sagan Center for the Study of Life in the Universe, includes the discovery of extrasolar planets, potentials for life on Mars and other bodies within the Solar System, and the habitability of the galaxy

“I believe alien life is quite common in the universe, although intelligent life is less so. Some say it has yet to appear on planet Earth. Look up at the stars and not down at your feet. Try to make sense of what you see, and wonder about what makes the universe exist.” In this talk, I would like to speculate a little, on the development of life in the universe, and in particular, the development of intelligent life. I shall take this to include the human race, even though much of its behaviour through out history, has been pretty stupid, and not calculated to aid the survival of the species. Two questions I shall discuss are, ‘What is the probability of life existing else where in the universe?’ and, ‘How may life develop in the future?’ It is a matter of common experience, that things get more disordered and chaotic with time. This observation can be elevated to the status of a law, the so-called Second Law of Thermodynamics. This says that the total amount of disorder, or entropy, in the universe, always increases with time. However, the Law refers only to the total amount of disorder. The order in one body can increase, provided that the amount of disorder in its surroundings increases by a greater amount. This is what happens in a living being. One can define Life to be an ordered system that can sustain itself against the tendency to disorder, and can reproduce itself. That is, it can make similar, but independent, ordered systems. To do these things, the system must convert energy in some ordered form, like food, sunlight, or electric power, into disordered energy, in the form of heat. In this way, the system can satisfy the requirement that the

Stephen Hawking

total amount of disorder increases, while, at the same time, increasing the order in itself and its offspring. A living being usually has two elements: a set of instructions that tell the system how to sustain and reproduce itself, and a mechanism to carry out the instructions. In biology, these two parts are called genes and metabolism. But it is worth emphasising that there need be nothing biological about them. For example, a computer virus is a program that will make copies of itself in the memory of a computer, and will transfer itself to other computers. Thus it fits the definition of a living system, that I have given. Like a biological virus, it is a rather degenerate form, because it contains only instructions or genes, and doesn’t have any metabolism of its own. Instead, it reprograms the metabolism of the host computer, or cell. Some people have questioned whether viruses should count as life, because they are parasites, and can not exist independently of their hosts. But then most forms of life, ourselves included, are parasites, in that they feed off and depend for their survival on other forms of life. I think computer viruses should count as life. Maybe it says something about human nature, that the only form of life we have created so far is purely destructive. Talk about creating life in our own image. I shall return to electronic forms of life later on. What we normally think of as ‘life’ is based on chains of carbon atoms, with a few other atoms, such as nitrogen or phosphorous. One can speculate that one might have life with some other chemical basis, such as silicon, but carbon seems the most favourable case, because it has the richest chemistry. That carbon atoms should exist at all, with the properties that they have, requires a fine adjustment of physical constants, such as the QCD scale, the electric charge, and even the dimension of space-time. If these constants had significantly different values, either the nucleus of the carbon atom would not be stable, or the electrons would collapse in on the nucleus. At first sight, it seems remarkable that the universe is so finely tuned. Maybe this is evidence, that the universe was specially designed to produce the human race. However, one has to be careful about such

arguments, because of what is known as the Anthropic Principle. This is based on the self-evident truth, that if the universe had not been suitable for life, we wouldn’t be asking why it is so finely adjusted. One can apply the Anthropic Principle, in either its Strong, or Weak, versions. For the Strong Anthropic Principle, one supposes that there are many different universes, each with different values of the physical constants. In a small number, the values will allow the existence of objects like carbon atoms, which can act as the building blocks of living systems. Since we must live in one of these universes, we should not be surprised that the physical constants are finely tuned. If they weren’t, we wouldn’t be here. The strong form of the Anthropic Principle is not very satisfactory. What operational meaning can one give to the existence of all those other universes? And if they are separate from our own universe, how can what happens in them, affect our universe. Instead, I shall adopt what is known as the Weak Anthropic Principle. That is, I shall take the values of the physical constants, as given. But I shall see what conclusions can be drawn, from the fact that life exists on this planet, at this stage in the history of the universe. There was no carbon, when the universe began in the Big Bang, about 15 bil lion years ago. It was so hot, that all the matter would have been in the form of particles, called protons and neutrons. There would initially have been equal numbers of protons and neutrons. However, as the universe expanded, it would have cooled. About a minute after the Big Bang, the temperature would have fallen to about a billion degrees, about a hundred times the temperature in the Sun. At this temperature, the neutrons will start to decay into more protons. If this had been all that happened, all the matter in the universe would have ended up as the simplest element, hydrogen, whose nucleus consists of a single proton. However, some of the neutrons collided with protons, and stuck together to form the next simplest element, helium, whose nucleus consists of two protons and two neutrons. But no heavier elements, like carbon or oxygen, would have been formed in the early universe. It is difficult to imag-

ine that one could build a living system, out of just hydrogen and helium, and anyway the early universe was still far too hot for atoms to combine into molecules. The universe would have continued to expand, and cool. But some regions would have had slightly higher densities than others. The gravitational attraction of the extra matter in those regions, would slow down their expansion, and eventually stop it. Instead, they would collapse to form galaxies and stars, starting from about two billion years after the Big Bang. Some of the early stars would have been more massive than our Sun. They would have been hotter than the Sun, and would have burnt the original hydrogen and helium, into heavier elements, such as carbon, oxygen, and iron. This could have taken only a few hundred million years. After that, some of the stars would have exploded as supernovas, and scattered the heavy elements back into space, to form the raw material for later generations of stars.

