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I think it will take far too long to find life on other planets unless we get lucky in our own solar system - even then, the sample size will be small. What we need to do is discover a chemical reaction similar to those occurring in the early earth which can result in the creation of a self-replicating molecule. "By chance" really means by chemistry.Quote:
Originally Posted by YesNo
Well It may depend on who you talk to ... and what formula's and numbers you employ ... The interstellar distances maybe to great to overcome ... [seeding maybe possible] ... I heard someone say we could go to the moon and collect bio-info from Earth's past located on the moon in micro-particles blown into the atmosphere and transmitted to it by gravity ... Anyways here's a rounded view of some idea's ... This may also involve agruments from poor design, which may or may not be applicable ... depending on your type of belief system. [These are just excerpts for stuff I have ... but I hope this can move the ARG forward ... I'm sure you'll come up with more detailed stuff ... I'll be in the background]
http://en.wikipedia.org/wiki/Hoyle%27s_fallacy
According to Hoyle's analysis, the probability of cellular life evolving was about one-in-1040000. He commented:
The chance that higher life forms might have emerged in this way is comparable to the chance that a tornado sweeping through a junkyard might assemble a Boeing 747 from the materials therein.
which is a reflection of his stance reported elsewhere:
Life as we know it is, among other things, dependent on at least 2000 different enzymes. How could the blind forces of the primal sea manage to put together the correct chemical elements to build enzymes?[4]
Hoyle's Fallacy is rejected by evolutionary biologists,[3] since, as the late John Maynard Smith pointed out, "no biologist imagines that complex structures arise in a single step."[5] The modern evolutionary synthesis explains how complex cellular structures evolved by analysing the intermediate steps required for precellular life. It is these intermediate steps that are omitted in creationist arguments, which is the cause of their over-estimating of the improbability of the entire process.[1]
Hoyle's argument is a mainstay of creationist, intelligent design, orthogenetic and other criticisms of evolution. It has been labeled a fallacy by Richard Dawkins in his two books The Blind Watchmaker and Climbing Mount Improbable.[1] Dawkins argues that the existence of God, who under theistic uses of Hoyle's argument is implicitly responsible for the origin of life, defies probability far more than does the spontaneous origin of life even given Hoyle's assumptions, with Dawkins detailing his counter-argument in The God Delusion, describing God as the Ultimate Boeing 747 gambit.
1. ^ a b c d e f g Lies, Damned Lies, Statistics, and Probability of Abiogenesis Calculations – An explanation at the TalkOrigins Archive by Ian Musgrave Last Update: December 21, 1998
3. ^ a b c d e Derek Gatherer, The Open Biology Journal, 2008, 1, 9–20, Finite Universe of Discourse: The Systems Biology of Walter Elsasser (1904–1991)
4. ^ Fred Hoyle, The Intelligent Universe (1983), ISBN 0-7181-2298-4
5. ^ a b John Maynard Smith, The Problems of Biology, p.49. (1986), ISBN 0-19-289198-7, "What is wrong with it? Essentially, it is that no biologist imagines that complex structures arise in a single step."
http://en.wikipedia.org/wiki/Fermi_paradox
The Fermi paradox (Fermi's paradox or Fermi-paradox) is the apparent contradiction between high estimates of the probability of the existence of extraterrestrial civilizations and the lack of evidence for, or contact with, such civilizations ... The equation was formulated by Dr. Frank Drake in 1961, a decade after the objections raised by Enrico Fermi, in an attempt to find a systematic means to evaluate the numerous probabilities involved in alien life. The speculative equation factors in: the rate of star formation in the galaxy; the fraction of stars with planets and the number per star that are habitable; the fraction of those planets which develop life, the fraction of intelligent life, and the further fraction of detectable technological intelligent life; and finally the length of time such civilizations are detectable. The fundamental problem is that the last four terms (fraction of planets with life, odds life becomes intelligent, odds intelligent life becomes detectable, and detectable lifetime of civilizations) are completely unknown. We have only one example, rendering statistical estimates impossible, and even the example we have is subject to a strong anthropic bias.
