The book’s predecessor introduced the world to Lieber’s “biological tides theory.” This theory maintains that since the moon causes ocean tides and the human body is 80 percent water, the moon’s gravitational pull also causes tides in the human body. If one accepts these premises, it’s a short step to believing that some people behave irrationally when their water balance is upset. Astronomers reject this argument as being based on a crude and misleading analogy. In a cogent review that appeared in the Spring 1979 Skeptical Inquirer, astronomer George O. Abell pointed out that the moon’s gravitational pull was less than the weight of a mosquito. Two of my colleagues, Roger Culver and Roger Ianna, subsequently showed that the moon’s “pull” was less than that of a wall of a building six inches away (see Culver and Ianna 1988).

This book contains very little that is new, as Lieber acknowledges: “When invited to revise and update the material in the present book, I was surprised to learn how slight the modifications were. Most of the earlier findings are still relevant” (p. 156).

It would take too much space to identify (let alone correct) all of the errors that precede this conclusion. However, Lieber’s claims have turned out to be wrong so often in the past that I felt compelled to do a line-by-line comparison of the two books. Lieber’s revisions served to save face. For example, Lieber’s first edition describes how he learned that the earth, sun, and moon would line up in January and February of 1974. Because this “cosmic coincidence” would cause high tides, Lieber alerted the Miami police, the local news media, and the emergency room of a public hospital to expect an outbreak of abnormal and criminal behavior. Lieber repeats this story in his revised edition, complete with the line: “Sure enough, all hell broke loose” (p. 61). After two pages of anecdotal evidence, his previous edition concluded by noting that there would be another cosmic coincidence in December 1990 and in January 1992. But of course these dates passed uneventfully. So it is not surprising to find that this is one of Lieber’s few revisions.

Another revision can be found in Lieber’s reference to The Jupiter Effect by John R. Gribbon and Stephen H. Plagemann (Random House, 1974), a book that, according to Lieber, reports “the significance of tides as triggers of earthquakes” (p. 86). He states that Gribbon and Plagemann are concerned that a coincidence of cosmic cycles “may trigger another great California earthquake.” But when? He gives no date. But, if we turn to Lieber’s earlier edition, we find that he gave a date: 1982. Of course, no earthquake of any note occurred in California that year.

Unfortunately, instead of correcting past errors, Lieber has added fourteen additional pages of faulty logic, distorted facts, and ad hominem arguments in the chapter entitled “New Research.” He reports that there have been “at least 43 data-based studies” since The Lunar Effect appeared in 1978. That number sounds about right. However, Lieber errs when he asserts that “critical review of documented findings reveals the following: positive and negative findings are pretty much equally divided” (p. 156). The fact is that most studies have failed to uncover anything resembling support for the lunar hypothesis, as I. W. Kelly, Roger Culver, and I have documented (Kelly, Rotton, and Culver 1996).

Lieber doesn't cite (let alone review) any of the “at least 43 studies” that he mentions, nor does his bibliography contain references to works that appeared since the first edition of his book. Instead of describing what other scientists have found, he devotes seven pages to a failure to replicate his work with C. R. Sherin. In a 1972 article, Lieber and Sherin uncovered what they claimed was “a lunar effect” for homicides in Dade County, where Miami is located. Their data spanned the years between 1956 and 1970. The present book contains a graph (on page 41) that seems to suggest that homicides peaked at the full moon. As Kelly, Culver, and I have documented (Kelly, Rotton, and Culver 1985-86), Lieber and Sherin based their claims on three tests that attained significance. They neglected to tell readers that they performed forty-eight tests of significance in all. Not divulging this information is like a gambler failing to tell us how many times a coin was tossed before three heads came up. Since Lieber and Sherin chose a conventional (p ¢ .05) level of significance, we would expect 2.4 (i.e., .05 3 48) of the tests to attain “significance” by chance alone.

Be that as it may, let’s take a closer look at Lieber’s new evidence. It consists of a plot of homicides in Dade County (2,714 new cases) between 1971 to 1980. Although Lieber does not give a value for his statistical test, he reports that it resulted in a “chi-square with a high significance (p ¢ .001).” But there’s a problem: Homicides did not peak when the moon was full! Rather, as Lieber reports, “the new-moon and full-moon peaks vanished. We found a peak midway between new moon and first quarter” (p. 160). This is obviously embarrassing, and Lieber suggests that “A. D. Pokorny and colleagues, Rotton and colleagues, and G. O. Abell would say ‘Aha, failure to replicate: previous results were Type I error. I told you so!'” (p. 161)

I can't speak for Pokorny, Abell, and others, but my guess is that Lieber’s result stemmed from his failing to control for weekend and other secular trends. Of particular importance is the fact that the 29.54 days in the moon’s synodic cycle is very close to 28-31 days in the months of the year. There are ways to avoid the biases that these trends introduce, as my colleagues and I describe in some of the articles that Lieber cites. However, instead of using these methods, which are pretty standard in econometric analyses, Lieber devotes a long paragraph to recounting all of the problems that have afflicted Miami during the 1970s: the Mariel boatlift, population increases, Cocaine Cowboys, et cetera. None of these would surprise viewers of Miami Vice, but one has to wonder why Lieber did not apply the same reasoning to his earlier study when Miami had to contend with Castro’s revolution, an influx of refugees, Watergate burglaries, and the five thousand deaths chronicled in Edna Buchanan’s Pulitzer Prize-winning The Corpse Had a Familiar Face.

After his long digression, Lieber uses a three-day moving average to smooth out the graph for 1971-80 homicides, and he applies the same operation to the data for 1956-70. Now, however, Lieber does not blame a full moon. He instead concludes that the curves reveal “an underlying semi-monthly lunar rhythm” (p. 165). Lieber has stumbled on an old truth that would be obvious to anybody who has taken a first-year course in econometrics: The easiest way to generate a curve is to average adjacent observations. The curve will be even more impressive if one superimposes a dotted sinewave over it, as Lieber does; doing so distracts attention from the data’s irregularities and differences between the graphs for homicides during the sixties and seventies. Those who teach statistics might want to use the graphs in this chapter to show students how figures can be made to lie.

Not only does Lieber distort his own work, he also misrepresents what others have written. As an example of sloppy scholarship, he refers to an article by Culver (1988), which was actually written by Culver, Kelly, and myself. He states that Culver committed a Type II error “when he [sic] reported on G. O. Gilbert’s findings” (p. 165).¹ As Lieber reports, Gilbert found that fewer assaults occurred when the moon was full. He takes my coauthor, Culver, to task for concluding that this is contrary to the biological tides theory: “This is a clear example of a Type II error that results when a researcher is either blind to the theoretical underpinnings of his subject or is blinded by unconscious bias” (p. 166). The fact is that it was Gilbert who concluded, in his thesis, that “the number of significant full moon correlations was only slightly greater than expected by chance. . . . Since the sign of the correlation [for assaults] was negative, the relationship was a new moon relationship rather than a full moon relationship” (p. 166). Unlike Lieber, who cites a page from Dissertation Abstracts as his source, my colleagues went to the trouble of obtaining a copy of Gilbert’s thesis. Ironically, Lieber lists Gilbert as one of two persons who are “finding lunar connections.” The other person he lists is a scholar (Michael Persinger) who has done interesting work on geomagnetic activity but who has never published an empirical study on lunar cycles.

By now it should be clear that Lieber interprets any and all departures from chance as a “lunar effect.” He began by claiming that he had uncovered a lunar effect when three out of forty-eight tests of statistical significance uncovered a greater number of homicides during the full moon in Miami between 1956 and 1970. He extended his theory to account for an apparent increase in homicides that occurred after full moon periods in Cleveland (see Sanduleak 1985). Now he interprets peaks during the new moon and first quarter as lunar effects.

Rather than deal with these inconsistencies, Lieber tries to distract attention away from flaws in his theory by attacking those who have raised questions about his theory and the data on which it is based. Referring to reviews written by Kelly, Culver, and myself, he charges:

While they intellectually can accept that much of the evidence (including their own) supports the existence of a small lunar effect on behavior, they were unable to comprehend that such small effects, under certain circumstances, can have dramatic impacts upon behavior. Their viewpoint suffers from the absence on their team of a researcher trained in neurochemical effects on behavior. . . . One marvels at how adept these authors were at waving a mathematical wand and causing to vanish the results of seventy years of field and laboratory research. (P. 159)

First, we have never accepted that “the evidence supports the existence of a small lunar effect.” We would not, and have not, used a term (namely, lunar effect) that implies causality when discussing alleged correlations. What we have stated, in more than one article, is that the effect size for lunar associations in this area is so small that it is best chalked up to chance. In Kelly, Rotton, and Culver 1996, we stated that meta-analyses of previously published findings indicated that phases of the moon “accounted for no more than 3/100 of 1 percent of the variability in activities usually termed lunacy” (18). Such a small percentage is too close to zero to be of any theoretical, practical, or statistical interest or significance.

Second, if I were a psychiatrist, I would point out that Lieber evidences a considerable amount of ambivalence toward statistics. On the one hand, he makes much of the fact that his results achieved statistical significance; on the other, he ends one chapter by repeating Carl Jung’s tired saw about “the ruinous influence of statistics,” and he complains about critics who utilize a “statistical sleight of hand” (p. 158). The fact of the matter is that my colleagues and I used the same statistical procedures that the medical community uses to evaluate empirical findings. I find it disturbing that a physician who lists the Miami Heart Institute as his affiliation shows such a disdain for statistical evidence.

Finally, Lieber’s remark about our research team’s needing “a researcher trained in neurochemical effects” comes close to being an ad hominem argument. However, rather than take umbrage, I will use this forum to invite Lieber to name a published neurochemist who would be interested in joining us in evaluating research on lunar periodicities. I suspect that Lieber is going to have trouble responding to my invitation, because I failed to uncover anything dealing with lunar periodicities and neurochemical changes when I did a computer search of the literature. My search included all of the works listed in PsychLit, the GENMED option on LEXIS-NEXIS, and the computer library for Dissertation Abstracts. I located fifty-three works, including Lieber’s original publications. To put this small number into perspective, I might note that LEXIS stopped searching after one thousand articles when I did a search on “circadian rhythms.”

Most of the lunar studies I found dealt with psychological variables (e.g., homicide, psychiatric disturbances). A good number were by scholars (e.g., Kelly, Saklosfke, Martin, Culver) whom Lieber dismisses as “skeptics.” Only a few considered substances that might interest a neurochemist, and none of these studies has been replicated. My search failed to uncover any studies linking lunar cycles to substances that have been implicated as possible correlates of stress and aggression (e.g., serotonin, melatonin, epinephrine, norepinephrine, testosterone, cortisol, vasopressin [directly relevant to fluid content], growth hormone, pH, 17-OHCS, adrenocrotropic hormone).

It is hard to believe that all of the researchers who have documented circadian rhythms in stress hormones didn't collect enough data to check for lunar cycles. It is even harder to imagine that nobody has looked for a biological tide in biochemical processes when one considers the number of times that physicians send blood and urine samples out to be assayed.

However, instead of presenting data that would support his claims, Lieber resorts to repeating what others have told him in undocumented conversations. To take one of many examples, he states that a scholar working at Stanford “told me that this remarkable finding was replicated by other researchers” (p. 168). It doesn't take a lawyer to recognize this as hearsay.

