Much Ado about (Practically) Nothing Books by David E. Fisher Novels Crisis Compartments A Fearful Symmetry The Last Flying Tiger The Man You Sleep With Variation on a Theme Katie’s Terror Hostage One The Man Nonfiction The Creation of the Universe The Creation of Atoms and Stars The Ideas of Einstein (Juvenile) The Third Experiment The Birth of the Earth A Dance on the Edge of Time: The Birth of Radar The Origin and Evolution of Our Own Particular Universe Fire and Ice: The Greenhouse Effect, Ozone Depletion, and Nuclear Winter Across the Top of the World The Scariest Place in the World Tube: The Invention of Television (with M. J. Fisher ) Strangers in the Night: A Brief History of Life on Other Worlds (with M. J. Fisher) Mysteries of the Past: Companion to the NOVA series (with M. J. Fisher) A Summer Bright and Terrible DAV I D E . F I S H E R Much Ado about (Practically) Nothing A History of the Noble z Gases 1 2010 3 Oxford University Press, Inc., publishes works that further Oxford University’s objective of excellence in research, scholarship, and education. Oxford New York Auckland Cape Town Dar Town Dar es Salaam Hong Kong Karachi Kuala Lumpur Madrid Melbourne Mexico City Nairobi New Delhi Shanghai Taipei Toronto With offi ces in Argentina Austria Brazil Chile Czech Republic France Greece Guatemala Hungary Italy Japan Poland Portugal Singapore South Korea Switzerland Thailand Turkey Ukraine Vietnam Copyright © 2010 by Oxford University Press, Inc. Published by Oxford University Press, Inc. 198 Madison Avenue, New York, NY 10016 www.oup.com Oxford is a registered trademark of Oxford University Press All rights reserved. No part of this publication may be reproduced, stored in a retrieval system, or transmitted, in any form or by any means, electronic, mechanical, photocopying, recording, or otherwise, without the prior permission of Oxford University Press. Library of Congress Cataloging-in-Publication Data Fisher, David E., 1932– Much ado about (practically) nothing : a history of the noble gases / David E. Fisher. p. cm. Includes bibliographical references and index. ISBN 978-0-19539396-5 ISBN 978-0-19539396-5 1. Gases, Rare. I. Title. QD162.F57 2010 546'.75—dc22 2009054365 9 8 7 6 5 4 3 2 1 Printed in the United States of America on acid-free paper For Jackson Henry and Louis Samuel What is the path? There is no path. On into the Unknown! —Niels Bohr, loosely translated from Goethe’s Faust If the magnetic axis was different from the rotational axis, the star would look just like a rotating beacon: you would see its light as a “pulse” when it swept across your line of vision. If I’m right, he said (and if neutron stars truly are the result of supernova explosions), we should see pulsars where once we saw supernovae. Nonsense, said the astronomers. The pulsar phenomenon was so surprising that a conference was immediately called to discuss it, and explanations were asked for. But when Tommy submitted his paper, it was rejected as too fantastic. Sounder heads prevailed at Nature, where it was subsequently published, and the next year when a pulsar was discovered at the center of the Crab Nebula (which is a remnant of a supernova spotted by the Chinese l i f e a n d d e at h o n m a r s a n d e a r t h S 217 in 1054), and when other pulsars were observed to slow down their spin as he had predicted, the explanation was accepted.3 So when he started talking about helium and petroleum, I listened.4 The accepted explanation for the origin of petroleum is, as every schoolboy knows, that it’s a “fossil fuel,” formed by the heat-and pressure-assisted decomposition of ancient life forms. (All living creatures, from asparagus to zebras, are formed of organic molecules, primarily carbon and hydrogen, known as hydrocarbons; petroleum—whether gas or oil—is made of the same stuff.) This explanation is as well founded and as universally accepted as that for the “aether” which at one time was understood to fi ll the universe. (Remember Lord Kelvin? “If there is one thing we are sure of concerning the universe, it is the existence of the aether.”) Of course, there are many more universally accepted explanations of scientifi c phenomena which have not turned out to be wrong; by the time a consensus has been reached among scientists, the explanation is probably correct. Still . . .? The story Tommy tells is frankly exasperating to nearly all petroleum petrologists, just as his explanation of a powdery surface of the moon was to NASA, his explanation of hearing was to audiologists,5 and his explanation of the pulsar was to astronomers. Like those stories, this one about the origin of petroleum is interesting and provocative, and perhaps, like those, it may turn out petroleum is interesting and provocative, and perhaps, like those, it may turn out to be right. It begins, as he told me that day, with the unexplained but silently accepted association of helium with the hydrocarbons 3. When a Nobel Prize was awarded, it didn’t go to Jo Bell, who discovered the fi rst pulsar, or to Gold, who explained them, but to Anthony Hewish, the head of Bell’s lab, who had initially rejected both Bell’s observation and Gold’s explanation. 