http://en.wikipedia.org/wiki/Drake_equation
[The Drake equation which is closely related to the Fermi paradox is] used to estimate the number of detectable extraterrestrial civilizations in the Milky Way galaxy. It is used in the field of Search for ExtraTerrestrial Intelligence (SETI). The equation was devised by Frank Drake, Emeritus Professor of Astronomy and Astrophysics at the University of California, Santa Cruz ... states:
http://upload.wikimedia.org/wikipedi...fd474d3aaa.png
where:
N = the number of civilizations in our galaxy with which communication might be possible;
and
R* = the average rate of star formation per year in our galaxy
fp = the fraction of those stars that have planets
ne = the average number of planets that can potentially support life per star that has planets
fℓ = the fraction of the above that actually go on to develop life at some point
fi = the fraction of the above that actually go on to develop intelligent life
fc = the fraction of civilizations that develop techs that releases detectable signs of existence
L = the length of time for which such civilizations release detectable signals into space
Considerable disagreement on the values of most of these parameters exists, but the values used by Drake and his colleagues in 1961 were:
R* = 10/year (10 stars formed per year, on the average over the life of the galaxy)
fp = 0.5 (half of all stars formed will have planets)
ne = 2 (stars with planets will have 2 planets capable of developing life)
fl = 1 (100% of these planets will develop life)
fi = 0.01 (1% of which will be intelligent life)
fc = 0.01 (1% of which will be able to communicate)
L = 10,000 years (which will last 10,000 years)
Drake's values give N = 10 × 0.5 × 2 × 1 × 0.01 × 0.01 × 10,000 = 10.
Michael Crichton, a science fiction author, stated in a 2003 lecture at Caltech:
The problem, of course, is that none of the terms can be known, and most cannot even be estimated. The only way to work the equation is to fill in with guesses. [...] As a result, the Drake equation can have any value from "billions and billions" to zero. An expression that can mean anything means nothing. Speaking precisely, the Drake equation is literally meaningless ...
http://www.science20.com/news_releas...h_like_planets
The Mathematical Probability Of Life On Other Earth-Like Planets - April 16th 2008
Infinity was invented to account for the possibility that in a never-ending universe, anything can happen. Life on other Earth-like planets, for example, is possible in an infinite universe, but not probable, according to a scientist from the University of East Anglia.
The mathematical model produced by Prof Andrew Watson suggests that the odds of finding new life on other Earth-like planets are low because of the time it has taken for beings such as humans to evolve and the remaining life span of the Earth. Structurally complex and intelligent life evolved late on Earth and this process might be governed by a small number of very difficult evolutionary steps.
According to Prof Watson a limit to evolution is the habitability of Earth, and any other Earth-like planets, which will end as the sun brightens. Solar models predict that the brightness of the sun is increasing, while temperature models suggest that because of this the future life span of Earth will be ‘only’ about another billion years, a short time compared to the four billion years since life first appeared on the planet.
“The Earth’s biosphere is now in its old age and this has implications for our understanding of the likelihood of complex life and intelligence arising on any given planet,” said Prof Watson. “At present, Earth is the only example we have of a planet with life. [Although Enceledus is showing signs of it for example] ... the timing of events is consistent with it being very rare indeed.”
“Complex life is separated from the simplest life forms by several very unlikely steps and therefore will be much less common. Intelligence is one step further, so it is much less common still,” said Prof Watson. His model, published in the journal Astrobiology, suggests an upper limit for the probability of each step occurring is 10 per cent or less, so the chances of intelligent life emerging is low – less than 0.01 per cent over four billion years. Each step is independent of the other and can only take place after the previous steps in the sequence have occurred.
http://www.evolutionfaq.com/articles/probability-life
Creationists often claim that the chances of a modern enzyme forming by random means are astronomically small, and therefore the chances of a complete bacterium (which is composed of hundreds or thousands of such enzymes & proteins) is so near to impossible that it would never happen in the 13 billion years or so since the universe took shape.
The main problem with this argument is that it assumes abiogenesis (the initial formation of life from simpler molecules) was a totally random process. It also assumes that in order for abiogenesis to be successful, a complete microbe would have had to form spontaneously. In fact, the same non-random forces which propel biological evolution also propelled abiogenesis. Specifically, Natural Selection.
