Scientists Offer 'Overwhelming' Evidence Terran Life Began in Space 556
An anonymous reader writes "Using data from recent comet-probing space missions, British scientists are reporting today that the odds of life starting on Earth rather than inside a comet are one trillion trillion (10 to the power of 24) to one against. That is, we're not originally from around here. Radiation in comets could keep water in liquid form for millions of years, they say, which along with the clay and organic molecules found on-board would provide an ideal incubator. 'Professor Wickramasinghe said: "The findings of the comet missions, which surprised many, strengthen the argument for panspermia. We now have a mechanism for how it could have happened. All the necessary elements - clay, organic molecules and water - are there. The longer time scale and the greater mass of comets make it overwhelmingly more likely that life began in space than on earth."'" jamie points out that the author of this paper has many 'fringe' theories. Your mileage may vary.
Re:They "could" keep water in liquid form? (Score:3, Informative)
Controversial result? (Score:5, Informative)
Re:Life is on earth (Score:2, Informative)
From the overly brief article, it appears that the "overwhelming" probability is largely an artifact of the greater mass of clay on comments than on a young Earth. This is overly simplistic, and more bluntly, wrong, for four reasons.
1) Ultraviolet light; surface area to volume. While the mass of clay on comets may exceed that on a young Earth, since Earth is one giant sphere and not a bunch of clumps of dirt flying through space, more ultraviolet light will strike Earth-based than comet-borne clay. The surface area exposed to space will be greater on Earth. Furthermore, given the lesser gravity on a comet, liquid water will likely be on the interior of a comet, vs. the exterior of Earth, another factor reducing the UV rays striking the clay and water on comets.
2) Consistency of conditions. Earth's orbit is much less elliptical than the orbits' of most comets. This is vital to life. Even if (and this is a big if) liquid water can exist on a comet throughout its orbit, extreme variations in radiation or temperature would still significantly hinder the formation of life.
3) Weather. Earth has weather, and comets don't. Weather, and lightning in particular, is pivotal in most theories regarding the origin of life. The Urey-Miller experiment, for example, proved that dynamic weather conditions can be extremely conducive to the formation of the complex molecules, such as amino acids, necessary for life to exist.
4) Most importantly, life is on Earth. We need to consider not the mass of all comets in the Solar System, or even all those harboring liquid water, but rather, all those harboring liquid water which collided with Earth at the time that life first originated. Since life is on Earth, we know that only a comet which collided with Earth could have been responsible for life on Earth. The mass of these comets which collided with Earth is clearly much less than that of the Earth itself.
Considering all of these factors, I think it is safe to say that in light of this research, life still likely originated on good old planet Earth.
Re:Extrapolation of probability using two variable (Score:5, Informative)
For those interested in why the tornado in a junkyard assembling a 747 is a useless analogy for the process of evolution, the simple explanation is that evolution works by a ratcheting effect: improvements are made one tiny step at a time, in sequence, for a cumulative effect of complexity. The selection process by which those steps are made - i.e. mutations that constitute an improvement in fitness survive and others die out - is simple and nonrandom. The tornado analogy implies instant emergence of full complexity, which is nothing at all like what actually happens.
Re:Yeah right (Score:2, Informative)
Of course, the ability to survive the fiery inferno of a comet impact is a whole 'nother story. . .
Sure... (Score:3, Informative)
1. Can survive being frozen for indefinite periods of time,
2. Can survive excessive radiation and heavy metal contamination,
3. Can survive without sunlight (remember, it's in the center of the comet),
4. Lives off unknown chemical reactions (organic chemicals mean squat without an energy source)
5. Exists in near equilibrium with its environment over millions of years, with trivial gains in material,
6. Has to then survive on Earth after
a) melting off a comet
b) drifting unprotected in the vacuum of space
c) floating down through Earth's atmosphere
or
d) evaporating in an impact event
And this theory (he says) is more plausible than life developing on Earth. I guess we need to consider ourselves very, very lucky to be here.
Re:Overwhelmingly underwhelming (Score:4, Informative)
Re:Extrapolation of probability using two variable (Score:2, Informative)
Re:No kidding (Score:5, Informative)
Re:No kidding (Score:3, Informative)
Since they were part of the computer, they were then capable of producing the answer just like any other part of the computer. Since their unplanned presence screwed up the calculations, the answer they came up with was close to the true answer, but with a flaw that rendered it basically nonsensical.
Re:Not so surprising (Score:3, Informative)
It seems to me that life originated right here on Terra, but I sure as hell can't prove it. But I see no reason to look to comets or panspermia or whatever. Occam's Razor, and all that. The early days of Terra provided some pretty exotic environments that could probably get the job done. Or, IMO, evidently got the job done.
Whatever.
