1

The Search for Extraterrestrial Life By Dr. John Millam*

In the last 40 years, however, there has been a tremendous surge in popular belief about life residing on planets outside our solar system. While such speculation used to be frowned upon, it is now commonly greeted with enthusiasm. Life on other planets is now popularly believed to be not just possible but virtually certain. Carl Sagan, among others, has led the campaign to popularize this idea and gave it scientific credibility. In particular, the movie Contact based on the book by Carl Sagan has done much to popularize to the public the notion of looking for and communicating with extraterrestrial civilizations. Science fiction movies (e.g. Star Wars and Star Trek) and books have also lent support to such notions and have helped these ideas to cross over from dry academic discussions into popular culture. NASA’s spectacular success of putting a man on the moon and the robotic exploration of other planets in our solar system has brought many of these ideas right into people’s homes and has made believing in other life sites seem more plausible. This emerging popular culture belief in the existence of extraterrestrial life can be traced in large part to developments within astronomy. Until this century, the possibility of life on other planets outside our solar system was seldom seriously considered even recognizing the vastness of the universe. Much of the skepticism was based on the prevailing view that planet formation was very unusual. If there were few other planetary systems, then the possibility of life on other planets would likewise be small. This began to change in the 1950’s as models of planet formation became more robust and reliable. There soon was a growing consensus among astronomers that as many as half of all the stars in our galaxy might harbor planets. This reopened the possibility of life on other planets. In September 1959, Cocconi and Morrison published the first paper discussing rudimentary ideas on how to detect and communicate with possible life forms on other planets using existing technology.1 Frank Drake led the first actual systematic search for extraterrestrial signals in 1960.2 Dubbed Project Ozma,3 Drake examined two nearby stars (Epsilon Eridani and Tau Ceti) but found no extraterrestrial signals. The following year, Frank Drake and J. Peter Pearman organized the first ever SETI (Search for Extra-Terrestrial Intelligence) conference of ten interested scientists. In attendance were Carl Sagan and Nobel Prize winning chemist, Melvin Calvin. In preparation for this first conference, Drake developed his now famous Drake Equation4 (see below) to help focus the participants on deciding which stars might be the best candidates for study. Using this equation, Drake estimated that there should be at least 1,000 to 10,000 intelligent communicating species within our galaxy alone. If these civilizations were evenly distributed throughout the galaxy, then the nearest civilization would be no more than 1,000 light years away. Given such optimistic estimates, the chance of actually detecting a signal would be very high. SETI projects to detect extraterrestrial signals include Harvard’s Project META5 and Project BETA,6 UC Berkeley’s Project SERENDIP7 and SETI@Home,8 and SETI Institute’s Project Phoenix.9 More detailed descriptions of SETI’s mission and philosophy can be found elsewhere.10, , ,11 12 13

* Ph.D. in Theoretical Chemistry from Rice University. Full permission is given to reproduce or distribute this document, or to rearrange/reformat it for other media, as long as credit is given and no words are added or deleted from the text.

2

Why is the question of extraterrestrial life so important? Aside from the scientific question itself, which most likely cannot be answered definitively anytime soon, there is an ongoing debate in our culture concerning man and man’s place in the universe. Is man “special” in some way or is life trivial and common? Are our planet, solar system, and galaxy “specially created” or is our favorable solar system virtually guaranteed to exist? These are deep questions that were once the realm of theology and philosophy only but now scientists are weighing in on the issue. Many of the scientists who are shaping the public debate do not have a strong theological or philosophical background. To make matters worse, reporters, philosophers, theologians, and other spokesmen for popular culture often lack the necessary scientific background and knowledge to properly assess the reliability of these scientific claims. It is important that we get solid information about this issue so that we can stand on a solid foundation and not be tossed back and forth by the winds of popular culture. Of great concern is a growing lack of skepticism toward claims of extraterrestrial life. This is well illustrated by the discovery in 1996 of possible remnants of life in a Martian meteorite.14, ,15 16 Before the scientific community could respond, the discovery was hailed by President Clinton and the newspapers were filled with many grand statements about the possible evidence for life on Mars. Some even used the initial report to support their own personal philosophical ideas.17,18 Enthusiasm over the Mars rock has since quieted down as evidence has accumulated against the original conclusion.19, ,20 21 The Mars rover and other studies indicating that Mars may have had liquid water in the past are popularized as evidence that Mars may have had life in the past. Similarly, the finding of evidence suggesting the possible presence of liquid water on Europa, one of Jupiter’s moons, has lead to wild speculation about the possibility of life there.22 Even the comets, like Hale-Bopp, have been promoted as playing a role in the origin of life by pro-extraterrestrial enthusiasts.23,24 This is in addition to the daily deluge of claims of UFO sightings and abductions, which thrive on the public’s lack of knowledge and skepticism about extraterrestrial life. The growing UFO movement, which claims that extraterrestrials are currently visiting our planet, has argued for the notion of life on other planets in order to gain scientific credibility for its own beliefs. Before moving on, it is important to point out the difference between the SETI movement and the UFO movement. While both affirm a belief in the existence of extraterrestrial life, they are radically opposed over the notion of whether or not we have been visited or contacted by these beings. SETI proponents will point out the enormous difficulties for an advanced civilization trying to travel to Earth. These problems include enormous distances to cross, inability to even approach the speed of light, long-term radiation exposure, multi-generational travel, and stellar hazards.25 Given these considerations and the lack of real scientific evidence for visitation by extraterrestrial spacecraft, SETI proponents conclude that we should look for extraterrestrial signals rather than spacecraft. Also the SETI movement is widely viewed as a scientific movement whereas UFO investigation is viewed as pseudo-science. The Copernican Principle (Principle of Mediocrity) One thing is certain; SETI proponents are firmly convinced that we will eventually find extraterrestrial life. For example, Frank Drake stated, “At this very minute, with almost absolute certainty, radio waves sent forth by other intelligent civilizations are falling on the Earth” (Emphasis mine).26 In explaining his initial conviction about the existence of extraterrestrials, Drake writes, “I could see no reason to think that humankind was the only example of civilization, unique in the universe.”27 Carl Sagan was no less vehement about the certainty of extraterrestrial life. He writes, “Given sufficient time and an environment which is not entirely

3

static, the evolution of complex organisms is, in this view, inevitable. The finding of even relatively simple life forms on Mars or other planets in our solar system would tend to confirm this hypothesis” (Emphasis mine).28 And again, we read, “There can be little doubt that civilizations more advanced than the earth’s exist elsewhere in the universe” (Emphasis mine).29

Why are SETI astronomers so convinced that alien civilizations must exist and hence that habitable planets must be abundant? What is really at the heart of these claims? In an article examining the possibilities of extraterrestrial civilizations, the associate editor of Astronomy magazine, Robert Naeye, explained that the unstated assumption underlying SETI and their optimistic projections is a belief in the Copernican principle.30

“On the surface, the most obvious evidence bearing on these questions [about the existence of extraterrestrial life] is the fact that our home world and host star seem so ordinary. Nicholas Copernicus shattered the prevailing notion that the Earth was seated at the center of creation. Succeeding generations of astronomers steadily reinforced the Copernican view as they discovered the true nature of the stars, the remote location of our home world within our Galaxy, and the existence of galaxies far, far beyond our own. So pervasive is this view that in the world of modern science, it is almost heresy to assert any special qualities to our solar system, our planet, and to ourselves. With an estimated 200 billion stars in the Galaxy … scientists and laymen naturally conclude that we could not be alone.” (Emphasis mine)31

The Copernican principle is the belief that we are cosmically mediocre and thus no special distinctions can be applied our sun or planet. It is as if Earth is just a single grain of sand on a giant cosmic beach and there is nothing to distinguish our grain of sand from any other grain of sand. If the Earth is cosmically average yet has life; then there should be millions of “Earths” each with its own intelligent life forms. The Drake Equation The embodiment of the Copernican principle and SETI thinking is the Drake equation.4 Starting with the Darwinian paradigm, Drake assumed that life is virtually guaranteed to spontaneously arise as long as certain basic conditions are present. Considering that there are an estimated 100 billion stars in our galaxy, Drake realized that it would be critical to narrow the focus of their search to only those stars that had the reasonable probability of supporting life. Drake developed his equation for the first SETI conference as an attempt to consider factors that would make a planet inhospitable for life and hence reduce the number of sites in which SETI astronomers should focus their efforts. One such factor comes from the almost universally agreed upon prerequisites for life – carbon and liquid water. (Regarding the possibility of other life chemistries, see What about “Weird Life”? A Chemist’s Perspective on page 18.) This criterion eliminates from contention stars that are either too hot or too cold and planets that are either too close or too far from their parent star. Extending this idea a little farther, Drake developed his equation to express in measurable terms the probability of finding intelligent life on planets elsewhere in the galaxy and making contact with them. Based on his work, it was estimated that the galaxy should be teeming with life. Estimates ranged from thousands to even millions of possible extraterrestrial civilizations in our galaxy alone thus lending legitimacy to SETI plans. While these original estimates are now considered wildly optimistic, many still believe that intelligent extraterrestrial civilizations are abundant.

4

The Drake equation expresses the number of extraterrestrial civilizations (N) in our galaxy that we could potentially make contact with as:

Lcfiflfenpfsf*RN ×××××××=

where:

R* is the rate of star formation in our galaxy. fs is the fraction of stars that are suitable for life. fp is the fraction of suitable stars with planetary systems. ne is the number of planets in a solar system with an environment suitable for life. fl is the fraction of suitable planets containing living organisms. fi is the fraction of planets containing intelligent living organisms. fc is the fraction of planets containing intelligent beings capable of communicating. L is the lifetime of communicating civilizations.

Each of these symbols represents a factor that affects the predicted number of intelligent communication civilizations in our galaxy. Let us look at each factor in the Drake equation to see how Drake, Sagan, and other SETI enthusiasts come up with their very optimistic projections. R* represents the rate of star formation in our galaxy. Of all the variables in the Drake equation, only R* can be stated with a high degree of certainty and is estimated at 5-20 stars/year.32 While this number may seem small, the cumulative number of stars formed over the lifetime of our galaxy is staggering. Astronomers estimate that our galaxy alone contains roughly 200 billion stars. This number is so large that it boggles the mind. Some would argue that this number alone virtually guarantees the existence of life elsewhere in our galaxy since even highly improbable events, such as someone correctly picking all of the numbers in a lottery, can be probable if there are enough tries. As we will see later, there are many factors that must be weighed before we can make any reliable conclusions. fs is the fraction of stars that are suitable for life. This factor represents the fraction of stars that are suitable suns for planetary systems. Some stars must be rejected because they are too small (such as type M stars) and others because they are too short-lived (such as stars of type O and B). Using these criteria, only about 10% of stars would be classified as suitable for life. fp is the fraction of suitable stars with planetary systems. Only suitable stars that contain planetary systems need to be considered, since life certainly requires planets for life to grow on. Hubble telescope observations of the Orion nebula has been able to see stars with proto-planetary disks that will eventually condense into planets. Very recently, there has been confirmed detection of a few actual planets (giant Jupiter-like gas planets) around other nearby stars and the even the detection of a star in the middle of planet formation. Because of these discoveries in conjunction with the modeling of planet formation using modern high-speed computers, there is a growing consensus that planetary systems can form relatively easily. It was estimated that about half of all stars might contain planetary systems.

