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THE CASE FOR A CREATOR - universe proof #2

from the book "THE Case for A CREATOR"

Taking Hits for Earth

Now that we were discussing our solar system, I wanted to delve into other "local" factors that make our planet habitable. "What is it about our solar system that contributes to life on Earth?" I asked.

"A surprising amount," said Gonzalez. "More and more, astronomers are learning how the other planets tie into the habitability of Earth. For example, George Wetherill of the Carnegie Institution showed in 1994 that Jupiter—which is huge, more than three hundred times the mass of the Earth—-acts as a shield to protect us from too many comet impacts. It actually deflects comets and keeps many of them from coming into the inner solar system, where they could collide with Earth with life-extinguishing consequences. This was illustrated very nicely by the impact of Comet Shoemaker-Levy 9 into Jupiter in July, 1994. This comet was attracted by Jupiter's tremendous gravitational pull and broke into fragments, with all of them hitting Jupiter. Even Saturn and Uranus participate in that kind of comet-catching. In addition, the other planets in our inner solar system protect us from getting bombarded by asteroids from the asteroid belt. The asteroids are mostly between the orbits of Mars and Jupiter. Our first line of defense is Mars, being at the edge of the asteroid belt. It takes a lot of hits for us. Venus does too. If you want to get an idea of the stuff that probably would have hit the Earth, look at the surface of the moon. The moon, unfortunately, has too little surface area to provide much protection, but it's a nice record."

"What about the Earths position in the solar system?" I asked. "How much does that contribute to its habitability?"

"There's a concept invented by astrobiologists called the Circum-stellar Habitable Zone. That's the region around a star where you can have liquid water on the surface of a terrestrial planet. This is determined by the amount of light you get from the host star. You can't be too close, otherwise too much water evaporates into the atmosphere and it causes a runaway greenhouse effect, and you boil off the oceans. We think that might be what happened to Venus. But if you get too far out, it gets too cold. Water and carbon dioxide freeze and you eventually develop runaway glaciation. The main point is that as you go further out from the sun, you have to increase the carbon dioxide content of the planets atmosphere. This is necessary in order to trap the suns radiation and keep water liquid. The problem is that there wouldn't be enough oxygen to have mammal-like organisms. It's only in the very inner edge of the Circum-stellar Habitable Zone where you can have low enough carbon dioxide and high enough oxygen to sustain complex animal life. And that's where we are."

"So if the Earth's distance from the sun were moved by say, five percent either way, what would happen?" I asked.

"Disaster," came his quick reply. "Animal life would be impossible. The zone for animal life in the solar system is much narrower than most people think."

"And that's why you need a circular orbit like the one Earth has," Richards added. "You don't just want to be in the Circumstellar Habitable Zone part of the time; you want to be in it continuously. It doesn't do you any good to have melted water for four months and then have the whole planet freeze up again."

Our Over achieving Sun

Obviously, the key to continued life on Earth is the sun, whose nuclear fusion, taking place at twenty-seven million degrees Fahrenheit at its core, provides us with consistent warmth and energy ninety-three million miles away. Ever since witnessing a solar eclipse as a child, carefully protecting my eyes by observing the phenomenon through a projected image inside a cardboard box, I have been fascinated by this fiery behemoth, whose mass is an incomprehensible three hundred thousand times greater than the Earth's. However, I had always been told that there was nothing out of the ordinary about the sun. As one text says flatly: "The sun is a common fixed star."33 And if the sun is truly so average, so typical, so undistinguished, then the logical implication would be that lots of life-bearing Earths must be orbiting around lots of similar suns throughout the universe.

"Today, astronomers know a lot more about stars than they did when I was growing up," I said to Gonzalez. "Is the consensus still that the sun is just a common star?"

"No, not at all," Gonzalez replied. "It's just recently that some new astronomy textbooks are finally starting to say that, well, the sun really is unusual after all. For instance, it's among the ten percent most massive stars in the galaxy. In fact, if you pick a star at random, you're likely to pick one that's far less massive than the sun, usually red dwarfs, which make up about eighty percent of stars. Another eight or nine percent are called G dwarfs, most of which also are less massive than the sun. The sun is a yellow dwarf; technically, it has a G2 Spectral Type."

His comment about the ubiquity of red dwarfs piqued my curiosity. "Since red dwarfs dominate the universe, let's talk about them for a moment. Are they conducive to having life-bearing planets orbiting them?" I asked.