Re:Extrapolation of probability using two variable (Score:2, Informative)
The tornado analogy is not meant to be an analogy for evolution; it's meant to be an analogy for the origin of life. Evolution may work as a gradual ratcheting up, but it only works amongst reproducing organisms. The simplest thing we have that is theorized to be capable of evolving is a bacterium, which is orders of magnitude more complex than a 747. While it is hypothesized that in the past there may have been simpler forms capable of reproduction and evolution, we would need to have a full-blown theory -- a workable model -- of such, to see whether such a thing would be more or less complex than a 747.
Re:Extrapolation of probability using two variable (Score:4, Informative)
Nonsense. Any replicator subjected to differential survival pressure is capable of evolving, and there are simpler replicators than bacteria.
Bad math? (Score:3, Informative)
Re:Extrapolation of probability using two variable (Score:0, Informative)
Re:Extrapolation of probability using two variable (Score:5, Informative)
There is a fairly (and far beyond me to explain) statistical aspect to evolutionary biology, but the main thing to keep in mind is that modern evolutionary theory predicts that all life, extant or extinct, will fit into a nested hieararchy. The bonus of the Modern Synthesis and of the last thirty or forty years of genetic research has given us a twin-nested hiearchy; not only do the fossils give us a pretty good notion of the faunal succession, but the genetic data, by and large, confirms and extends those observations.
This is the root of why evolution is a well-supported scientific theory. It's nice to have a single line of data, but when you get to evidentiary lines that fit together as well as the fossil and genetic data does, I don't think it's any great leap of any kind to state "Here is evidence for common descent".
Let's remember the flip side of all of this, and that's falsification. For common descent to be falsified, one need only provide some examples of organisms that fall outside of the twin-nested hieararchy, or of fossils that violate the faunal succession. So, if you can produce some bacteria that uses an entirely different genetic scheme that is not related in any way to the way life as we know it does, then common descent has been falsified (though, you'll note, evolution has not). As to the faunal succession, if you pull a rabbit fossil out of strata, say, 3 billion years ago, where bacterial colonies represented the most complex organisms around, then we have a very serious problem.
Now, how do we falsify a common Creationist retort; that God (or the Designer(s) or whatever) used a common toolkit, and that's why all life uses the same basic nucleotide system, or genetic language if you will. On the face of it, it seems a reasonable retort, until your factor in that said Designer likely could use any genetic he/she/it/they pleased, and there's every reason to expect that there might be a half a dozen, or a hundred or any number you like (and can expect to be likely to be useful for inheritance) such systems as there is just one. In short, any and all observations are essentially compatible with the claim "God did it" (or whatever formulation of God/designer/alien scientist/etc. you want to invoke).
The reason Creationists are picked on for their "million to one, 747 out of a scrapyard" arguments is because those arguments do not in fact address anything that modern evolutionary theory or Common Descent states, but rather knock down oversimplified and rather silly strawmen of what those theories claim happened. There's nothing positive in their claims, simply just fallaciously-formulated arguments against everything from the Big Bang to the formation of the first cell.
If one observers that all extant organisms fit into a hieararchy, then I don't think it's an inference too far to state that that relationship is more than just happenstance. If that observation fits within the predictive nature of a specific theory, then is it unreasonable to state that that observation is in fact a piece of evidence for that theory?
Re:Extrapolation of probability using two variable (Score:3, Informative)
In the absence of pre-existing organic life, none of those things are self-replicating. Ideas evolve as well, even simple ones, but that is again not helpful in determining the simplest thing which can (without help from another organism) replicate. To my knowledge, bacteria, or the bacteria-like organisms thought to precede them, are the simplest such things currently known, or in any meaningful way theorized. It's been speculated that maybe there was an RNA-based life form that was simpler, but I don't believe any actual model for such has ever been suggested.
Re:Extrapolation of probability using two variable (Score:1, Informative)
Nonsense...ever done PCR? ALL DNA and RNA can self replicate without being inside a living organism.
Re:Oh right. (Score:3, Informative)
"You believe that there is one God. Good! Even the demons believe that--and shudder." - James 2:19
Everyone in hell, according to the non-straw-man version of the Christian worldview, will be there because they have rejected God's offer of free righteousness in Jesus Christ:
All faith acceptable to God throughout all time has been on the basis that God would send someone to establish the righteousness that we humans had made ourselves and continue to make ourselves incapable of producing on our own by rejecting God. Throughout the centuries he was known by different names: the Seed of the woman, Shiloh, the Messiah, etc. When he came, he was known as Jesus of Nazareth.
This has nothing, per se, to do with accepting or rejecting facts. You can accept all the right facts to be true, and still reject the person and the offer. No one is sent to hell for ignorance: we are all continuously shaping our souls into beings capable of heaven, or beings not capable of heaven.
Jesus, the one promised by God, made it possible for things to be right between God and humans again. Do you want that? Do you want Him? Or do you want to be your own god?