Lieber ends his book with his response to a question posed to him in October 1978. Two things make Lieber’s response worth quoting. First, it gives a feel for the kind of nonsense that Lieber offers as evidence in this book. Second, I am astounded that anybody could remember such a long soliloquy. When asked to elaborate on how “[m]an’s responsiveness to subtle and persuasive effects provides us with an option for survival of our species,” he responded:

By virtue of our innate responsiveness to these imperceptible influences, we have within us a mechanism for survival under the most adverse of terrestrial circumstances. Suppose that at a time in the future a nuclear conflagration occurs. The only survivors are those lucky enough to have descended into underground shelters or caves located far below the Earth’s surface. Solar and societal timing cues soon would be eliminated in such a hostile environment. The only forces that penetrate to Earth’s core are gravity and geomagnetism; because our systems are capable of resonating with these two forces, we are able to synchronize our body’s rhythms with them. . . . Our biological clocks would not run down, as neurospora aboard Spacelab I did. Man becomes ill and nonfunctional when his body rhythms are disorganized; having the capacity to use gravity and geomagnetism to synchronize rhythms provides us with a crucial survival option.

Maybe. However, I suspect that having a biological clock out of sync is the last thing most of us would be worrying about after a nuclear conflagration.

Notes

I thank W. H. Laverty and P. Quincey for sharing their thoughts about Lieber’s book and I. W. Kelly for commenting on an earlier draft of this review.

1. A Type II error is a statistical concept described in introductory textbooks. Investigators commit a Type II error when they fail to reject a null hypothesis that is, in fact, false. However, it is more common to discuss the probability of a Type II error in terms of its complement (namely, power). There are several ways to increase the power of statistical tests (see Rotton and Schönemann 1978). The most common way in research on lunacy is to base one’s conclusions on larger samples and data sets that cover a long period of time. As Kelly, Rotton, and Culver (1985-86) report, neither is associated with the probability of significant results in this area.

References

• Culver, Roger and Roger Ianna. 1988. Astrology: True or False? Amherst, N.Y.: Prometheus.
• Culver, Roger, James Rotton, and I. W. Kelly. 1988. Moon mechanisms and myths: A critical appraisal of explanations of purported lunar effects on human behavior. Psychological Reports 62: 683-710.
• Kelly, I. W., James Rotton, and Roger Culver. 1985-86. The moon was full and nothing happened. Skeptical Inquirer, Winter: 129-43.
• —. 1996. The moon was full and nothing happened. In The Outer Edge, edited by Joe Nickell, Barry Karr, and Tom Genoni. Amherst, N.Y.: Prometheus. (A revised version of Kelly, Rotton, and Culver 1985-86.)
• Lieber, Arnold L. 1978. The Lunar Effect: Biological Tides and Human Emotions. Garden City, N.J.: Anchor Press.
• Lieber, Arnold L. and Carolyn R. Sherin. 1972. Homicides and the lunar cycle: Toward a theory of lunar influence on human emotional disturbance. American Journal of Psychiatry 129: 69-74.
• Rotton, James, and P. H. Schönemann. 1978. Power tables for analysis of variance. Psychological and Educational Measurement 13: 213-18.
• Sanduleak, Nick. 1985. The moon is acquitted of murder in Cleveland. Skeptical Inquirer, Spring: 236-42.

What is the connection between skepticism and politics? What are the appropriate politics for a skeptic? Does being skeptical automatically dictate one’s political outlook, or are there alternative points of view consistent with skepticism?

I ask these questions because I think skeptics have not devoted enough attention to them. This is hardly surprising, considering our nature. As skeptics, we are accustomed to deliberation, evaluation of evidence, and the insistence upon extraordinary evidence in support of extraordinary claims. These traits are not important to the political process, which instead rewards appeals to emotion and the successful manipulation of human passion. It is no wonder we are uncomfortable in the political world. It represents everything we reject in our search for understanding.

And yet, we are faced with inescapable evidence of the importance of politics. Like it or not, many aspects of our lives are affected and will continue to be affected by the political process. Simple self-interest, therefore, suggests that skeptics should address political issues. Perhaps more importantly, skeptics have a great deal to offer their fellow citizens. The visibility afforded to the political process could provide a useful platform for rational inquiry so conspicuously missing from modern debate.

This article will explore the connection between skepticism and politics. I begin with a discussion of the testability of political claims. I then discuss a well known view of the distinction between politics and morality and its relevance to the skeptic. I next examine the defining institutions of politics, developments in the social sciences that could affect the politics of a skeptic, and issues that skeptics find especially troublesome. I conclude with some of the political options for skeptics, along with a choice that is, in my judgement, unacceptable.

The Importance of Testability

To a skeptic, the testability of a claim is its most important feature. Unfortunately, the testability of political hypotheses is extremely low, due to the difficulty of controlled experimentation. One wonders if the term “political science” in fact has any meaning at all.

Suppose, for example, we wish to evaluate the effectiveness of income redistribution in reducing poverty. We cannot create two identical societies, giving one a placebo income tax and the other a real one, administered in double-blind fashion. The political process affects all members of a given community; there are no disinterested observers to evaluate the outcome.

We must instead live with the imperfect alternative of cities, counties, states, and nations as poorly conducted experiments in social organization. Although these experiments lack controls, counterfactuals, and take long periods of time before they produce measurable results, they are the skeptic’s best source of factual information on political issues.

Thus a skeptic should be familiar with history, politics, and economics, despite their lack of strong predictive value as social sciences. A skeptic should know how human beings have tried to organize themselves socially. When a skeptic makes a claim about the feasibility of some political outcome, she should be familiar with similar examples from history. When a skeptic challenges a political claim, he should ask for those same examples in support of the position. The more extraordinary the claim, the more credible the examples must be.

Skepticism and Morality

Many political claims, of course, are not falsifiable at all:

• “We have a duty to help those members of society unable to help themselves.”
• “Homosexuality is not the moral equal of heterosexuality”
• “Health care is a right, not a privilege”
• “Government must inculcate virtue in its citizens”

These are not empirical claims, but moral ones: statements indicating deeply felt values of the speaker. They serve as axioms of a belief system¹. The adherence to moral values is not incompatible with skepticism, although a skeptic’s moral axioms may be more amenable to change over time than most given her mental habits of constant questioning and re-evaluation. What can we say, though, about the relationship between a skeptic’s moral values and her politics?

Skepticism and Government

The key insight, I believe, is that while politics and morality are related, they are not identical. All political actions should be moral, but the converse does not hold. There is a large regime of action which includes morality but which, in a just society, excludes politics. This view is essentially that of classical liberalism, which views human beings as agents with rights that governments are established to secure, not as means to be used to a given end. Such a view recognizes the right of the individual to make moral decisions without state interference, so long as the rights of others are respected.

Politics is socially sanctioned force: political solutions to problems are all about forcing people into a course of action. This provides a way to distinguish moral statements from political ones. If the statements above are made in a political context, they are more appropriately interpreted as:

• “People must be forced to help those who cannot help themselves”
• “Government policies should distinguish between heterosexuality and homosexuality”
• “Government must provide health care, even it means compelling people to do so”
• “People should be made to be virtuous”

A perspective that recognizes this distinction between politics and morality may permit skeptics to engage people with different moral values on political questions, despite seemingly insurmountable differences of opinion.

Skeptics themselves, in fact, may hold widely differing moral values. If they are to successfully reconcile their politics and their skepticism, however, then they should apply the same techniques of critical inquiry toward the institutions of politics that they apply to all other institutions. The institution of government and the use of coercion as a social tool, the two central characteristics of politics, should be examined critically. In my judgment, economic theory, the evidence of history, and simple daily experience suggest that government is a very poor tool for solving social problems. If this view is correct, then it has profound implications for the politics of skepticism.

Skepticism and Public Choice Theory

Readers who have long maintained a belief in the effectiveness of politics as a means to achieving social ends should be aware of recent developments in the social sciences. The theory of public choice, in particular, warrants careful study. Public choice theory, developed by the economist James Buchanan, generates testable predictions about the behavior of political institutions. These predictions are supported through empirical observation, suggesting that every skeptic should have at least a working knowledge of them. For his work in the development of public choice theory, James Buchanan received the 1986 Nobel Prize in Economics.

Briefly, public choice theory applies the economic principles to the public sector that were, in prior scholarship, applied only to the private sector. Earlier methods of economic analysis assumed that while human self-interest was dominant in private affairs, public affairs were different. When private actions led to “market failure", public institutions were assumed to be able to correct it due to superior knowledge, motivation, or other attributes. In other words, governments were assumed to be “above” self-interest and thus more effective in solving social problems.

Public choice theory suggests that this assumption is not correct. Self-interest is dominant in all human affairs, both public and private. This means that, when addressing a political solution to a possible incidence of market failure, the possibility of political failure must also be considered. Political failure is simply the situation that occurs when the political solution does not work, has negative unintended consequences, and/or creates worse situations than the problem it was intended to solve. Research in public choice theory suggests that political failure is both much more likely and much more difficult to correct than market failure.

Readers who are interested in learning more about public choice theory are referred to Buchanan’s original work (Buchanan 1964) and a summary of the supporting evidence 20 years later (Buchanan 1984). Copies of these books belong on every skeptic’s bookshelf.

Difficult Issues for Skeptics

If skepticism about government is warranted, then the skeptic is placed in a difficult position on issues where science and public policy overlap. On the one hand, our commitment to the highest principles of objective inquiry and our understanding of the manifest contributions of science suggest we should support governmental activity in science education, increased federal funding for scientific research, the banning of medicines not proven safe and effective, and so forth. On the other hand, skepticism about government tells us that these policies as implemented in practice are likely to have unintended consequences, precisely because government is involved (Martino 1992), (Fagin 1993).

One cannot help being outraged, for example, at the modern tragedy of faith healing so eloquently described by James Randi in his book The Faith Healers (Randi 1987). The venality, corruption, and baseness of its practitioners seem to be exceeded only by the gullibility of its followers. And yet, those who are skeptical should ask how effective political approaches might be. Should faith healers be taxed, since they're not a “legitimate” religion? If so, who would decide religious legitimacy? Should faith healers be prosecuted for fraud, even if their victims continue to believe? If so, how would such prosecutions be undertaken? How would a Department for the Investigation of Faith Healing actually behave in practice? How effective has coercive action been historically in coming between desperate, deluded people and something they want to believe in? The answers to these questions, it seems to me, put skeptics in the position of reluctant laissez-faire. Although we may abhor faith healing, and want to see faith healers out of business, we should recognize that the institutions of politics are ill- suited to deal with this issue.

A similar, but more controversial example of the dilemma skeptics face in the public arena occurred in these pages (Barrett 1995) and in succeeding letters to the editor (Lantz 1995), concerning the role of the FDA in the regulation of medical practice. On the one hand, skeptics understand that science is the best way to find out how the world works. People who choose to avail themselves of medical techniques that have not been substantiated scientifically are, at best, wasting their money and at worst endangering their lives.

