TCS Daily

How Strange Can Life Be?

By Kenneth Silber - January 23, 2006 12:00 AM

Peter D. Ward is a biologist with contrarian tendencies on various questions about extraterrestrial life. His 2000 book, Rare Earth, coauthored with astronomer Donald Brownlee, argued that complex life is probably uncommon in the universe, such that there is little prospect of encountering or even detecting any alien civilizations.

Naturally, this put Ward at odds with scientists involved in the Search for Extraterrestrial Intelligence, or SETI. In 2002, at a scientific gathering at the home of billionaire philanthropist and Microsoft co-founder Paul Allen, Ward tried to give a copy of Rare Earth to his host, who was standing with a woman who turned out to be SETI astronomer Jill Tarter (the inspiration for the lead character in the film and Carl Sagan novel Contact). In Ward's telling, Tarter shrank back from the book, as in "those movie moments when a cross is stuck in the face of a vampire," and promptly hustled Allen away. (The billionaire went on to fund a major SETI project, the Allen Telescope Array.)

Ward's new book Life as We Do Not Know It: The NASA Search for (and Synthesis of) Alien Life recounts that anecdote and maintains Ward's skepticism about finding intelligent aliens. However, the book builds on the less-noticed flip side of Ward and Brownlee's "Rare Earth Hypothesis" -- that simple life may be fairly common. In this view, microbial life may evolve rather readily from non-life, and can sustain itself in a wide range of conditions, but only rarely does a planet or moon remain habitable long enough for complex life to develop (and such life is far more fragile than microbes).

Finding extraterrestrial life, for Ward, thus becomes a question of hunting alien microbes, and he regards it as quite plausible that these will be found within our solar system. Life as We Do Not Know It provides an intriguing discussion of possible varieties of alien organisms, and a world-by-world survey of the prospects for finding them in our own cosmic backyard. Ward also proposes some changes to standard scientific thinking about how to define and classify life, and he makes a case for sending humans, not just robotic probes, to search for life on other worlds -- in particular Mars and Saturn's moon Titan.

How different from Earth life might alien life be? Even while remaining focused on the microscopic, Ward notes a considerable range of possibilities. Extraterrestrial microbes might have a thoroughly distinct genetic code, using novel configurations of the DNA molecule or a different molecule altogether, such as RNA. They might store information among proteins rather than nucleic acids. Instead of needing water as a solvent, they may use liquids such as sulfuric acid or methane. Unlike all Earth life, which is composed mainly of "CHON" (carbon, hydrogen, oxygen and nitrogen), aliens might be silicon-based, or perhaps take the form of silicon/carbon clay crystals that grow and evolve.

Extraterrestrial life, in Ward's view, may be so simple that scientists will have difficulty recognizing it as life. In fact, he argues, the scientific community has defined life on Earth too narrowly. He suggests the tree of life be modified to include viruses (currently seen as nonliving because they cannot replicate without a host) and maybe the disease-causing proteins known as prions. Some viruses contain RNA rather than DNA, prompting Ward to speculate that our own planet may harbor yet-unknown RNA life.

Ward scans a number of possible locales for life in the solar system. Mercury seems an unlikely habitat for anything. Venus, too, is unpromising, but possibly could have life in its cloud layers. Earth's lifeless moon may have fossils from other worlds in its impact craters. As for Mars, Ward regards it as a plausible abode for past or present life; among the evidence he cites is the presence of methane and water vapor in its atmosphere. The red planet might hold life that originated there or that was transported from Earth via meteoroids; or perhaps, life on Earth had a long-ago origin on Mars.

Unlike some scientists, Ward sees little prospect for biology on Jupiter's ice-covered oceanic moon Europa; that body, in his view, is too cold and lacks sufficient energy sources. He finds greater promise, however, in Titan, Saturn's largest moon. The presence of methane in Titan's thick atmosphere could be a direct result of life or an indicator of volcanic activity that is conducive to life. Titan, in Ward's view, could be home to diverse living things, including ones that use ammonia or are made of silicon.

Life as We Do Not Know It laudably blends speculation and caution in assessing the prospects for life in our solar system. Ward makes an interesting case for human exploration of Mars and, eventually, Titan. His call for sending a paleontologist to the red planet aptly notes the difficulty of locating fossils with even sophisticated machines. More unusually, he suggests sending a microbiologist to Titan to look for subtle signs of life. Even a one-way mission, he believes, would not lack for scientific volunteers.



Whatever shape it takes and however advanced it got will be there for us to discover, if it's there.

So far as I can discern, the expectation that life exists elsewhere in the Universe, in any form whatsoever, is based on the premise that life evolved spontaneously on Earth. There may be some thought among Bible Believers that God could have formed life elsewhere without checking with Man first, but except for this I think the excitement that the Universe is teeming with intelligent life, fueled by Hollywood, is based on the premise that life evolved on Earth and so it could have done so elsewhere.

And then it appears to me that expectations for discovering life are not commensurate with reality. It may in fact demonstrate some other problem people have that they would literally ache to find intelligent life elsewhere. Hmmm.

Then there is the problem that life has never been observed to have spontaneously appeared (please don't respond by describing jars of gases with sparks passing through them), nor has anyone, given any circumstances whatsoever, ever been able to bring about such a thing.
I'm not trying to reduce this to yet another ID argument, just demonstrate what a strong mental link there is between belief in the spontaneous formation of living cells and existence of extra-terrestrial life. It may the most difficult of all things for many to believe, that we are the only life anywhere in the entire Universe. Some claim to think scientifically, but there really is no evidence at all that life exists elsewhere.