If this were the theory of abiogeneisis, and if it relied entirely on random chance, then yes, it would be impossible for life to form in this way. However, this is not the case. Abiogenesis was a long process with many small incremental steps, all governed by the non-random forces of Natural Selection and chemistry. The very first stages of abiogenesis were no more than simple self-replicating molecules, which might hardly have been called alive at all.
http://www.science20.com/stars_plane...d_begin_chance
Calculating The Odds That Life Could Begin By Chance By Dave Deamer, April 30th 2009
Proponents of intelligent design believe that the components of life are so complex that they could not possibly have been produced by an evolutionary process. To bolster their argument, they calculate the odds that a specific protein might assemble by chance in the prebiotic environment. The odds against such a chance assembly are so astronomically immense that a protein required for life to begin could not possibly have assembled by chance on the early Earth. Therefore, the argument goes, life must have been designed.
It is not my purpose to argue against this belief, but the intelligent design argument uses a statistical tool of science -- a probability calculation -- to make a point, so I will use another tool of science, which is to propose an alternative hypothesis and test it ... For the purposes of today’s column I will go through the probability calculation that a specific ribozyme might assemble by chance. Assume that the ribozyme is 300 nucleotides long, and that at each position there could be any of four nucleotides present. The chances of that ribozyme assembling are then 4^300, a number so large that it could not possibly happen by chance even once in 13 billion years, the age of the universe.
[this rest of the article is very good ... I'm omitting alot of detail]
http://www.icr.org/article/4348/
Chemistry by Chance: A Formula for Non-Life by Charles McCombs, Ph.D. *
Can random chemical "accidents" produce the building blocks of life? The following eight obstacles in chemistry ensure that life by chance is untenable.
1. The Problem of Unreactivity
2. The Problem of Ionization
3. The Problem of Mass Action
4. The Problem of Reactivity
5. The Problem of Selectivity
6. The Problem of Solubility
7. The Problem of Sugar
8. The Problem of Chirality
The chemical control needed for the formation of a specific sequence in a polymer chain is just not possible through random chance. The synthesis of proteins and DNA/RNA in the laboratory requires the chemist to control the reaction conditions, to thoroughly understand the reactivity and selectivity of each component, and to carefully control the order of addition of the components as the chain is building in size. The successful formation of proteins and DNA/RNA in some imaginary primordial soup would require the same level of control as in the laboratory, but that level of control is not possible without a specific chemical controller. Any one of these eight problems could prevent the evolutionary process from forming the chemicals vital for life.
http://news.nationalgeographic.com/n...e-chakrabarti/
Now that astronomers know where to look for Galaxy X, they should be able to find it, especially if they conduct the search in dust-penetrating infrared light, Chakrabarti said.
"Say you're looking for a car with very dim headlights, in the fog," she said. "If you know approximately where to look, you would have a better chance of finding it." Chakrabarti hopes to do some looking herself within the next few months and is seeking to secure time at a large infrared telescope. Even if Galaxy X isn't confirmed, she said, her findings will still shed new light on a shady subject. The absence of X would mean there's some other oddity out there throwing off the calculations—perhaps an unexpected distribution pattern of the halo of dark matter thought to surround the Milky Way. "We still stand to learn something very fundamental," she said.
http://en.wikipedia.org/wiki/Universe
As such the conditional probability of observing a universe that is fine-tuned to support intelligent life is 1. This observation is known as the anthropic principle and is particularly relevant if the creation of the universe was probabilistic or if multiple universes with a variety of properties exist (see below).
Effectively, the multiverse evolves as a universal wavefunction. If the big bang that created our mutliverse created an ensemble of multiverses, the wave function of the ensemble would be entangled in this sense. The least controversial category of multiverse in Tegmark's scheme is Level I, which describes distant space-time events "in our own universe". If space is infinite, or sufficiently large and uniform, identical instances of the history of Earth's entire Hubble volume occur every so often, simply by chance. Tegmark calculated our nearest so-called doppelgänger, is 1010115 meters away from us (a double exponential function larger than a googolplex).[75][76] In principle, it would be impossible to scientifically verify an identical Hubble volume. However, it does follow as a fairly straightforward consequence from otherwise unrelated scientific observations and theories. Tegmark suggests that statistical analysis exploiting the anthropic principle provides an opportunity to test multiverse theories in some cases.