"I don't think they are," Gonzalez said.

"Why not?"

"Several reasons. First, red dwarfs emit most of their radiation in the red part of the spectrum, which makes photosynthesis less efficient. To work well, photosynthesis requires blue and red light. But a much greater problem is that as you decrease the mass of a star, you also decrease its luminosity. A planet would have to orbit this kind of star much closer in order to have sufficient heat to maintain liquid water on its surface. The problem is the tidal force between the star and the planet gets stronger as you move in, so the planet will spin down and eventually end up in what's called a tidally locked state. This means it always presents the same face towards the star. That's very bad, because it causes large temperature differences between the lit side and the unlit side. The lit side would be terribly dry and hot, while the unlit side would be prohibitively icy and cold. And there's another problem-—red dwarfs have flares."

"But," I said, "the sun has flares too."

"That's right. And the intensity of flares on red dwarfs is about the same as on our sun. The difference is that red dwarfs as a whole emit much less total light, so they're much less luminous. That means in comparison to the luminosity of the star, the output of the flare is high."

"Whoa!" I said, putting up my hand in protest. "You've lost me."

Gonzalez regrouped. "Okay, let me get to the bottom line: for this kind of star, flares cause the star's total luminosity to vary. In fact, astronomers call them 'flare stars,' and they watch as they get much brighter for a while and then dimmer again. We don't pay too much attention to the solar flares of our sun, because the sun is so luminous that the flares are like a little blip. You barely notice them."

"And remember we're ninety-three million miles from the sun," Richards said. "With a red dwarf, your planet would have to be much closer to the star."

"Right," said Gonzalez. "The luminosity increase would cause temperature spikes on the surface of an orbiting planet. But just as bad would be the increased particle radiation that would result from the flares. On Earth, we get a very mild effect called the aurora borealis. This is where there's a flare on the sun, the particles eventually reach the Earth, they're funneled down the magnetic field to the north and south poles, and we see the aurora borealis as these beautiful lights in the northern hemisphere. However, particle radiation has the effect of quickly stripping away the atmosphere, increasing the surface radiation levels, but most importantly, destroying the ozone layer, which we need to protect from radiation. All of this would be deadly for any life on a planet near a red dwarf. And then red dwarfs have one more problem: they don't produce much ultraviolet light, which you need early on to build up oxygen in the atmosphere. Scientists believe that the oxygen in the Earth's atmosphere was built up at first by the ultraviolet radiation that broke up water into oxygen and hydrogen. The oxygen was allowed to build up in the atmosphere, while the hydrogen escaped into space, because it's lighter. But you get very little blue light from a red dwarf, so this phenomenon wouldn't occur as rapidly and you wouldn't get the build up of the oxygen you need to sustain life. Fortunately, our sun is not only the right mass, but it also emits the right colors-—-a balance of red and blue. As a matter of fact, if we were orbiting a more massive star, called an F dwarf, there would be much more blue radiation that would build up the oxygen and ozone layer even faster. But any momentary interruption of the ozone layer would subject the planet to an immediate flood of highly intense ultraviolet radiation, which would be disastrous to life. Also, the more massive stars don't live as long-—-that's the major problem. Stars that are even just a little more massive than the sun live only a few billion years. Our sun is expected to last a total of about ten billion years on its main sequence, burning hydrogen steadily, whereas stars just a few tens of percent more massive have considerably less lifetime on the main sequence. And while on the main sequence, they change luminosity much faster. Everything on their lifecycle happens faster."

"Anything else that makes our sun unusual?" I asked.

"Yes, the sun is metal-rich; in other words, it has a higher abundance of heavy elements compared to other stars of its age in this region of the galaxy. As it turns out, the sun's metallicity may be near the golden mean for building Earth-size habitable terrestrial planets. And the sun is highly stable, more so than most comparable stars. Its light output only varies by one-tenth of one percent over a full sunspot cycle, which is about eleven years. This prevents wild climate swings on Earth. Another way it's anomalous is that the sun's orbit is more nearly circular in the galaxy than most other stars of its age. That helps by keeping us away from the galaxy's dangerous spiral arms. If the sun's orbit were more eccentric, we could be exposed to the kind of galactic dangers I mentioned earlier, such as explosions of supernovae."