4. On the other hand, a lot of us listened when he attempted to demolish the Big Bang with his innovative Steady State theory of the non-origin of the universe, a theory which though quite lovely turned out to be quite wrong. 5. He also overturned the classical (Helmholtz, nineteenth century) theory of how our ears hear; his idea wasn’t accepted for thirty years, but is now known to be right. 218 S much ado about (practically) nothing that form petroleum. The data themselves are incontrovertible. When the U.S. Bureau of Mines wanted to fi nd commercially important helium sources, the places they looked were known gas and oil fi elds, and there they found the helium. And con-versely, every petrologist knows that where you fi nd helium, you’re likely to be looking at a petroleum-rich fi eld. Portable helium detectors, known as “snifters,” are routinely used in petroleum exploration, and where you fi nd a lot of helium seeping out of the ground, it turns out to be a good bet that there’s some exploitable petroleum hiding under it, so start drilling and don’t ask questions. Surprisingly, despite the very strong association, aside from a few Russian geologists who were not part of the Western dis-course no one asked the obvious question until Gold did: “Why should a chemically inert gas like helium be associated so strongly with ancient biological remains?” Even now, two recent reviews go into great detail about the monumental sets of data, but never once address that question. address that question. But perhaps it’s not surprising. To challenge—even to politely question—the hard-core belief of generations of petrologists is a daunting task. What takes it into the realm of sheer entertainment is the way Tommy Gold went about it: not politely questioning, but arrogantly informing all of them that they were not only wrong but damned fools for not seeing the obvious. Well, that was the way of him, God rest him. I remember one day at a fi lled conference hall when his breezy dismissal of the idea of God (a laughable concept, he called it) brought at least one Catholic scientist, John O’Keefe, to his feet in a sputtering, stuttering, red-faced frenzy. In much the same manner, instead of begging their pardon for suggesting a heresy, he simply informed the petrologists that the petroleum hydrocarbons are not fossil remains at all, not formed over the aeons by the pressurized and heated decay of once-living organisms, but are instead a primordial goo left over from the formation of the earth. How else to explain their close association with helium? l i f e a n d d e at h o n m a r s a n d e a r t h S 219 What he told me that day he has continued to hammer home: “The association of helium with hydrocarbons is probably the most striking fact that the biogenic theory fails to account for.” The standard response of the traditional petrologists is “Ho hum, whatever.” Just a minor unexplained point only slightly marring a complete theory. For if petroleum is not a fossil fuel, they ask, why is it found precisely where traditional petrologists look for it (based on their fossil fuel model)? Easily explained, Gold laughs. Because it’s everywhere. So no matter how false your theory is, if it tells you to look someplace, that’s where you’ll fi nd it. You think success verifi es your theory, but any theory will give the same result. Actually it’s buried deep in the mantle and distributed everywhere on earth. Dig deep enough at any random spot and you’ll fi nd it. Ah, “deep enough”; there’s the rub. How deep is deep enough? That depends on the overlying rock. Gold’s thesis is—well, fi rst, the conventional theory: since the various components of petroleum are a series of conventional theory: since the various components of petroleum are a series of organic molecules, hydrocarbons, which are the chemicals of which life is composed; and since wherever petroleum deposits are found, they are intimately