Life on Mars?
an Interview with Frank Zindler
Ever since word was released by NASA that a team of scientists had found compelling evidence for the existence of life on Mars in the remains of the Allan Hills 84001 meteorite sample, social commentators and theologians have been debating the implications of this for human culture. The religious response to the discovery has been mixed: fundamentalists have tended to reject the claim, while other religious groups such as Roman Catholics and Muslims have proven more receptive.
But how good is the evidence of fossil remains? We put that question, and others, to American Atheists Science Advisor Frank Zindler, a nationally-known expert and spokesman in the creationism-evolution debate. Mr. Zindler also serves as Editor of the American Atheist Magazine and Newsletter, and is the new Director of American Atheist Press.
AANEWS: Based on what you've learned so far, how good is the evidence for fossil remains from Mars in this piece of meteoritic material?
ZINDLER: It's problematic at several levels.
Perhaps the weakest link in my mind, is the proof that the meteorite did in fact come from Mars. Although the micro-paleontologist William Schopf -- overall a skeptic on the Martian fossil question -- rated the probability of this as being 9 on a scale of 10, I'm less sanguine. I do not remember clearly what the evidence for this was when the paper(s) came out in Science several years ago. I remember only that I was not fully convinced of the Martian provenance after reading about the Antarctic meteorites. In general, the evidence would have to be an isotopic "signature" of some sort that would be reliable planet-wide. Certainly, rocks differ in their isotopic compositions from one place to another on earth, and so it should be on Mars also. The possibility that small volumes of Martian atmosphere became trapped in the meteorite and were brought to earth cannot be ruled out, however; and it could supposed than an atmospheric isotopic signature would be valid for an entire planet unless one were sampling volcanic out-gassing plumes! It's reported that there are indeed atmospheric gases trapped inside ALH84001, and that they match those sampled in the Martian atmosphere in 1976. We must suppose that the Martian atmosphere evolves and that its isotopic signature has changed over billions of years. Whether it changes significantly over millions of years, however, is unclear, and it is possible that 15 or 16 million years ago (when the meteorite is supposed to have been blasted off the surface of The Red Planet) the atmosphere was substantially the same as it is today. When atmospheric gases become trapped in the rock, however, is unclear and it could be a holdover from truly primal times. If so, I would take that as evidence against the Martian provenance of our specimen. That is, although some other place may have had an atmosphere billions of years ago resembling the current atmosphere of Mars, because Mars' atmosphere must have evolved greatly over the eons, its ancient atmosphere must have been different from the current one.
You also have to remember that once upon a time Mars had quite a lot of water. Where did it go? While some may have become trapped beneath the Martian crust and under the dry-ice icecap, most of it has been lost, I believe, by photolysis of waster molecules in the upper atmosphere of the planet. Because Mars is so much smaller than Earth, its gravitational strength is much less, and hydrogen is more easily lost from the planet. So, when water is broken up into hydrogen and oxygen, the hydrogen flies off into space, leaving the oxygen to diffuse down to the planet's surface to oxidize the minerals thereon. As water has disappeared from Mars, the planet has progressively used. So much oxygen has been produced over the eons that the planet has not just been oxidized, it's been peroxidized. All this can be taken to indicate that the present hostile environment of Mars is probably not representative of the earlier history of the planet, when it much have been much more hospitable to the presence of life.
The presence of organic chemicals in the meteorite isn't very convincing to me, since all the substances found have been found in other meteorites and can be considered primordial chemicals rather than the products of living systems. But at the same time, I must admit that the combination of the various chemicals and minerals is highly suggestive of a biotic origin. The one nagging doubt I have in this area springs from the fact that so far I have seen no evidence that the surface on which the alleged microbes have been found shows any signs of weathering. How microbes could live on a surface without that surface undergoing changes recognizable as weather is a question needing to be answered.
Finally, pseudo fossils are very well known here on earth, and are the bane of every beginning geologist and every practicing creationist. I have found mineral formations that looked incredibly similar to certain types or corals. But it has been shown conclusively that these objects are not of biotic origin. I've also found concretions that looked like giant doughnuts, hammerheads, and the coastal outline of Antarctica. Creationists find "human footprints" and other fanciful objects formed in stone. And there's the infamous Eozoon canadense -- an alleged microfossil that fooled people for so long that when it was shown not be a real fossil it became almost impossible for anyone to believe that the real microfossils found by William Schopf and others were in fact genuine. While the Mars "microbes" are indeed suggestive of fossil life, cross-sections must be obtained to see if there is any internal structure that can corroborate the external evidence.
AANEWS: Do you think that the NASA/Stanford team exercised good judgment in choosing to make the announcement of their alleged finding through a press conference, before their case was presented in Science?
ZINDLER: It is my understanding that the NASA team held a press conference to announce their findings because word was leaking out before their papers could be published. I see nothing wrong with this, since their work had already been refereed by a prestigious journal and was just about to come out. It's not as though their only presentation was the press conference. It seems quite different, say, than the case of "cold fusion."
AANEWS: There has been a wide range of reaction to the announcement from different religious groups. Does this surprise you?