5

ne is the number of planets in a solar system with an environment suitable for life. It is generally agreed that any conceivable life form must have liquid water. While water is abundant in the galaxy, liquid water is scarce. We know that planets that are too close to the sun (e.g. Mercury and Venus) are too hot to maintain liquid water and planets to far from the sun (e.g. Mars, Jupiter, and Saturn) are so cold that any water would be frozen.33 Between these two extremes is the Continuously Habitable Zone (a.k.a. the “Goldilocks” zone) where the planet is at just the right distance from the star to maintain liquid water. For our solar system, typically only the Earth is viewed as being in the Goldilocks zone (ne ≈ 1), however, some would also consider Mars and Venus as being included in this zone (ne ≈ 3). fl is the fraction of suitable planets containing living organisms. Given a planet that is kept at the right temperature for liquid water and contains simple organic molecules, it is believed by SETI enthusiasts that life will spontaneously arise. The discovery of organic molecules in space is considered as evidence that organic molecules are sufficiently abundant and hence is taken as an evidence for a large value of fl. Since life appears suddenly and early on Earth under very harsh conditions, then perhaps life can form elsewhere under similarly harsh conditions. The discovery of extremophiles (bacteria capable of living under extremely conditions) living in salt-saturated water, under high temperatures and pressures, and even in solid ice suggest to many that life can exist in many more places than originally believed. The value of fl is unknown but SETI enthusiasts generally consider it to be very significant, 50% or higher. fi is the fraction of planets containing intelligent living organisms. If any planet other than our own contains life, there is no guarantee that any of the organisms will posses sufficient intelligence to communicate with us. (Since most animals and even some insects can display signs of rudimentary intelligence in their behavior, we must restrict our use of the term intelligence here to mean the ability to comprehend and communicate.) Some believe that intelligence is a natural consequence of evolution and so fi could be as high as 20%-100%. Again, this value is unknown and is very speculative. fc is the fraction of planets containing intelligent beings capable of communicating. The term “communicating” here refers to the ability to send signals to other solar systems. Almost certainly, the communication would be in the form of electromagnetic radiation. A civilization with advanced electronics (or similar technology) would almost certainly emit detectable signals (such as radio and TV broadcasts) even if they were not intentionally trying to broadcast a message. Cocconi and Morrison1 proposed radio waves as the best place to search for extraterrestrial signals but SETI astronomers are also looking in the microwave and even the optical portion of the electromagnetic spectrum. The value of fc is unknown but is believed by SETI proponents to be very high (perhaps 20%-50%). L is the lifetime of communicating civilizations. Even if intelligent beings with the ability to communicate with us were to evolve elsewhere in the galaxy, there may only be a brief window of opportunity for us to make contact with them. Some note that for life here on Earth, development of nuclear weapons occurred concurrently with the availability to send and receive extraterrestrial signals. This suggests that advanced civilizations might destroy themselves before they could make contact with other civilizations. Severe environmental pollution and large asteroidal collisions are additional dangers that could devastate an advanced civilization to the point that they were no longer able to

6

communicate. As such, pessimists might argue for a small value of L, perhaps only a few hundred years. However, Carl Sagan, Frank Drake, and most SETI proponents opt for a very optimistic view that most advanced beings will manage to avoid destroying themselves and might last thousands or even millions of years. Some even take this one step farther and suggest communicating civilizations that do survive self-destruction might be able to guide less advanced civilizations and help them avoid self-destruction.34 In the absence of any real information about other beings, the best we can do is set a minimum value for L of about 60 years, the length of time that we have had the technology to communicate with extraterrestrials. SETI Estimates for Communicating Civilizations: Some of the earliest estimates of the number of advanced extraterrestrial civilizations come from Frank Drake’s 1965 paper and a book by Iosef Shklovskii and Carl Sagan in 1966. Their optimistic appraisal has diminished little over the last 40 years as is illustrated by the comparison to estimates taken from three contemporary web sites. Frank Drake35 Carl Sagan36 Active Mind37 SEDS38 Life in the Universe39

R* 1 10 10 20 3-5 fs 10% 10% fp 50% 100% 20% 50% 20% ne 2-3 1 3-5 1 .05-.5 fl 100% 100% 50% 50% 100% fi 100% 10% 20% 100% ? fc 100% 10% 10-20% 50% .1%-1% L 1,000-10,000 10,000,000 10,000 > 60 10,000-100,000 N 1,000-15,000 1,000,000 600-2,000 > 15 ? Fermi’s Paradox: So Where Are They? Given the bold assertion by SETI proponents that there might be 10,000 or even a million advanced civilizations in our galaxy alone, how can we test this claim? The ultimate test would be to travel to each and every possible solar system and look for life. This is impossible now and will remain so for the foreseeable future. The next obvious test is to scan the heavens in hopes of intercepting a broadcast from one of these civilizations, which is the cardinal idea behind the SETI program. For the last 40 years, SETI has been listening but has failed to confirm even one genuine extraterrestrial signal.40, , , ,41 42 43 44 The central drawback to the SETI search is that it is effectively unfalsifiable, that is, a failure to detect extraterrestrial signals is never sufficient to rule out the possibility of extraterrestrial civilizations. For the most part, SETI astronomers remain as upbeat about the prospects of finding signals as they were 40 years ago despite a failure to produce any evidence. In the summer of 1950, Nobel physicist Enrico Fermi came up with a simple yet remarkable challenge to the belief that the universe is full of advanced beings. On the way to lunch at Los Alamos National Labs, Fermi, Edward Teller, Herbert York, and Emil Konopinski were talking about the possibility of flying saucers, faster-than-light travel, and extraterrestrial beings. During the lunch-time conversation with his three friends, Fermi interjected the question, “Where is everybody?”45 Everyone immediately understood that the “everybody” referred to in the prior conversation about extraterrestrial beings. Fermi had reasoned that if extraterrestrial civilizations were as abundant as expected, then many of them would have

7

technology far beyond our own and would have spread out from their original solar system by colonizing other planets. Eventually, even the distant colonies would eventually feel the pressure to spread out to even more distant solar systems. The first such civilization to colonize the stars would have the advantage of facing no opposition to their expansion. Thus, given some reasonable assumptions, this would lead to an exponential expansion that would eventually colonize the entire galaxy within a few million years, which is a cosmically brief period of time.46,47 This immediately leads to Fermi’s paradox – if extraterrestrial civilizations are abundant in our galaxy then they (or their robotic probes) should have reached Earth by now. Thus, if there is no evidence that we have been visited, we should logically conclude that advanced extraterrestrials are rare or non-existent. Looking around, we see absolutely no evidence that Earth or our solar system has been visited. Our asteroid belt would be a prime target for extraterrestrials to come and mine large quantities of valuable metals (such as nickel and iron), yet it remains untouched and our solar system remains in totally pristine condition. Nor have UFO investigators confirmed even one extraterrestrial visit. Given the existing evidence, Fermi’s paradox leads us to believe that we might be alone in the galaxy and hence that at least some of SETI’s assumptions are wrong. While Fermi’s question has drawn much criticism, it has yet to receive an adequate answer in the last 50 years. Some have argued that traveling to other stars would remain too expensive or too difficult and hence that aliens would simply never reach much beyond their own solar system. Others have argued that advanced creatures are likely to destroy themselves or be destroyed by a large asteroidal bombardment before they can spread out to other solar systems. And still others suggest that aliens may have already visited Earth but either we haven’t noticed them or they are cleverly keeping themselves hidden. All of these solutions to Fermi’s paradox seem improbable and contrived. Even worse, such arguments would have to apply equally to all extra-terrestrial civilizations, since if even one had the capacity of spreading through the galaxy, it would have already reaching us.45,48 So, Fermi’s argument against the prevalence of extraterrestrial civilizations remains strong even after 50 years. Discovery of Extra-solar Planets – The Failure of the Copernican Principle The Copernican principle holds that there is nothing special about our solar system and hence other stars in our galaxy should have their own solar systems that resemble our own. Our own solar system contains four small inner rocky planets (Mercury, Venus, Earth, and Mars), two gas giant planets (Saturn and Jupiter), and three ice planets (Uranus, Neptune, and Pluto).49 SETI expectations were built on the assumption that most other solar systems should be veritable carbon copies our own. As such, the discovery and characterization of extra-solar planets was expected to be the crowning vindication of the hopes and expectations of SETI astronomers. The first official detection of an extra-solar planet came in October 1995 with the detection of a Jupiter-sized object orbiting about the star 51 Pegasi about 50 light years away from us. This confirmed for the first time that planets do indeed exist outside our solar system. Since that time, over 100 planets have been discovered orbiting other stars.50,51 Now that we have a large enough sample of planets to analyze, what can we learn from them? 52,53

1) Newly discovered solar systems are not like our own. Based on the Copernican principle, astronomers expected other solar systems should be much like our own. However, even a quick survey of the newly discovered solar systems shows that all of them differ radically from our own. So different are these solar systems from anything predicted that it begs the question, “Who ordered that?”54 The extra-solar planets can be split into three categories. (a) Large Jupiter-like gas giant planets that orbit extremely close to their star, such as the planet near

8

51 pegasi. Such a massive planet would eject, destroy, or prevent from forming small rocky planets that are necessary for life. (b) Large Jupiter-like gas giant planets that orbit at near the correct distance but have highly eccentric orbits. Eccentric means that the planets orbit in an elliptical (rather than near circular) pattern. Because of their mass, Jupiter-like planets with eccentric orbits would disrupt the orbit of smaller inner planets. (c) Solar systems containing no giant gas planets. Through gravitational lensing,55 astronomers were able to detect one small planet (with a mass between that of Earth and Neptune) near the star MACHO 98-BLG-35.56 This planetary system is missing a large Jupiter-like planet necessary to protect the smaller planet from cometary bombardment. In all of these cases, there is no hope for finding any form of advanced life.

2) Gas giant planets are rare. Our Jupiter acts a “cosmic shield” protecting Earth by either deflecting or absorbing (as in the case of the recent Shoemaker-Levy collision) comets and asteroids that wander into the solar system.57,58 Without Jupiter, Earth would have been bombarded 1,000 times more often than we had been. Such an increased bombardment would regularly wipe out any advanced life. Prior to the discovery of the first extra-solar planet, astronomer George Wetherill predicted that most young solar-type stars lose the gas in their proto-planetary disks before gas giant planets (like Jupiter and Saturn) can form.59, ,60 61 Based on spectroscopic analysis of 20 young stars, only one retained enough gases to form gas giant planets. Wetherill also noted that a search of two dozen solar-type stars had failed to find any planets. Based on current discoveries, only about 6% of solar-type stars can be expected to have giant planets, which is consistent with Wetherill’s theoretical predictions.62

3) Planets require lots of “metals.” Astronomers are finding that planets only form around “metal”-rich stars. To astronomers, “metals” refers to any element heavier than helium. Since the big bang produced only hydrogen and helium, “metals” can only be produced later in the history of the universe from the nuclear furnaces of stars. As such, the concentration of metals in a forming solar system is critically dependent upon its having formed upon the metal enriched ashes of two previous generations of stars. Since planets are built up almost entirely of metals, it is not surprising that a certain minimum amount of metals are required to have planets. Our own sun is very rare because it is so metal-rich (with metals making up about 2% of the solar mass) compared to stellar neighbors of roughly the same age and type. Almost all of the extra-solar planets discovered so far orbit very metal-rich stars. While the exact relationship between metals and planet formation is still unknown, the requirement for metals certainly reduces the number of possible planetary systems.

4) Drifting gas giant planets. A probe dropped into Jupiter’s atmosphere showed that the planet still contained high levels of argon, krypton, and xenon. The only way to explain the presence of these noble gases is that the planet formed under very cold conditions (below -406 ºF). These conditions only exist outside the orbit of Pluto, which means that Jupiter must have formed there and later drifted inward to its current position.63 This drift has to be fine-tuned, since if it drifted to close to the sun, it would destroy the inner planets. If it didn’t drift in far enough, it would not have protected our planet from cometary bombardment. If it drifted the right distance but did not maintain a circular orbit, it would disrupt the inner planets.64 In nearly all of the 100 extra-solar planets, these large gas giant planets either drifted in very close to their star or ended up with very eccentric (non-circular) orbits.65

Galactic Habitability - Dangerous Stellar Neighborhoods Astronomers have discovered that our own galaxy is full of dangers that are capable of

9

disrupting or destroying possible life sites. Where as Drake and Sagan confidently assumed that only the nature of the star and its planets were relevant to the question of habitability, we are now forced to recognize that a star’s stellar neighborhood and its position in the galaxy are no less critical. To quote a famous real estate adage, it’s all about “location, location, location.” Several aspects about a star and its relationship to its parent galaxy must be considered.

1) Galactic dangers. While astronomers have long known about dangers to solar systems caused by nearby objects, they are now considering hazards posed by even some very distant objects. One such danger comes from supernovae. A supernova is a tremendous explosion that occurs when a massive star runs out of fuel and explodes, showering everything around it with high-energy particles and deadly gamma-ray radiation. For a brief time, a supernova can shine brighter than 100 billion suns! A nearby supernova would sterilize a planet and alter its atmosphere but even more distant supernovae can put out enough to cause mass extinctions. A new type of galactic danger, gamma-ray bursts, poses an even greater threat than supernovae. Gamma-ray bursts occur when ultramassive stars run out of fuel and collapse into a black hole. For a brief moment, a gamma-ray burst event can radiate brighter than 10 billion billion suns (i.e. 100 million times that of a supernova) and cause damage to solar systems 1,000 (or even 10,000) light years away.66 Very distant gamma-ray bursts may have been responsible for some large-scale extinction events on the earth.67

2) Galactic habitable zone. The galactic habitable zone represents another of Goldilocks’ “just right” compromises. Stars located too far from the center of the galaxy will lack sufficient material for the formation of rocky planets. For stars that are located too close to the center of the galaxy, the density of stars would be so large there would be a high probability of disruption caused by stellar neighbors that come too close. In addition, stars close to the center would also be subject to large amounts of radiation from the galaxy’s core.

3) Dangerous galactic spiral arms. Astronomer William Keel has shown that it is important for a habitable planet stay out of the galactic spiral arms.68 The spiral arms contain a much higher density of stars such that the gravity from nearby stars would likely pull planets out of their habitable zone. In addition, the spiral arms contain many supergiant stars. Supergiant stars are extremely massive and luminous stars that pump out so much radiation that they would damage the atmosphere of planets around neighboring stars. Dust in the galaxy resides primarily in solar arms and acts as a blanket shielding stars outside the spiral arms from this dangerous radiation. When supergiant stars collapse, they become supernovae and become an even greater threat to nearby stars.