I realized after Gonzalez's comments that I would never look at the bejeweled night sky as I had in the past. I used to see stars as being fungible, which is a legal term meaning one is just as good as the other. But now I understood why the vast majority of stars would be automatically ruled out as being capable of supporting life-bearing planets. It would take a star with the highly unusual properties of our sun— the right mass, the right light, the right composition, the right distance, the right orbit, the right galaxy, the right location-—to nurture living organisms on a circling planet. That makes our sun, and our planet, rare indeed.

As much as I have been fascinated by the sun, I've also frequently stared in wonder at the other dominant celestial body in our sky—-the moon. Curious to find out whether this barren, rocky satellite contributes anything to its host planet-—other than inspiration for poets and other romantics—I proceeded to turn our discussion toward lunar issues.

Our Life-Supporting Moon

Centuries ago, the dark patches on the moon—low-lying areas that had been flooded with basaltic lava-—were thought to be oceans that provided life-giving water to its unseen population. They were called maria, Latin for "seas."3 The name has stuck; to this day, for example, we still refer to Mare Tranquilitatis, or the Sea of Tranquility. Johannes Kepler, the seventeenth-century astronomer who fanned the flames of the Copernican Revolution, gazed at the moon and believed he discerned caves that were populated by moon people. He even wrote a book in which he fantasized about what their lives might be like.35 A century later, William Herschel, who gained fame by discovering Uranus, thought he made out cities, highways, and pyramids on the lunar landscape."36 As scientific knowledge grew, dreams of finding lunar civilizations dissipated. Everyone came to agree that the moon cannot support life. Yet surprising discoveries in recent years have shown the opposite to be true: the moon really does support life—ours! Scientific evidence confirms how this parched, airless satellite actually contributes in unexpected ways to creating a lush and stable environment a quarter of a million miles away on Earth.

When I asked Gonzalez about how the moon helps support life on our planet, the first thing he brought up was a discovery that only dates back to 1993.

"There was a remarkable finding that the moon actually stabilizes the tilt of the Earth's axis," he said. "The tilt is responsible for our seasons. During the summer, in the northern hemisphere the north pole axis is pointed more toward the sun. Six months later, when the Earth is on the other side of the sun, then the south pole is more pointed toward the sun. With the Earth's tilt at 23.5 degrees, this gives us very mild seasons. So in a very real way, the stability of our climate is attributable to the moon."

"What would happen," I asked, "if the moon were not there?"

"Then our tilt could swing wildly over a large range, resulting in major temperature swings. If our tilt were more like ninety degrees, the north pole would be exposed to the sun for six months while the south pole would be in darkness, then vice-versa. Instead, it varies by only about one and a half degrees—just a tiny variation, because the gravity from the moon's orbit keeps it stabilized. The moon's large size compared to its host planet is unique in the inner solar system," he continued. "Mercury and Venus have no moons. Mars has two tiny moons-—-probably captured asteroids-—-and they don't do anything to stabilize the axis of Mars. Its axis is pretty close to Earth's right now, but that's only by coincidence. It actually varies over a huge range. In fact, all three of these planets have chaotic variations in their tilt. The moon also helps in another crucial way, which is to increase our tides. The moon contributes sixty percent to the tides; the sun accounts for the other forty percent. Tides serve an important role by flushing out nutrients from the continents to the oceans, which keeps them more nutrient-rich than they otherwise would be. Scientists discovered just a few years ago that the lunar tides also help to keep large-scale ocean circulation going. That's important because the oceans carry a lot of heat, which is necessary to keep the temperature of the higher latitudes relatively mild."

I asked, "What if the moon were larger than it is?"

"If it were more massive and in the same place, the tides would be much too strong, which would create serious difficulties. You see, the moon is slowing down the Earth's rotation. The tides pull on the Earth and slow it down a little bit, while at the same time the moon moves out in its orbit. We can actually measure this. Astronauts left mirrors on the moon and astronomers have been bouncing lasers off them since the early 1970s. They've documented that the moon is moving out in its orbit at 3.82 centimeters a year. If the moon were more massive, it would slow down the Earth much more. That would be a problem because if the days became too long, then you could have large temperature differences between day and night."

James Kasting, a professor of geosciences and meteorology at Pennsylvania State University, has confirmed that "Earths climatic stability is dependent to a large extent on the existence of the moon." Without the moon, he said, the Earths tilt could "vary chaotically from zero to eighty-five degrees on a time scale of tens of millions of years," with devastating results.