And yet, skeptics should ask if a ban on unproved medications and unconventional medical practices truly represents an improvement. Public choice theory suggests, and the evidence shows, that agencies like the FDA act to increase their budgets and regulatory authority far beyond that which was originally intended. They tend to err on the side of caution, trading lives saved by banning unproved products for lives lost due to delays in new device and drug approval. The right way to make such a tradeoff is far from obvious (Higgs 1994a and 1994b). There are also serious difficulties in treating “safety” as an objective concept. To a bureaucrat, safety can only be shown by a multi-year drug study using careful controls and rigorous scientific standards. To a young man dying of AIDS, the safety of a drug means something quite different.

The way out of these dilemmas, it seems to me, is provided by the distinction between politics and morality. Even though we as skeptics understand that science is the best way of discovering truth about the physical world, others do not understand this, or at least find discovering truth about the physical world peripheral to other concerns. So long as their actions do not harm others, we must regrettably permit others to act on these beliefs, simply because coercion is unlikely to improve the situation. We can hope to persuade voluntarily, through personal example and through vigorous articulation of why science and critical thinking are important, but skepticism about the defining institutions of politics demands that we not use force against people who believe in faith healing, laetrile, and channeling.

The Politics of a Skeptic

What does this mean for skeptics who wish to affiliate politically? What kind of political activism is most appropriate for skeptics? These issues are especially difficult today, since the application of a critical perspective to the institution of government distinguishes the politics of a skeptic from both liberalism and conservatism.

Liberals hold an almost religious belief in the effectiveness of government as a social tool. They tend to regard human society as inherently beset with problems, problems that government is called on to fix. When challenged on the evidence of the effectiveness of government, many retreat to a moral belief in the legitimacy of government as an institution for achieving “social justice". If evidence suggests that present policies are ineffective, then the answer is believed to be “reform", better accountability from government officials, or similar panaceas. The response to the confirmation of the predictions of public choice theory is an appeal for less self-interest, a call for more legislation, or (perhaps not surprisingly) demands for still greater political involvement. A willingness to question the effectiveness of government as a solver of social problems is not characteristic of modern liberalism. It is therefore difficult to reconcile with the politics of skepticism.

But neither is conservatism a friend of critical inquiry. Conservatives maintain an unwillingness to examine assumptions about the effectiveness of government as an inculcator of virtue and a cultivator of values. Their support of drug prohibition and the regulation of pornography on the internet², for example, despite the massive failures of the former and the sheer impossibility of the latter, can in my judgement only be explained by an ignorance of the predictions of public choice theory and a belief that the effectiveness of such policies is at best peripheral to their desirability. Such a perspective also seems difficult to reconcile with skepticism.

Conclusions

It seems to me that skeptics who wish to be politically active have a limited number of choices. They can affiliate with the growing libertarian movement, which has a historically informed view as to the limited sphere of action within which government can effectively operate, and accepts public choice theory as the one most compatible with existing evidence. This is what I have done. Another possibility is to work with the Democratic Party, using reason and historical evidence to show that government is not an effective tool for improving the lives of the poor in any meaningful sense. Still a third possibility is to work with the Republican Party, suggesting that the same factors that limit the effectiveness of government in managing the economy limit its effectiveness in personal affairs as well. This is the approach adopted by the Republican Liberty Caucus.

But renouncing politics altogether is a luxury that skeptics cannot afford. When faced with the de facto increase in the politicization of American life, even in the face of a newly elected Congress that claims to champion limited government, skeptics cannot afford to sit on the sidelines. If we remain aloof, then by our silence we will have contributed to a world where people believe that they can have things without paying for them, that compelling charity is compassion, and that banning vice is virtue. Now, more than ever, American politics needs reason and clear thinking. If we do not provide it, who will?

References

• Barrett, Stephen, 1995, Notes on the tryptophan disaster, Skeptical Inquirer, July/August 1995 (Health Watch).
• Buchanan, James and Tullock, Gordon, 1964, The Calculus of Consent: Logical Foundations of Constitutional Democracy, Ann Arbobr, Mich.: University of Michigan Press.
• Buchanan, James and Tollison, Robert, 1984, Theory of Public Choice II, University of Michigan Press.
• Corn-Revere, Robert 1995, New age comstockery: Exon vs. the internet, Cato Policy Analysis #232, Cato Institute, Washington DC.
• Fagin, Barry 1993, The application of public choice theory to science and engineering policy, Proceedings of the 1993 International Conference of the American Society for Engineering Education, Champaign-Urbana, Illinois.
• Higgs, Robert 1994 (a), Banning a risky product cannot improve any consumer’s welfare (properly understood), with applications to FDA testing requirements, Review of Austrian Economics, Vol 7 pp 3-20.
• Higgs, Robert 1994 (b), Should the government kill people to protect their health?, The Freeman, Vol 44, pp 13-17.
• Lantz, Richelson, and Woods, 1995, Policy and the tryptophan disaster, Skeptical Inquirer November/December 1995 (Letters to the Editor).
• Martino, Joseph, 1992, Science Funding, Transaction Publishers Inc, Rutgers, NJ.
• Randi, James, 1987, The Faith Healers, Prometheus Books, Buffalo NY.

Notes

1. I use the term “axiom” casually here, since belief systems in modern politics are seldom consistent.
2. I am referring here to the Communications Decency Act, signed into law on February 8th as part of the Telecommunications Reform Act of 1996. On July 29th, in a thoughtful and articulate decision, a U.S. District Court in Philadelphia found the CDA unconstitutional. The case will be heard by the Supreme Court this March. Interested readers are invited to visit rmii.com for further information.
3. For an analysis of the civil liberties challenges and enforcement problems of the Communications Decency Act, see (Corn-Revere 1995).

The Council, established last June by the Committee for the Scientific Investigation of Claims of the Paranormal (CSICOP), held its first meeting and first news conference January 9 at the Los Angeles Airport Hilton Hotel. The Council was formed to closely monitor and quickly respond to distorted treatments of science and uncritical presentations of paranormal and fringe-science claims in the media.

The Council attacked the major television networks for running two or three pseudoscientific specials almost every month. “Recently there have been programs on prophecies, astrology, psychic powers, creationism, Noah’s Ark, angels, and alien abductions,” said the Council. All of them posed, in some way, as being based on scientific fact.

The Council also criticized the many talk shows devoted to the paranormal in which claims in favor of the paranormal are given a platform but the scientific viewpoint is rarely allowed.

The Council’s two co-chairs, entertainer and author Steve Allen and Nobel laureate nuclear chemist Glenn T. Seaborg, called for the television industry to exercise greater responsibility toward science and truth.

Allen emphasized that the Council’s concerns are not with entertainment programs that honestly present themselves as fictional dramas. “We are talking about shows that are presented as if they are true, as reality,” said Allen, creator and host of the original Tonight Show, producer of the award-winning Meeting of Minds television series, and author of nearly fifty books, including “Dumbth”: And 81 Ways to Make Americans Smarter (Prometheus 1991). Allen has been a long-time advocate of critical thinking.

He and other speakers emphasized that series like Star Trek and The Twilight Zone never crossed that line and are not of concern. But a recent disturbing trend is “reality-based” TV programming in which fictional dramas or pseudodocumentaries claim or at least imply that they are based on truth and scientific fact.

“I call them damn lies,” said Allen. “How,” he said, referring to their producers, “do you approve of irresponsibility and lies?”

Seaborg, discover or co-discoverer of eleven elements including plutonium, former chairman of the Atomic Energy Commission, and current associate director at large of the Lawrence Berkeley National Laboratory, pointed to the discouraging state of scientific literacy in American society.

“I have been interested in the general problem of scientific literacy since just before Sputnik,” said Seaborg. “So I have been an advocate of scientific literacy for nearly forty years.” He was a leader behind the famous study “A Nation at Risk” that identified a need for renovation of pre-college science education to advance scientific literacy.

“We have a problem with regard to the amount of pseudoscience facing us,” Seaborg said. “One solution is increasing the scientific literacy of the general public.” Unfortunately, he said, too much television programming has the opposite effect.

CSICOP founder and chairman Paul Kurtz said the media have now virtually replaced the schools, colleges, and universities as the main source of information for the general public.

“The irresponsibility of some of the media in the area of science and the paranormal is a worldwide problem. But it especially applies to the United States, where the media have been distorting science, and in particular presenting pseudoscience as genuine science. Indeed, we are appalled by the number of ‘documentaries’ that are really entertainment programs presenting fringe science as real science.

“We believe that the media have presented a distorted view of science,” Kurtz said, and that they have a responsibility to provide a more balanced view of what is real science and what is pseudoscience.

“We are asking only for some balance. We are asking TV not to dramatize pseudoscience as real science.

“We are not, of course, asking that TV producers not run these shows or make a profit,” Kurtz added. “We surely do not wish to censor the media. We only ask that they provide some balance and some appreciation of the scientific approach. The Council will monitor such programs and attempt to persuade producers, directors, writers, and the general public to leave room for the appreciation of scientific methods of inquiry.”

Kurtz, recovering at the time from surgery, spoke to the news conference via videotape. Barry Karr, CSICOP’s executive director, hosted.

Council member Eugenie Scott, director of the National Center for Science Education in Berkeley, California, said the concern is that science be presented honestly. “We offer to provide our help, our expertise to help you do a better job,” she said. “We would like to encourage you to consider that science, in and of itself, is exciting, creative, and wonderful.

“You don't have to present the crackpot stuff to be interesting.”

CSICOP staff member Tom Flynn lamented the increasing blurring of entertainment and fact-based programming. He showed excerpts from NBC’s notorious 1996 pseudoscientific, documentary-style ”Mysterious Origins of Man,” which presented, as Flynn put it, “the utterly baseless idea that dinosaurs and man lived at the same time.”

“This program did probably more than any other to reinforce the idea that dinosaurs and man co-existed.”

Scott, a physical anthropologist, agreed that much of what goes on in school is absolutely swamped by television. The day after the NBC program aired, she said, science teachers throughout the United States were deluged with questions from their students about dinosaur-human coexistence. She said this single program set back science education on this topic by decades.

—Kendrick Frazier, Editor

Nye, Aykroyd Receive Council’s First Awards

Bill Nye, creator, writer, and host of the award-winning PBS and syndicated television series Bill Nye the Science Guy, was honored by the Council for Media Integrity for his program, targeted at young people, which presents science as a lively, creative, and fun endeavor. Nye was given the Council’s first “Candle in the Dark” Award for his outstanding contributions to the public’s understanding of science and scientific principles.

Bill Nye the Science Guy (see SI, January/February 1997) is a joint production of PBS, Disney, and the National Science Foundation and is telecast daily in most big-city markets. He was presented his award by Kendrick Frazier, editor of the Skeptical Inquirer.

Nye was once a student of Carl Sagan’s at Cornell University. He said he was delighted to receive an award linked in any way to Sagan, who died December 20 and whose last book, The Demon-Haunted World, was subtitled “Science as a Candle in the Dark.” He thanked CSICOP and the Council for recognizing his program as a contribution to the nation’s science education.

In marked contrast to Nye’s award, the actor Dan Aykroyd was presented in absentia the Council’s “Snuffed Candle” Award. Aykroyd is host of the new television program Psi Factor and has been a long-time promoter of all sorts of paranormal claims. The award recognized Aykroyd “for encouraging credulity, presenting pseudoscience as genuine, and contributing to the public’s lack of understanding of the methods of scientific inquiry.”