4) Staying between galactic spiral arms. Our solar system resides safely between two galactic spiral arms remaining safe from both. However, it is not enough to simply reside between spiral arms but to do so for most of the lifetime of the solar system. This will only happen if the parent star is orbiting the center of the galaxy at the same rate as the spiral arms. If the star is revolving too fast or too slow around the galactic core, it will eventually be swept into either of the spiral arms where it will be subjected to gravitational disturbances and radiation from supergiant stars. Only stars, such as our own, that reside near the galactic corotation distance will remain in sync with the spiral arms and be able to avoid being swept into them.69

5) Z-axis bounce. As a star orbits around the center of the galaxy, its motion may take it above or below the plane of the galaxy. Stars for which this motion is too large in either direction will be hit by large doses of radiation coming from the galactic core. Only stars that remain close to the plane of the galaxy will be protected from this harmful radiation.

10

Reassessing the Drake Equation The discovery of extra-solar planets as well as newer models of solar system formation have shattered the assumption that our solar system is the cosmic norm. A plethora of other discoveries about our own solar system are showing just how many things had to be “just right” in order for Earth to be habitable. A comprehensive listing of these factors is included in Fine-Tuning for Life on Earth on page 22. The best way to evaluate the implications of these new discoveries is to reevaluate each term of the Drake Equation in light of this flood of new data. Just what makes a star “suitable” – reassessing fs For a planet to even have a chance of being habitable, it must orbit a “suitable” star. In his original work, Drake realized that certain types of stars would be too extreme to keep even one of its planets at the right temperature to maintain liquid water. Drake, however, did not go far enough in considering other stellar properties that might render a star “unsuitable.” For the last 40 years, astronomers have been cataloguing many additional properties of a star that affect its ability to support a habitable planet. Only a few prominent criteria are listed here.

(1) Roughly half of all known stars are binary stars (pairs of stars that orbit each other). The idea of a planet having multiple suns is very romantic idea (look at the planet Tantoine in the movie Star Wars) but is unsuited for the presence of life. Any planets in orbit around binary stars would have very unstable orbits at best, which would subject the planet to large temperature oscillations.

(2) Of non-binary stars, we can safely rule out non-main sequence stars, such as white dwarf stars (too cold), red giants (too hot), and neutron stars (too violent). For main sequence stars, the star’s life time and hence its “suitability” is determined by its mass. Large stars (at least 65% larger than our sun) will use up their nuclear fuel so fast that they would burn out too rapidly. Smaller stars (at least 40% smaller than our sun) would have a “Goldilocks” zone that would be too small. That is, the region around the star that maintains the planet at the right temperature is so close to the star that it subjects the planet to tidal forces that would disrupt the rotational period of the planet. Such a disruption would result in one side of the planet always facing its sun, which would overheat while the opposite side would freeze. Of all known star types, only bachelor G2 stars (a class of yellow stars like our own) are likely candidates for life. Only these stars have the right size, brightness, and long-term stability to considered suitable for life.

(3) Only third generation stars have enough heavy elements to allow the formation of rocky planets. The earliest stars to form started with only hydrogen and helium from the big bang. As these first generations die in supernovae explosions, they produce and expel heavier elements. The second generation stars, drawing on the ashes of first generation stars, still lack the elements to make rocky planets needed for life. Only after this second generation of stars die in supernovae are there enough heavy elements for the third generation of stars to have rocky planets. (Fourth generation stars do exist but these are rare.)

(4) In addition to the star’s mass, the star’s age is also a factor to consider. If the star is either too young or too old, the luminosity (brightness) of the star will vary too much. Large fluctuations in the star’s luminosity would result in runaway freezing or runaway heating of the planets. Such fluctuations would be disastrous to possible life forms. Just how common are planets? - reassessing fp Drake, Sagan, and other SETI astronomers assumed that about half of all stars should

11

have planets based on the existing models of their day. New evidence is showing that planet formation is much less frequent than had been expected. The Hubble Space Telescope was used to look for planets in the globular cluster of stars70 called 47 Tucanae. Based on existing expectations, they should have found 17 planets but instead found zero.71 Based on this new evidence, planet formation is at least 100 times less common than was anticipated (fp ≈ .1%). Just what makes a planet “suitable” for life – reassessing ne Again, we encounter the notion of being “suitable.” Just what is “suitable” for life? The very favorable value of ne used by SETI enthusiasts, is based on assuming that there is just one criterion: the planet must be in the “Goldilocks” zone so that it can support liquid water. There are, however, many other factors about the solar system as well as the planet itself that must be properly balanced for life to be possible. Analysis of the recently discovered solar systems located around other stars show that favorable solar systems are certainly not guaranteed. Only a few prominent criteria are listed here.

1) “Just right” Jupiter. Our Jupiter acts a “cosmic shield” protecting Earth from deadly bombardment that would exterminate life. A solar system not having a large Jupiter-like gas giant would subject inner planets frequent deadly bombardment. However, having a large gas giant planet is not enough, because it must also have a near-circular orbit, have the right mass, and must orbit the right distance away from the star. If not, these gas giants would wreak havoc with the delicate inner planets eliminating any possibility of life. The discovery of extra-solar planets have confirmed that “just right” Jupiters are not guaranteed or even likely.

2) “Just right” Moon. Our moon is more than just a beautiful light to fill the night—it is a critical component to maintaining life on this planet.72,73 The moon plays a key role in stabilizing the obliquity (tilt of the rotation axis relative to the orbital plane) of the Earth. Without the moon, the Earth’s tilt would be unstable, causing destructive climatic changes on Earth. What makes the moon so unusual is that it is quite large relative to the mass of the Earth. The moon’s large mass means that our moon is more like a second planet than a moon. Current models suggest that our moon formed when a Mars sized boulder struck the Earth at an angle kicking up a lot of debris that would eventually coalesce in the moon. Such a collision requires a high degree of fine-tuning! A direct collision would have been disastrous and a glancing blow would not have given rise to the moon. (This moon forming impact may also explain why we do not have a thick CO2 atmosphere like Venus that would have kept the Earth too hot for liquid water and life.)

3) “Just right” Planet. Simply having a planet the right distance from the star is not enough for a planet to be habitable. A careful study of our own planet has revealed that there are at least 20 different aspects of our planet that must be carefully balanced for there to be life and this list is growing every year! These parameters include plate tectonics, orbital eccentricity, surface gravity, magnetic field, and the thickness of the crust to name a few. Habitability and hence life are critically dependent upon all of these things balanced between opposing extremes and the failure of a planet to stay within these narrow boundaries on even one parameter would prevent or exterminate life on that planet. A more comprehensive list of parameters is given in Fine-Tuning for Life on Earth on page 22. The question of the origin of life – reassessing fl Currently, only our planet is known to harbor life and there is still much debate about how life began here. SETI proponents assume that since life appears very early in Earth’s history, life arises easily, spontaneously, and without help from God. Such optimistic

12

speculation is the basis of the SETI philosophy and is the whole motivation behind the search for life elsewhere in the universe. Advances in biochemistry and genetics show in increasing detail the incredible degree of complexity in even the simplest organism. Information theory applied to the origin of life question shows us that not even the simplest organism will form by purely natural processes, even given the long periods of time involved. A detailed discussion of this subject is beyond the scope of this paper.74, , , , ,75 76 77 78 79 Given the evidence, we have to conclude that fl is zero! Is intelligence guaranteed? – reassessing fi It has long been assumed that intelligence is guaranteed by evolution and hence that fi should be large. In more recent times, there have been a number of challenges to this assumption. One argument for a small value for fi comes from the Carter’s dilemma. Brandon Carter noticed that while microorganisms show up very early in the fossil record, intelligent life (namely us) doesn’t show up until very late in the history of our planet.80 That is, intelligent life did not appear until nearly half the available time (the lifetime of our sun) was gone. So, even if intelligent life was guaranteed to evolve (and of course there is no such guarantee), there is no guarantee that it would appear soon enough before being wiped out by its dying sun or by other catastrophes.81,82

Not only would intelligent life have to occur before the death of its parent sun, it would have to be kept sufficiently safe from various disasters over astronomical periods of time. There are many disasters that could halt or even destroy life on a planet. Recent work on Mars, suggests that our planetary neighbor might have been much more habitable than it is now and may even have had liquid water. Any life that might have existed (except possibly microbes) would have been destroyed by whatever forces brought about this catastrophic change in Mars’ climate.83 Today, Mars is cold, barren and unfit for life. Our “Just Right” Galaxy Over the last 40 years, we have discovered that a great number of things have to be “just right” in our solar system in order to have life on Earth. The discovery of planets orbiting other stars underscores this point by showing that habitable solar systems are certainly not guaranteed. We are now faced with the realization that even given the vastness of our galaxy, the probability of having even one other planet forming by natural processes alone with the necessary conditions to support advanced life is negligible. Given the improbability of having even one other habitable planet in our galaxy, the quest for extraterrestrial beings will be forced to look outside our own galaxy. According to the Copernican principle, most galaxies should be like our own. Since our galaxy contains at least one intelligent civilization (namely us) and there are an estimated 10 billion galaxies in our universe, one might expect that there should be at least 10 billion advanced civilizations in our universe. (If we used SETI’s optimistic estimates instead this would skyrocket to a staggering trillion or even a quadrillion intelligent civilizations in the universe.) Recent findings by astrophysicists are showing the Copernican principle fails even for galaxies so that the vast number of galaxies does little to bolster the idea of extra-terrestrial civilizations. For example, only spiral galaxies like our own can support star formation long enough to have very metal-rich stars that are capable of having rocky planets. Similarly, galaxies that are located close to other galaxies are unsuitable because the gravity of nearby companions would disrupt solar systems. A galaxy capable of supporting habitable planets must be a middle-aged, medium-sized, spiral galaxy with sustained star formation located in a safe cosmic “neighborhood.” Using only five of these galactic parameters, we can rule out 99.999%

13

of all galaxies as possible candidates for having habitable solar systems. Given current trends, it is likely that the number of galactic fine-tuning parameters will only increase, not decrease. We indeed reside in a very privileged portion of the universe. (For more details see Fine-Tuning for Life on Earth on page 22.) The Design Inference Astronomers now recognize that our sun, planet, and even our galaxy had to have a lot of things “just right” in order for us to be here. For example, if the distance from Earth to the sun were just slightly larger or smaller than the current value, there would be a catastrophic runaway freezing or heating that would exterminate or prevent life on our planet. This quality of being “just right” or “fine-tuned” is sometimes referred to as “design” because of the comparison with humanly designed systems. For example, the gears in a mechanical watch must be precisely the right size in order to connect with other gears. In addition to that, the gear sizes must also be precisely chosen for the watch to correctly measure time. Even small changes in the components of the watch would cause the watch to fail or keep the wrong time. We explain the correct functioning of a watch by recognizing that the watch was designed by an intelligent being (the watchmaker). If our solar system and planet have the property of being “fine-tuned” like a watch, then we may infer that if the watch needs a designer, then so must our solar system and planet. This is known as the design inference and stands in direct opposition to the Copernican principle. During the inception of SETI and the Drake equation in the 1960’s, astronomers assumed that a solar system only had to get a two things right (i.e. the right star type and stable planets) in order for there to be a suitably earth-like habit for life.84 By 1970 when SETI was just a decade old, the number of design parameters (things that have to be “just right”) jumped from just 2 to 8. Each new design parameter reduced the predicted number of possible life sites in our universe. By 1980 this number rose to 23, by 1990 it was up to 32 parameters, by 1995 it had reach 41 and in 2001 it reached 128. Currently, there are at least 153 design parameters and this list of parameters continues to grow with no apparent end in sight.85 Given these design parameters, we can conservatively estimate that even given the entire universe with 10 billion galaxies each containing 100 billion stars and planets, the probability of having even one solar system form by chance that has the necessary properties for life is less than 1 chance in 10172! (See Probabilities for Life on Earth on page 32.) Clearly then, the Earth cannot simply be a fortuitous accident but is the product of design by a caring Designer. For the most part, SETI proponents have simply chosen to ignore this growing list of requirements for habitability. Except for the addition of the term, fs, the Drake Equation has remained the same, effectively refusing to recognize the advances and discoveries of the last 40 years. Similarly, estimates of the number of advanced civilizations have remained almost constant, although modern estimates are a bit more conservative. (See SETI Estimates for Communicating Civilizations above.) SETI believers who have commented on these design requirements, typically dismiss them as mere quirks or eccentricities of our own solar system and are not really essential requirements for habitability.86 Sadly, outside of astronomy, most of these design parameters are not well known, and when they are presented, typically only a few are mentioned. The popular press has done little to challenge the popular SETI notions or educate the public about this growing body of evidence for design.