To me, it was amazing enough that the moon "just happens" to be the right size and in the right place to help create a habitable environment for Earth. Again, it was piling on more and more "coincidences" that were making it harder to believe mere chance could be responsible for our life-sustaining biosphere. But then Kasting made one more intriguing observation that adds yet another mind-blowing improbability to already extraordinary circumstances. "The moon is now generally believed to have formed as a consequence of a glancing collision with a Mars-sized body during the later stages of the Earths formation," he said. "If such moon-forming collisions are rare ... habitable planets might be equally rare."37

The Dangers of a Water World

Having explored the moons contribution to the Earth's life-support system, I decided it was time to focus on our planet itself. I had studied enough geology to know that the Earth is more than just an undifferentiated spinning rock, but that its interior is a dynamic and complex system eight thousand miles in diameter, with a solid iron core surrounded by iron that has been rendered liquid by the heat. At its center, where the pressure is more than three million times greater than at the planet's surface, temperatures soar to nine thousand degrees Fahrenheit.

"What," I said to Gonzalez, "are some of the phenomena on Earth that contribute to its ability to sustain life?"

"First lets talk about the Earths mass," Gonzalez said. "A terrestrial planet must have a minimum mass to retain an atmosphere. You need an atmosphere for the free exchange of the chemicals of life and to protect inhabitants from cosmic radiation. And you need an oxygen-rich atmosphere to support big-brained creatures like humans. Earths atmosphere is twenty percent oxygen—just right, it turns out. And the planet has to be a minimum size to keep the heat from its interior from being lost too quickly. It's the heat from its radioactive decaying interior that drives the critically important mantle convection inside the Earth. If Earth were smaller, like Mars, it would cool down too quickly; in fact, Mars cooled down and basically is dead."

"What if the Earth were a little more massive than it is?" I asked.

"The bigger the planet, the higher the surface gravity, and the less surface relief between the ocean basins and the mountains," he said. "The rocks at the bases of mountains can only withstand so much weight before they fracture. The higher the surface gravity of a planet, the greater the pull of the gravity on the mountains, and the tendency would be toward creating a smooth sphere. Think what would happen if our planet were a smooth sphere. The Earth has a lot of water in its crust. The only reason we're not a water world right now is because we have continents and mountains to rise above it. If you were to smooth out all the land, water would be at a depth of two kilometers. You would have a water world-—-and a water world is a dead world."

That perplexed me. "If you need water for life," I said, "why doesn't more water mean more life?"

Gonzalez replied, "We have life on Earth because we have the energy-rich sunlit surface of the oceans, which is teeming with mineral nutrients. Tides and weathering wash the nutrients from the continents into the oceans, where they feed organisms. In a water world, many of the life-essential minerals would sink to the bottom. That's the basic problem. Besides, the salt concentration in a water world would be prohibitively high. Life can only tolerate a certain level of saltiness."

"Our oceans and seas are salty," I said. "How does Earth manage to regulate this?"

"We have large, marshy areas along some coasts. Because these are shallow, water comes in from the ocean and evaporates quickly, leaving salt behind. So you get huge salt deposits accumulating on the continents, and the salt content of the ocean doesn't get out of control. But in a water world, eventually the excess salt would saturate the water and settle to the bottom. This would create a super-saturated salt solution that would be inhospitable to life."

"Even so," I said, "some scientists have theorized that life might exist inside Jupiter's frozen moon Europa, where a theoretical ocean might be located. It doesn't sound like you think life would be possible in an environment like that," I said.

"No, I don't think so," he replied. "I don't believe it would be habitable. There would be no way to regulate the salt, so I certainly don't imagine there are any dolphins swimming around in there."

Mountains and continents, then, are crucial for a life-flourishing planet. But where did they come from? I soon learned that they are partly the product of elaborate choreography involving radioactive elements and plate tectonics-—-absolutely essential ingredients for any planet to sustain a thriving biosphere.

The Engine of the Earth

Scientists over the last several decades have established the surprising centrality of plate tectonics, and the related continental drift, to the sustaining of life on Earth. Continental drift refers to the movement of a dozen or more massive plates in the Earths lithosphere, which is the outer, rigid shell of the planet. One crucial byproduct of plate tectonics is the development of mountain ranges, which are generally created over long periods of time as the plates collide and buckle. Scientists are finding that the importance of plate tectonics is difficult to overstate. "It may be," said Ward and Brownlee in Rare Earth, "that plate tectonics is the central requirement for life on a planet."38 Interestingly, they added that "of all the planets and moons in our solar system, plate tectonics is found only on Earth."39 In fact, any heavenly body would need oceans of water as a prerequisite to having plate tectonics, in order to lubricate and facilitate the movement of the plates.