ZINDLER: No. Naturally, the less educated, fundamentalist groups are denying the whole affair. Their reading of the Bible makes it clear that the earth is the center of the universe, and only here can there be life. Angels are living forms too, but they don't fossilize! The more sophisticated religionists, however, the types that think they can reconcile Christianity with the reality of evolution (i.e. theistic evolutionists) may be accepting the putative Martian fossils as "just more evidence of the glory of God."
AANEWS: Fundamentalists seem to have a problem with even the possibility of relatively unsophisticated life forms on another planet, let alone intelligent, advanced life. What biblical sources do they base this attitude on?
ZINDLER: Fundamentalists can't allow life elsewhere in the universe for the simple reason that the creation stories in the first two chapters of Genesis indicate that the objects above the earth, like the "firmament" and "great lights" were put there solely for the sake of man, and perhaps woman. "For times and for seasons" the stars were zapped into the underbelly of the solid sky. If the stars -- including planets in biblical understanding -- were put up there for us, how could they have anything living out a purpose separate from ours? Ergo, there cannot be life on other worlds.
AANEWS: "Scientific" creationist arguments a la Gish have not done very well in refuting the vast body of evidence on behalf of evolutionary mechanisms. From what you've seen about the Allan Hills 84001 meteoritic specimen, might they have a bit more success in trying to undermine claims about possible life on Mars?
ZINDLER: I think the creationists will have no trouble obfuscating the Martian studies and their findings. Only after we can return to Mars and dig deep beneath the peroxides to retrieve material resembling the present meteorite could we hope to produce evidence solid enough that the creationists would be seriously discomfited thereby.
AANEWS: Some scientists are just gushing over this find. Carl Sagan calls it "evocative and very exciting." Do you think he's over reacting?
ZINDLER: My understanding is that Sagan was initially very skeptical about this case. The "evocative and very exciting" I though was just a trailer comment made after he had expressed all his doubts. Certainly I too can say the same thing.
AANEWS: Even if other specimens of ejected Martian materials show more promising evidence of life, we're still not talking about "ET" and "Independence Day."
ZINDLER: Indeed, we are not talking about any likelihood of sentient life-forms on Mars. If my model of the evolution of the Martian atmosphere is at all correct, the planet would have become inhospitable for life long before microbes could have evolved into multicellular, sentient forms. On earth, for instance, single-celled life existed for at least 2.5 billion years before multicellular forms appeared. While we should not expect evolution on other planets to imitate that on earth in any particulars, overall, it's unreasonable to suppose that intelligent life could have evolved on Mars during the short window of time I believe was available.
AANEWS: Some religious groups -- Muslims, even a few Catholic theologians -- see no conflict with the prospect of even advanced life elsewhere. How would you account for the differences in their reactions with, say, those of Jerry Falwell?
ZINDLER: Well, the Muslims have the "Lord of the Worlds" in their Koran and that would actually require other inhabited places -- all of course being ruled by our own Allah. Allah Akbar, after all! The Catholics, on the other hand, have learned through long years of fighting science how to adapt to science and incorporate it. They've learned to use the scientific technology of the twentieth century C.E. such as communications satellites, to broadcast the ideology of the twentieth century B.C.E.! The secret, of course, is to set words loose from precise definitions. By "morphing" language sufficiently, they can accommodate anything. The same is true of liberal Protestant groups.
AANEWS: People are pretty excited about even this tenuous evidence for extraterrestrial life. Would clear evidence of such life really have such a profound effect on human culture as some suggest?
ZINDLER: While the discovery of life on Mars should have a profound effect, I doubt that such will in fact be the case. The discovery that the earth is not the center f the universe should have had such an effect. But despite the claims of some scholars that that did shake our species out of its dogmatic slumber, I'm hard pressed to find any evidence that more than a small percentage of our kind have been awakened by this stimulus. Recent surveys show that roughly one out of five Americans is unaware that the earth goes around the sun.
AANEWS: Let's muse a bit. If we did encounter an advanced alien civilization, would their attitudes toward a "god" have anything to do with how our culture would react? In other words, if we encountered religious aliens of any kind, would worldly religions see that as confirmation, perhaps, of their own doctrines?
ZINDLER: If there were aliens and if they too believed in "god," that certainly would give a boost to supernaturalist forces here on earth. If there were aliens and if they didn't believe in gods, they probably would just be identified as "tools of Satan" or some other thing. Probably predicted precisely in the Book of Daniel or the third chapter of Revelation.
AANEWS: Any other thoughts on this admitted out-of-this-world matter?
ZINDLER: Well, I don't think Atheists are going to be able to
get as much mileage out of this as might be hoped. First of all, there
is the reasonable worry that the evidence is not sufficient for proof.
Secondly, even if it should prove to be sufficient for proof, there is
the resilience of religionists alluded to a moment ago. Some Fundies might
give up their faith in the face of forcefully presented argumentation and
evidence. But the religious liberals will continue to be unfazed. We might
as well box with marshmallows, or hot-nail Jell-O to the ceiling!