Other stars are too far away, for us to be able to see directly, if they have planets going round them. But certain stars, called pulsars, give off regular pulses of radio waves. We observe a slight variation in the rate of some pulsars, and this is interpreted as indicating that they are being disturbed, by having Earth sized planets going round them. Planets going round pulsars are unlikely to have life, because any living beings would have been killed, in the supernova explosion that led to the star becoming a pulsar. But, the fact that several pulsars are observed to have planets suggests that a reasonable fraction of the hundred billion stars in our galaxy may also have planets. The necessary planetary conditions for our form of life may therefore have existed from about four billion years after the Big Bang. Our solar system was formed about four and a half billion years ago, or about ten billion years after the Big Bang, from gas contaminated with the remains of earlier stars. The Earth was formed largely out of the heavier elements, including carbon

and oxygen. Somehow, some of these atoms came to be arranged in the form of molecules of DNA. This has the famous double helix form, discovered by Crick and Watson, in a hut on the New Museum site in Cambridge. Linking the two chains in the helix, are pairs of nucleic acids. There are four types of nucleic acid, adenine, cytosine, guanine, and thiamine. Iâ&#x20AC;&#x2122;m afraid my speech synthesiser is not very good, at pronouncing their names. Obviously, it was not designed for molecular biologists. An adenine on one chain is always matched with a thiamine on the other chain, and a guanine with a cytosine. Thus the sequence of nucleic acids on one chain defines a unique, complementary sequence, on the other chain. The two chains can then separate and each act as templates to build further chains. Thus DNA molecules can reproduce the genetic information, coded in their sequences of nucleic acids. Sections of the sequence can also be used to make proteins and other chemicals, which can carry out the instructions, coded in the sequence, and assemble the raw material for DNA to reproduce itself.

We do not know how DNA molecules first appeared. The chances against a DNA molecule arising by random fluctuations are very small. Some people have therefore suggested that life came to Earth from elsewhere, and that there are seeds of life floating round in the galaxy. However, it seems unlikely that DNA could survive for long in the radiation in space. And even if it could, it would not really help explain the origin of life, because the time available since the formation of carbon is only just over double the age of the Earth. One possibility is that the formation of something like DNA, which could reproduce itself, is extremely unlikely. However, in a universe with a very large, or infinite, number of stars, one would expect it to occur in a few stellar systems, but they would be very widely separated. The fact that life happened to occur on Earth, is not however surprising or unlikely. It is just an application of the Weak Anthropic Principle: if life had appeared instead on another planet, we would be asking why it had occurred there. If the appearance of life on a given planet was very unlikely, one might have expected it to take a long time. More precisely, one might have expected life to appear just in time for the subsequent evolution to intelligent beings, like us, to have occurred before the cut off, provided by the life time of the Sun. This is about ten billion years, after which the Sun will swell up and engulf the Earth. An intelligent form of life, might have mastered space travel, and be able to escape to another star. But otherwise, life on Earth would be doomed.

There is fossil evidence, that there was some form of life on Earth, about three and a half billion years ago. This may have been only 500 million years after the Earth became stable and cool enough, for life to develop. But life could have taken 7 billion years to develop, and still have left time to evolve to beings like us, who could ask about the origin of life. If the probability of life developing on a given planet, is very small, why did it happen on Earth, in about one 14th of the time available. The early appearance of life on Earth suggests that thereâ&#x20AC;&#x2122;s a good chance of the spontaneous generation of life, in suitable conditions. Maybe there was some simpler form of organisation, which built up DNA. Once DNA appeared, it would have been so successful, that it might have completely replaced the earlier forms. We donâ&#x20AC;&#x2122;t know what these earlier forms would have been. One possibility is RNA. This is like DNA, but rather simpler, and without the double helix structure. Short lengths of RNA, could reproduce themselves like DNA, and might eventually build up to DNA. One can not make nucleic acids in the laboratory, from non-living material, let alone RNA. But given 500 million years, and oceans covering most of the Earth, there might be a reasonable probability of RNA, being made by chance. As DNA reproduced itself, there would have been random errors. Many of these errors would have been harmful, and would have died out. Some would have been neutral. That is they would not have affected the function of the gene. Such errors would