When I asked Gonzalez why plate tectonics is so crucial, he launched into describing an improbable series of highly coordinated natural processes that left me amazed once more at how finely tuned our planet really is.

"Not only does plate tectonics help with the development of continents and mountains, which prevent a water world, but it also drives the Earth's carbon dioxide—rock cycle," he said. "This is critical in regulating the environment through the balancing of greenhouse gases and keeping the temperature of the planet at a livable level. You see, greenhouse gases, like carbon dioxide, absorb infrared energy and help warm the planet. So they're absolutely crucial. The problem is that their concentration in the atmosphere needs to be regulated as the sun slowly brightens. Otherwise, the Earth would not be able to stabilize its surface temperature, which would be disastrous. Plate tectonics cycles fragments of the Earths crust-—-including limestone, which is made up of calcium, carbon dioxide, and oxygen atoms-—down into the mantle. There, the planet's internal heat releases the carbon dioxide, which is then continually vented to the atmosphere through volcanoes. It's quite an elaborate process, but the end result is a kind of thermostat that keeps the greenhouse gases in balance and our surface temperature under control. What's driving plate tectonics is the internal heat generated by radioactive isotopes—Potassium-40, Uranium-235, Uranium-238, Thorium-232. These elements deep inside the Earth were originally produced in supernovae, and their production in the galaxy is declining with time because the supernova rate is declining with time. That will limit the production of Earth-like planets in the future, because they won't generate as much internal heat as the Earth does. This, radioactive decay also helps drive the convection of the liquid iron surrounding the Earth's core, which results in an amazing phenomenon: the creation of a dynamo that actually generates the planets magnetic field. The magnetic field is crucial to life on Earth, because it shields us from low-energy cosmic rays. If we didn't have a magnetic shield, there would be more dangerous radiation reaching the atmosphere. Also, solar wind particles would directly interact with the upper atmosphere, stripping it away, especially the molecules of hydrogen and oxygen from water. That would be bad news because water would be lost more quickly.

Now, remember how I said that plate tectonics helps regulate global temperatures by balancing greenhouse gases? Well, there's also another natural thermostat, called the Earths albedo. Albedo refers to the proportion of sunlight a planet reflects. The Earth has an especially rich variety of albedo sources—oceans, polar ice caps, continental interiors, including deserts—which is good for regulating the climate. Whatever light isn't reflected by Earth is absorbed, which means the surface gets heated. This is self-regulated through one of the Earths natural feedback mechanisms. To give you an example, some marine algae produce dimethy-sulfide. This helps to build cloud condensation nuclei, or CCN, which are small particles in the atmosphere around which water can condense to form cloud droplets. If the ocean gets too warm, then this algae reproduce more quickly and release more dimethy-sulfide, which leads to a greater concentration of CCN and a higher albedo for the marine stratus clouds. Higher cloud albedo, in turn, cools the ocean below, which then reduces the rate at which the algae reproduce. So this provides a natural thermostat. On the other hand, Mars lacks oceans, so it doesn't have this albedo component. It only has deserts, small polar caps, and very thin, occasional clouds. So Mars is far less capable of adjusting its albedo as its more eccentric orbit takes it closer and then further from the sun. That's one of the reasons why it experiences larger temperature swings than Earth."

Giant plates of shifting rock that precariously balance greenhouse gases; decaying radioactive isotopes acting as a life-sustaining underground furnace; an internal dynamo that generates a magnetic field which deflects cosmic dangers; precision feedback loops that unite biology and meteorology—I had to pause and marvel at the complex and interconnected processes that orchestrate our planet's environment.

And that was just the beginning. I knew Gonzalez could go on and on about scores of other fine-tuned phenomena. Among them are the elaborate physical processes that resulted in valuable ores being deposited near the planets surface, enabling them to be efficiently mined for our technological development. Geologist George Brimhall of the University of California at Berkeley has observed:

The creation of ores and their placement close to the Earths surface are the result of much more than simple geologic chance. Only an exact series of physical and chemical events, occurring in the right environment and sequence and followed by certain climatic conditions, can give rise to a high concentration of these compounds so crucial to the development of civilization and technology.41

When I took this together with all of the various "serendipitous" circumstances involving our privileged location in the universe, I was left without a vocabulary to describe my sense of wonder. The suggestion that all of this was based on fortuitous chance had become absurd to me. The tell-tale signs of design are evident from the far reaches of the Milky Way down to the inner core of our planet.