CSICOP Senior Research Fellow and Council member Joe Nickell said he had been trying to inform Aykroyd of the award by mental telepathy but had not yet had any response. He said he would attempt to send the handsome plaque to Aykroyd by telekinesis.

Following up on the events in Los Angeles, Nickell wrote to Aykroyd on behalf of the Council requesting that Aykroyd and OSIR (Office of Scientific Investigation and Research — the research group behind the “cases” presented on Psi Factor) provide “full particulars” on a Psi Factor episode in which NASA scientists are killed while investigating a meteor crash and giant eggs are found and incubated, yielding a flea the size of a hog. Nickell made the request in response to a statement by Aykroyd on Entertainment Tonight that skeptics would have to withdraw their criticism once they've seen the OSIR data. It remains to be seen whether Aykroyd and OSIR will provide the data.

CSICOP to Become Shareholder in TV Networks

To provide leverage for its response to the television networks’ lucrative commercial marketing of fringe science and pseudoscience, CSICOP is asking friends and supporters to help it acquire common stock in media conglomerate companies. This will allow CSICOP to take part in shareholder meetings, where it can question the infatuation with the paranormal increasingly demonstrated in television programming.

“We are deliberately targeting each of the four major television networks, which is to say, the well-known media conglomerates Westinghouse (CBS), General Electric (NBC), NewsCorp (Fox), and Disney (ABC),” said a CSICOP statement issued in Los Angeles. Also targeted is Time Warner.

“As a ‘shareholder,' CSICOP will have opportunities to attend shareholder meetings, submit viewpoints to shareholder publications, and sponsor shareholder resolutions. While exercising these and other shareholder rights, we will be representing the broad constituency of readers and donors who support CSICOP and the Skeptical Inquirer magazine.”

Twenty-eight years after Chariots of the Gods? author Eric von Däniken brought pseudoscience to new lows by suggesting that our ancestors were too stupid to create the pyramids, Stonehenge, and other monuments without the help of space aliens, his ideas are alive and well thanks to a prime-time September 26, 1996, ABC-TV special, ”Chariots of the Gods? The Mysteries Continue.”

The show suggested that there might be new information to support von Däniken’s theories that ancient drawings depict spaceships and our ancestors’ knowledge of the universe must have come from extraterrestrials.

The odd thing was that the program gave plenty of hints to suggest that von Däniken is a crank. Yet ABC chose to gloss over the problems.

One of the first hints came when von Däniken talked about the ruins of the Aztec city of Tenochtitlán, where the main ceremonial plaza with its huge flat-topped pyramids was supposedly laid out in a way that produced “a remarkably accurate scale model of our solar system,” complete with Uranus, Neptune, and Pluto, three planets invisible to the naked eye.

If anybody at ABC had known anything about astronomy, they should have questioned several aspects of the “model.” First, if it was so accurate, why was the only big gap between Saturn and Uranus? (Answer: The layout wasn't intended to be a model of the solar system.) Why did von Däniken choose not to put a planet in the circle next to Uranus, which looked tailor-made to house a planet? (Answer: Then the “model” wouldn't fit right.)

And if space aliens really developed the solar system model, why is Pluto included? These days, because of its size, orbit, and origin, astronomers barely regard Pluto as a real planet. It retains that distinction out of tradition.

The hour-long program was filled with such problems.

On another artifact, an image of what appeared to be a snake became, in von Däniken’s eyes, a light bulb filament. In another case, three lines of stones that formed a jagged line were, instead, magically converted into two equilateral triangles and a right-angle triangle — supposed proof that space aliens gave our ancestors geometry, trigonometry, and the Pythagorean theorem. The famous markings on the Nazca Plains in Peru were shown, with host Richard Karn (of the ABC comedy series Home Improvement) stating that “without the ability to fly, experts don't know how the Nazcans gained the perspective needed to create such elaborate figures on such a huge scale.” Von Däniken and the folks at ABC are probably still wondering how the streets of New York City or Washington, D.C., could have been laid out so precisely when none of the engineers responsible had ever been in an airplane, or how hoaxers can create intricate crop circle patterns in the dead of night — best viewed from the air — without high-tech equipment.

The problem with such shows is that they are often produced by the network’s entertainment division, where accuracy and fairness don't have a high priority.

But the ”Chariots of the Gods?” special was followed by a Turning Point program on ”Alternative Medicine: Hope or Hype?” that was produced by ABC News. It featured respected moderator Hugh Downs talking about therapeutic touch, hypnosis, iridology (the alleged ability to discern diseases by looking at the colored part of the eye), and ozone enemas.

The program was a mix of messages. While Downs cited several alternative medical methods and pointed out that “no medical studies have proven that any of these systems work,” he also spoke of trying “unorthodox treatments with mind-boggling results.”

It featured a patient of cardiac surgeon Mehmet Oz, of Columbia-Presbyterian Hospital in New York, who has decided to offer some of his patients a menu of techniques — hypnosis, Yoga, therapeutic touch — in an effort to see what works. Left unanswered was the question of how he’s going to be able to tease out which discipline is beneficial and which is bogus if each patient is being given several types of treatments.

The show also profiled a former ABC News producer with breast cancer who decided not to have radiation treatments so she could, instead, follow the guidance of Park Avenue physician Dr. Nicholas J. Gonzalez. Gonzalez, according to the program, had her taking 134 nutritional supplement pills a day, performing two coffee enemas a day, and drinking glasses of Epsom salts, olive oil, and whipping cream every few weeks. Gonzalez freely acknowledged that there were no scientific studies to back up his regimen.

Downs and ABC didn't seem particularly alarmed by all this, approaching the story with sometimes-bemused curiosity and making it sound like we'll soon know whether this stuff works.

But from the consumer’s point of view, there’s a big difference between a medical treatment where the scientific evidence is not yet in, and one where tests have been conducted and the results show that the treatment is bogus.

ABC repeatedly failed to make that distinction.

Take iridology, for example. The network pointed out that there was no proof that iridology worked. That’s true. But that’s only half the truth. Iridology is not just unproven; it has been tested and shown to be bogus.

ABC also took a hands-off approach to reporting on therapeutic touch, neglecting to note that there are legitimate scientific reasons why doctors are skeptical. The program mentioned that the people who perform therapeutic touch claim to be able to massage and mold an invisible energy field into a healthier shape. But in order for therapeutic touch to work, (1) an energy aura must exist around the human body, (2) practitioners must be able to sense it, (3) the aura must be malleable by human hands, and (4) changes in the shape of the aura must translate into effects on the health of the body.

Downs and his ABC team neglected to note that nobody’s been able to prove that the field exists, never mind that it’s malleable. (Therapeutic touch promoters try to counter with the argument that the field has been photographed using Kirlian photography, which supposedly captures energy around living things. They usually have trouble responding if someone asks, in turn, why energy auras have been seen around Kirlian photographs of inanimate objects like paper clips.)

The network boasts that “more Americans get their news from ABC.” But if news means giving viewers the whole story, this was one night when ABC did a disservice to its audience.

Dixon became famous for predicting the assassination of President John F. Kennedy. Yet hers was a forecast that nobody has been able to document.

Various obituaries made reference to a 1956 article in Parade magazine in which she supposedly said that a tall, young, blue-eyed, Democratic president elected in 1960 would die in office.

Actually, the May 13, 1956, article in Parade said, “Mrs. Dixon thinks (the 1960 election) will be dominated by labor and won by a Democrat. But he will be assassinated or die in office, ‘although not necessarily in his first term."' As Terence Hines noted in Pseudoscience and the Paranormal (Prometheus Books, 1988, p. 43), her prediction covers a lot of possibilities. In fact, she predicted in a 1960 forecast that “John F. Kennedy would fail to win the presidency.”

Nonetheless, virtually every obituary gave her far more credit than her actual forecast deserved. USA Today, in its January 27 edition, bluntly stated that “her prediction that President John F. Kennedy would die in office came true.”

Most news outlets tempered their stories by mentioning a few of her mistakes, most notably her forecast that the Soviet Union would beat the United States to the moon and that World War III would begin in 1958. Unfortunately, the “sometimes she was right, but sometimes she was wrong” attitude doesn't cut it. Because nobody expects a psychic to be perfect, the failed forecasts may have simply reinforced the idea in the minds of some that her gifts were real.

In fact, Dixon seldom made a real forecast. She was the queen of equivocation. Her predictions in the supermarket tabloid the Star were so full of ifs, coulds, and mights, she almost always had an excuse if a prediction failed to come true.

Consider, for example, her predictions for last year: “This winter, Nelson Mandela faces a personal crisis — and danger could return in April. His former wife Winnie could win an election and be returned to government (Star, January 9, 1996, emphasis added). For 1997, she said, “Late October could bring another plane tragedy over water,” “Roseanne is headed for big health problems if she doesn't slow down,” and “A temptress or even a female assassin could be waiting for President Clinton on a foreign trip. His best defense to ward off trouble will be to bring along his wife Hillary” (Star, January 7, 1997, emphasis added).

She also could be extraordinarily vague. The February 11, 1997, issue of the Star, which carried an eight-page tribute to her, had to stretch to find seventeen “amazingly accurate” predictions. The magazine gave her credit for forecasting the March 24, 1989, Exxon Valdez oil spill because she reportedly said, “A shipping accident will make headlines in the spring.” The tabloid gave her credit for predicting the AIDS epidemic, which surfaced in the early 1980s, because she said, in 1978, that “a dreadful plague will strike down thousands of people in this country.”

On the unusual occasion when she made an unequivocal prediction for an unexpected event that would be guaranteed to make news, her forecasts nearly always flopped. In the 1995 issue of the Star, she said it would be the year “Pope John Paul II will have a hand in liberating Cuba from Castro” and “a whole new world of dinosaurs will be discovered in Central Asia.”

With Dixon’s death, members of the media had a chance to set the record straight about a woman whose name had become a household word, largely on the basis of a myth. By and large, they missed the opportunity.

Since then, IBM has released the 1997 World Book Multimedia Encyclopedia (Windows, $50), and the good news is that it scores even higher than Grolier, garnering 21 points on the scale. From astrology to UFOs, when it covers pseudoscience topics, it often does so in a way to give readers some idea why there is reason for skepticism.

Part of the reason for the high score may be that CSICOP fellows James Oberg and James Alcock contributed to the sections on UFOs and parapsychology, respectively. But other topics reflect a similarly skeptical viewpoint.

While the article on astrology says that “people declare there is no scientific basis for astrology” (it’s not clear who these “people” are or why their declaration should carry any weight), the article goes on to note that discoveries made by Copernicus and Tycho Brahe conflict with astrology, and that the constellations have shifted over the past two thousand years to the point where most astrologers don't even know a person’s true sun sign.

The entry on creationism, although brief, is one of the best I've seen. Although it doesn't get into specifics, World Book makes it clear that the debate is actually a religious battle over biblical literalism.

The Bigfoot and abominable snowman sections note that scientists believe some evidence, including footprints, have been faked and that the sun can often melt footprints in the snow, making them appear unnaturally large.