Another presumption I have observed is that of "chance", as if probablility were animate and something could possibly come out of nothing. I don't know with certainty that there is no life elsewhere, and I'm not arguing from that point. I just know that merely stating that of all the stars in the Universe (and all the planets blah blah blah) certainly the odds are blah blah blah, is like saying that of all the grains of sand in the World, surely one of them must speak French. It's just that silly, if there is no evidence otherwise.

If you want me to say something with certainty, it is this. No one alive today will live long enough to find out. Hoping for some scientific encounter by radio or otherwise, with life beyond Earth within your lifetime, is probably indicative of some dark human condition and nothing more or less. I love Science, and make a living in technology. But this presumption that the Universe is full of life really strikes me as stupid. Whenever I speak with someone about this, they get angry that I would mention the possibility that we are totally alone. That convinces me all the more, that they are hardly scientific.

Virus versus Life
"How different from Earth life might alien life be? Even while remaining focused on the microscopic, Ward notes a considerable range of possibilities."

What Science defines as life on Earth is still an open matter. A common defintion requires
1) organization, 2) metabolism, 3) growth, 4) adaptation, 5) response to stimuli and 6) reproduction.

Yet the common VIRUS up-ends our notion of life, because it can neither grow nor reproduce. In fact all viruses are just a small bit of DNA that, when grabbed by a healthy cell, trick the cell into making more viruses while working it to death. Consequently, viruses have yet to be formally designated as life or non-life.

But is it art?
Ward's book raises a question akin to that arising from the recent nanomanipulation of iodobenzene molecules to produce benzyl free radicals that were then assembled into a variety of heterocyclic compounds, some of which , though stable once assembled, would never form spontaneously in the chemical sense. These 'molecular sculptures ' were created by design, and assembled outside the thermal realm of life as we know it- at 20 kelvin in a hard vacuum.

But novel as they are - as works of art, they imply nothing about alien biology simply because the reaction pathways leading to their deliberate assembly are just as anti- thermodynamically unlikelyto allow them to arise in the state of nature on he far side ofthe universe as across the street.

The Drake Equation describes the probability of life
The Drake Equation is really just a is not complete. I think there are MANY more variables which would reduce the overall probability of life existing elsewhere.

If it can be demonstrated that life arises spontaneously in a repeatable experiment, then I would accept the theory of ubiquitous life. Otherwise, my limited knowledge of chemistry and biology (from a layman's perspective mostly), leads me to believe life (even simple life) to be very rare ...and life in the form of mammalian speciation is probably unique in all the universe.

Obviously, we are possible, because we exist. Therefore the universe possesses some capacity to produce us (and perhaps even more than us). But that capacity (in sheer probabilistic terms) may not be as straightforward as one might think relative to the size and longevity of the known universe.

I don't want to digress, but if the theory of an open universe turns out to be proven beyond a reasonable doubt, and we get to a point where we can link the probability of life's complexity to the size and longevity of the currently known universe, this may offer evidence that there are an infinite number of Big Bangs out there as well (i.e. other universes)...remember now, that galaxies were "discovered" in the early part of the last century!!!

The US bible belt and the middle east
Are the only places were the idea that life came about by natural forces doesn't hold sway. For the rest of us including most Christians the thought that life could exists else were and that if might be as smart or smarter then us is a appealing idea worth investigating. So either side of the debate common or uncommon could be true. The way to prove either is the same search for it. The Universe hold more then a trillion trillion stars so it will take us awhile.

Ps No amount of proof about any subject that contravenes a fundamentalist pov will ever be enough.

"No amount of proof"
Dear Mr. Geek,
As a duly registered Bible-belt fundamentalist, I would like to comment on the word, 'proof.' As a physician, proof means to me something like reproducibility of data, e.g., such and such a medicine used in so many thousands of patients really prolonged their absence of cardiovascular morbidity and mortality.

To the contrary, proof would NOT be something like, "Gee, I think that if we search long enough in enough places we might find something like life."

Personally, I am totally neutral on the issue of life in other places. Skeptical, perhaps, as to its plausibility, but neutral as far as any sociological or theological implications.

Drake's equation
Not only may there be more variables, but the value of most of the variables in the current equation are little more than guesses.

The fact remained that while bacteria did show up quite early in the history of the earth, it took 3 billion years for those bacteria to evolve into the first multi-celled life form.
On a planet less stable then ours, bacteria might not have that 3 billion years before one catastrophe or another wipes them out.

There have been many, many things that were once widely believed, that we laugh at now.

Regarding unwillingness to examine the evidence, the same can be said of most evolutionists.
Heck, things that were disproven years ago are still being taught in many evolution texts.
The experiments that put electric arcs through what was thought to be a copy of the early atmosphere producing amino acids. We now know that the atmosphere was not what this experiment assumed, yet many texts still give this example.
The drawings showing how widely disimilar animals have similar fetal development have been shown to be a fraud.

The arguments regarding irreducible complexity are waved off as meaningless. To the evolutionist, their answer is the only answer, and any problems with it are dismissed with the claim that someday we will find the answers. Yet somehow that someday never manages to arrive.

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