14

Rare Earth After decades of mounting evidence, only now are other scientists beginning to reevaluate their expectations for life elsewhere in the universe. Using only eight criteria (design parameters) for the existence of intelligent life on other planets, Robert Naeye, concludes that we likely to be alone in the galaxy. He states:

“Recent studies in a variety of fields suggest that life must pass through a series of bottlenecks on the road to intelligence. On Earth, a long sequence of improbable events transpired in just the right way to bring forth our existence, as if we had won a million-dollar lottery a million times in a row. Contrary to the prevailing belief, maybe we are special. Maybe humanity stands alone on a fertile island in the largely sterile waters of the galactic ocean.”87

It should be recognized, Naeye comes to this conclusion based on existing evidence even though he sincerely hopes that SETI will eventually prove him wrong by detecting life.87 If only eight design parameters are enough to convince him that we are likely alone in the galaxy, we can only wonder what conclusions he would make if he considered all 153 design parameters! Astrobiologists Peter Ward and Donald Brownlee are also among a growing number of scientists who are challenging the prevailing view that advanced life is common in the universe. Based on their own compilation of requirements for habitable planets, they conclude that intelligent life is exceedingly rare in the universe, even though they start from the assumption that life can arise spontaneously.88 In the introduction to their book Rare Earth, they state:

“In this book, we will argue that not only intelligent life, but even the simplest of animal life, is exceedingly rare in our galaxy and in the Universe. We are not saying that life is rare—only that animal life is… We combine these two predictions of the commonness of simple life and the rarity of complex life into what we will call the Rare Earth Hypothesis.” (Emphasis theirs.)89

After surveying what the last 40 years of astronomy has indicated about the possibility of extraterrestrial life sites, they conclude their findings by giving a revised version of the Drake Equation that includes additional factors to incorporate a few of these new findings. They conclude:

“Many new factors will be known, and the list of variables involved will undoubtedly be amended. But it is our contention that any strong signal can be perceived when only sparse data is available. To us, the signal is so strong even at this time, it appears that Earth indeed may be extraordinarily rare.” (Emphasis mine.)90

It then appears that the Copernican revolution has come full circle. So, while we are clearly not at the geometrical center of the universe, evidence for design is showing that we are indeed very special. “Nobody Here But Us Earthlings” University of Washington astronomer Guillermo Gonzalez is frequently asked, “Are we alone?” In his article, “Nobody Here But Us Earthlings,” he states that:

“My answer to the question [‘Are we alone?’] almost always catches people off guard: Very likely yes, we are alone. When one looks at the astronomical data with an open mind, it becomes quite obvious why we have not

15

found any evidence of extraterrestrial life.”91

Contrary to the popular assertions of Carl Sagan, Frank Drake, SETI, and others, we are likely to be alone in the entire universe, not just in our galaxy. Multiple lines of evidence are converging to support this conclusion. To summarize what we have found:

1) Fermi’s Paradox. The complete lack of any credible evidence for extraterrestrials having already visited our solar system argues that advanced extraterrestrial civilizations are rare or non-existent.

2) Failure to Detect Any Signals. After 40 years of searching, we have not found even a single blip from an extraterrestrial civilization. While this doesn’t completely eliminate the possibility of advanced beings, it certainly does put strong limits on their existence and level of technology.

3) Discovery of Extra-Solar Planets. Both Frank Drake and Carl Sagan confidently assumed that other solar systems should resemble our own. The newly discovered planets have completely turned this assumption on its head. None of these solar systems are even remotely hospitable. This is perhaps the strongest experimental evidence against SETI claims.

4) Dangerous Stellar Neighborhood. It is not enough to have the right star and planet in order to have a habitable planet. A star must be located in just the right portion of the galaxy where they can be protected from radiation and gravitational disruption from stars in its local neighborhood for the lifetime of the planet. Supernovae and gamma-ray bursts represent violent endings to massive stars that pump out unimaginable amounts of energy capable of destroying life and disrupting planetary atmospheres out to hundreds or even thousands of light years.

5) Failure of the Copernican Principle. When SETI was born, astronomers assumed that a solar system only had to have two things right in order to have a habitable planet and so habitable planets should be plentiful. Scientists now recognize that a great number of attributes must fall within narrow limits to even have a chance of being hospitable.

6) Failure of Naturalistic Explanations for the Origin of Life. A naturalistic origin of life is prerequisite for life on other planets. In Darwin’s time, cells appeared to be little more than bags of protoplasm, so the origin of life seemed like it should be very easy. Now, scientists realize that even the simplest organism is more complicated and better managed than even the finest human factories. The DNA of a single cell contains more information than several sets of the Encyclopedia Britanica. Naturalistic theories fail to account for this intricate design and information content.

7) Late Appearance of Advance Life (Carter’s Dilemma). While single celled organisms appear very early in Earth’s history, advanced life appears very late. So, even if simple organisms were to develop, there is no guarantee that advanced life would appear before the death of its sun or other cosmic catastrophes.

“Why Are We Here?” Under the SETI paradigm (Copernican principle), our existence is guaranteed without God’s help simply by virtue of the billions of galaxies each containing billions of possible stars and planets. However, given the enormous and growing body of evidence for design, we can safely rule out the possibility of finding other habitable planets teeming with intelligent life.

16

(See Probabilities for Life on Earth on page 32.) Clearly the Earth cannot simply be a fortuitous accident and thus, we are very likely alone in the universe. This gives us reason to pause and reflect on the meaning of it all. At the end of his article, “Nobody Here But Us Earthlings,” Guillermo Gonzalez concludes:

“We should not be asking: ‘Are we alone?’ We should be asking instead: ‘Why are we here?’”92

The question of our existence used to be the domain of theology alone but now science is adding some new details to the story. Modern astronomy is testifying to the fact that our galaxy, our solar system, and our planet reflect the careful craftsmanship of a Designer rather than the random fortune of the Copernican Principle. Long ago, King David looked up at the heavens and concluded, “The heavens declare the glory of God, the skies proclaim the work of his hands.”93 If only King David could have seen the universe as we see it today. Further Reference: M. J. Behe, Darwin’s Black Box: The Biochemical Challenge to Evolution, Touchstone, New

York 1996. G. Gonzalez, “Rare Sun,” Facts For Faith (Q2 2002), p. 14-21. F. Heeren, “Exoplanets, SETI, and the Likelihood of Contact,” Cosmic Pursuit, Spring 1999, p.

20-27, 57-62. B. Nemati, “The Search for Life on Other Planets,” Facts For Faith (Q4 2000), p. 22-31. H. Ross, The Fingerprint of God, Promise Publishing Co., Orange, CA 1989. --, The Creator and the Cosmos, 3rd Ed., NavPress, Colorado Springs, CO 2001. --, “Exotic Life Sites: The Feasibility of Far-Out Habitats,” Facts For Faith (Q4 2001),

p. 20-25. --, “Search for Planets Draws a Blank,” Facts For Faith (Q2 2001), p. 9. H. Ross, K. Samples, and M. Clark, Lights in the Sky & Little Green Men, NavPress, Colorado

Springs, CO 2002. --, “The RUFO Hypothesis,” videotape, (available from Reasons To Believe,

http://www.reasons.org/). H. Ross and G. Gonzalez, “You Must Be Here”, Facts For Faith (Q1 2000), p. 36-41. S. Shostak, “Getting in Touch with ETI,” Cosmic Pursuit, Spring 1999, p. 8-15, 54-56. --, “Listening for Life,” Astronomy, October 1992, pp. 26-33. --, “When E.T. Calls Us,” Astronomy, September 1997, pp. 37-51. C. B. Thaxton, W. L. Bradley, and R. L. Olsen, The Mystery of Life’s Origin: Reassessing

Current Theories, Lewis and Stanley, Dallas, TX 1992. P. Ward and D. Brownlee, Rare Earth: Why Complex Life is Uncommon in the Universe,

Copernicus, NY 2000. D. Wilkinson, Alone in the Universe?, InterVarsity Press, Downers Grove, IL 1997. Magazine References: Connections, Reasons To Believe newsletter (1999-current). Downloadable versions available at http://www.reasons.org/resources/connections/ Facts & Faith, Reasons To Believe quarterly newsletter (1986-1999). Downloadable versions available at http://www.reasons.org/resources/faf/ Facts For Faith, Reasons To Believe quarterly magazine (2000-2002).

17

Magazine may be purchased at http://www.factsforfaith.com/. Selected downloadable articles available at http://www.reasons.org/resources/fff/ Cosmic Pursuit, Day Star Ministries magazine (1997-1999). Magazine may be purchased at http://www.daystarcom.org/resources/book_tape.htm

18

What about “Weird Life”? A Chemist’s Perspective All our experience with life is ultimately based on earth life. If life were to spontaneously arise on another planet, almost certainly it would not look anything like us. Sorry to disappoint you Star Trek fans but aliens certainly wouldn’t look humanoid with two eyes, two ears, a mouth, and a nose as is seen in virtually every sci-fi movie, book, and TV series. Likewise, such alien life forms probably wouldn’t even be based on the familiar molecules that make up earth life—DNA, RNA, and proteins. (Although such life would still require molecules to perform similar functions.) If alien life is not likely to resemble earth life, then perhaps we can take that idea one step farther and consider that such life might not be carbon-based or not even require liquid water. This idea of “weird life” (non-carbon/water based life forms) has largely been the realm of science fiction, although some astrobiologists are seriously studying these possibilities.94 If life could indeed arise without the need for liquid water or carbon, then perhaps such life might be able to thrive in environments radically different than our own. This possibility could greatly increase the number of possible extraterrestrial life sites and increase the odds of SETI discovering alien intelligences. Could there be a grain of science fact in this science fiction? While some still hold out hopes for alternative life chemistries, chemists have largely ruled out this possibility for the last 40 years. But how can we be so certain about possible life forms that we can only imagine? All conceivable life, even “weird life,” must be able to perform certain basic functions to live. First, life must be able to take in matter and energy from its environment and process it for food, motion, and reproduction. Likewise, life must be able to replicate itself and so requires the ability to store its own blue prints. Using our modern understanding of chemistry, we can rule out systems that do not have adequate versatility to support these essential functions. All conceivable forms of life require complex chemicals reactions and a liquid state is the ideal environment for such reactions. Liquids can dissolve both gasses and solids, thus allowing all three phases to participate in reactions and sustain a wide variety of chemical environments. In a gaseous environment, molecules lie too far apart limiting the ability to store information in complex molecules needed for life. In a solid state, molecules are locked in place greatly slowing the ability to synthesize compounds, transfer information, and reproduce. Even if life were to somehow arise based on a solid rather than a liquid matrix, its evolution would be so slow that it wouldn’t develop advanced life before the death of its parent sun. 95 (For perspective, advance life on Earth appeared about half way through our sun’s stable lifetime. So even slow down by a factor of two in life’s ability to adapt and evolve would mean that advanced life would arrive too late, and solid-based life forms would likely be slower than liquid-based life by many many orders of magnitude.) Of course, not all liquids are created equal. Water (H2O) stands alone in its ability to serve as a host environment for life chemistries.95 Water’s unusual bent shape, with its three atoms forming a 104.5° angle, combined with its high degree of polarity96 gives water a large permanent dipole moment. This gives water the ability to dissolve more substances and in greater quantities than any other liquid, and so is known as the universal solvent. Solubility is critical for the transport of nutrients and waste material. In addition, solubility allows all of the molecules for life chemistry to be available in solution to quickly carry out needed reactions. Water isn’t simply passive but plays an active role in many different reactions. Its high dielectric constant and large dipole moment help stabilize many reactive intermediates allowing certain reactions. Neutral water can also be easily split into two ions (H+ and OH-), which is critical in a

19

lot of energy producing reactions, such as photosynthesis. These are but a few of water’s chemical and physical properties that are vital for life.97 When water is compared to other related substances, we see that water ranks highest or second highest in at least ten of these important properties.98,99

Only ammonia (NH3) comes close to rivaling water. Yet it is 1/5th as polar and cannot match water’s versatility. Also, ammonia is much more reactive and volatile than water and so would not be as abundant or ubiquitous as liquid water. Other suggested replacements for water include methane (CH4), hydrogen sulfide (H2S), carbon dioxide (CO2), hydrogen fluoride (HF) and sulfur dioxide (SO2). All of these are less than 1/10th as polar as water and do not share many of water’s anomalous properties.97 Just as life requires water, it also requires carbon. In 1961, physicist Robert Dicke argued, “It is well known that carbon is required to make physicists.”100 His statement still stands today because no other element can match the versatility of carbon. The field of organic chemistry focuses exclusively on carbon compounds and their chemistry; yet it is richer and more diverse than the chemistry of all other elements combined (the field of inorganic chemistry). Carbon easily forms strong double and triple bonds as well as being able to form up to four single bonds. This gives carbon the widest array of possibilities for forming chemical compounds. Most important, however, is carbon’s ability to form indefinitely long chains. Simple molecular units can be strung together in innumerable combinations to form very complex molecules. It is these long complex molecules that provide the capacity to store large amounts of complex biological information. Silicon is by far the most commonly suggested alternative to carbon and is a popular favorite in science fiction works. Its greatest value to SETI, however, is in its great abundance, being available in more places and in far greater quantity than carbon. Silicon, for example, makes up 28% of the Earth’s crust (second only to oxygen), while carbon represents only a trace element (less than 1%). While, silicon shares carbon’s ability to form four single bonds, it lacks carbon’s ability to make strong multiple bonds, greatly limiting its possible uses. By far, its greatest weakness is its inability to form long chains needed to store life information, as it becomes too unstable for sufficiently long chains. Boron is the only other significant challenger to carbon. It has the opposite problem of silicon, having the ability to form strong multiple bonds but generally forms no more than 3 (rather than 4 bonds). While the chemical flexibility of boron has still not been completely explored, it suffers from being far less abundant than carbon. The net result is that wherever boron is found, carbon will also be found, so even if boron-based life were to arise, it would likely be beaten out by carbon-based life.