None of the encyclopedias scored well on the topic of homeopathy, and World Book missed the biggest criticism of this “alternative” medical system — that its medicines are so diluted, no active ingredient may even be present.

But overall, it’s nice to see that Grolier isn't alone in giving a rational, scientific assessment of topics that the public finds so fascinating.

Professor Carl Sagan had the whole lecture hall looking down on a small organism that was ingesting tiny creatures for sustenance. Well, it turned out we were looking at a picture taken from a satellite of a swimming pool. The ingested creatures were swimmers—people like us.

Professor Sagan had a way of surprising you. He could do it, because he had an intimate knowledge, perhaps deeper than anyone else we’ll ever meet, of how one part of the world connected with the rest of the cosmos. He described our universe with words like “elegant, exquisite, and astonishing.” And, it is. He made you feel it.

Many of us think of him as a popularizer of science. Bear in mind he was also a top notch scientist, as well. He predicted the atmospheric physics of dust storms on Mars. He alerted the world to the catastrophic changes in Earth’s climates should we recklessly allow an exchange of nuclear weapons. And, he tirelessly checked the purveyors of pseudoscience in steady, compelling essays and debates.

I met him a few times over the years after I took his astronomy course. Each meeting left me refreshed with a new and more intimate understanding of what we had discussed. It came from his easy, deep, and passionate grasp of things. I was always a little awed after each exchange.

He lived at a time when human exploration of space was, for the first time in human history, revealing to us the true nature of Nature. From his boyhood, Carl Sagan not only embraced this new awareness, he understood its significance in a way that most of us don’t. He often said, “We are all made of starstuff,” an astonishing idea. He encouraged you to prove to yourself that it was true. His presence as an orator was compelling, his writing is riveting, and his influence on the world’s appreciation of science is hard to reckon. It’s big; he will be missed.

Bill Nye, who took Introductory Astronomy from Carl Sagan in 1977, is now “The Science Guy” on public and syndicated television.

Leon Jaroff

Carl’s imagination and creativity were boundless—and grist for journalists. My first contact with him was in the late ’60s, after Mariner 9, in orbit around Mars, had sent back the first close-up pictures of the Red Planet. Instead of the hoped-for signs of civilizations past or present, the pictures showed what seemed to be a bleak, lifeless surface marred by craters.

Young Carl, ever the optimist, promptly wrote a paper reporting that he had scanned thousands of weather satellite pictures of Earth, and on only one of them had he spotted any evidence that intelligent life might exist on Earth. Thus, civilizations might well be thriving on Mars, he suggested, just a little beyond the resolution of Mariner’s camera. My story in Time magazine, based on an interview with the then little-known Carl, was entitled “Is There Life on Earth?”

Not long afterward, Carl turned his attention to Jupiter and held out the possibility that life could exist on the gas giant. How? In the form of creatures composed largely of gas bags and floating freely in the Jovian atmosphere. That hypothesis, made perhaps with tongue in cheek, was also too much to resist. My Time story was entitled (appropriately) “The Gas Bags of Jupiter.”

Over the years, I hounded Carl for stories and seldom came up empty-handed. He was patient, courteous, friendly, and always seemed flattered by my interest. His explanations of difficult concepts were lucid, his quotes lively, and his insights unique. In short, he was a science writer’s dream source.

When I last saw Carl at his sixtieth birthday celebration in Ithaca, he seemed a happy, fulfilled man. He had reason to be, secure in the knowledge that he was admired around the world as science’s most articulate and imaginative spokesman.

What a loss.

Leon Jaroff was a senior editor and the science editor of Time, for which he still writes, and the founder and first managing editor of Discover.

Neil deGrasse Tyson

The following is a eulogy for Carl Sagan (edited slightly) that was delivered by Neil deGrasse Tyson at a memorial service held at the Cathedral of St. John the Divine in New York City. Other speakers included Sagan’s wife, two of his children, Stephen Jay Gould, and Vice President Al Gore.

What can I say about Carl Sagan that has not already been said?

Carl Sagan was at the helm of many ships. But the one I have in mind carries people, who, as part of life’s priorities, seek to enlighten the public about the beauty of science. Collectively, all of us on this ship deliver lectures, write books, and give interviews with the media. But for each engagement, somehow we know that Carl has been there before—if not in person then in spirit. He has made our work easier, having painted the landscape that now frames our efforts to reach the layperson. I cannot count the number of times I have jump-started an encounter with the public by directly or indirectly referencing a jeweled quote from one of his many literary or media expositions on the universe. With Carl’s passing, I now feel that sense of insecurity reminiscent of when you first leave home. I feel not only the loss of a friend but the loss of a leader.

I first met Carl when I was in high school in the mid-1970s. My letter of application to Cornell University was dripping with an interest in the universe. The admissions office, unbeknownst to me, forwarded the application to Carl Sagan’s attention. Within weeks I received a personal letter from Carl, inviting me up to Ithaca to visit him. . . . I visited Carl on a snowy afternoon in February. He was warm, compassionate, and demonstrated what appeared to be a genuine interest in my life’s path. At the end of the day, he drove me back to the Ithaca bus station and jotted down his home phone number—just in case the buses could not navigate through the snow and I needed a place to stay.

I never told him this, but at every stage of my scientific career that followed, I modeled my encounters with students after my first encounter with Carl.

Although I did not ultimately attend Cornell University, Carl and I re-met several more times over the years. . . .

I last saw him at his sixtieth birthday celebration at Ithaca. An entire evening was spent by friends, loved ones, and colleagues, heaping praises upon Carl. Each testimony was grander than the next. There was the undergraduate who majored in science after a single encounter with Carl. There was the graduate student who shifted his thesis focus to planetary atmospheres upon becoming excited by the science that Carl had described to him. There was the letter to Carl (read by the Astronomy Department Chair) from a student in Africa who launched an astronomy club in his home village after reading Cosmos. Topping that moment, the department had actually flown the student to Ithaca for the occasion and introduced him to Carl in person. Then there were the letters read from top officials of international governments. And then there was the announcement that an asteroid would be named after Carl’s wife, Annie Druyan, whose orbit was in eternal resonance with another asteroid that had already been named for Carl.

The praise seemed unending, which led me to ask myself whether the life of any human being could be worthy of this much praise. The next evening, Carl gave a public talk to a standing-room-only crowd in Cornell’s Uris Auditorium. His topic was inspired by the contents of his recent book Pale Blue Dot. During the hour of his talk, and the hour that followed of questions he fielded from the audience, I realized that the praise I had witnessed the night before was only the beginning of the praise that he truly deserves—and will continue to receive.

I will miss him.

Neil deGrasse Tyson is the Frederick P. Rose Director of New York City’s Hayden Planetarium. He is also a visiting Research Scientist and Lecturer at the Department of Astrophysics, Princeton University.

James Oberg

Sagan’s greatest gift, which enriched and rewarded us far more than it did him, was his transparent enthusiasm to “find out and tell about” the advance of human understanding of the universe. He vividly humanized what had been previously regarded as cold-blooded “scientific curiosity”; and in advertising science “with a human face,” he brought all the strengths and weaknesses of a human being onto the stage. For all of us exposed to his messages, he encouraged our fervent hope that the human intellect, with all of its inefficiencies and distractions to which none of us are immune, could still come to understand, bit by bit, the incomprehensible universe.

James Oberg is a science journalist and space engineer in Houston.

E. C. Krupp

Only three astronomers have appeared on the cover of Time magazine, and Carl Sagan was one of them. Such spotlighting in the national media was not his greatest triumph, but it makes his impact very clear. When he went dipping his toe in that cosmic ocean, he took a huge crowd with him. Anyone who advocates the democratization of knowledge has to be grateful. He showed us there is romance and adventure in the disciplined, systematic acquisition of knowledge.

With an imaginative reach anchored in rational thought, he brought the stars down to Earth and persuaded its inhabitants to examine their connection with the cosmos. He wasn’t Man of the Year, but he spoke for Earth.

E. C. Krupp is director of Griffith Observatory in Los Angeles.

Jerry Hosmer

As a science educator, I know I speak for many in my profession when I try to express how greatly Dr. Sagan will be missed. I believe he did more to encourage young people to seek out knowledge and truth than anyone else in the last thirty years. He made science “cool” and inspired not only students but many teachers as well. Carl Sagan will not soon be forgotten.

Jerry M. Hosmer teaches chemistry and is chair of the Science Department at Poplar Bluff R-1 School District in Poplar Bluff, Missouri.

Dave Larson

I’ve been thinking a lot about Carl Sagan the last few weeks. He never knew me, but he saved my life, and I never got to thank him. I was a screwed-up kid in the late ’70s. I was a high school dropout who spent too much time partying and none building a future. I was on the fast road to nowhere and badly in need of something larger than myself to give my life direction. Then came Cosmos.

As a child I had been fascinated by science and in awe of the starry sky, but somehow I lost sight of it in the confusion of growing up. Then Carl Sagan brought it back to me. He gave me back my sense of wonder at the mystery of the universe—something I wasn’t even aware I’d lost. After viewing the series, I received a copy of the companion book from a friend. I stayed up for two days reading it, then began to buy and read his other books as he published them. Gradually, I began to see the world in a different way and make changes in my life. I quit partying all the time, read everything I could get my hands on in the way of general science, and even worked through a few “Teach Yourself” books on astronomy, physics, and other subjects. I hadn’t had math or advanced science in school, but I was encouraged by my understanding of Dr. Sagan’s explanations. It took several years, until the late ’80s, but I finally got around to trying college. A few years ago I earned a B.S. in physics.

I intended at the time to pursue graduate study in astronomy, following in the footsteps of the master, and I hoped to study directly with Dr. Sagan; but I had to leave school for a while to make some money. Still, I thought I might one day get a chance to sit in his classroom. I would have liked to hear him describe in person the billions of stars in the universe, to hear his eloquent speech without the limitations of television, to tell him how much his teaching meant to me, to say thank you, but I guess it wasn’t to be.

I wasn’t even aware that he was ill until I heard of his death. It really shook me up. For several days I kept thinking of him and how the world had lost some of its heart, how science had lost its greatest champion. And slowly I began to realize a loss of a more personal nature, of something I didn’t even know I had. A Hero. Hero worship has always put me off, but it is now apparent that I’ve had a hero for years. This man has been my hero. This man, who never knew me, but saved my life, and whom I never got to thank. Well, Carl Sagan, thank you. I never sat in your class, but you were my greatest teacher. There may be billions of stars in the universe, but few have shined as brightly as you.

Dave Larson currently works in telecommunications in Rowlett, Texas. He hosts a web site dedicated to the advancement of science at http://web2.airmail.net/dlarson1/science.

Mike DiMuzio

Carl Sagan was a person I long admired. I, like Carl, had become fascinated with astronomy at a young age, only about four years old. Recently, I hoped that he was looking forward to the launch of the Cassini probe to Saturn, considering his particular interest in its moon Iapetus.

Now he is gone. I do not believe in an afterlife; however, I feel we can achieve a type of immortality through others. As long as we speak, read, and think of what Carl Sagan spoke, read and thought, then he will be alive forever in our thoughts and our hearts.

As long as I am alive, I will remember him. I believe that I will not be alone in this. And, long after we are gone, I hope there will be a new generation of children inspired by Cosmos, Broca’s Brain, and even The Demon-Haunted World.

