IN THE BEGINNING. Welby Thomas Cox, Jr.

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СКАЧАТЬ acidic fluids. In contrast, the vents in the new study -- first hypothesized by scientist Michael Russell of JPL in 1989 -- are gentler, cooler and percolate with alkaline fluids. One such towering complex of these alkaline vents was found serendipitously in the North Atlantic Ocean in 2000 and dubbed the Lost City.

      "Life takes advantage of unbalanced states on the planet, which may have been the case billions of years ago at the alkaline hydrothermal vents," said Russell. "Life is the process that resolves these disequilibria." Russell is lead author of the new study, published in the April issue of the journal Astrobiology.

      Other theories of life's origins describe ponds, or "soups," of chemicals, pockmarking Earth's battered, rocky surface. In some of those chemical soup models, lightning or ultraviolet light is thought to have fueled life in the ponds.

      The water world theory from Russell and his team says that the warm, alkaline hydrothermal vents maintained an unbalanced state with respect to the surrounding ancient, acidic ocean -- one that could have provided so-called free energy to drive the emergence of life. In fact, the vents could have created two chemical imbalances. The first was a proton gradient, where protons -- which are hydrogen ions -- were concentrated more on the outside of the vent's chimneys, also called mineral membranes. The proton gradient could have been tapped for energy -- something our own bodies do all the time in cellular structures called mitochondria.

      The second imbalance could have involved an electrical gradient between the hydrothermal fluids and the ocean. Billions of years ago, when Earth was young, its oceans were rich with carbon dioxide. When the carbon dioxide from the ocean and fuels from the vent -- hydrogen and methane -- met across the chimney wall, electrons may have been transferred. These reactions could have produced more complex carbon-containing, or organic compounds -- essential ingredients of life as we know it. Like proton gradients, electron transfer processes occur regularly in mitochondria.

      "Within these vents, we have a geological system that already does one aspect of what life does," said Laurie Barge, second author of the study at JPL. "Life lives off proton gradients and the transfer of electrons."

      As is the case with all advanced life forms, enzymes are the key to making chemical reactions happen. In our ancient oceans, minerals may have acted like enzymes, interacting with chemicals swimming around and driving reactions. In the water world theory, two different types of mineral "engines" might have lined the walls of the chimney structures.

      "These mineral engines may be compared to what's in modern cars," said Russell.

      "They make life 'go' like the car engines by consuming fuel and expelling exhaust. DNA and RNA, on the other hand, are more like the car's computers because they guide processes rather than make them happen."

      One of the tiny engines is thought to have used a mineral known as green rust, allowing it to take advantage of the proton gradient to produce a phosphate-containing molecule that stores energy. The other engine is thought to have depended on a rare metal called molybdenum. This metal also is at work in our bodies, in a variety of enzymes. It assists with the transfer of two electrons at a time rather than the usual one, which is useful in driving certain key chemical reactions.

      "We call molybdenum the Douglas Adams element," said Russell, explaining that the atomic number of molybdenum is 42, which also happens to be the answer to the "ultimate question of life, the universe and everything" in Adams' popular book, "The Hitchhiker's Guide to the Galaxy." Russell joked, "Forty-two may in fact be one answer to the ultimate question of life!"

      The team's origins of life theory applies not just to Earth but also to other wet, rocky worlds.

      "Michael Russell's theory originated 25 years ago, and, in that time, JPL space missions have found strong evidence for liquid water oceans and rocky sea floors on Europa and Enceladus," said Barge. "We have learned much about the history of water on Mars, and soon we may find Earth-like planets around faraway stars. By testing this origin-of-life hypothesis in the lab at JPL, we may explain how life might have arisen on these other places in our solar system or beyond, and also get an idea of how to look for it."

      For now, the ultimate question of whether the alkaline hydrothermal vents are the hatcheries of life remains unanswered. Russell says the necessary experiments are jaw-droppingly difficult to design and carry out, but decades later, these are problems he and his team are still happy to tackle.

      The California Institute of Technology in Pasadena manages JPL for NASA.

      Chapter 6

      THE NUMBER 42

      Douglas Adams said it was the answer to the meaning of life, the universe, and everything. He meant it as a joke, but a new book shows how the number 42 has played a significant role

      When Douglas Adams wrote The Hitchhiker's Guide to the Galaxy, he added a central joke which has become more famous over the years than the novel itself: "The answer to the ultimate question of life, the universe and everything is 42." Geeks have since wasted years and massive effort trying to ascribe some deep, symbolic significance to the number and its occurrences.

      Now, in an attempt to cash in on their obsession, a new book published this week, 42: Douglas Adams' Amazingly Accurate Answer to Life, the Universe and Everything, looks at real-life occurrences of the number 42. The book is timed to coincide with the 10th anniversary of Adams's death this spring.

      Scores of adolescents have posited theories about significance of the number. The actor Stephen Fry claimed to know the true answer, but won't tell, saying he'll take it to his grave. The author himself rather undermined the myriad analyses when he dismissed them all with the simple answer that the choice of the number was a joke.

      "The answer to this is very simple," Adams said. "It was a joke. It had to be a number, an ordinary, smallish number, and I chose that one. Binary representations, base 13, Tibetan monks are all complete nonsense. I sat on my desk, stared into the garden and thought 42 will do. I typed it out. End of story."

      Throughout history, various numbers have had special meanings ascribed to them. Plato called the study of number symbolism "the highest level of knowledge" while Pythagoras believed numbers had souls as well as magical powers.

      Meanwhile, millions of Hitchhiker's fans to this day persist in trying to decipher what they imagine was Adams' secret motivations. Here are 42 things to fuel their fascination with the number 42.

      1 Queen Victoria's husband Prince Albert died aged 42; they had 42 grandchildren and their great-grandson, Edward VIII, abdicated at the age of 42.

      2 The world's first book printed with movable type is the Gutenberg Bible which has 42 lines per page.

      3 On page 42 of Harry Potter and the Philosopher's Stone, Harry discovers he's a wizard.

      4 The first time Douglas Adams essayed the number 42 was in a sketch called "The Hole in the Wall Club". In it, comedian Griff Rhys Jones mentions the 42nd meeting of the Crawley and District Paranoid Society.

      5 Lord Lucan's last known location was outside 42 Norman Road, Newhaven, East Sussex.

      6 The Doctor Who episode entitled "42" lasts for 42 minutes.

      7 Titanic was travelling at a speed equivalent to 42km/hour when it collided with an iceberg.

      8 The marine battalion 42 Commando insists that it be known as "Four two, Sir!"

      9 In east Asia, including parts of China, tall buildings often avoid having a 42nd floor because of СКАЧАТЬ