contribute to a gradual genetic drift, which seems to occur in all populations. And a few errors would have been favourable to the survival of the species. These would have been chosen by Darwinian natural selection. The process of biological evolution was very slow at first. It took two and a half billion years, to evolve from the earliest cells to multi-cell animals, and another billion years to evolve through fish and reptiles, to mammals. But then evolution seemed to have speeded up. It only took about a hundred million years, to develop from the early mammals to us. The reason is, fish contain most of the important human organs, and mammals, essentially all of them. All that was required to evolve from early mammals, like lemurs, to humans, was a bit of fine-tuning. But with the human race, evolution reached a critical stage, comparable in importance with the development of DNA. This was the development of language, and particularly written language. It meant that information can be passed on, from generation to generation, other than genetically, through DNA. There has been no detectable change in human DNA, brought about by biological evolution, in the ten thousand years of recorded history. But the amount of knowledge handed on from genera tion to generation has grown enormously. The DNA in human beings contains about three billion nucleic acids. However, much of the information coded in this sequence, is redundant, or is inactive. So the total amount of useful information in our genes, is probably something like a hundred million

bits. One bit of information is the answer to a yes no question. By contrast, a paper back novel might contain two million bits of information. So a human is equivalent to 50 Mills and Boon romances. A major national library can contain about five million books, or about ten trillion bits. So the amount of information handed down in books, is a hundred thousand times as much as in DNA. Even more important, is the fact that the information in books, can be changed, and updated, much more rapidly. It has taken us several million years to evolve from the apes. During that time, the useful information in our DNA, has probably changed by only a few million bits. So the rate of biological evolution in humans, is about a bit a year. By contrast, there are about 50,000 new books published in the English language each year, containing of the order of a hundred billion bits of information. Of course, the great majority of this information is garbage, and no use to any form of life. But, even so, the rate at which useful information can be added is millions, if not billions, higher than with DNA. This has meant that we have entered a new phase of evolution. At first, evolution proceeded by natural selection, from random mutations. This Darwinian phase, lasted about three and a half billion years, and pro-

duced us, beings who developed language, to exchange information. But in the last ten thousand years or so, we have been in what might be called, an external transmission phase. In this, the internal record of information, handed down to succeeding generations in DNA, has not changed significantly. But the external record, in books, and other long lasting forms of storage, has grown enormously. Some people would use the term, evolution, only for the internally transmitted genetic material, and would object to it being applied to information handed down externally. But I think that is too narrow a view. We are more than just our genes. We may be no stronger, or inherently more intelligent, than our cave man ancestors. But what distinguishes us from them, is the knowledge that we have accumulated over the last ten thousand years, and particularly, over the last three hundred. I think it is legitimate to take a broader view, and include externally transmitted information, as well as DNA, in the evolution of the human race. The time scale for evolution, in the external transmission period, is the time scale for accumulation of information. This used to be hundreds, or even thousands, of years. But now this time scale has shrunk to about 50 years, or less. On the other hand, the brains with which we process this information have evolved only on the Darwinian

time scale, of hundreds of thousands of years. This is beginning to cause problems. In the 18th century, there was said to be a man who had read every book written. But nowadays, if you read one book a day, it would take you about 15,000 years to read through the books in a national Library. By which time, many more books would have been written. This has meant that no one person can be the master of more than a small corner of human knowledge. People have to specialise, in narrower and narrower fields. This is likely to be a major limitation in the future. We certainly can not continue, for long, with the exponential rate of growth of knowledge that we have had in the last three hundred years. An even greater limitation and danger for future generations, is that we still have the instincts, and in particular, the aggressive impulses, that we had in cave man days. Aggression, in the form of subjugating or killing other men, and taking their women and food, has had definite survival advantage, up to the present time. But now it could destroy the entire human race, and much of the rest of life on Earth. A nuclear war, is still the most immediate danger, but there are others, such as the release of a genetically engineered virus. Or the green house effect becoming unstable. There is no time, to wait for Darwinian

evolution, to make us more intelligent, and better natured. But we are now entering a new phase, of what might be called, self designed evolution, in which we will be able to change and improve our DNA. There is a project now on, to map the entire sequence of human DNA. It will cost a few billion dollars, but that is chicken feed, for a project of this importance. Once we have read the book of life, we will start writing in corrections. At first, these changes will be confined to the repair of genetic defects, like cystic fibrosis, and muscular dystrophy. These are controlled by single genes, and so are fairly easy to identify, and correct. Other qualities, such as intelligence, are probably controlled by a large number of genes. It will be much more difficult to find them, and work out the relations between them. Nevertheless, I am sure that during the next century, people will discover how to modify both intelligence, and instincts like aggression. Laws will be passed, against genetic engineering with humans. But some people won’t be able to resist the temptation, to improve human characteristics, such as size of memory, resistance to disease, and length of life. Once such super humans appear, there are going to be major political problems, with the unimproved humans, who won’t be able to compete. Presumably, they will die out, or become unimportant.