20

SETI Related Questions Am I opposed to looking for extraterrestrials? No. While I don’t believe that SETI will ever detect signals from alien beings, I’m never opposed to genuine research. My opposition is to the propagation of SETI philosophy in the guise of science. The public is regularly hammered in newspapers and on television with the “where there is water there is life” myth and so the possible presence of liquid water on Mars or Europa is given as evidence for extraterrestrial life. Articles sympathetic to the SETI belief in extraterrestrials are given frequent and unchallenged support, while those who challenge these assumptions receive little attention or are trivialized. Not only am I not opposed to research on the possibility of extraterrestrial life, I recognize that such research has been indirectly responsible for demonstrating just how special our solar system genuinely is. SETI research has also led to improvements in signal processing and telescope design as well as helping hunt for pulsars and mapping hydrogen gas in the galaxy. Is Christianity opposed to the idea life on other planets? No. The central focus of this paper is that scientific evidence rules out the possibility of life and habitable planets by purely natural processes without God’s intervention. God certainly could create life elsewhere in the universe. In fact, some Christians argue that God’s creative nature suggests that He would create life elsewhere, while other Christians disagree. Ultimately, the Bible is silent on this issue leaving room for debate and discussion among Christians.101

If we are alone in the universe, then is the universe just a waste of space? Many have argued that the discovery of intelligent life elsewhere in the universe would be evidence against the existence of God. If, in fact, the opposite is true and the universe is a vast barren desert with no advanced civilizations other than our own, what then should we conclude? Ironically, some have interpreted this possibility as also being evidence against God. For example, the movie Contact, based on the book by Carl Sagan, has the main character expressing the thought that if there are no other intelligent beings in the universe, then the vast universe is just a “waste of space.” Physicist Stephen Hawking likewise make a similar charge declaring that it is “very hard to believe” that God would make so many useless stars if His intent was just to make a home for man.102 If God had created the universe for mankind, wouldn’t God only need to create one planet and one solar system? Astrophysics is now shedding light on this dilemma and revealing that the vast universe is in fact a necessary part of God’s design and not a waste. It turns out that the mass density of the universe is a sensitive catalyst for nuclear fusion. Thus, if the mass density were any less, the universe would contain only hydrogen and helium. If the mass density were any greater, the universe would only contain elements heavier than iron. The carbon, oxygen, and nitrogen necessary for life are only possible in a universe with a hundred billion trillion observable stars. The universe reveals that God loved man so much that He was willing to create a hundred billion trillion stars just for our benefit.103

What is the anthropic principle? The term “anthropic principle” was coined in 1974 by British mathematician Brandon Carter in the wake of growing evidence that our universe was not an accident but was in fact finely tuned to allow for our existence.104 In his own words, the “anthropic principle” expresses

21

0

the notion that “although our situation is not necessarily central it is necessarily privileged to some extent.”80 As we have already examined in the main body of this paper, our planet, sun, and galaxy exhibit a high degree of fine-tuning. (See Fine-Tuning for Life on Earth on page 22.) This fine-tuning also extends to the very laws and constants of physics. “In 1961, astronomers acknowledged just two characteristics of the universe as ‘fine-tuned’ to make physical life possible.10 The more obvious one was the ratio of the gravitational force constant to the electromagnetic force constant. It cannot differ from its value by any more than one part in 1040 (one part in ten thousand trillion trillion trillion) without eliminating the possibility for life. Today, the number of known cosmic characteristics recognized as fine-tuned for life—any conceivable kind of physical life—stands at thirty-eight.105 Of these, the most sensitive is the space energy density (the self-stretching property of the universe). Its value cannot vary by more than one part in 10120 and still allow for the kinds of stars and planets physical life requires.106 … An account of scientific evidence in support of the anthropic principle fills several books.107 The authors’ religious beliefs run the gamut from agnosticism to deism to theism, but virtually every research astronomer alive today agrees that the universe manifests exquisite fine-tuning for life.108” 109 While the anthropic principle is not directly relevant to the question of SETI since other stars and planets share the same laws of physics, it is relevant to the design argument and directly contradicts the Copernican Principle. What if life is found on Mars? For several decades now, there has been both implicit and explicit expectations about possible implications of finding life (or its remains) on Mars. The logic goes like this: if life is found on Mars, then this is proof positive that life can arise easily and naturally and hence life must be common in the universe. Carl Sagan popularized this idea as far back as 1966.28 In other words, the public has been trained to accept that evidence for life on Mars would nullify all of the evidences presented here in this paper and hence should greet such claims with enthusiasm, not skepticism. This was clearly demonstrated with the report of the remnants of life on Mars rock in 1996, as described earlier in this paper. Credit should be given to those bold scientists who were willing to challenge popular belief and demonstrate that the “fossils” were not the remnants of life. In the debate over the proposed Mars rock finding, one point was completely ignored by both sides: we will find the remnants of life of Mars! This may seem strange considering the thesis of this paper, but it in fact does not contradict it. Just as rocks from Mars can be transported to Earth, so Earth rocks can be transported to Mars. Also the solar wind can blow hearty microorganisms to Mars and the rest of the solar system. In other words, we have plenty of evidence that terrestrial microorganisms will contaminate other planets in our solar system. Since all of our current probes and tests are not capable of distinguishing between terrestrial and Martian life, we must guard against assuming that remains of life on Mars equals extraterrestrial life evolving on Mars. This argument was in print at least 8 years before the Mars rock debacle!110,111

22

Fine-Tuning for Life on Earth Remarkable fine-tuning must take place in order for life to exist on any planet in any planetary system. Earth exists in the only known planetary system able to demonstrate all the characteristics required for life to survive. The following essential characteristics for life show Earth’s matchless fine-tuning within its parameters. (Reprinted from Lights in the Sky & Little Green Men, Appendix A, pp. 171-184. A list of scientific references supporting these design parameters is included at the end of the book.) 1. Galaxy cluster type.

If Earth’s galaxy cluster were too rich, galaxy collisions and mergers would disrupt the solar orbit.

If Earth’s galaxy cluster were too sparse, there would be insufficient infusion of gas into the Milky Way to sustain star formation there for a long enough period of time.

2. Galaxy size.

If the Milky Way were too large, infusion of gas and stars would disrupt the sun’s orbit and ignite too many galactic eruptions.

If the Milky Way were too small, there would be insufficient infusion of gas to sustain star formation for a long enough period of time.

3. Galaxy type.

If the Milky Way were too elliptical, star formation would have ceased before sufficient heavy elements had built up for life chemistry.

If the Milky Way were too irregular, radiation exposure on occasion would be too severe and heavy elements for life chemistry would not be available.

4. Galaxy mass and distribution.

If too much of the Milky Way’s mass resided in the central bulge, the Earth would be exposed to too much radiation.

If too much of the Milky Way’s mass resided in the spiral arms, the Earth would be destabilized by gravity and radiation from adjacent spiral arms.

5. Galaxy location.

If the Milky Way were located too close to a rich galaxy cluster, the Earth would be gravitationally disrupted.

If the Milky Way were located too close to a very large galaxy (or galaxies), the Earth would be gravitationally disrupted.

6. Supernovae eruptions.

If supernovae had occurred too close, life on Earth would be exterminated by radiation.

If supernovae had occurred too far away, there would not be enough heavy element ashes for the formation of rocky planets like Earth.

If supernovae had occurred too infrequently, there would not be enough heavy elements ashes for the formation of rocky planets.

23

If supernovae had occurred too frequently, life on Earth would be exterminated. If supernovae had occurred too soon, there would not have been enough heavy

element ashes for the formation of rocky planets. If supernovae had occurred too late, life on Earth would be exterminated by radiation.

7. White dwarf binaries.

If there were too few white dwarf binaries, there would be insufficient fluorine for life chemistry.

If there were too many white dwarf binaries, planetary orbits would be disrupted by stellar density and life on Earth would be exterminated.

If white dwarf binaries had appeared too soon, there would not be enough heavy elements for efficient fluorine production.

If white dwarf binaries had appeared too late, fluorine would be made too late for incorporation in Earth’s protoplanet.

8. Proximity of solar nebula to a supernovae eruption.

If the solar nebula were farther away, the Earth would have absorbed insufficient heavy elements for life.

If the solar nebula were closer, the nebula would be blown apart. 9. Timing of solar nebula formation relative to supernovae eruption.

If the solar nebula had formed earlier, the nebula would have been blown apart. If the solar nebula had formed later, the nebula would not have absorbed enough

heavy elements. 10. Number of stars in parent star birth aggregate.

If there were too few stars in the parent star birth aggregate, there would have been insufficient input of certain heavy elements into the solar nebula.

If there were too many stars in the parent star birth aggregate, planetary orbits would be too radically disturbed.

11. Star formation history in planet star vicinity.

If there had been too much star formation going on in the vicinity of the sun, planetary orbits would be too radically disturbed.

12. Birth date of the star-planetary system.

If the system had been born too early, the quantity of heavy elements would have been too low for large, rocky planets like Earth to form.

If the system had been born too late, the sun would not yet have reached its stable burning phase. Furthermore, the ratio of potassium-40, uranium-235, uranium-238, and thorium-232 to iron would be too low for long-lived plate tectonics to be sustained on Earth.

13. Planet star distance from center of galaxy.

If the sun were too far from the center of the galaxy, the quantity of heavy elements would have been insufficient to make rocky planets like Earth. In addition, there would be the wrong abundances of silicon, sulfur, and magnesium relative to iron for appropriate planet core characteristics.

24

If the sun were too close to the center of the galaxy, galactic radiation would be too great and stellar density would disturb planetary orbits. Again, there would be the wrong abundances of silicon, sulfur, and magnesium relative to iron for appropriate planet core characteristics.

14. Parent star distance from closest spiral arm.

If the distance were too great, the quantity of heavy elements would be too small for rocky planets to form.

If the distance were too small, the solar system would experience gravitational disturbances and radiation exposure.

15. Z-axis height of star’s orbit.

If the z-axis height were too high, exposure to harmful radiation from the galactic core would be too great.

16. Number of stars in the planetary system.

If there were multiple stars in the solar system, tidal interactions would disrupt Earth’s orbit.

If there were no stars in the system, Earth would have insufficient heat to support life. 17. Parent star age.

If the sun were older, its luminosity would change too quickly. If the sun were younger, its luminosity would change too quickly.

18. Parent star mass.

If the sun’s mass were greater, its luminosity would change too quickly and it would burn too rapidly.

If the sun’s mass were smaller, the range of planet distances that would make life possible would be too narrow. In addition, tidal forces would disrupt Earth’s rotation period. Also, ultraviolet radiation would be inadequate for plants to make sugars and oxygen.

19. Parent star metallicity.

If the sun’s metallicity were too small, there would be insufficient heavy elements for life chemistry.

If the sun’s metallicity were too large, life would be poisoned by heavy-element concentrations. Furthermore, radioactivity would be too intense for life.

20. Parent star color.

If the sun were redder, photosynthetic response would be insufficient. If the sun were bluer, photosynthetic response would be insufficient.

21. Galactic tides.

If galactic tides were too weak, the comet ejection rate from the giant planet region would be too low.

If galactic tides were too strong, the comet ejection rate from the giant planet region would be too high.

25

22. H3+ production.

If H3+ production had been too small, simple molecules essential to planet formation

and life chemistry would not form. If H3

+ production had been too large, planets would form at the wrong time and place for life.

23. Flux of cosmic ray protons.

If the proton flux had been too small, there would be inadequate cloud formation in Earth’s troposphere.

If the proton flux had been too large, there would be too much cloud formation in Earth’s troposphere.

24. Solar wind.

If the solar wind were too weak, too many cosmic rays protons would reach Earth’s troposphere, causing too much cloud formation.

If the solar wind were too strong, too few cosmic ray protons would reach Earth’s troposphere, causing too little cloud formation.

25. Parent star luminosity relative to speciation.

If the sun’s luminosity had increased too soon, a runaway greenhouse effect would develop on Earth.

If the sun’s luminosity had increased too late, runaway glaciation would develop on Earth.

26. Surface gravity (escape velocity).

If surface gravity were stronger, Earth’s atmosphere would retain too much ammonia and methane.

If surface gravity were weaker, Earth’s atmosphere would loose too much water. 27. Distance from parent star.

If Earth’s distance from the sun were greater, Earth would be too cool for a stable water cycle.

If Earth’s distance from the sun were lesser, Earth would be too warm for a stable water cycle.

28. Inclination of orbit.

If Earth’s orbital inclination were too great, temperature differences would be too extreme.

29. Orbital eccentricity.

If Earth’s orbital eccentricity were too great, seasonal temperature differences would be too extreme.

30. Axial tilt.

If Earth’s axial tilt were greater, surface temperature differences would be too great. If Earth’s axial tilt were lesser, surface temperature differences would be too great.