And yet there was more—a whole new dimension of evidence that suggests this astounding world was created, in part, so we could have the adventure of exploring it.

The Power of an Eclipse

The story begins with an unabashed love for solar and lunar eclipses that helped drive a young Guillermo Gonzalez into a life-long study of stellar mysteries.

Mesmerized by the partial eclipses he had witnessed as an amateur astronomer, Gonzalez longed to see the zenith of them all: a total eclipse of the sun, where the moon just barely covers the suns photosphere. He finally got his chance in 1995. Aware that an eclipse was going to occur on October 24 of that year, he scheduled his research so he could witness the event in northern India, one of the few places where it was going to be fully visible.

"One thing about eclipses," he told me, "is that a seasoned astronomer could be standing next to someone from a remote village, and they would both have tears in their eyes. They're both in awe. At my eclipse camp, as soon as the total phase of the eclipse ended, when you could see the sun's beautiful corona and it was relatively dark, people spontaneously applauded as if rewarding a show. It was just so beautiful!"

Gonzalez photographed the eclipse and made scientific measurements. But he wasn't done. His mind wouldn't let go of an insight: eclipses are better viewed on Earth than they would be from any other planet in our solar system. There's a striking convergence of rare properties that allow people on Earth to witness perfect solar eclipses," he said. "There's no law of physics that would necessitate this. In fact, of the nine planets with their more than sixty-three moons in our solar system, the Earth's surface is the best place where observers can witness a total solar eclipse, and that's only possible for the near-term future.42 What's really amazing is that total eclipses are possible because the sun is four hundred times larger than the moon, but it's also four hundred times further away. It's that incredible coincidence that creates a perfect match. Because of this configuration, and because the Earth is the innermost planet with a moon, observers on Earth can discern finer details in the sun's chromosphere and corona than from any other planet, which makes these eclipses scientifically rich. What intrigued me," he said, "was that the very time and place where perfect solar eclipses appear in our universe also corresponds to the one time and place where there are observers to see them."

That "coincidence" was so fascinating to me that I asked him to repeat his last statement before we continued. After he did, he added: "What's more, perfect solar eclipses have resulted in important scientific discoveries that would have been difficult if not impossible elsewhere, where eclipses don't happen."

"What discoveries?" I asked.

"I'll give you just three examples," he said. "First, perfect solar eclipses helped us learn about the nature of stars. Using spectroscopes, astronomers learned how the sun's color spectrum is produced, and that data helped them later interpret the spectra of distant stars.

"Second, a perfect solar eclipse in 1919 helped two teams of astronomers confirm the fact that gravity bends light, which was a prediction of Einstein's general theory of relativity. That test was only possible during a total solar eclipse, and it led to general acceptance of Einstein's theory.

"Third, perfect eclipses provided a historical record that has enabled astronomers to calculate the change in the Earth's rotation over the past several thousand years. This enabled us to put ancient calendars on our modern calendar system, which was very significant."

Richards, who had been listening intently, spoke up. "What's mysterious," he said, "is that the same conditions that give us a habitable planet also make our location so wonderful for scientific measurement and discovery. So we say there's a correlation between habitability and measurability. Not only does the specific configuration of the Earth, sun, and moon allow for perfect eclipses, but that same configuration is also vital to sustaining life on Earth. We've already discussed how the size and location of the moon stabilizes our tilt and increases our tides, and how the size of the sun and our distance from it also make life possible here. Our main point," he concluded, "is that there's no obvious reason to assume that the very same rare properties that allow for our existence would also provide the best overall setting to make discoveries about the world around us. In fact, we believe that the conditions for making scientific discoveries on Earth are so fine-tuned that you would need a great amount of faith to attribute them to mere chance."

Habitability and Measurability

Prompted by the study of perfect solar eclipses, Gonzalez and Richards began to investigate the incredible convergence of habitability and measurability in scores of other settings. They came up with a wide range of examples that merely served to amplify their amazement.