Instead, there will be a race of self-designing beings, who are improving themselves at an ever-increasing rate. If this race manages to redesign itself, to reduce or eliminate the risk of self- destruction, it will probably spread out, and colonise other planets and stars. However, long distance space travel, will be difficult for chemically based life forms, like DNA. The natural lifetime for such beings is short, compared to the travel time. According to the theory of relativity, nothing can travel faster than light. So the round trip to the nearest star would take at least 8 years, and to the centre of the galaxy, about a hundred thousand years. In science fiction, they overcome this difficulty, by space warps, or travel through extra dimensions. But I don’t think these will ever be possible, no matter how intelligent life becomes. In the theory of relativity, if one can travel faster than light, one can also travel back in time. This would lead to problems with people going back, and changing the past. One would also expect to have seen large numbers of tourists from the future, curious to look at our quaint, old-fashioned ways. It might be possible to use genetic engineering, to make DNA based life survive indefinitely, or at least for a hundred thousand years. But an easier way, which is almost within our capabilities already,

would be to send machines. These could be designed to last long enough for interstellar travel. When they arrived at a new star, they could land on a suitable planet, and mine material to produce more machines, which could be sent on to yet more stars. These machines would be a new form of life, based on mechanical and electronic components, rather than macromolecules. They could eventually replace DNA based life, just as DNA may have replaced an earlier form of life. This mechanical life could also be self-designing. Thus it seems that the external transmission period of evolution, will have been just a very short interlude, between the Darwinian phase, and a biological, or mechanical, self design phase. This is shown on this next diagram, which is not to scale, because there’s no way one can show a period of ten thousand years, on the same scale as billions of years. How long the self-design phase will last is open to question. It may be unstable, and life may destroy itself, or get into a dead end. If it does not, it should be able to survive the death of the Sun, in about 5 billion years, by moving to planets around other stars. Most stars will have burnt out in another 15 billion years or so, and the universe will be approaching a state of complete disorder, according to the Second Law of Thermodynamics. But Freeman Dyson has

shown that, despite this, life could adapt to the ever-decreasing supply of ordered energy, and therefore could, in principle, continue forever. What are the chances that we will encounter some alien form of life, as we explore the galaxy. If the argument about the time scale for the appearance of life on Earth is correct, there ought to be many other stars, whose planets have life on them. Some of these stellar systems could have formed 5 billion years before the Earth. So why is the galaxy not crawling with self designing mechanical or biological life forms? Why hasn’t the Earth been visited, and even colonised. I discount suggestions that UFO’s contain beings from outer space. I think any visits by aliens, would be much more obvious, and probably also, much more unpleasant. What is the explanation of why we have not been visited? One possibility is that the argument, about the appearance of life on Earth, is wrong. Maybe the probability of life spontaneously appearing is so low, that Earth is the only planet in the galaxy, or in the observable universe, in which it happened. Another possibility is that there was a reasonable probability of forming self reproducing systems, like cells, but that most of these forms of life did not evolve intelligence. We are used to thinking of intelligent life, as an inevitable consequence of evolution. But the Anthropic Principle should warn us to be wary of such arguments. It is more likely that evolution is a random process, with intelligence as only one of a large number of possible outcomes. It is not clear that intelligence has any long-term survival value. Bacteria, and other single cell organisms, will live on, if all other life on Earth is wiped out by our actions. There is support for the view that intelligence, was an unlikely development for life on Earth, from the chronology of evolution. It took a very long time, two and a half billion years, to go from single cells to multi-cell beings, which are a necessary precursor to intelligence. This is a good fraction of the total time available, before the Sun blows up. So it would be consistent with the hypothesis, that the probability for life to develop intelligence, is

low. In this case, we might expect to find many other life forms in the galaxy, but we are unlikely to find intelligent life. Another way, in which life could fail to develop to an intelligent stage, would be if an asteroid or comet were to collide with the planet. We have just observed the collision of a comet, Schumacher-Levi, with Jupiter. It produced a series of enormous fireballs. It is thought the collision of a rather smaller body with the Earth, about 70 million years ago, was responsible for the extinction of the dinosaurs. A few small early mammals survived, but anything as large as a human, would have almost certainly been wiped out. It is difficult to say how often such collisions occur, but a reasonable guess might be every twenty million years, on average. If this figure is correct, it would mean that intelligent life on Earth has developed only because of the lucky chance that there have been no major collisions in the last 70 million years. Other planets in the galaxy, on which life has developed, may not have had a long enough collision free period to evolve intelligent beings. A third possibility is that there is a reasonable probability for life to form, and to evolve to intelligent beings, in the external transmission phase. But at that point, the system becomes unstable, and the intelligent life destroys itself. This would be a very pessimistic conclusion. I very much hope it isn’t true. I prefer a fourth possibility: there are other forms of intelligent life out there, but that we have been overlooked. There used to be a project called SETI, the search for extra-terrestrial intelligence. It involved scanning the radio frequencies, to see if we could pick up signals from alien civilisations. I thought this project was worth supporting, though it was cancelled due to a lack of funds. But we should have been wary of answering back, until we have develop a bit further. Meeting a more advanced civilisation, at our present stage, might be a bit like the original inhabitants of America meeting Columbus. I don’t think they were better off for it.