Goodbye, Carl . . . you beat all of us to the stars.

Mike DiMuzio is Planetarium Lecturer and Observatory Director at Youngstown State University’s Ward Beecher Planetarium.

Al White

Sagan’s Sonnet

(July 4, 1996)

The deep wrought-iron July sky
was that evening briefly ablaze. Mostly
and most briefly with rockets thrown
in a deliberate craze of patriot novae—
syncopated concussions, overloaded brains
in faint choral echo. Less so (but not so less)
winged neurons whizzed past ears
in Permian blood-lust. Hands clapped
in adaptive patterns as rocket launch
or needled proboscis insisted. Almost unnoticed
Jupiter’s constancy in the southeast brought you
to mind; just this one. So nanobits of strontium
and carbon valence burn, slow and warm,
hot and fast, filled a deeper sky with form.

V. Alan White is a professor of philosophy and the 1996-97 Carnegie Wisconsin Professor of the Year, University of Wisconsin Centers.

Following is just a brief sampling of other letters received from readers.

—The Editor

The death of Carl Sagan has left the world a poorer place. His contributions to society have been prodigious and will be considered even more so when social historians of the future assess his overall beneficial impact upon a civilization in dire need of the “big picture” perspective. He was only 62 years old at his death in December of 1996, and I worry that without another twenty years or so of his typically consummate and compassionate rationality, there might not even be social historians of the future in a position to render appropriate judgment at all! Perhaps an overstatement, perhaps not.

Our survival as a dominant species on this planet has depended upon and will increasingly require the application of rational thought, often best exemplified through the scientific method. Our progress is threatened by ignorance and superstition, particularly under the guises of fundamentalist religious dogma, creation “science,” astrology, New Age channeling, and numerous other silly pseudosciences. Sagan, in his gentle way, extracted the best from the scientific method, combining it with a true morality filtered from the Judeo-Christian ethic, delighting all those of open mind and goodwill who read his works or heard him speak.

I will miss the articulate exuberance with which he celebrated the wonders of our cosmos and his stern but sympathetic admonitions against those of us who would succumb to easy preconceptions about ourselves and our world—in the process engendering some short-term emotional comfort but, in the long run, only erecting obstacles to deeper understanding. He was without question one of history’s greatest proponents for scientific advancement, a magnificent ambassador of knowledge, teaching us along the way that, without the deep data provided by rigorous application of the scientific method, we make ourselves vulnerable to charlatans and shallow “experts” offering glibly authoritative answers to profoundly difficult questions. Philosophically, he was a strong logician, but his approach to teaching was a bit whimsical, even spiritual, and always honest.

Carl, I will miss your newest books and articles, your appearances on television and, especially, fundamentally, your good-humored and incisive courage in dealing with the phony pseudoscientists and fuzzy thinkers abounding in our culture. I hope some of us can carry your shining torch.

—Evan Thomas

Twin Falls, Idaho

In 1994 I had the privilege of meeting and talking with Dr. Carl Sagan, when he delivered the keynote address at the CSICOP conference in Seattle. As a fan of Dr. Sagan’s since I watched him on Cosmos, I was enormously flattered at having him compliment me on a question I asked at the conference.

When I heard he was ill, I sent him a get-well card at Cornell University. Unfortunately, I have no idea whether he received it. Only a month or so ago, I was so happy to hear that he thought he was getting better. Now he is dead, and coincidentally, that same day I received a call from the local library to say that the long-awaited copy of The Demon-Haunted World was ready for me to pick up.

So I’ve decided to remember Dr. Sagan in a way he’d be sure to enjoy: by making a contribution to CSICOP’s Center for Inquiry, and by devouring his last, fascinating book.

—Barbara-Anne Eddy

Vancouver, B.C., Canada

Carl Sagan was one of the few public figures on this planet who made you proud to be a member of the human race. It takes little imagination to realize that your magazine will be inundated with letters mourning the loss, and while at the moment it does little to relieve the sorrow, it is a comfort to acknowledge the legacy he has left us.

By coincidence, when I heard the news I happened to be rereading his marvelous book The Dragons of Eden, still a masterpiece of informed speculation. My eye fell on one paragraph in particular that I think sums up what I most admire in Carl Sagan, and it also encapsulates my own feelings:

In a way, science might be described as paranoid thinking applied to Nature: we are looking for natural conspiracies, for connections among apparently disparate data. Our objective is to abstract patterns from Nature . . . but many proposed patterns do not in fact correspond to the data. Thus all proposed patterns must be subjected to the sieve of critical analysis. . . . The search for patterns without critical analysis, and rigid skepticism without a search for patterns, are the antipodes of incomplete science. The effective pursuit of knowledge requires both functions. (Dragons of Eden, 1977)

—Ross Sargent

Folkestone, Kent, U.K.

I am just a regular guy who likes to read and think. But the passing of the great Carl Sagan is a horrible loss. I bought his book Shadows of Forgotten Ancestors in November 1992. I could not believe how much scientists knew about evolution. Before this book, I had only a very vague idea of evolution.

It opened my eyes to the true story of life on this planet and caused me to read many other books and discover my favorite science writer Richard Dawkins. Explaining science without dumbing it down takes brilliance, and Carl Sagan was one of the best: along with Dawkins, Stephen Jay Gould, and Isaac Asimov.

When I think about all those other books I have read and continue to read—all the pleasure of learning—I have to thank Carl Sagan for his impact on my thinking. He never knew me, but in every sense he was my teacher. I can’t get the point across strongly enough. Thanks to Carl Sagan for getting me thinking and interested in science and philosophy. I love him for it.

—Dan Schuelke

Alta, Iowa

Universe Man

(In Memory of Carl Sagan)

Take me on a trip to the stars
Melt me into Mercury
Mold me into Mars
Take me to where it all began
Oh won’t you take me, Universe Man

Your brain was big as Jupiter
Your passion blazed like Venus
But I never felt the stupid-er
In the presence of your genius

Your need to know was infinite
Your energy contagious
You lifted me outside myself
and showed me something ageless

There are millions of planets above us
Ev’ry one with a different hue
And billions of stars in the heavens
But, Carl, there was only one you

Now nothing can keep you grounded
Not even gravity’s hand
At last you’re free, for you get to be
One with the universe, man

Take me on a trip to the stars
Melt me into Mercury
Mold me into Mars
Oh, to be where it all began
Wait for me there, Universe Man

—Richard Machin

Louisville, Ky.

As the millennium approaches, the media are playing up asteroid and comet impacts. Ten popular-level books were published in 1995 and 1996 dealing with the dangers of cosmic impacts, and now we are seeing a spate of television and movie productions, both factual and fictional, that describe the impact threat. It is easy to dismiss all this as media hype and millennial madness, but it would be a mistake to do so. While some books and films may be motivated by a desire to milk public credulity for a quick buck, most are serious efforts to inform the public about a real danger that is recognized by the scientific community. In this article, I summarize the background for the recent interest in impact catastrophes and then provide a comparative review of the current trade books that deal with this topic.

Background

Most scientists first thought about the role of impacts in Earth history in response to the now-famous paper published in Science in 1981 by Luis and Walter Alvarez and their colleagues, suggesting that an impact sixty-five million years ago produced the mass extinction that terminated the Cretaceous era. What was new in this paper was not the fact that Earth was struck by cosmic debris, but the idea that even relatively modest impacts might have a catastrophic effect on the environment. That Earth is subject to impacts is obvious from an examination of the cratered surface of our companion in space, the Moon. Planetary probes, beginning in 1964 with Mariner 4, have demonstrated that impact cratering is a universal process in the solar system. A heavy bombardment occurred early in planetary history, but it did not end then; a lower-level “rain of rocks” continues today, as comets and asteroids occasionally intersect the orbits of the planets. Those that come close and can pose a danger to Earth are collectively called Near-Earth Objects, or NEOs. On average, Earth should still expect to be struck by a fifteen-kilometer NEO every hundred million years or so. But the Alvarez paper and the research it stimulated also show that such impacts generate global-scale wildfires and dust storms, and thus are capable of killing most life forms and profoundly influencing the course of biological evolution. Impacts are the ultimate environmental disasters, more important than volcanic eruptions or other more familiar events in shaping the history of life on the planet.

Fortunately for us, impacts large enough to produce mass extinctions are rare, taking place at average intervals of tens of millions of years. However, there is a spectrum of comet and asteroid sizes, with many more small impacts than large ones. Based on what we know today, impacts much larger than the Cretaceous-Tertiary (K-T) event are possible in the future (although very improbable). And impacts smaller than the K-T event — say by objects one kilometer or a few kilometers in diameter — occur much more frequently. The planet is struck by a one-kilometer asteroid or comet at average intervals of about 100,000 years.

Another important aspect of these impacts is that they are, as far as we know, randomly distributed in time. The chances are equal that a big one could hit in 1997 or in 2248 or in any given year in the far future. Further, although a few teams of astronomers have been searching for NEOs, the census of these objects is far from complete. For instance, of the roughly two thousand kilometer-scale asteroids that are expected in Earth-crossing orbits, fewer than two hundred have actually been found. We are confident that Earth will not be struck in the foreseeable future by any of the known objects, but we can say nothing about the 90 percent that are not yet discovered. It is because we have not yet carried out a comprehensive search that we must speak in terms of probabilities. In reality, this is not a game of chance. There either is or is not an NEO out there aimed to hit us next year or in the next century. But we don't know about it yet.

Finally, we should realize that only a small fraction of the space around Earth is being monitored today and that the most probable warning for a kilometer-scale impact is zero — the first we would likely know of a strike is when we feel the ground shake and watch the fireball rising above the horizon. While several national and international observing programs have been proposed to accelerate the discovery of threatening objects, so far no government funds have been spent to deal with large-scale searches or any other efforts to mitigate the impact threat. There has been much talk, but little action beyond the efforts of a few individuals in the scientific and military communities.

Current Issues

Most of the books and TV specials deal broadly with the issues described above, including graphic descriptions of the destructive potential of impacts of various sizes and impact energies. The catastrophic climate changes that caused the death of the dinosaurs and other species at the end of the Cretaceous era are fascinating to scientists and laypersons alike. Another common element is the description of the 1994 collision of some twenty-three fragments of Comet Shoemaker-Levy 9 with Jupiter. This remarkable event, observed by hundreds of telescopes on Earth and in space, provided direct data on the nature and consequences of cosmic impacts. But a number of questions arise when we discuss the contemporary impact danger and consider whether — and how — to protect ourselves against future catastrophes. There is a considerable divergence among scientists in how such issues are framed and discussed, and an even wider disparity on the way these issues are presented to the public.

Let us begin with what I call the “standard paradigm” — that of random impacts on Earth by small comets and asteroids. This is the consensus view of most scientists, and it is reflected in two NASA reports to the U.S. Congress, the Spaceguard Survey Report of 1992 and the follow-up report in 1995 inspired by public interest in the collision of Shoemaker-Levy 9 with Jupiter. As the principal author of the Spaceguard Survey Report and a member of the follow-up working group (chaired by Gene Shoemaker), I identify with this consensus position.