"For example," said Gonzalez, "not only do we inhabit a location in the Milky Way that's fortuitously optimal for life, but our location also happens to provide us with the best overall platform for making a diverse range of discoveries for astronomers and cosmologists. Our location away from the galaxy's center and in the flat plane of the disk provides us with a particularly privileged vantage point for observing both nearby and distant stars. We're also in an excellent position to detect the cosmic background radiation, which is critically important because it helped us realize our universe had a beginning in the- Big Bang. The background radiation contains invaluable information about the properties of the universe when it was only about three hundred thousand years old. There's no other way of getting that data. And if we were elsewhere in the galaxy, our ability to detect it would have been greatly hindered."

Richards offered a few other illustrations. "The moon stabilizes the Earth's tilt, which gives us a livable climate-—and it also consistently preserves the deep snow deposits in the polar regions. These deposits are a tremendously valuable data recorder for scientists," he said.

"By taking core samples from the ice, researchers can gather data going back hundreds of thousands of years. Ice cores can tell us about the history of snowfall, temperatures, winds near the polar regions, and the amount of volcanic dust, methane, and carbon dioxide in the atmosphere. They record the sunspot cycle through variations in the concentration of beryllium-10. They even record the temporary weakening of the Earth's magnetic field forty thousand years ago. In 1979, scientists identified a tentative link between nitrate spikes in an Antarctic ice core with nearby supernovae. By taking deeper cores, it might be possible to catalog all nearby supernovae of the last few hundred thousand years —-something that would be otherwise impossible."

"Another example of the strange correlation between habitability and measurability," Richards said, "is the clarity of our atmosphere. The metabolisms of higher organisms require from ten to twenty percent oxygen in the atmosphere-—-which is also the amount needed to facilitate fire, allowing for the development of technology," Richards said.43 "But it just so happens that the very composition of our atmosphere also gives it transparency which it wouldn't have if it were rich in carbon-containing atoms, like methane. And a transparent atmosphere allows the science of astronomy and cosmology to flourish."

"Wait a second," I said. "Doesn't the water vapor in our atmosphere cause cloudiness that can hinder astronomy? That's why putting a telescope in space has been such a breakthrough."

"Actually, astronomers prefer a partly cloudy atmosphere to one that's completely cloudy or always windy and dusty," Gonzalez said.

"Besides, we're not saying that every condition of measurability is uniquely and individually optimized on Earth. Our argument depends on what's called an optimal negotiation of competing conditions. As Henry Petroski said in his book Invention by Design, 'A11 design involves conflicting objectives and hence compromise, and the best designs will always be those that come up with the best compromise.'44 To come up with discoveries in a wide range of scientific disciplines, our environment must be a good compromise of competing factors—and we find that it is."

Another interesting connection between habitability and measurability involves plate tectonics. As Gonzalez and Richards explained earlier, plate tectonics is essential to having a livable planet. One byproduct of the movement of these crustal plates is earthquakes, which, in turn, have provided scientists with research data that would otherwise be difficult to obtain.

"Thousands of seismographs all over the planet have measured earthquakes through the years," Richards said. "In the past few decades, scientists have been able to use that data to produce a three-dimensional map of the structure of the Earths interior."

Over and over again, he said, the extraordinary conditions that create a hospitable environment on Earth also happen to make our planet strangely well-suited for viewing, analyzing, and understanding the universe.

"Is that merely some sort of cosmic quirk?" Richards asked. "Are we just lucky? I think wisdom entails the ability to discern the difference between mere coincidence and a meaningful pattern. We have more than a coincidence here. Much more."

The Trilemma of Life

When trying to explain the existence of life, said Gonzalez and Richards, we face a trilemma. One possibility is that some natural necessity, like the laws of physics, inexorably leads to life. Advocates of SETL—-the Search for Extra-Terrestrial Intelligence—-like that possibility. However, more and more scientific discoveries are showing how incredibly improbable it is to marshal the right conditions for life. Many scientists are concluding that intelligent life is, at minimum, far rarer than was once thought. In fact, it may very well be unique to Earth. The second possible explanation is chance: life is a fluke. Create enough planets circling enough stars and the odds say at least one of them will have life. Brownlee and Ward, who wrote Rare Earth, seem to gravitate toward this explanation. But there's also a third possibility: life was created. After studying all of the extraordinarily rare circumstances that have contributed to life on Earth, and then overlaying the amazing way in which these conditions also open the door to scientific discoveries, Gonzalez and Richards have landed in this camp.