Name Distance Volume Diameter Location Age

Horseshoe Nebula 3 Light Years 1.134 billion cubic tons 2.5 Light Years 242,185,573 4 billion years

HUBBLE TELESCOPE Manufactured By Launch Mass Dimensions Power Telescope Type Diameter Focal Length Collecting Area Wavelengths

Perkin-Elmer (optics) Lockheed (spacecraft) 24,490 lbs. 43 ft. x 14 ft. 2800 watts Ritchey–Chrétien reflector 7.9 ft. 189 ft. 48 sq. ft. Near-infrared Visible Light Ultraviolet

The Hubble Space Telescope (HST) is a space telescope that was launched into low Earth orbit in 1990, and remains in operation. With a 2.4-meter (7.9 ft) mirror, Hubble’s four main instruments observe in the near ultraviolet, visible, and near infrared spectra. The telescope is named after the astronomer Edwin Hubble. Hubble’s orbit outside the distor tion of Earth’s atmosphere allows it to take extremely high-resolution images with negligible background light. Hubble has recorded some of the most detailed visible-light images ever, allowing a deep view into space and time. Many Hubble observations have led to breakthroughs in astrophysics, such as accurately determining the rate of expansion of the universe.

KEPLER TELESCOPE Launch Mass Dry Mass Payload Mass Dimensions Power

Ball Aerospace & Technologies 2,320 lbs. 2,294 lbs. 1,054 lbs. 15.4 ft × 8.9 ft 1100 watts

Telescope Type Diameter Collecting Area Wavelengths

Schmidt 3.1 ft. 7.62 sq ft. 430 – 890 nm

Manufactured By

Kepler is a space observatory launched by NASA to discover Earth-like planets orbiting other stars. The spacecraft, named after the Renaissance astronomer Johannes Kepler, was launched on March 7, 2009. Designed to survey a portion of our region of the Milky Way to discover dozens of Earthsize extrasolar planets in or near the habitable zone and estimate how many of the billions of stars in our galaxy have such planets, Kepler ‘ s sole instrument is a photometer that continually monitors the brightness of over 145,000 main sequence stars in a fixed field of view. These data are transmitted to Earth, then analyzed to detect periodic dimming caused by extrasolar planets that cross in front of their host star.

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12 35

KEPLER-186

KEPLER-62 186f

186e

186d

186c

186b

62b

62c

62d

62e

62f

KEPLER-69

69b

69c

SOLAR SYSTEM

Mercury

Venus

Earth

Mars

HABITABLE ZONE

Name Distance Volume Diameter Location Age

Crab Nebula 6 Light Years 2.77 billion cubic tons 3 Light Years 242, 185, 573 7 billion years

KEPLER 186 Using NASA’s Kepler Space Telescope, astronomers have discovered the first Earthsize planet orbiting a star in the “habitable zone” -- the range of distance from a star where liquid water might pool on the surface of an orbiting planet. The discovery of Kepler-186f confirms that planets the size of Earth exist in the habitable zone of stars other than our sun. While planets have previously been found in the habitable zone, they are all at least 40 percent larger in size than Earth and understanding their makeup is challenging. Kepler-186f is more reminiscent of Earth. “The discovery of Kepler-186f is a significant step toward finding worlds like our planet Earth,” said Paul Hertz, NASA’s Astrophysics Division director at the agency’s headquar-

ters in Washington. “Future NASA missions, like the Transiting Exoplanet Survey Satellite and the James Webb Space Telescope, will discover the nearest rocky exoplanets and determine their composition and atmospheric conditions, continuing humankind’s quest to find truly Earth-like worlds.” Although the size of Kepler-186f is known, its mass and composition are not. Previous research, however, suggests that a planet the size of Kepler-186f is likely to be rocky. “We know of just one planet where life exists -- Earth. When we search for life outside our solar system we focus on finding planets with characteristics that mimic that of Earth,” said Elisa Quintana, research scientist at the SETI Institute at NASA’s Ames Research Center in Moffett Field, Calif., and

lead author of the paper published today in the journal Science. “Finding a habitable zone planet comparable to Earth in size is a major step forward.” Kepler-186f resides in the Kepler-186 system, about 500 light-years from Earth in the constellation Cygnus. The system is also home to four companion planets, which orbit a star half the size and mass of our sun. The star is classified as an M dwarf, or red dwarf, a class of stars that makes up 70 percent of the stars in the Milky Way galaxy. “M dwarfs are the most numerous stars,” said Quintana. “The first signs of other life in the galaxy may well come from planets orbiting an M dwarf.”