The standard paradigm uses the cratering history of the Moon and other evidence to deduce the average historical rate of impacts on Earth by objects of different sizes or impact energies. It then assesses the destructive potential of impacts of different energies on Earth today in terms of probable casualties, noting in particular the existence of a threshold at about one million megatons of energy (corresponding to a two-kilometer asteroid) at which the global climate is severely affected and everyone is at risk, independent of proximity to the impact. One conclusion of such studies is that the statistical risk is greatest for impacts near the global threshold, amounting to an average risk of death for each individual on Earth of nearly one in a million per year, comparable to the risk of other more frequent (but less catastrophic) events such as earthquakes, severe storms, and volcanic eruptions. It is also noted that, unlike other natural disasters, impacts can be avoided entirely by deflecting an incoming object, if several years warning time is available.

Although most people agree that the greatest risk is posed by objects two kilometers or larger in diameter, others focus their attention on smaller impactors, especially those in the 200- to 500-meter range. When impacts of this size occur in the ocean, they produce tsunamis capable of inundating large stretches of coastline. Although the average risk for inhabitants of the planet is less from tsunamis than from the global catas-trophes caused by larger impacts, the risk for persons living on shorelines may be greater. This fact, together with the higher frequency of smaller impacts, leads some to argue that we need a defense system against any object larger than 200 meters diameter.

A major divergence of opinion concerns what our response to the impact threat should be. Most of the scientists involved in such assessments conclude that there is a significant risk and that governments should take some action (especially in searching for potential impactors), but that it is premature to build any defense systems in the absence of a specific identified threat. Others, the best known being Edward Teller (the father of the H-bomb), argue strongly for a more aggressive approach to asteroid defense. They would initiate experiments, eventually to include nuclear explosives, designed to learn more about how to deflect or destroy asteroids and comets. Some even advocate construction of a standing nuclear defense system to deal with the smaller impactors, for which the warning time might be short. But at least, they assert, we should start now to develop the technology for such a system.

These arguments concerning the magnitude of the threat and the most appropriate response make good TV and newspaper copy. They can lead to serious analyses of the various threats that we face on Earth and of the role of governments in dealing with potential disasters, both natural and human. All fit within the standard paradigm. But there is another viewpoint, held by a handful of British neo-catastrophists, that challenges this position.

The British Neo-Catastrophist School

The alternative viewpoint is advocated in its extreme form by astronomers Victor Clube and Bill Napier, who interpret historical records as indicating that Earth has been subject to extreme battering from space within the past few millennia. In their popular books The Cosmic Serpent and The Cosmic Winter, they take the position that the emergence of astrology in the western Mediterranean, the association of gods with planets in many ancient cultures, the widespread fear of comets and belief in angels, and many other aspects of our cultural and religious history are a reflection of massive bombardment of the planet a few thousand years ago. They further conclude that more recent historical events, including the collapse of the Roman Empire, the Dark Ages, and even the English Civil War, are related to climate changes induced by exceptional deposition of cosmic dust in Earth’s atmosphere. Although their historical analysis is suspiciously similar to that of Immanuel Velikovsky, Clube and Napier adamantly reject the association, arguing that unlike Velikovsky they root their explanations in sound physical and astronomical principles.

Supporting Clube and Napier are British astronomers Duncan Steel and Mark Bailey, who have concluded that the solar system is currently experiencing the aftermath of the break-up of a giant comet some millennia in the past. Our planet still intersects debris from this comet in what they call the Taurid complex of dust, small comets, and asteroids. They term this theory coherent catastrophism. Steel and Bailey estimate that the present lull in impacts will end in about a thousand years, when our orbit again crosses the denser parts of the Taurid complex, at which time the impact risk will rise by at least a factor of a hundred. All of these neo-catastrophists argue that urgent action is required to prevent the collapse of civilization under the next cosmic onslaught.

Most of us find these neo-catastrophist arguments difficult to swallow. Putting aside the issue of the Velikovskian interpretation of history and legend, the impact rate is still constrained by the cratering history of the Moon, which reflects the long-term average. If there are huge “spikes” in the frequency of impacts, produced by the break-up of giant comets, they must be compensated by much lower flux rates between peaks. Yet Clube, Steel, and their colleagues simultaneously assert that the consensus group underestimates the current impact rate, and that a big spike is coming. You can't have it both ways. If they are correct that almost all impacts occur during the spikes, then the present danger must be very low, and we have centuries to prepare to deal with the next peak. But they don't see it that way, and neither do the authors of several of the recent books.

Impact Science and Pseudoscience

While I believe that the British neo-catastrophists are wrong about the threat to Earth, their work is science, not pseudoscience. They are making their case to other scientists, and time will sort out who is right and who is wrong. They do, however, sometimes attract the attention of fringe elements. For example, the Society for Interdisciplinary Studies (SIS), a British group that espouses a skeptical philosophy but includes many defenders of Velikovskian ideas, is sponsoring a conference that features Clube and focuses on evidence for cosmic catastrophes in the ancient world. In fact, the work of Clube and Napier attracts many people who were once impressed by Velikovsky, such as Leroy Ellenberger, at one time a member of the Velikovsky inner circle and now one of the most outspoken critics of his current followers.

Every week I receive two or three inquiries from the public asking if some story they have read or heard about an imminent world-shattering impact is correct. These stories are not confined to the supermarket tabloids but have apparently attracted a following on the World Wide Web. Some people ask about a comet called Wormwood, with obvious reference to the apocalyptic vision in Revelation 8:10-11, when “the third angel sounded, and there fell a great star from heaven, burning as it were a lamp. . . . And the name of the star is called Wormwood.”

Then there is Comet Hale-Bopp. In November 1996 the press gave general coverage to a wild claim that this comet was accompanied by a spaceship and was headed toward an impact with Earth. (See Alan Hale, ”Hale-Bopp Comet Madness,” SI, March/April 1997.) The story apparently started when an amateur astronomer photographed the comet near a moderately bright star. In a curious logical progression he assumed the star was a spacecraft, that the spacecraft was at the same distance as the comet, and that the over-exposed stellar image represented the angular diameter of the craft, which would make it comparable in size to the giant planet Saturn. Others embellished the story by concluding that the spacecraft was traveling in the same orbit with the comet and that the trajectory was about to shift toward Earth. The mystery to me is why this fantasy was given serious media attention, even on a slow news day. I fear that we may see more of this sort of thing as the public becomes more aware of the threat of impacts.

Presenting the Issues to the Public

Of the ten books reviewed here, three are strongly in the Clube/Steel camp, and several of the others give their neo-catastrophism considerable attention. This is perhaps understandable, since these are the scientists who are most strongly claiming that the sky is falling. Besides, the connections they make between impacts and the more familiar fields of history and religion have an obvious public appeal.

In contrast, the public policy issues surrounding the development of a space defense system and the possible testing of nuclear explosives in space are barely touched on in most of these books. In part, this represents the secretive nature of the defense scientists, who (unlike the more gregarious astronomers) tend to avoid talking with journalists or appearing in TV documentaries. But the issues are real, and the first steps toward an asteroid defense are being initiated by the Pentagon’s just-approved Clementine 2 space mission to intercept three near-Earth asteroids and fire high-speed projectiles into their surfaces. It would be more useful if these policy questions, rather than the idea that cosmic dust caused the English Civil War, were being prominently addressed in public discussion of the impact threat.

On the positive side, the impact issue is proving to be an excellent vehicle for communicating some interesting aspects of contemporary science to the public. The topic, bringing together astronomy, environmental threats, and dinosaurs, is a natural. It focuses on the way historical science works (how can we figure out what really made the dinosaurs go extinct?), on the fragility of the environment (how can one small impact have global consequences?), on the nature of evolution (why were the mammals who succeeded the dinosaurs so different from them?), and on the nature of probability (if big impacts take place only once every million years, why worry now?). There is great potential here to teach good science as well as stimulate a useful public policy debate. Let’s hope these lofty goals are achieved in practice.

Artist’s concept of a catastrophic asteroid impact with Earth. Life near the impact would be instantly wiped out from the effects of high temperatures and pressures. Injection of huge masses of dust (and gases) into the atmosphere would effectively block out sunlight for long periods of time to the point that most life could not be sustained ("Nuclear Winter”). Painting by Don Davis, courtesy of NASA.

The Standard Reference on Impacts

In January 1993 more than one hundred experts met in Tucson, Arizona, to discuss all aspects of NEO impacts, from the extinction of the dinosaurs to the nature of impact-induced tsunamis to the deflection of an incoming asteroid by nuclear explosions. A wide spectrum of opinion was represented, as exemplified by the appearance of old antagonists Carl Sagan and Edward Teller on the same platform. In 1994 the edited, refereed product of this meeting was published by the University of Arizona Press, edited by Tom Gehrels, as Hazards Due to Comets and Asteroids. This 1,300-page book, with 120 authors, is the definitive reference on the impact hazard. Indeed, is it the only published source for much of the work, which has not appeared in technical journals. This is the best place to find detailed information on the subject, but more current reports are also on the World Wide Web at the Asteroid and Comet Impact Hazard Homepage (http://impact.arc.nasa.gov).

Books That Represent the Standard Paradigm

The following five books adhere generally to the standard view of the NEO impact threat, as represented in the NASA reports and the refereed conference volume Hazards Due to Comets and Asteroids.

John S. Lewis. Rain of Iron and Ice: The Very Real Threat of Comet and Asteroid Bombardment. Addison-Wesley, 1996, 236 pp., $25.00. John Lewis, professor of planetary science at the University of Arizona and one of the leading proponents of the use of asteroid resources for long-term space development, has written the best popular volume on the impact hazard. This book is written primarily for the scientifically literate lay audience, but it contains a great deal of information — and no small number of pointed barbs — directed toward scientific colleagues who study NEOs professionally. Lewis covers all the relevant issues of the nature of NEOs, the impact history of the solar system, the impact hazard, and mitigation. His writing style is compact, clear, and comprehensive.

In addition to his solid coverage of the basics, Lewis probes in depth three areas that are often missing in other treatments. (1) He clearly places Earth impacts in their broader solar-system context, with extensive discussion of the lessons learned from the cratering histories of the Moon, Mercury, and Venus. (2) He places strong emphasis on the long history of eyewitness reports of terrestrial bolides, meteorite showers, and atmospheric detonations, many of which have done considerable damage. This evidence, he stresses, is overlooked by most workers in the field. (3) He uses current models of the impact flux and the entry physics for impactors to “reconstruct” ten different one-century scenarios, with specific details of individual impacts and their damage, as a way to illustrate the variety of impact events. This same list allows Lewis to address the question of which scenarios (had they happened in the twentieth century) would likely have led to a widespread appreciation of the impact hazard and which scenarios probably would have been ignored or misinterpreted. The real history of the twentieth century is intermediate; Lewis argues that had the circumstances of the 1908 explosion of a 60-meter asteroid in the atmosphere over Siberia’s Stony Tunguska River been just a little different, we might never have known about it and foolishly continued to ignore the impact hazard up to the end of the century. (The Tunguska explosion flattened 2,000 square kilometers of forest and created a pressure wave recorded around the world.) This is the best introduction to the field, standing far above any of its competitors.