26

31. Rate of change of axial tilt. If Earth’s rate of change of axial tilt were greater, climatic changes and surface

temperature differences would be too extreme. 32. Rotation period.

If Earth’s rotation period were longer, diurnal temperature differences would be too great.

If Earth’s rotation period were briefer, atmospheric wind velocities would be too great.

33. Rate of change in rotation period.

If the rate of change in Earth’s rotation period were more rapid, the surface temperature range necessary for life would not be sustained.

If the rate of change in Earth’s rotation period were less rapid, the surface temperature range necessary for life would not be sustained.

34. Planet age.

If the Earth were too young, it would rotate too rapidly. If the Earth were too old, it would rotate too slowly.

35. Magnetic field.

If the Earth’s magnetic field were stronger, electromagnetic storms would be too severe. Also, too few cosmic ray protons would reach Earth’s troposphere, and this would inhibit adequate cloud formation.

If the Earth’s magnetic field were too weak, the ozone shield would be inadequately protected from hard stellar and solar radiation.

36. Thickness of crust.

If the Earth’s crust were thicker, too much oxygen would be transferred from the atmosphere to the crust.

If the Earth’s crust were thinner, volcanic and tectonic activity would be too great. 37. Albedo (ratio of reflected light to amount falling on surface).

If the Earth’s albedo were greater, runaway glaciation would develop. If the Earth’s albedo were smaller, a runaway greenhouse effect would develop.

38. Asteroidal and cometary collision rate.

If this rate were greater, too many species would become extinct. If this rate were lesser, the Earth’s crust would be too depleted of materials essential

for life. 39. Mass of body colliding with primordial Earth.

If the body were smaller, Earth’s atmosphere would have been too thick and the moon would have been too small.

If the body were greater, Earth’s orbit and form would have been too greatly disrupted.

27

40. Timing of body colliding with primordial Earth. If the collision had occurred earlier, Earth’s atmosphere would be too thick and the

moon would be too small. If the collision had occurred later, the Earth’s atmosphere would be too thin and thus

the sun would be too luminous for advanced life. 41. Location of body colliding with primordial Earth.

If the body had just grazed the Earth, there would have been insufficient debris to form a large moon. Furthermore, the collision would have been inadequate to annihilate Earth’s primordial atmosphere. Also, there would have been inadequate transfer of heavy elements to Earth.

If the body had collided too close to dead center, damage from the collision would have destroyed necessary conditions for (future) life.

42. Oxygen-to-nitrogen ratio in atmosphere.

If this ratio were larger, advanced life functions would proceed too quickly. If this ratio were smaller, advance life functions would proceed too slowly.

43. Carbon dioxide level in atmosphere.

If the level were greater, a runaway greenhouse effect would develop. If the level were lesser, planets would be unable to maintain efficient photosynthesis.

44. Water vapor level in atmosphere.

If the Earth’s water vapor level were greater, a runaway greenhouse effect would develop.

If the Earth’s water vapor level were smaller, rainfall would be too meager for advanced life on land.

45. Atmospheric electric discharge rate.

If the discharge rate were greater, too much fire destruction would occur. If the discharge rate were smaller, too little nitrogen would be fixed in the

atmosphere. 46. Ozone level in atmosphere.

If the ozone level were greater, surface temperatures would be too low and there would be too little ultraviolet radiation for plant survival.

If the ozone level were too high, surface temperatures would be too high and there would be too much ultraviolet radiation for plant survival.

47. Oxygen quantity in atmosphere.

If the oxygen quantity were greater, planets and hydrocarbons would burn up too easily.

If the oxygen quantity were lesser, advanced animals would have too little oxygen to breathe.

28

48. Ration of 40K, 235U, 238U, 232Th to iron. If this ratio were too low, there would be inadequate levels of plate tectonic and

volcanic activity. If this ratio were too high, the levels of radiation, earthquakes, and volcanoes would

be too high for advanced life. 49. Rate of interior heat loss.

If the rate were too low, there would be inadequate energy to drive the required levels of plate tectonic and volcanic activity.

If the rate were too high, plate tectonic and volcanic activity would shut down too quickly.

50. Seismic activity.

If seismic activity were greater, too many life forms would be destroyed. If seismic activity were lesser, nutrients on the ocean floors from river runoff would

not be recycled to continents through tectonics. Furthermore, not enough carbon dioxide would be released from carbonates.

51. Volcanic activity.

If volcanic activity were lower, insufficient amounts of carbon dioxide and water vapor would be returned to the atmosphere. Also, soil mineralization would become too degraded for life.

If volcanic activity were higher, advanced life would be destroyed. 52. Rate of decline in tectonic activity.

If the rate were slower, advanced life could never survive on Earth. If the rater were faster, advanced life could never survive on Earth.

53. Rate of decline in volcanic activity.

If the rate were slower, advanced life could never survive on Earth. If the rater were faster, advanced life could never survive on Earth.

54. Timing of birth of continent formation.

If the formation had begun too early, the silicate-carbonate cycle would have been destabilized.

If the formation had begun too late, the silicate-carbonate cycle would have been destabilized.

55. Oceans-to-continents ratio.

If the ratio were greater, diversity and complexity of life forms would be limited and the silicate-carbonate cycle would be destabilized.

If the ratio were smaller, diversity and complexity of life forms would be limited and the silicate-carbonate cycle would be destabilized.

56. Rate of change in oceans-to-continents ratio.

If the rate was slower, advanced life would lack the needed landmass area. If the rate was faster, advanced life would be destroyed by the radical changes.

29

57. Global distribution of continents. If the continents were located too much in the southern hemisphere, seasonal

differences would be too severe for advanced life. 58. Frequency and extent of ice ages.

If these were smaller, insufficient fertile, wide, and well-watered valleys would have been produced for diverse and advanced life.

If these were greater, Earth would experience runaway freezing. 59. Soil mineralization.

If the Earth’s soil were too nutrient-poor, the diversity and complexity of life forms would be limited.

If the Earth’s soil were too nutrient-rich, the diversity and complexity of life forms would be limited.

60. Gravitational interactions with a moon.

If the gravitational interaction were greater, tidal effects on the oceans, atmosphere, and rotational period would be too severe.

If the gravitational interaction were lesser, orbital obliquity changes would cause climatic instabilities. Movement of nutrients and life from the oceans to the continents and vice versa would be insufficient. Also the magnetic field would be too weak.

61. Jupiter distance.

If the distance from Earth to Jupiter were greater, too many asteroid and comet collisions would occur on Earth.

If the distance from Earth to Jupiter were lesser, Earth’s orbit would be unstable. 62. Jupiter mass.

If Jupiter’s mass were greater, Earth’s orbit would be unstable. If Jupiter’s mass were lesser, too many asteroid and comet collisions would occur on

Earth. 63. Drift in major planet distances.

If the planet drift were greater, Earth’s orbit would be unstable. If the planet drift were lesser, too many asteroid and comet collisions would occur on

Earth. 64. Major planet eccentricities.

If the eccentricities of the major planets in this solar system were greater, Earth would be pulled out of the life support zone.

65. Major planet orbital instabilities.

If the orbital instabilities were greater, Earth would be pulled out of the life support zone.

30

66. Atmospheric pressure. If atmospheric pressure on Earth were too slight, liquid water would evaporate too

easily and condense too infrequently. Additionally, weather and climate variation would be too extreme and lungs could not function.

If atmospheric pressure on Earth were too great, liquid water would not evaporate easily enough for land life. Also, insufficient sunlight and ultraviolet life would reach the planet’s surface. There would be insufficient climate and weather variation. And lungs would not function.

67. Atmospheric transparency.

If atmospheric transparency were lesser, an insufficient range of wavelengths of solar radiation would reach Earth’s surface.

If atmospheric transparency were greater, too broad a range of wavelengths of would reach Earth’s surface.

68. Magnitude and duration of the sun spot cycle.

If the magnitude of the cycle were lesser or the duration briefer, there would be insufficient variation in climate and weather.

If the magnitude of the cycle were greater or the duration longer, variation in climate and weather would be too great.

69. Continental relief.

If the relief were smaller, there would be insufficient variation in climate and weather.

If the relief were greater, variation in climate and weather would be too great. 70. Chlorine quantity in atmosphere.

If there were less chlorine, erosion rates, the acidity of rivers, lakes, and soils, and certain metabolic rates would be all be insufficient for most life forms.

If there were more chlorine, erosion rates, the acidity of rivers, lakes, and soils, and certain metabolic rates would be too high for most life forms.

71. Iron quantities in oceans and soils.

If there were less iron, the quantity and diversity of life would be too limited to support advanced life. And if the quantity were very small, no life would be possible.

If there were more iron, iron poisoning of at least advanced land life would result. 72. Troposphere ozone quantities.

If there were less tropospheric ozone, insufficient cleansing of biochemical smog would result.

If there were more tropospheric ozone, the respiratory failure of advanced animals, reduced crop yields, and the destruction of ozone-sensitive species would result.

31

73. Stratosphere ozone quantity. If there were less stratospheric ozone, too much ultraviolet radiation would reach the

Earth’s surface, causing skin cancers and reducing plant growth. If there were more stratospheric ozone, too little ultraviolet radiation would reach the

Earth’s surface, causing reduced plant growth and insufficient vitamin production for animals.

74. Mesospheric ozone quantity.

If there were less mesospheric ozone, circulation and chemistry of mesospheric gases would be so disturbed as to upset relative abundances of life-essential gases in the lower atmosphere.

If there were more mesospheric ozone, circulation and chemistry of mesospheric gases would be so disturbed as to upset relative abundances of life-essential gases in the lower atmosphere.

75. Quantity and extent of forests and grass fires.

If these were lesser, growth inhibitors in the soils would accumulate. Soil nitrification would be insufficient. Also, there would be insufficient charcoal production for adequate soil water retention and absorption of certain growth inhibitors.

If these were greater, too many plant and animal life forms would be destroyed. 76. Quantity of soil sulfur.

If there were less sulfur in the soil, plants would become deficient of certain proteins and die.

If there were more sulfur in the soil, plants would die from sulfur toxins. The acidity of water and soil would become too great for life. Also, nitrogen cycles would be disturbed.

77. Biomass-to-comet-infall ratio.

If this ratio were smaller, greenhouse gases would accumulate, triggering runaway surface temperature increase.

If this ratio were larger, greenhouse gases would decline, triggering a runaway freeze.

32

Probabilities for Life on Earth This appendix presents an estimate for the probability of attaining the necessary parameters for life support on a planet. It includes 153 known parameters. (Reprinted from Lights in the Sky & Little Green Men, Appendix B, pp. 185-189. A list of scientific references supporting these design parameters is included at the end of the book.) Parameter

Probability that feature will fall in the required range for physical life

Local abundance and distribution of dark matter .1 Galaxy cluster size .1 Galaxy cluster location .1 Galaxy size .1 Galaxy type .1 Galaxy mass distribution .2 Galaxy location .1 Variability of local dwarf galaxy absorption rate .1 Star location relative to galactic center .2 Star distance from corotation circle of galaxy .005 Star distance from closest spiral arm .1 Z-axis extremes of star orbit .02 Proximity of solar nebulae to a type I supernovae eruption .01 Timing of solar nebula formation relative to type I supernova eruption .01 Proximity of solar nebulae to a type II supernovae eruption .01 Timing of solar nebula formation relative to type II supernova eruption .01 Flux of cosmic ray protons .1 Variability of cosmic ray proton flux .1 Number of stars in birthing cluster .01 Star formation history in parent star vicinity .1 Birth date of the star-planetary system .01 Number of stars in the system .7 Number and timing of close encounters by nearby stars .01 Proximity of close stellar encounters .1 Masses of close stellar companion .1 Star age .4 Star metallicity .05 Ratio of 40K, 235U, 238U, 232Th to iron in star-planetary system .02 Star orbital eccentricity .1 Star mass .001 Star luminosity change relative to speciation types and rates .00001 Star color .4 Star magnetic field .1 Star magnetic field variability .1 Stellar wind strength and variability .1 Short period variation in parent star diameter .3 Star’s carbon-to-oxygen ratio .01

33

Star’s space velocity relative to Local Standard of Rest .05 Star’s short-term luminosity variability .05 Star’s long-term luminosity variability .05 Amplitude and duration of star spot cycle .1 Number and timing of solar system encounters with interstellar gas clouds .1 Galactic tidal forces on planetary system .2 H3