Using NASA’s Kepler Space Telescope, astronomers have discovered the first Earthsize planet orbiting a star in the “habitable zone” -- the range of distance from a star where liquid water might pool on the surface of an orbiting planet. The discovery of Kepler-186f confirms that planets the size of Earth exist in the habitable zone of stars other than our sun. While planets have previously been found in the habitable zone, they are all at least 40 percent larger in size than Earth and understanding their makeup is challenging. Kepler-186f is more reminiscent of Earth. “The discovery of Kepler-186f is a significant step toward finding worlds like our planet Earth,” said Paul Hertz, NASA’s Astrophysics Division director at the agency’s headquarters in Washington. “Future NASA missions, like the Transiting Exoplanet Survey Satellite and the James Webb Space Telescope, will discover the nearest rocky exoplanets and determine their composition and atmospheric conditions, continuing humankind’s quest to find truly Earth-like worlds.” Although the size of Kepler-186f is known, its mass and composition are not. Previous research, however, suggests that a planet the size of Kepler-186f is likely to be rocky. “We know of just one planet where life exists -- Earth. When we search for life outside our solar system we focus on finding planets with characteristics that mimic that of Earth,” said Elisa Quintana, research scientist at the SETI Institute at NASA’s Ames Research Center in Moffett Field, Calif., and lead author of the paper published today in

the journal Science. “Finding a habitable zone planet comparable to Earth in size is a major step forward.” Kepler-186f resides in the Kepler-186 system, about 500 light-years from Earth in the constellation Cygnus. The system is also home to four companion planets, which orbit a star half the size and mass of our sun. The star is classified as an M dwarf, or red dwarf, a class of stars that makes up 70 percent of the stars in the Milky Way galaxy. “M dwarfs are the most numerous stars,” said Quintana. “The first signs of other life in the galaxy may well come from planets orbiting an M dwarf.” Kepler-186f orbits its star once every 130days and receives one-third the energy from its star that Earth gets from the sun, placing it nearer the outer edge of the habitable zone. On the surface of Kepler-186f, the brightness of its star at high noon is only as bright as our sun appears to us about an hour before sunset. “Being in the habitable zone does not mean we know this planet is habitable. The temperature on the planet is strongly dependent on what kind of atmosphere the planet has,” said Thomas Barclay, research scientist at the Bay Area Environmental Research Institute at Ames, and co-author of the paper. “Kepler-186f can be thought of as an Earthcousin rather than an Earth-twin. It has many properties that resemble Earth.” The four companion planets, Kepler-186b, Kepler-186c, Kepler-186d, and Kepler-186e, whiz around their sun every four, seven, 13,

and 22 days, respectively, making them too hot for life as we know it. These four inner planets all measure less than 1.5 times the size of Earth. The next steps in the search for distant life include looking for true Earth-twins -- Earthsize planets orbiting within the habitable zone of a sun-like star -- and measuring the their chemical compositions. The Kepler Space Telescope, which simultaneously and continuously measured the brightness of more than 150,000 stars, is NASA’s first mission capable of detecting Earth-size planets around stars like our sun. Ames is responsible for Kepler’s ground system development, mission operations, and science data analysis. NASA’s Jet Propulsion Laboratory in Pasadena, Calif., managed Kepler mission development. Ball Aerospace & Technologies Corp. in Boulder, Colo., developed the Kepler flight system and supports mission operations with the Laboratory for Atmospheric and Space Physics at the University of Colorado in Boulder. The Space Telescope Science Institute in Baltimore archives, hosts and distributes Kepler science data. Kepler is NASA’s 10th Discovery Mission and was funded by the agency’s Science Mission Directorate.

If we do discover intelligent alien life anytime soon, what will the outcome be? Will they be civil and diplomatic? Or will they be in the process of colonizing the galaxy, destroying our human race and taking over our planet with no remorse? Unfortunately, the answer to this question is and will forever be unknown, until that fateful day when they decide to descend upon us either coming in peace or blasting everything in sight with their space lasers.

“They’re made out of meat.” “Meat?”

“Nope. We thought of that, since they do have meat heads, like the weddilei. But I told you, we probed them. They’re meat all the way through.”

“Meat. They’re made out of meat.”

“Oh, there’s a brain all right. It’s just that the brain is made out of meat! That’s what I’ve been trying to tell you.” “So ... what does the thinking?”

“I was hoping you would say that.”

“You’re not understanding, are you? You’re refusing to deal with what I’m telling you. The brain does the thinking. The meat.”

“It seems harsh, but there is a limit. Do we really want to make contact with meat?”

“Meat?”

“That’s impossible. What about the radio signals? The messages to the stars?” “They use the radio waves to talk, but the signals don’t come from them. The signals come from machines.” “So who made the machines? That’s who we want to contact.” “They made the machines. That’s what I’m trying to tell you. Meat made the machines.” “That’s ridiculous. How can meat make a machine? You’re asking me to believe in sentient meat.” “I’m not asking you, I’m telling you. These creatures are the only sentient race in that sector and they’re made out of meat.” “Maybe they’re like the orfolei. You know, a carbon-based intelligence that goes through a meat stage.” “Nope. They’re born meat and they die meat. We studied them for several of their life spans, which didn’t take long. Do you have any idea what’s the life span of meat?” Spare me. Okay, maybe they’re only part meat. You know, like the weddilei. A meat head with an electron plasma brain inside.”