"To find that we have a universe where the very places where we find observers are also the very best overall places for observing—that's surprising," Richards said. "I see design not just in the rarity of life in the universe, but also in this very pattern of habitability and measurability."

I turned toward Gonzalez. "What's your conclusion?" I asked.

"My conclusion, frankly, is that the universe was designed for observers living in places where they can make scientific discoveries," he replied. "There may be other purposes to the universe, but at least we know that scientific discovery was one of them."

Ever the theologian, Richards jumped back in. "In the Christian tradition, this is quite at home," he said. "Christians have always believed that God testifies to his existence through the book of nature and the book of Scripture. In the nineteenth century, science effectively closed the book of nature. But now, new scientific discoveries are reopening it."

"But if the universe was designed with us in mind, why is it so incredibly vast?" I asked. "There's a lot of empty space out there. Isn't that wasteful and unnecessary?"

"Because the universe was designed for discovery, we need something to discover," Richards replied. "The universe is vast and we're small, but we have access to it. That's what is amazing. We can see background radiation that has come from more than ten billion light years away."

"Plus," added Gonzalez, "we needed supernovae to build up the heavy elements so life-bearing planets could develop. And one particular type of supernovae is incredibly useful as a 'standard candle.' Type la supernovae have 'calibratable liminosities' so we can use them to determine distances and to probe the expansion history of the universe. So, again, we see the connection between habitability and measurability."

Richards made one other interesting observation. "Darwin once complained that pollen couldn't have been designed. After all, he said, look at the waste! Millions upon millions of particles are produced, but very, very few are used in the development of flowers. However, what he didn't realize was that pollen is one of the most useful tools we have in the scientific exploration of the past, in part, because it can be dated through Carbon 14. When we find pollen in lake sediments and ice cores, we can use it to gauge how old the layered deposits are and what the ancient climate was like. Darwin only looked at pollen from a biological standpoint; when we look at the big picture, we see it has another use he never anticipated. Perhaps the same is true in many other instances throughout the universe."

A Cherished Group of Creatures

I pushed my chair back from the table as if I had just consumed a hearty meal. In a sense, I had. Gonzalez and Richards had served me a remarkable feast-—-fact upon fact, evidence upon evidence, discovery upon discovery that compelled an incredible conclusion. As I sat there and digested the data, my mind turned to the book God and the Astronomers, which I had been reading on the airplane just prior to our interview. In one chapter, John A. O'Keefe describes how he went away to school at the age of fourteen and began to get into arguments with his roommate about God. These encounters turned him toward astronomy, a field where scientists were beginning to find new and exciting evidence about the possibility of a Creator. After earning degrees from Harvard and the University of Chicago, O'Keefe went on to become a renowned astronomer and pioneer in space research. The late Eugene Shoemaker called him "the godfather of astrogeology." He was awarded many honors, including the Goddard Space Flight Centers highest award, and is credited with numerous breakthrough discoveries in his scientific research at NASA.45

It was the discoveries of astronomy that bolstered O'Keefe's faith in God. He once ran calculations estimating the likelihood of the right conditions for life existing elsewhere. He concluded that if his assumptions were correct, then based on the mathematical probabilities "only one planet in the universe is likely to bear intelligent life. We know of one-—-the Earth—but it is not certain that there are many others, and perhaps there are no others."

O'Keefe said he would have no theological problem if, indeed, other civilizations existed. That's the position of many Christians. 7 God certainly could have created other life-populated planets that the Bible doesn't reveal. But it was the sheer improbability of the coincidences that conspired to create life on Earth that led O'Keefe to this conclusion:

We are, by astronomical standards, a pampered, cossetted, cherished group of creatures; our Darwinian claim to have done it all ourselves is as ridiculous and as charming as a baby's brave efforts to stand on its own feet and refuse his mother's hand. If the universe had not been made with the most exacting precision we could never have come into existence. It is my view that these circumstances indicate the universe was created for man to live in.48

And for humankind to explore. The findings of Gonzalez and Richards that the cosmos was designed for discovery have added a compelling new dimension to the evidence for a Creator. And frankly, their analysis makes sense.

If God so precisely and carefully and lovingly and amazingly constructed a mind-boggling habitat for his creatures, then it would be natural for him to want them to explore it, to measure it, to investigate it, to appreciate it, to be inspired by it-—and ultimately, and most importantly, to find him through it.

For Further Evidence