Dana Desonie. Cosmic Collisions. Henry Holt & Co. (A Scientific American Focus Book), 1996, 128 pp., $9.95. The Scientific American Focus Books are inexpensive paperbacks aimed at an intermediate or high school audience. Dana Desonie is a science writer with a doctorate in geochemistry. Her short, well-illustrated (in black and white) book is a straightforward introduction to cosmic impacts, beginning with solar-system formation, moving to comets and asteroids, then to Earth impacts (including the K-T event), Tunguska, current ideas about the impact hazard, and possible planetary defense. This is a serious, well-focused discussion that includes a lot of information in a book that can be read in a couple of hours.

David H. Levy. Impact Jupiter: The Crash of Comet Shoemaker-Levy 9. Plenum Press, 1995, 290 pp., $25.95. In this delightful memoir, writer and amateur astronomer David Levy provides a personal perspective on the history of Comet Shoemaker-Levy 9, from its discovery in the spring of 1993 until its death in July 1994. Writing for a lay audience, Levy tells with infectious enthusiasm of his adventures and those of many colleagues dealing with both the comet itself and the barrage of journalistic scrutiny it inspired. Only a few chapters concern the impact hazard, and defense issues are hardly mentioned, but Levy’s technical explanations are simple and clear. This is not a detailed reference work, and its real pleasure lies less in the science than in the many personal stories and the sense of involvement achieved by the diary-like presentation of events.

John Spencer and Jacqueline Mitton, editors. The Great Comet Crash: The Impact of Comet Shoemaker-Levy 9 on Jupiter. Cambridge University Press, 1995, 118 pp. John Spencer is a scientist at Lowell Observatory and an expert on Jupiter and its satellites; Jacqueline Mitton is a writer and Public Information Officer of the Royal Astronomical Society. They have collaborated to produce a timely and well-edited volume on the great comet impact, with chapters contributed by many of the leading researchers in their fields. Of all the books discussed here, this one has by far the best photographs, intelligently selected and beautifully reproduced. Only about a quarter of the book deals with the impact hazard, but these few chapters are by the experts and provide an excellent overview.

Philip M. Dauber and Richard A. Muller. The Three Big Bangs: Comet Crashes, Exploding Stars, and the Creation of the Universe. Addison-Wesley, 1996, 207 pp., $25.00. The first third (about seventy-five pages) of this popular-level book on modern astronomy is devoted to NEO impacts (and not just comets, as the title implies). The authors are physicists from the University of California at Berkeley, and Muller is one of the originators of the Nemesis hypothesis to explain periodicities in the terrestrial extinction record. Given the limited space available and the nonscientist audience toward which their book is aimed, Dauber and Muller do a good job of explaining the impact hazard story, with emphasis on the K-T extinction event and its lessons for the impact history of Earth. Both authors describe themselves as proteges of Luis Alvarez, and they are at their best in describing the events associated with the pioneering work that led to the identification of the extraterrestrial cause of the K-T event and the grand generalization of this evidence into a new theory of mass extinctions. In a few other areas, however, including discussions of the current hazard and of the Spaceguard Survey proposals, they oversimplify to the point of significant distortion. This book is a good read, but should be taken with quite a few grains of salt.

Books That Represent the British Neo-Catastrophist School

These three books by British authors all argue for a much higher level of danger from cosmic impacts and appeal to the record of the immediate past for evidence of the major role played by impacts in our history.

Duncan Steel. Rogue Asteroids and Doomsday Comets: The Search for the Million Megaton Menace That Threatens Life on Earth. Wiley, 1995, 308 pp., $24.95. Duncan Steel is well known in Australia and worldwide as a leader in NEO searches, a researcher on orbits of meteor streams, and a popularizer of the NEO impact risk. He writes well, and he covers all the issues of the nature of NEOs, the impact history of the solar system, the impact hazard, and mitigation. Roughly the first half of the book is on a par with Lewis and can be recommended with equal enthusiasm. In many other places, however, Steel departs dramatically from the mainstream to advocate the extreme neo-catastrophist position; in some places he admits that his positions are unorthodox or even bizarre, but elsewhere he neglects to make this distinction. Steel feels that the cratering flux is highly time-variable and states that “we are now fairly certain that terrestrial craters are, up to a large extent, formed during distinct periods of higher impactor flux.” In dynamics, he espouses the radical idea that “the main [asteroid] belt is not being depleted to supply meteorites and Earth-crossing asteroids, but quite the opposite.” He includes a highly personal chapter on the neo-catastrophist interpretation of Stonehenge that was characterized in another review (in Sky & Telescope) as “fiction, not even science fiction.” Perhaps some of these unorthodox ideas are deserving of serious scientific discussion, but their inclusion as fact in a popular-level book detracts significantly from its overall value, since the nonscientist reader has no way of separating the speculation from reliable information.

Gerrit L. Verschuur. Impact: The Threat of Comets and Asteroids. Oxford University Press, 1996, 237 pp., $25.00. Gerrit Verschuur, a well-known radio astronomer, educator, and author, presents a detailed (and very small print) discussion that lays out the full impact story. Throughout the book, Verschuur emphasizes data and interpretations that maximize the impact flux as well as the damage that can be done by impactors of a given yield. Since there are substantial uncertainties in many of these estimates, it is possible, by always selecting the worst case, to conclude that the danger is orders of magnitude greater than the values usually quoted. This is the tack taken by Verschuur, in general agreement with the arguments in Steel’s book reviewed above. Verschuur’s writing style is clear and witty, and I would happily recommend the first ninety-four pages. However, I cannot agree with the increasingly alarmist interpretations that dominate the book after page 95, on which Verschuur first introduces Clube and Napier. He argues that the “patterns in history” they have found should be the basis for policy decisions on protecting Earth from cosmic impacts, which he concludes produce worldwide flooding from asteroid impact every five thousand years or so. He writes that “we are perpetually poised on the edge of extinction and have been very lucky to get this far,” and “[t]he number of casualties resulting from an ocean impact . . . may be 10,000 times larger than given by Chapman and Morrison [in a 1994 paper in Nature].” In general, this book compares well with Steel’s, but with the same fatal flaw (from my perspective) of its emphasis on coherent catastrophism, and an even worse tendency to exaggerate the current impact hazard, often by several orders of magnitude.

John and Mary Gribbin. Fire on Earth: Doomsday, Dinosaurs, and Humankind. St. Martin’s Press, 1996, 264 pp., $23.95. British science writers John and Mary Gribbin have written a general overview of impacts and impact dangers for the lay public. Printed in large type and presented without illustrations, the book is significantly shorter than the two reviewed above, in spite of its similar page count. In essence, this book is a popularization of suggestions by Clube and Napier that human history has been greatly influenced by cosmic apparitions and cosmic impacts. They anticipate that “the world is in for another bout of fire from the heavens in about a thousand years’ time.” This is a pretty grim picture; hence their title, which literally refers to fires that may sweep Earth a few centuries in the future. The book contains a number of factual errors, but the main problem is that everything is slanted toward maximizing the impact flux and the associated danger. They assert that impact-associated atmospheric dust has been responsible for the recent ice ages, and that the climate of Earth today “rests on a knife edge,” ready to drop into another ice age with the smallest cosmic perturbation (no worry about global warming here!). This is a well-written book, but basically it adds little that is new. It seems to me that if one wants to explore the ideas of the British neo-catastrophist school, then one might just as well skip Gribbin and Gribbin and turn directly to the primary sources, in books by Clube and Napier and by Steel.

Unacceptable Books

The following two books should never have been published. The authors seem to be covering the field, but when you look in detail you find error and inconsistency on almost every page.

Patricia Barnes-Svarney. Asteroid: Earth Destroyer or New Frontier? Plenum Press, 1996, 292 pp., $25.95. Science writer and educator Patricia Barnes-Svarney has written an extremely frustrating book. She has attempted the ambitious task of covering for a lay audience the entire field of asteroid and comet studies, impacts, solar-system history, the hazard of Earth impacts, and the use of asteroids as space resources. Unfortunately, she is out of her depth in most of these areas, leading her repeatedly into conceptual and technical errors.

Barnes-Svarney loves technical jargon, mining the fields of astronomy, geology, and meteoritics for their numerous terms and then going on to invent a few of her own. Throughout the book she undercuts her own conclusions with words such as perhaps, seems, and probably even when she is reporting simple facts, as in the extreme example (p. 241) where she writes, “Right now, the best guess seems to be that there is no asteroid or comet known to be on an immediate collision course with the Earth.”

There is a lot of information in the book, but frequently it is presented as isolated “factoids,” rather than integrated into a self-consistent whole. For example, the author quotes half a dozen different values for the current terrestrial impact flux, but each in different units, so one cannot readily compare the results. Too often she gets things entirely backwards, as in her statement (p. 240), “Space scientists will tell you that everything within budgetary reason is now being done to search for more near-Earth asteroids.” I can't imagine any of the current observers, all of them starved for support, making such a statement. Barnes-Svarney also has some unusual opinions about NEO impacts. Although she writes at length about the K-T impact, she does not believe it played a role in the extinction of the dinosaurs; and even for other species, the most she says is that this impact is “thought to have helped in the Cretaceous-Tertiary extinctions.” Yet she credits impacts in the past with initiating plate tectonics, triggering volcanism, and generating Earth’s magnetic field — all highly dubious assertions. The book is especially weak in all things quantitative, riddled with inconsistencies and often misquoting sources.

Donald W. Cox and James H. Chestek. Doomsday Asteroid: Can We Survive? Prometheus Books, 1996, 338 pp., $26.95. The authors, popular science writer Don Cox and retired aerospace engineer James Chestek, have written about the impact hazard in the context of an argument for expanded human activity in space, including a major effort to visit the asteroids, colonize them, and mine them for space resources. Most of the factual material is from secondary sources such as Science News and the New York Times. The authors have obviously not attended any of the technical meetings on impacts held during the 1990s, and they do not understand many of the technical issues. From the beginning they tell us that the asteroids are most likely the result of an exploded planet, an idea that has had no scientific support for nearly fifty years. But this does not inhibit them from passing harsh judgment on the various teams of scientists who have participated in framing the NEO issue during the past five years. A special target of Cox and Chestek is the 1992 NASA Spaceguard strategy to search for asteroids, which they compare with the drunk who searches for his keys under the street lamp instead of where he lost them. They completely miss the point of carrying out a search to discover the objects as they periodically come close to Earth, but long before they actually hit. The direction from which they make their final approach is irrelevant. Because of this misunderstanding, they devote most of their search chapter to a simplistic argument that many impacting asteroids approach Earth from the sunward side, and on this basis they insist that a space system, with telescopes far from Earth, is required. The tone of much of the book is bitter and negative, and the attitude of the authors toward the research community is captured in the following paragraph:

An early warning space telescope certainly need not cost anywhere near as much money as the Hubble telescope. That was a research project, and many high-priced scientists and their graduate students spent many years charging their time to the project. Here we are discussing a simple early warning system, which the military knows how to build. The cost will only be for some engineering, not a lot of research, so it can be vastly cheaper.

The technical errors and widespread confusion displayed by Cox and Chestek in this book and by Patricia Barnes-Svarney her book reviewed above suggest that the filters against bad science writing for the public are not very effective. There seems to be no equivalent of peer review for science books, even at top publishers. Caveat emptor.