Terry Bisson

They’re Made Out of Meat?

“Both.” “Officially, we are required to contact, welcome and log in any and all sentient races or multibeings in this quadrant of the Universe, without prejudice, fear or favor. Unofficially, I advise that we erase the records and forget the whole thing.”

“No brain?”

“There’s no doubt about it. We picked up several from different parts of the planet, took them aboard our recon vessels, and probed them all the way through. They’re completely meat.”

“Officially or unofficially?”

“Thinking meat! You’re asking me to believe in thinking meat!” “Yes, thinking meat! Conscious meat! Loving meat. Dreaming meat. The meat is the whole deal! Are you beginning to get the picture or do I have to start all over?” “Omigod. You’re serious then. They’re made out of meat.” “Thank you. Finally. Yes. They are indeed made out of meat. And they’ve been trying to get in touch with us for almost a hundred of their years.”

“I agree one hundred percent. What’s there to say? ‘Hello, meat. How’s it going?’ But will this work? How many planets are we dealing with here?” “Just one. They can travel to other planets in special meat containers, but they can’t live on them. And being meat, they can only travel through C space. Which limits them to the speed of light and makes the possibility of their ever making contact pretty slim. Infinitesimal, in fact.” “So we just pretend there’s no one home in the Universe.” “That’s it.”

“Omigod. So what does this meat have in mind?” “First it wants to talk to us. Then I imagine it wants to explore the Universe, contact other sentiences, swap ideas and information. The usual.” “We’re supposed to talk to meat.” “That’s the idea. That’s the message they’re sending out by radio. ‘Hello. Anyone out there. Anybody home.’ That sort of thing.” “They actually do talk, then. They use words, ideas, concepts?” “Oh, yes. Except they do it with meat.” “I thought you just told me they used radio.” “They do, but what do you think is on the radio? Meat sounds. You know how when you slap or flap meat, it makes a noise? They talk by flapping their meat at each other. They can even sing by squirting air through their meat.” “Omigod. Singing meat. This is altogether too much. So what do you advise?”

“Cruel. But you said it yourself, who wants to meet meat? And the ones who have been aboard our vessels, the ones you probed? You’re sure they won’t remember?” “They’ll be considered crackpots if they do. We went into their heads and smoothed out their meat so that we’re just a dream to them.” “A dream to meat! How strangely appropriate, that we should be meat’s dream.” “A n d we m a r ke d t h e e nt i re s e c to r unoccupied.” “Good. Agreed, officially and unofficially. Case closed. Any others? Anyone interesting on that side of the galaxy?” “Yes, a rather shy but sweet hydrogen core cluster intelligence in a class nine star in G445 zone. Was in contact two galactic rotations ago, wants to be friendly again.” “They always come around.” “And why not? Imagine how unbearably, how unutterably cold the Universe would be if one were all alone ...”

BIBLIOGRAPHY Web

NASA. NASA. Web. 7 May 2015.

Dunbar, Brian. NASA. NASA. Web. 7 May 2015.

“Alien Quotes.” Alien Quotes. Web. 7 May 2015.

“Drake Equation.” Drake Equation. Web. 7 May 2015.

Dunbar, Brian. NASA. NASA. Web. 7 May 2015.

NASA. NASA. Web. 7 May 2015.

“Fermi Paradox.” Fermi Paradox. Web. 7 May 2015.

“Fermi Paradox - Crystalinks.” Fermi Paradox Crystalinks. Web. 7 May 2015.

Hawking, Stephen. “Life in the Universe - Stephen Hawking.” Life in the Universe - Stephen Hawking. Web. 7 May 2015.

“Hubble Space Telescope.” Wikipedia. Wikimedia Foundation. Web. 7 May 2015.

“Kepler (spacecraft).” Wikipedia. Wikimedia Foundation. Web. 7 May 2015.

“Planetary Habitability.” The Center for Planetary Science. Web. 7 May 2015.

“Hubble Space Telescope.” Wikipedia. Wikimedia Foundation. Web. 7 May 2015.

“SETI Institute.” SETI Institute. Web. 7 May 2015.

“Stephen Hawking Looks at the History of Aliens Having a Fine Old Time.” Web. 7 May 2015.

“TERRY BISSON of the UNIVERSE.” Meat. Web. 7 May 2015.

“Stephen Hawking Looks at the History of Aliens Having a Fine Old Time.” Web. 7 May 2015.

“Alien Quotes.” Alien Quotes. Web. 7 May 2015.

Hawking, Stephen. “Life in the Universe - Stephen Hawking.” Life in the Universe - Stephen Hawking. Web. 7 May 2015.