+ production .1 Supernovae rates and locations .01 White dwarf binary types, rates, and locations .01 Structure of comet cloud surrounding planetary system .3 Planetary distance from star .001 Inclination of planetary orbit .5 Axis tilt of planet .3 Rate of change of axial tilt .01 Period and size of axial tilt variation .1 Planetary rotation period .1 Rate of change in planetary rotation period .05 Planetary rotation period .2 Planetary orbit eccentricity .3 Rate of change of planetary orbital eccentricity .1 Rate of change of planetary inclination .5 Period and size of eccentricity variation .1 Period and size of inclination variation .1 Number of moons .2 Mass and distance of moon .01 Surface gravity (escape velocity) .001 Tidal force from sun and moon .1 Magnetic field .01 Rate of change and character of change in magnetic field .1 Albedo (planet reflectivity) .1 Density .1 Reducing strength of planet’s primordial mantle .3 Thickness of crust .01 Timing of birth of continent formation .1 Oceans-to-continents ratio .2 Rate of change in oceans-to-continents ratio .1 Global distribution of continents .3 Frequency, timing, and extent of ice ages .1 Frequency, timing, and extent of global snowball events .1 Asteroidal and cometary collision rate .1 Rate of change in asteroidal and cometary collision rate .1 Mass of body colliding with primordial Earth .002 Timing of body colliding with primordial Earth .05 Location of body’s collision with primordial Earth .05 Position and mass of Jupiter relative to Earth .01 Major planet eccentricities .1 Major planet orbital instabilities .05 Drift and rate of drift in major planet distances .05

34

Number and distribution of planets .01 Distance of gas giant planets from mean motion resonances .02 Atmospheric transparency .01 Atmospheric pressure .01 Atmospheric viscosity .1 Atmospheric electric discharge rate .01 Atmospheric temperature gradient .01 Carbon dioxide level in atmosphere .01 Rate of change in carbon dioxide level in atmosphere .1 Rate of change in water vapor level in atmosphere .01 Rate of change methane level in early atmosphere .01 Oxygen quantity in atmosphere .01 Nitrogen quantity in atmosphere .01 Chlorine quantity in atmosphere .1 Carbon monoxide quantity in atmosphere .1 Cobalt quantity in crust .1 Arsenic quantity in crust .1 Copper quantity in crust .1 Boron quantity in crust .1 Fluorine quantity in crust .1 Iodine quantity in crust .1 Manganese quantity in crust .1 Nickel quantity in crust .1 Phosphorus quantity in crust .1 Tin quantity in crust .1 Zinc quantity in crust .1 Molybdenum quantity in crust .05 Vanadium quantity in crust .1 Chromium quantity in crust .1 Selenium quantity in crust .1 Iron quantity in oceans .1 Tropospheric ozone quantity .01 Stratospheric ozone quantity .01 Mesospheric ozone quantity .01 Water vapor level in atmosphere .01 Oxygen-to-nitrogen ratio in atmosphere .1 Quantity of greenhouse gases in atmosphere .01 Rate of change in greenhouse gases in atmosphere .01 Quantity of forest and grass fires .01 Quantity of sea salt aerosols .1 Soil mineralization .1 Quantity of anaerobic bacteria in the oceans .01 Quantity of aerobic bacteria in the oceans .01 Quantity, variety, and timing of sulfate-reducing bacteria .001 Quantity of decomposer bacteria in soil .01 Quantity of mycorrhizal fungi in soil .01 Quantity of nitrifying microbes in soil .01 Quantity and timing of vascular plants introductions .001

35

Quantity, timing, and placement of carbonate-producing animals .00001 Quantity, timing, and placement of methanogens .00001 Quantity of soil sulfur .1 Rate of interior heat loss for planet .01 Quantity of sulfur in the planet’s core .1 Quantity of silicon in the planet’s core .1 Quantity of water at subduction zones in the crust .01 Quantity of high-pressure ice in subducting crustal slabs .1 Hydration rate of subducted minerals .1 Tectonic activity .05 Rate of decline in tectonic activity .1 Volcanic activity .1 Rate of change of volcanic activity .1 Continental relief .1 Viscosity at Earth core boundaries .01 Viscosity of lithosphere .2 Biomass-to-comet infall ratio .01 Regularity of cometary infall .1 Number, intensity, and location of hurricanes .02 Dependency factors estimate 1030

Longevity requirements 1013

The probability of a planet anywhere in the universe fitting within all 153 parameters is approximately 10-194. The maximum possible number of planets in the universe is estimated to be 1022. Thus, less than 1 chance in 10172 (100 thousand trillion trillion trillion trillion trillion trillion trillion trillion trillion trillion trillion) exists that even one such planet would occur anywhere in the universe.

36

Fine-Tuning for Life in the Universe For life to be possible in the universe, several characteristics must take on specific values, and these are listed below. In the case of several of these characteristics, and given the intricacy of their relationship, the indication of fine-tuning seems incontrovertible. (Reprinted from Lights in the Sky & Little Green Men, Appendix C, pp. 191-192. A list of scientific references supporting these design parameters is included at the end of the book.) 1. Strong nuclear force constant. 2. Weak nuclear force constant. 3. Gravitational force constant. 4. Electromagnetic force constant. 5. Ratio of electromagnetic force constant to gravitational force constant. 6. Ratio of proton to electron mass. 7. Ratio of number of protons to number of electrons. 8. Expansion rate of the universe. 9. Mass density of the universe. 10. Baryon (proton and neutron) density of the universe. 11. Space energy density of the universe. 12. Entropy level of the universe. 13. Velocity of light. 14. Age of the universe. 15. Uniformity of radiation. 16. Homogeneity of the universe. 17. Average distance between galaxies. 18. Average distance between stars. 19. Average size and distribution of galaxy clusters. 20. Fine structure constant. 21. Decay rate of protons. 22. Ground state energy level for helium-4. 23. Carbon-12 to oxygen-16 nuclear energy level ratio. 24. Decay rate for beryllium-8. 25. Ratio of neutron mass to proton mass. 26. Initial excess of nucleons over antinucleons. 27. Polarity of the water molecule. 28. Epoch for supernova eruptions. 29. Frequency of supernovae eruptions. 30. Epoch of white dwarf binaries. 31. Density of white dwarf binaries. 32. Ratio of exotic matter to ordinary matter. 33. Number of effective dimensions in the early universe. 34. Number of effective dimensions in the present universe. 35. Mass of the neutrino. 36. Magnitude of big bang ripples. 37. Size of the relativistic dilation factor. 38. Magnitude of the Heisenberg uncertainty principle.

37

Footnotes:

1 G. Cocconi and P. Morrison, “Searching for Interstellar Communication”, Nature 184, pp. 844-846. 2 F. Drake, “Project Ozma,” Physics Today, 14, 4 (1961), pp. 40-46. 3 The name Ozma was taken from L Frank Baum’s book, Ozma of Oz. 4 The Drake equation was first developed by Frank Drake in 1961 as an attempt to determine the feasibility of

actually detecting extraterrestrial signals. There are a number of variations of this equation that are commonly used today. His published equation and estimates for each of the terms is given in Ref. 35. The factor, fs, is absent in Drake’s original formulation but is included here because SETI enthusiasts commonly use it today.

5 META stands for Mega-channel Extraterrestrial Assay and was a five year project that ended in 1993. P. Horowitz and C. Sagan, “Five Years of Project META: An All-Sky Narrow-band Radio Search for Extraterrestrial Signals,” Astrophysical Journal, 415 (1993), pp. 218-235.

6 BETA stands for Billion-channel Extraterrestrial Assay. More information on Project BETA can be found at http://www.planetary.org/html/UPDATES/seti/BETA/default.html

7 SERENDIP stands for Search for Extraterrestrial Emissions from Nearby Developed Intelligent Populations. More information on Project SERENDIP can be found at http://seti.ssl.berkeley.edu/serendip/.

8 SETI@Home is project whereby individual computer owners can allow radio telescope data from Project SERENDIP to be automatically downloaded onto their computer, processed, and sent back using only unused computer time. By harnessing Internet-connected computers all over the country (this is referred to as distributed computing), SETI is able to fully analyze the enormous amount of data being collected and allow individual citizens to participate in SETI’s search for extra-terrestrials. More information can be found at http://setiathome.ssl.berkeley.edu/.

9 Project Phoenix received its name after its government funding was canceled but it was revived from its “ashes” by public sponsorship. http://www.seti-inst.edu/seti/our_projects/project_phoenix/Welcome.html.

10 C. Sagan and F. Drake, “The Search for Extraterrestrial Intelligence,” Scientific American, 232, May 1975, pp. 80-89.

11 I. S. Shklovskii and C. Sagan, Intelligent Life in the Universe, Holden-Day, San Francisco, 1966. 12 Seth Shostak, “Listening for Life,” Astronomy, October 1992, pp. 26-33. Seth Shostak, “When E.T. Calls Us,”

Astronomy, September 1997, pp. 37-51. 13 Sky and Telescope magazine web site with information on SETI: http://skyandtelescope.com/resources/SETI/ 14 D. McKay, E. Gibson Jr., K. Thomas-Keprta, H. Vali, C. Romanek, S. Clemett, X. Chillier, C. Maechling, R.

Zare, “Search for Past Life on Mars: Possible Relic of Biogenic Activity in Martian Meteorite ALH84001,” Science, 273 (1996), p. 924.

15 J. Hartsfield and D. Salsbury, “Meteorite Yields Evidence of Primitive Life on Early Mars,” NASA News, World Wide Web, Aug. 7, 1996, p. 1.

16 J. Shreeve, “Find of the Century?” Discover, Jan. 1997, pp. 40-41. 17 T. Monmaney, “Impact of Mars meteorite may be ‘cosmological blow’ for mankind,” Houston Chronicle, Sept. 2,

1996, p. 11A. 18 A. Albee, “Mars find could be rock of ages,” The Arizona Republic, Aug. 18, 1996, p. H1. 19 E. Wilson, “Meteorite worms: Martian nanofossils or lab gunk?” C&EN, Dec. 8, 1997, p. 8. 20 A. Chaikin, “Life on Mars: The Great Debate,” Popular Science, July 1997, pp. 60-65. 21 E. Wilson, “Cold Water Thrown on Martian Life Hypothesis,” C&EN, Jan. 7, 1998, pp. 8-9. 22 R. Cowen, “Biology on Europa,” Science News, 151 (1997), p. 210. 23 D. Cruikshank, “Comet Hale-Bopp: Stardust Memories,” Science, 275 (1997), pp. 1895-1896.

38

24 New York Times News Service, “Comets Scattering Seeds of Life? Hale-Bopp Findings Boost Theory,” April 1,

1997. 25 The problems that would be faced by an advanced civilization trying to cross vast interstellar distances are

discussed in depth in H. Ross, K. Samples, and M. Clark, Lights in the Sky & Little Green Men, NavPress, Colorado Springs, CO 2002, p. 55-64

26 Timothy Ferris, “Seeking an end to cosmic loneliness,” The New York Times Magazine, October 23rd, 1977, p. 97. 27 Frank Drake, Is Anyone Out There? 1992. 28 I. S. Shklovskii and C. Sagan, Intelligent Life in the Universe, Holden-Day, San Francisco, 1966, p. 411. 29 Carl Sagan and Frank Drake, “The Search for Extraterrestrial Intelligence,” Scientific American, 232, May 1975,

p. 80. 30 The Copernican Principle was actually coined by Immanuel Kant, not Nicholas Copernicus, based on his work

that our sun was but one of the myriads of stars that inhabit our galaxy. Kant was philosophically opposed to the idea that God intervened in any way in the formation of the solar system, our planet, or even earth life, hence neither the sun nor the Earth could be “special” in any way since they would have been produced by the exact same laws of physics as other planets and stars. Thus the Copernican Principle is really a philosophical principle rather than a scientific one. Copernicus would certainly have rejected this principle that bears his name.

31 R. Naeye, “OK, Where Are They?” Astronomy, July 1996, p. 38. 32 R* is the rate of star formation in the past when stars like our own sun were forming, rather than the current rate of

formation. Star formation was more common earlier in the galaxy’s history. 33 There has been some speculation that Europa, a moon of Jupiter, has a layer of liquid water under its icy exterior

and hence could be a possible sight for life even though Jupiter and Europa both lie outside the “Goldilocks” zone of our sun. While this is an unsettled question, it is not relevant for our discussion here since we are specifically concerned only with “intelligent communicating” life.

34 I. S. Shklovskii and C. Sagan, pp. 413. 35 F. Drake, “The Radio Search for Intelligent Extraterrestrial Life,” Current Aspects of Exobiology, edited by G.

Mamikunian and M. Briggs, Pergamon Press (1965), pp. 323-345. 36 I. S. Shklovskii and C. Sagan, pp. 408-413. 37 Values taken from http://www.activemind.com/Mysterious/Topics/SETI/drake_equation.html (as of Nov. 9,

2002). This site organized the Drake equation in a slightly different way and so the numbers were adjusted to fit the format used here.

38 Values taken from http://www.seds.org/~rme/drake.html (as of Nov. 9, 2002). SEDS stands for Students for the Exploration and Development of Space.

39 Values taken from http://www.lifeinuniverse.org/noflash/Drakeequation-07-02.html (as of Nov. 9, 2002). Not all of their values were stated clearly but are presented as fairly as possible.

40 Eleven “events” were been detected by project META that satisfy most of SETI’s criteria for possible extraterrestrial communication but none of these signals were subsequently redetected and so cannot be considered genuine signals. P. Horowitz and C. Sagan, “Five Years of Project META: An All-Sky Narrow-band Radio Search for Extraterrestrial Signals,” Astrophysical Journal, 415 (1993), pp. 218-235.