75. ^ Tegmark M. (2003). "Parallel universes. Not just a staple of science fiction, other universes are a direct implication of cosmological observations". Scientific American 288 (5): 40–51. PMID 12701329. http://www.scientificamerican.com/ar...llel-universes.
76. ^ Max Tegmark (2003). "Parallel Universes". In "Science and Ultimate Reality: from Quantum to Cosmos", honoring John Wheeler's 90th birthday. J. D. Barrow, P.C.W. Davies, & C.L. Harper eds. Cambridge University Press (2003): 2131. arXiv:astro-ph/0302131. Bibcode 2003astro.ph..2131T.
http://www.christianitytoday.com/ct/...rch/26.44.html
Math and theology have had a long and checkered relationship ... in 1744, John Wesley confessed: "I am convinced, from many experiments, I could not study either mathematics, arithmetic, or algebra … without being a deist, if not an atheist." Three numbers in particular suggest evidence for God's existence. They are 1/1010123, 10162, and eπi.
http://www.christianitytoday.com/ct/...rch/26.44.html
The first recent number that points to God [infinity or improbablity] is 1 in 10 to the 10 to the 123. This number comes from astronomy. Oxford professor Roger Penrose discusses it in his book The Large, the Small, and the Human Mind. It derives from a formula by Jacob Beckenstein and Stephen Hawking and describes the chances of our universe being created at random ...
I understand that life needs three things: (1) an energy source, (2) a fluid to move in and (3) the right molecules. These have been found on Mars and NASA's Curiosity is heading there now to look for life: http://www.nasa.gov/mission_pages/msl/index.htmlQuote:
Originally Posted by Polednice
So life might be found in the solar system this year.
I understand there are moons of Jupiter and Saturn that have the conditions for life as well. In this case the energy comes from gravitation.
So given that, what does it mean for life to start by chance alone? My suspicion based on some of the things that I've read from KillCarneyKlan's posts is that this happening should be so rare that our planet should be the only one with life. I don't know. But if that is the case, finding microscopic life on Mars should be the end to the chance argument.
I particularly love Saturn's moon, Enceladus - I hope we can find something there!Quote:
Originally Posted by YesNo
I think the argument that life is a one-off is one that we can't seriously entertain. I mean, that seems to me to fall into the line of other anthropocentric mistakes we've made - i.e. the earth was at the centre of the universe, no? Well our solar system is then. No? Well our galaxy is then. No? Well we're still the only life-forms.
I just don't think it's conceivable. Finding self-aware life-forms will be a hell of a task, but I'd bet anything on finding microbial life.
On reflection, I think terms like life arising "by chance" is actually a very subtle way of hiding a value judgement in the statement. Because life is viewed as important, chance is considered demeaning and so is only employed as ridicule. If you look at this mechanistically, it's really as ridiculous as saying, "given a load of hydrogen atoms, what's the possibility that a star would form by chance?" *scoff scoff* - it's not chance, it's a natural consequence of physical laws.
I think we agree, Polednice, on the prospects of finding life on other planets than Earth in the solar system.
My only point with this is that I don't like using chance as an explanation. Chance is good for modeling, but in the case of life (microbial at least), what are the odds that it arose by chance? I don't know, but I suspect KillCarneyKlans is right that it is very unlikely.
However, I suspect life didn't start by chance and finding microbial life on Mars would mean that biologists would need to come up with a more interesting cause. At the moment, chance is OK, since Earth is the only planet where we know microbial life exists. Perhaps we just got lucky, but if Mars also got lucky and probably Enceladus as well, that would force one to look for an explanation other than chance.
Saying chance caused something is no better than saying some God caused something. I have an agenda when I claim this: if a deterministic cause cannot be found, we should look for a non-deterministic cause. This leads us back to the Kalam argument. There is no known deterministic cause for the universe to come into being, but there still needs to be a cause.