NASA. NASA. Web. 7 May 2015. “SETI Institute.” SETI Institute. Web. 7 May 2015. “Fermi Paradox.” Fermi Paradox. Web. 7 May 2015. Dunbar, Brian. NASA. NASA. Web. 7 May 2015. “TERRY BISSON of the UNIVERSE.” Meat. Web. 7 May 2015. Hawking, Stephen. “Life in the Universe - Stephen Hawking.” Life in the Universe - Stephen Hawking. Web. 7 May 2015.

“Drake Equation.” Drake Equation. Web. 7 May 2015. NASA. NASA. Web. 7 May 2015. “Hubble Space Telescope.” Wikipedia. Wikimedia Foundation. Web. 7 May 2015. “Planetary Habitability.” The Center for Planetary Science. Web. 7 May 2015. “TERRY BISSON of the UNIVERSE.” Meat. Web. 7 May 2015.

“Kepler (spacecraft).” Wikipedia. Wikimedia Foundation. Web. 7 May 2015.

“Hubble Space Telescope.” Wikipedia. Wikimedia Foundation. Web. 7 May 2015.

“SETI Institute.” SETI Institute. Web. 7 May 2015. “Fermi Paradox.” Fermi Paradox. Web. 7 May 2015.

“Planetary Habitability.” The Center for Planetary Science. Web. 7 May 2015.

Dunbar, Brian. NASA. NASA. Web. 7 May 2015.

“Drake Equation.” Drake Equation. Web. 7 May 2015.

“Alien Quotes.” Alien Quotes. Web. 7 May 2015.

“Stephen Hawking Looks at the History of Aliens Having a Fine Old Time.” Web. 7 May 2015.

“Fermi Paradox - Crystalinks.” Fermi Paradox Crystalinks. Web. 7 May 2015.

“Stephen Hawking Looks at the History of Aliens Having a Fine Old Time.” Web. 7 May 2015.

Images

NASA. NASA. Web. 7 May 2015. “Alien Quotes.” Alien Quotes. Web. 7 May 2015. “Drake Equation.” Drake Equation. Web. 7 May 2015. Dunbar, Brian. NASA. NASA. Web. 7 May 2015. “Fermi Paradox.” Fermi Paradox. Web. 7 May 2015. “Fermi Paradox - Crystalinks.” Fermi Paradox Crystalinks. Web. 7 May 2015. Hawking, Stephen. “Life in the Universe - Stephen Hawking.” Life in the Universe - Stephen Hawking. Web. 7 May 2015.

Hawking, Stephen. “Life in the Universe - Stephen Hawking.” Life in the Universe - Stephen Hawking. Web. 7 May 2015. “Drake Equation.” Drake Equation. Web. 7 May 2015. NASA. NASA. Web. 7 May 2015. “Hubble Space Telescope.” Wikipedia. Wikimedia Foundation. Web. 7 May 2015. “Planetary Habitability.” The Center for Planetary Science. Web. 7 May 2015. “TERRY BISSON of the UNIVERSE.” Meat. Web. 7 May 2015.

“Hubble Space Telescope.” Wikipedia. Wikimedia Foundation. Web. 7 May 2015.

“Kepler (spacecraft).” Wikipedia. Wikimedia Foundation. Web. 7 May 2015.

“SETI Institute.” SETI Institute. Web. 7 May 2015. “Fermi Paradox.” Fermi Paradox. Web. 7 May 2015.

“Planetary Habitability.” The Center for Planetary Science. Web. 7 May 2015.

Dunbar, Brian. NASA. NASA. Web. 7 May 2015.

“SETI Institute.” SETI Institute. Web. 7 May 2015.

“Alien Quotes.” Alien Quotes. Web. 7 May 2015.

“Stephen Hawking Looks at the History of Aliens Having a Fine Old Time.” Web. 7 May 2015.

“Fermi Paradox - Crystalinks.” Fermi Paradox Crystalinks. Web. 7 May 2015.

“TERRY BISSON of the UNIVERSE.” Meat. Web. 7 May 2015.

“Stephen Hawking Looks at the History of Aliens Having a Fine Old Time.” Web. 7 May 2015.

Typeface

The text is set in Univers designed by Adrian Frutiger. T he headings are set in New Baskerville designed by John Quaranda

Software

Adobe Creative Cloud, I n D e s i g n , I l l u s t r a to r, Photoshop

Equiptment

MacBook Pro 17-in. 2.3 GHz Epson Stylus 1430

Paper

Epson Premium Presentation Paper Matte 47. lbs, White, 4 star

Printing & Binding

Printed on Epson St ylus 1430

Publisher

P rometheus Books, S an Francisco, Ca.

Designer

Eric Dosier

Photography & Illustration

Photographs: NASA JPL Illustrations: Eric Dosier

About The Project

This is a student project. No part of this book or any other part of the project was produced for commercial use.

This book explores the idea of intelligent life in the universe, from our own Milky Way galaxy to the farthest reaches of deep space. Hop on the spaceship of your imagination and open your mind to the idea that weâ&#x20AC;&#x2122;re not alone after all...