41 R. Dixon, “The Ohio SETI Program--The First Decade,” The Search for Extraterrestrial Life: Recent Developments (Dordrecht: Reidel, 1985), pp. 305-314.

42 In 1977, Ohio State University detected a signal known as the “WOW!” signal (because someone scribble this word next to the signal). This signal has been scrutinized but never redetected. R. H. Grey, “A Search of the ‘WOW’ Locale for intermittent Radio Signals,” Icarus, 112, 1994, pp. 485-489.

43 C. F. Chyba, “Life Beyond Mars,” Nature, volume 382, 1996, pp. 577.

39

44 A. J. LePage, “Where They Could Hide: The Galaxy Appears Devoid of Supercivilizations, but Lesser Cultures

Could Have Eluded the Ongoing Searches,” Scientific American, July 2000, p. 40-41. 45 S. Webb, If the Universe is Teeming with Aliens … Where is Everybody? Fifty Solutions to the Fermi Paradox

and the Problem of Extraterrestrial Life, Copernicus, New York, 2002. 46 I. Crawford, “Where Are They?” Scientific American, July 2000, pp. 38-43. 47 Numerous variations on this argument have been proposed in the literature. Because of the enormous difficulties

in sending and maintaining living beings for stellar distances, civilizations might just send embryos or simply their DNA, which could then be brought to maturity at the destination. This is also known as panspermia. An alternative possibility is self-replicating robots (also known as Von Neumann machines). An example of this later position is given in F. J. Tipler, “Extraterrestrial Intelligent Beings Do Not Exist,” Physics Today, April 1981, pp. 9, 70-71; and associated commentary in Physics Today, March 1982, pp. 26-38.

48 M. H. Hart, “An Explanation for the Absence of Extraterrestrials on Earth,” Quarterly Journal of the Royal Astronomical Society, 16, (1973), pp. 128-135.

49 For a good description of our solar system and the unique features of each of the planets, see S. R. Taylor, Destiny or Chance, Cambridge University Press, Cambridge, Great Britain (2000).

50 Current technology is primarily limited to the detection of very large planets the size of Saturn, Jupiter, or larger but future telescopes should be able to detect smaller inner planets. Most of the new planets have been discovered by detecting a faint wobble in the star due to the gravitational attraction of its planets. This methods is only able to determine the minimum mass of a planet, so some of these “planets” may actually be brown dwarf stars. Future work with the Hubble Space Telescope will be able to establish the actual mass of the very nearby planets. Other detection methods including gravitational lensing and transit method.

51 An up-to-date catalog of known extra-solar planets can be found at http://www.obspm.fr/encycl/catalog.html. 52 G. Gonzalez, “New Planets Hurt Chances for ETI,” Facts & Faith, Vol. 12, No. 4 (1998), pp. 3-4. 53 S. Flamsteed, “Impossible Planets,” Discover, Sept. 1997, pp. 78-83. 54 “Who ordered that?” was the exclamation of mock horror by Columbia University physicist I. I. Rabi upon

receiving news of the discovery of the muon, a new and totally unpredicted subatomic particle. 55 Gravitational lensing is where the gravity of an intermediate object acts as a lens enabling us to see things that we

normally would not be able to see. Only star systems that are correctly aligned behind a gravitational source can be viewed this way and such alignment is extremely is rare.

56 S. H. Rhie et al., “On Planetary Companions to the MACHO 98-BLG-35 Microlens Star,” Astrophysical Journal 533 (2000), pp. 378-91.

57 The editors, “Our Friend Jove,” Discover, July 1993, p. 15. 58 H. Ross, “Computer Models Reveal New Evidence of God’s Care,” Facts & Faith, Vol. 7, No. 3 (1993), p. 1-3. 59 G. Witherill, “How Special is Jupiter,” Nature, 373 (1995), p. 470. 60 B. Zuckerman, T. Forveille, and J. Kastner, “Inhibition of Giant-Planet Formation by Rapid Gas Depletion

Around Young Stars,” Nature, 373 (1995), pp. 494-496. 61 R. Jayawarhana, “No Alien Jupiters,” Science, 265 (1994), p. 1527. 62 H. Ross, “Rarity of Jupiter-sized Planets Confirmed,” Facts & Faith, Vol. 9, No. 2 (1995), p. 3. 63 H. Ross, “Drifting Giants Highlight Jupiter’s Uniqueness,” Facts & Faith, Vol. 10, No. 4 (1996), p. 4. 64 H. Ross, “Jupiter’s Miracle Migration,” Connections, Vol. 4, No. 1 (2002), pp. 1,5. 65 H. Ross, “New Planets Raise Unwarranted Speculation About Life Sites,” Facts & Faith, Vol. 10, No. 1 (1996),

pp. 1-3. 66 J. van Paradijs, “From Gamma-Ray Bursts to Supernovae,” Science, 286 (1999), p. 693-695. 67 J. Scalo and J. C. Wheeler, “Astrophysical and Astrobiological implications of Gamma-Ray Burst Properties,”

Astrophysical Journal, 566 (2002), p. 723-737.

40

68 Ray White III and William C Keel, “Direct Measurement of the Optical Depth in a Spiral Galaxy,” Nature 359

(1992), 129-130. 69 Yu N. Mishurov and L. A. Zenina, “Yes, the Sun is Located Near the Corotation Circle,” Astronomy and

Astrophysics 341, (1999), pp. 81-85. 70 A globular cluster is a spherical grouping of stars and represents some of the oldest stars in a galaxy. 71 R. L. Gilliland, et al., “A Lack of Planets in 47 Tucanae from a Hubble Space Telescope Search,” Astrophysical

Journal Letters, 545, 2000, p. L47-51. 72 H. Ross, The Creator and the Cosmos, NavPress, CO, 1993, pp. 128-129. 73 H. Ross, “Lunar Origin Update,” Fact & Faith, Vol. 9, No. 1 (1995), pp. 1-3. 74 H. Ross, The Creator and the Cosmos, 3rd Ed., NavPress, CO, 2001, pp. 201-212. 75 M. Ludwig, Computer Viruses, Artificial Life, and Evolution, American Eagle Publications, AZ 1993. 76 C. B. Thaxton, W. L. Bradley, and R. L. Olsen, The Mystery of Life’s Origin: Reassessing Current Theories,

Lewis and Stanley, TX 1992. 77 R. Shapiro, Origins: A Skeptic’s Guide to the Creation of Life on Earth, (New York, Summit Books, 1986). 78 H. Yockey, Information Theory and Molecular Biology (Cambridge, UK, Cambridge University Press, 1992). 79 M. J. Behe, Darwin’s Black Box: The Biochemical Challenge to Evolution, Touchstone, New York 1996. 80 B. Carter, “The Anthropic Principle and its Implications for Biological Evolution,” Proc. Royal Soc. Discussion

Meetings on the Constants of Physics, edited by W. H. McRea and M. J. Rees, R. Soc., London, 1983 and in Philos. Trans. R. Soc. London, A310, p. 347-355.

81 R. Breuer, The Anthropic Principle: Man as the Focal Point of Nature, Bukhäuser, Boston, 1991. 82 “Why Life May Be Common and Intelligence Rare,” Sky and Telescope, February 2003, p. 26. 83 B. M. Testa, “What killed Mars? Signs of water there drive theories about what depleted its atmosphere,”

Houston Chronicle, April 12, 1996, p. 6D. 84 I. S. Shklovskii and C. Sagan, pp. 343-350. 85 Design statistics were collected by astronomer Dr. H. Ross. In H. Ross, The Creator and the Cosmos, NavPress,

CO, 1993, pp. 123-135, he lists 33 design parameters with explanations and estimates. In the second edition of the book (1995, pp. 132-144) this was expanded to include 41 design parameters. By the third edition (2001, pp. 175-199), this list had increased to 128. H. Ross, K. Samples, and M. Clark, Lights in the Sky & Little Green Men, NavPress, Colorado Springs, CO 2002, pp. 171-189, gives the current listing of 153 design parameters. These design parameters are reproduced in the appendices of this paper.

86 For example, the SETI institute’s response: http://www.seti-inst.edu/seti/seti_science/rare_earth/rare_earth.html. 87 R. Naeye, p. 43 88 It is important to note that the author of this paper does not accept the conclusion that life arises by purely natural

processes for the reasons stated earlier in this paper. This reference is included here to emphasize that the belief that the earth and sun are indeed special is not depended upon a belief in Biblical creation or a rejection of abiotic evolution. In other words, even if we were to grant SETI proponents abiotic evolution purely for the sake of argument, their case would still fail.

89 P. Ward and D. Brownlee, Rare Earth: Why Complex Life is Uncommon in the Universe, Copernicus, NY 2000, p. xiv.

90 P. Ward and D. Brownlee, p. 275. 91 G. Gonzalez, “Nobody Here but Us Earthlings,” The Wall Street Journal, July 16, 1997, p. A22. This article

along with three contrasting viewpoints and a follow-up response by G. Gonzalez can be found in Cosmic Pursuit, Spring 1999, 16-19, 63.

92 G. Gonzalez, “Nobody Here but Us Earthlings,” p. A22.

41

93 Psalms 19:1, New International Version. 94 “Scientists get serious about ‘weird life,’” The Kansas City Star, December 1, 2002, p. A8. 95 R. Naeye, p. 38-39. 96 Polarity refers to an unequal distribution of electrons so that some portions of a molecule have a partial positive

charge and other parts have a partial negative charge. For water, the oxygen atom has a stronger pull on the electrons that the hydrogen atoms do, so the oxygen has a partial negative charge and the two hydrogens have a partial positive charge.

97 R. Breuer, p. 209-218. 98 R. A. Horne, Marine Chemistry: The Structure of Water and the Chemistry of the Hydrosphere, Wiley, 1969.

Horne lists ten “anomalous” chemical properties of water, their importance in biology, and comparisons to other solvents. The 10 properties are water’s heat capacity, heat of fusion, heat of vaporization, thermal expansion, surface tension, dissolving power, dielectric constant, electrolytic dissociation, transparency, and conduction of heat

99 F. H. Stillinger, “Water Revisited,” Science 299 (1990), p. 451-457. Stillinger notes 8 “notable” properties of water and comments, “Some of these attributes are shared with other substances; perhaps we will eventually discover that they all are. Nevertheless, it is striking that so many eccentricities should occur together in one substance.”

100 R. H. Dicke, “Dirac’s Cosmology and Mach’s Principle,” Nature 192, 1961, p. 440. 101 An overview of different Christian views on extraterrestrial life and its possible implications for Christianity can

be found in D. Wilkinson, “Some Alien Problems for God?” Cosmic Pursuit, Sprint 1999, pp. 28-33, 63-64. 102 S. Hawking, A Brief History of Time, Bantam Books, New York 1988, pp. 126-127. 103 H. Ross, “The Haste to Conclude Waste,” Facts & Faith, Vol. 11, No. 3 (1997), p. 1-3. 104 Brandon Carter, “Large Number Coincidences and the Anthropic Principle in Cosmology,” Proceedings of the

International Astronomical Union Symposium, No. 63: Confrontation of Cosmological Theories with Observational Data, ed. M. S. Longair (Dordrecht-Holland/Boston, U.S.A.: D. Reidel, 1974), 291-298.

105 H. Ross, K. Samples, and M. Clark, Lights in the Sky & Little Green Men, NavPress, Colorado Springs, CO 2002, Appendix C, p. 171-184. This appendix is given in Fine-Tuning for Life in the Universe on page 36.

106 Lawrence M. Krauss, “The End of the Age Problem and the Case for a Cosmological Constant Revisited,” Astrophysical Journal 501 (1998): 461-66.

107 John D. Barrow and Frank J. Tipler, The Anthropic Cosmological Principle (New York: Oxford University Press, 1986); F. Bertola and U. Curi, eds., The Anthropic Principle (Cambridge: Cambridge University Press, 1993); Paul Davies, The Cosmic Blueprint (New York: Simon & Schuster, 1988); Michael J. Denton, Nature’s Destiny (New York: The Free Press, 1998); George Greenstein, The Symbiotic Universe (New York: William Morrow, 1988); Hugh Ross, The Creator and the Cosmos, 3d ed.(Colorado Springs, CO: NavPress, 2001); Peter D. Ward and Donald Brownlee, Rare Earth (New York: Copernicus, 2000).

108 Quotes from nineteen astronomers who have done research on the anthropic principle may be found in Hugh Ross, The Creator and the Cosmos, 3rd Ed., NavPress, CO, 2001, p. 157-60.

109 H. Ross, “A Precise Plan for Humanity,” Facts For Faith (Q1 2002), pp. 25-31. 110 H. Ross, “Life on Mars as Proof of Evolution?” Facts & Faith, Vol. 2, No. 3, 1998, pp. 1-2; H. Ross, “Life on

Mars Revisited,” Facts & Faith, Vol. 3, No. 2, 1989, p. 2; H. Ross, “Ahead to Mars, or Back to Babel? Facts & Faith, Vol. 5, No. 2, 1991, p. 1-3.

111 H. Ross, The Creator and the Cosmos, NavPress, CO, 1993, pp. 144-146.