Life Here Began out There

PART ONE

LIFE HERE BEGAN OUT THERE

COPYRIGHTED MATERIAL

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Are You Alive?

he original 1978 Battlestar Galactica began with the narrated words “ There are those who believe that life began out there. ” In the 2003 miniseries, Commander William Adama cites the T opening lines of the sacred scrolls of the Colonial civilization, which reiterate the idea. Here on Earth, many religions and more than a few scientists also suggest that life was brought to a lifeless Earth from elsewhere in the universe. What is life? How did it begin? What is the story of the origin of life? Life has always been a tricky concept to deﬁ ne. Many people and cultures have tried as soon as they were able to ask the question. Because life seemed to be something magi- cal, something that could not be explained Number Six: Are by ordinary means, many of them looked you alive? Military Liaison: Yes. to spiritual or extra - or paranormal Number Six: Prove it. ways to explain life. Life, for many — Miniseries, Part I

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cultures, had a certain divine spark to it, a spark that could not be understood by ordinary humans. Gradually, as reason came to replace mysticism, life developed a different defi nition. The mystical aspects of life were lost and scientists viewed life as a continuing process — or rather, several processes: inges- tion, excretion, growth, reproduction, response to stimuli, and death. The idea that “life is what it does ” was incomplete; a skilled debater could always fi nd exceptions. What if, for instance, a living creature existed on a much slower (or much faster) time scale than ours? Pick up a rock. Look at its various layers, or embedded crystals. Now ask yourself why you know that this rock is not alive. The rock in your hand might very well be ingesting, excreting, growing, reproducing, react- ing, and dying — but on a scale of millions of years. At that rate, you ’ d never detect any of its activity. The rock would seem to be dead. Or take the case of mayfl ies. They live their entire lives from birth to death in one day, just long enough for us to understand what they ’ re up to. But would we be able to recognize creatures that lived their entire lives in one hour? One minute? One second? A fraction of a second? To us, their entire existence would appear like a fl ash of faraway lightning, so brief we wouldn ’ t be sure it was there at all. To them, we would be like rocks, unmoving and unchangeable, the stable backdrop against which they go about their lives. * Since we ’ re dealing with a science fi ction show that takes place in space, we should perhaps use a defi nition of life developed by people looking for life in outer space. In the early 1990s, a NASA astrobiology panel defi ned “ life ” as a self- sustaining chemical system capable of undergoing Darwinian evolution. † It’ s not perfect, but it’ ll do. The best scientifi c explanation available to the Colonials is that life would have begun on Kobol sometime around 3.8 billion years ago, when the planet had fi nally solidifi ed, and water vapor in the atmosphere precipitated out to form liquid water on the surface. The water acted as a solvent for other chemicals, and the constant intermixing

* This idea was explored very well in the Star Trek TOS episode “ Wink of an Eye.” † That innocuous deﬁ nition is under debate to this day, even within NASA itself.

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Caprica Six and Baltar on Caprica, before the attack.

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created a bouillabaisse of various chemicals and molecules just waiting to be put into the right order. According to our current understanding, somehow —we still don ’t know the details — the raw chemicals of life (usually nothing more elaborate than hydrogen, carbon, oxygen, and nitrogen) came together in various confi gurations in millions of places in the oceans over millions of years. In all this turmoil, eventually one confi guration became able to produce crude copies of itself. This particular molecule, by the virtue of copying itself, eventually came to dominate the early environment. By continually mutating and adapting, some copies became more and more effi cient at copying themselves, and others became less effi cient. The ones that were less effi cient at copying themselves were by defi nition unfi t, and they quickly died out. The ones that survived also developed ways to fi nd sources of energy in the immediate vicin- ity. By acquiring energy from the environment, the process became self - sustaining, and met NASA ’ s defi nition for life. As Kobol formed from smaller asteroids and comets, the last pieces of comet ice to arrive became the water and gases that made Kobol’ s oceans and atmosphere. These comets were essentially small chemistry sets. In addition to water, comets are reliably thought to have seeded

the newborn planet with methane (CH 4), ammonia (NH 3 ), hydrogen 3 Ϫ sulfi de (H2 S), phosphate (PO4 ) radicals, carbon dioxide (CO2 ) and carbon monoxide (CO). With those chemicals you can build a king- dom of life. It is very likely that Kobol ’ s fi rst atmosphere was primarily made of fi ve gases: nitrogen, carbon dioxide, carbon monoxide, ammonia vapor, and methane. There was no oxygen in this atmosphere, hence no ozone layer. * With no ozone layer there would be almost no fi lter for ultraviolet radiation from the sun, so almost all of it would reach the surface. To anyone who is already alive, this would be a bad thing, but on a sterile Kobol before the creation of life, it could be just what was needed. The discovery of lightning in the clouds of Venus and Jupiter (whose atmosphere is quite similar to that of early Kobol) means

* The chemical formula for ozone is O3 .

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that it is very likely that Kobol ’ s early atmosphere was also rent by the occasional lightning bolt. Both ultraviolet radiation and lightning are mechanisms that could have put enormous amounts of energy into Kobol ’s oceans and atmosphere. Chemical reactions need some sort of energy to get going, and Kobol had that in abun- dance. When you have millions of years to work with, nearly any type of energy is enough to make some form of organic compound out of those ingredients. This isn ’ t just speculation. In 1953, two scientists at the University of Chicago, Stanley Miller and Harold Urey, created complex organic molecules out of simple elements. Miller and Urey built a small plan- etary ecosystem in their laboratory. They started with a ﬂ ask ﬁ lled

with liquid water and the appropriate salts and chemicals (CH4 , NH3 , H 2 ) dissolved in it to represent Earth ’ s early ocean. They connected that ﬂ ask to a series of glass tubes and reservoirs that contained the gaseous mixture that represented Earth ’s early atmosphere. In the glass reservoir that held the “ atmosphere, ” they placed two electrodes, posi- tioned just so to create a spark gap. A condenser at the bottom of the “ atmosphere ” precipitated the water vapor and closed the loop by sending it back into the “ocean. ” Miller and Urey gently warmed their ocean to evaporate some of the water into the atmosphere, and then ran a simple electric spark through the resulting gas to simulate the action of lightning. They ran the experiment for a week and watched as the water in their ocean turned pink and then brown. After a week they analyzed the ocean ﬂ uid and discovered that it was full of complex organic molecules, the most exciting of which were the simple amino acids glycine and alanine, two of the building blocks of protein. Amino acids 1 are not life per se, but without amino acids there would be no proteins or enzymes, and without proteins or enzymes there would be no life as we know it. Subsequent similar experiments by Miller and Urey and by other scientists had even more interesting results. By adding ammonium cyanide to the mixture, it is possible to syn- thesize adenine, a nucleic acid and one of the building blocks of DNA! Think about that —one of the pieces of the control mecha- nism that makes you the unique being that you are can be made on

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practically any planet that has a similar atmosphere, similar ocean, similar energy sources. Even further experiments along the Miller- Urey line discovered that with a slightly different concentration of starter materials, one could create fatty acids or lipids. Because of the nature of fats, they naturally tend to collect themselves into spherical globules, which is nearly perfect for encapsulating and concentrating various types of material — such as the material that makes up a living cell. Every living cell is essentially a bubble of fat with sweetened protein - water gunk inside it, and every piece of that cell could have come from a few simple chemicals and a spark.

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