Life on Neptune?
Okay, this is extremely speculative, but I think it merits some consideration. In 1994 Carl Sagan wrote the following about the blue coloration of Neptune and Uranus:
Conventional wisdom holds that the absorption by methane and the Rayleigh scattering of sunlight by the deep atmosphere together account for the blue colors on Uranus and Neptune. But analysis of Voyager data be Kevin Baines of JPL seems to show that these causes are insufficient. Apparently very deep--maybe in the vicinity of hypothesized clouds of hydrogen sulfide--there is an abundant blue substance. So far no one has been able to figure out what it might be. Blue materials are very rare in Nature.
(Pale Blue Dot: A Vision of the Human Future in Space)
Sagan is careful not to speculate any further, but I can't help wondering if the blue substance might be oxygen. Oxygen is an extremely rare substance in Nature. The only phenomenon we know of that can create large amounts of it is life, and it doesn't have to be complex multicellular life, either. Simple bacteria could get the job done, and they wouldn't even have to have arisen there. A large comet or asteroid striking the earth billions of years ago would have been capable of sending chunks of bacteria-laden rocks into space where they bacteria would lay dormant until an eventual impact with one of the gas giants. This is not so improbable; bacteria are highly adaptable. In 1969 the Apollo 12 crew recovered a camera left previously by the Surveyor 3 probe, containing living microbes that had "survived launch, space vacuum, 3 years of radiation exposure, deep-freeze at an average temperature of only 20 degrees above absolute zero, and no nutrient, water or energy source." So the discovery of an unexplained blue substance on Neptune certainly does beg the question, yet strangely, it is a question no one seems to be asking. I've checked around on the web, and everyone seems to be giving the same methane-related explanation for the planet's blue color, the one that Sagan specifically stated in the above quotation nearly a decade ago could not account for it. (Examples can be found here, here, and here.) Perhaps some form of Neptunian conspiracy is at work.
Theory of Evolution Confirmed:
Until recently, I was very skeptical of evolutionary theory, not for religious reasons, but rather because it simply sounded farfetched. There is no question that evolution has been occurring; the fossil record is irrefutable. Over millions of years, life adapts to its environment by undergoing changes that eventually give rise to new and, in general, more complex species. My problem was with the mechanism. The idea that the entire process is governed by a combination of chance mutations and the principle of survival-of-the-fittest seemed utterly unbelievable, and there is no way to observe the process directly (at least not until science has been around continuously for a few million years to document it). Furthermore, there is no other known process in the natural world that behaves similarly. In other words, we know it occurs, but the theory as to exactly how it occurs seemed little more than guesswork. Then I learned about genetic algorithms, which are common knowledge only to people involved with Computer Science.
Basically genetic (or Darwinian) algorithms are computer programs that mirror the evolutionary process, as we understand it, to produce the design for a product through generations of simulations or to produce a new computer program. The process begins with a population of simple randomized representations. Each one is tested, and the ones that come closest to whatever the objective is have their traits combined together randomly to form the individuals of the next generation, along with a few random mutations sprinkled in for variety. Then the process is repeated again and again over successive generations. Examples of this are creating programs that allow computer generated characters to move realistically without having all their movements choreographed in advance
and designing robots that can locomote efficiently in the real world. (You can even download the program yourself to evolve your own robots.)
What's so intriguing about genetic algorithms is how accurately they mirror the behavior of evolution as seen in the fossil record. For one thing, there is a huge gain in complexity over the course of many generations. (There is a wonderful demonstration of this phenomenon here.) Also, there is a tendency for periods of stagnation over many generations with very little change, and then suddenly one individual is produced with a mutation that is so advantageous that there is a sudden developmental spurt in the population where the rate of change of the population accelerates tremendously as the new trait is assimilated, improved upon, and combined with new traits. Finally, the end product (the individual of the final generation which most best fulfills the criteria set forth by the programmer) is often of a level of efficiency and elegance that no human programmer or engineer could possibly match, or in many cases, even comprehend. Yes, that's right; using genetic algorithms, it is not at all uncommon for computers today to design/evolve chips that work better than anything a human could design and whose workings are beyond human understanding -- the very same situation we face in the study of biology.
So . . . maybe it's time I rethought my skepticism. It seems as though natural selection and survival-of-the-fittest can, in fact, account for the increasing level of biological complexity observed on the earth over time.
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