mixed with various biological markers—that is, clear indications of living processes—it clearly follows that the petroleum is the remains (the fossil remains) of living organisms. No, says Gold. First, the undisputed fact that petroleum is composed of organic molecules is not prima facie evidence of past life, for such organics are found in conditions where no one pretends life is to be found: in meteorites, in vast seas on Titan, in comets and asteroids, fl oating around in space6—in fact, everywhere. Organics are ubiquitous in the universe. They are the building blocks of life, yes, but not necessarily the products. They 6. On April 21, 2009, workers in Germany reported at a meeting celebrating the European Week of Astronomy and Space Science that they had identifi ed the presence of ethyl formate and n-propyl cyanide in interstellar space. Such complex organics had previously been thought to be biogenic, but there is no life in interstellar space. 220 S much ado about (practically) nothing are necessary but not suffi cient evidence of life: you can’t have life without them, but you can certainly have them without life.7 Okay, everyone agrees with that. It’s the second point of his thesis that irritates: while biological markers are always found in petroleum fi elds, it’s not because the hydrocarbons there are the remains of life but instead because they are good food for life. Wherever petroleum is, life will follow in its endless search for food. The deep earth is literally crawling with life, he insists: it’s what he calls the deep hot biosphere. It follows from these two points that since organic compounds form naturally and abundantly in the universe, they would have formed a substantial part of the particles that formed the earth, and therefore we can expect the deep interior of the earth to be rich in them. Also distributed throughout the earth— with no possible causal relationship to living creatures or their fossil remains— are uranium and thorium, which radioactively decay to produce helium. So how does the petroleum come to be associated with helium? does the petroleum come to be associated with helium? Couldn’t be simpler, Gold explains. The helium is produced as individual atoms, which are generally trapped in the rock matrix deep underground as well as in the upper tier of sedimentary rock (where the biogenic theory says all petroleum deposits must be). The diffusion of helium through the rock strata toward the surface is a very slow process. Petroleum deposits, on the other hand, are present not as individual atoms but as vast underground fi elds, and as such they can break through weak rock structures and force their way toward the surface. As they do, Gold reasons, they will sweep up any helium atoms they meet along the way, just like the helium Ray Davis used in order to fl ush out the individual atoms of argon formed by neutrino reactions in his tank cars of chlorine; the gaseous hydrocarbons—mainly methane— will act as the same sort of carrier gas, in this case bringing the 7. Glycine, an amino acid used by living organisms to make proteins, has recently been found in a comet. On earth, its presence would certainly be claimed to be a bio-marker, indicative of life, but no one pretends there are living creatures in a comet. l i f e a n d d e at h o n m a r s a n d e a r t h S 221 helium along wherever the hydrocarbon concentration is great enough. In fact, the amounts of helium present will be an indication of the depth of origin of the methane, for the longer the pathway to the surface, the greater the amount of helium brought along. His analysis shows that helium comes from the deepest levels, gas from the next deepest, and oil from the next, but all of these come from levels much deeper than the crustal sedimentary layer where the biogenic theory says all petroleum must lie. This is buttressed by an independent report of helium and methane in Canada: “The coincidence of methane and helium anomalies with known tectonic features also indicates fracture leakage from depth and the possible existence of oil and gas fi elds”—that is, deeper in the earth than the sedimentary layer postulated by the biogenic theory. If Gold is right, the earth holds vast reservoirs of petroleum in general and methane gas in particular. The deposits we have found are only the tip of the iceberg, where the local geology allowed the stuff to percolate close to the surface. If we could just dig deep enough, we’d fi nd it everywhere. But deep enough means miles deep, beyond our current capabilities.