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kashi
2003-Oct-16, 12:22 PM
Could our ultimate evolutionary source lie with complex organic molecules capable of replicating themselves.

Amazing article:
http://www.cogsci.indiana.edu/farg/harry/b...t/lifestart.htm (http://www.cogsci.indiana.edu/farg/harry/bio/lifestart/lifestart.htm)
Includes a nifty simulation of the begginings of cell reproduction on Earth.

I'd love to hear peoples' thoughts. This has interesting implications for the ability of life to arise on other planets.

Kashi

Haglund
2003-Oct-16, 02:52 PM
I have suspected (I'm not an expert in biology) that there must have been something we would call evolution before there was what we now call living organisms. It makes great sense that it all is the result simply of the laws of nature and the properties of matter.

kashi
2003-Oct-17, 09:15 AM
Indeed. It's obvious that evolution can, does, and has occured. But what's a bit less known, is whether "life" can come out of nothing (i.e. just chemical compounds) when molecules randomly collide.

Matthew
2003-Oct-17, 09:33 AM
Thats probably what occured, or a huge bolt of lightning struck the ocean and created life.

Haglund
2003-Oct-17, 09:55 AM
Large inputs of energy was probably required, if the temperature is too low the possibilities are less.

Matthew
2003-Oct-17, 10:05 AM
Well the higher the temperature, the greater energy atoms/molecules have to move around increasing their chance of hitting one another increasing the chance of a reaction.

kashi
2003-Oct-18, 05:07 AM
That's a very a good point. I guess that means all the other variables that affect rate of reaction would also have an impact on the length of time it took life to establish. Small volumes of water containing larger amounts of minerals, moving currents in the water etc.

Maybe the amount of available energy (kinetic, electrical etc.) on a planet could be a valid variable to include in the drake equation. What do you think?

Matthew
2003-Oct-18, 07:47 AM
It would be. Lightning may have been what 'started' the chemical reactions which created life on Earth. So energy is the main variable (I think) for there being life. If there was no energy, then there would be no chemical reactions.

Haglund
2003-Oct-18, 07:55 AM
The Drake equation: N = R* x fp x ne x fl x fi x fc x L

The variables ne (the number of planets per solar system with an environment suitable for life) and fl (the fraction of suitable planets where life appears) could perhaps be more refined if we knew anything about what role the energy amount plays... or, it could be another variable on its own perhaps.

Matthew
2003-Oct-18, 08:05 AM
The Drake equation: N = R* x fp x ne x fl x fi x fc x L

What do all the other variable mean, Parker?

Haglund
2003-Oct-18, 08:18 AM
N=Number of communicative civilizations in this galaxy

R*=The rate of formation of suitable stars (every year)
fp=The fraction of those stars with planets
ne=The number number of planets in the habitable zone per planetary system
fl=The fraction of those planets where life develops
fi=The fraction life sites where intelligence develops
fc=The fraction of planets where technology develops (to the point where they can do and desire interstellar communication)
L=The "Lifetime" of communicating civilizations (in years)

This equation can of course not estimate the number of technological civilizations including those who cannot or wish not communicate, and not non-technological but intelligent species either, so the number of intelligent species in the galaxy should be higher than N.

Drake equation:
http://www.space.com/searchforlife/seti_dr...e_equation.html (http://www.space.com/searchforlife/seti_drake_equation.html)
http://www.seds.org/~rme/drake.html

Here you can enter your own values:
http://www.seds.org/~rme/drakeeqn.htm

kashi
2003-Oct-18, 01:18 PM
I'm going to ask the writer of that article to comment on what we have discussed (i.e. that immense energy could speed up the process of creating the first replicating molecules).

Kashi

QJones
2003-Oct-19, 01:35 AM
What do you mean "Immense energy"?

An ample supply of molecules with oxidative potential?
A warm planet?
A sun?
Access to different radiation types?

The neat thing about a self-propulgating system is that, once it's started - it continues until it is stopped. IF, out of the chaos, a self-ordering system starts (such as life), then it's there. The odds of occurence are minute, but the neat thing is that once something has occurred, it's done.

kashi
2003-Oct-19, 01:52 AM
Indeed. The simulation which is part of the original link I posted here shows that. Once you have a replicator molecule (which can take a while), you're unlikely to lose it, although it is possible (if it strikes a "poison" molecule that breaks it down).

Well originally Matthew suggested that a lightning bolt could have provided significant amounts of energy to speed up the rate of collision. A thought I just had though, is that it could also provide enough energy to break apart any replicator molecules already in existence. I think it is obviously a very complicated process with many variables involved.

Foundalis
2003-Oct-22, 10:03 PM
Hi, thank you all for commenting on my web-page on the origins of life.

Some readers proposed lightning bolts as a source of sufficient energy for starting up reactions that would eventually lead to replicator molecules. I would like to make the following comments:

I don't think our current state of knowledge is sufficient to understand whether plenty of energy would be beneficial or detrimental. As one reader observed (Kashi, I think), a lightning could destroy what otherwise started gradually and inconspicuously. We simply don't know (yet). What I wanted to emphasize in my article was that even though we can't know the exact details at this point, we can, however, discern the overall pattern, the general principle under which life got started on our planet. This principle, of course, is known by biologists, but they are concerned more with the exact *conditions* (e.g., are lightnings good or bad?) that would be necessary for the first replicators to appear. To me, it seems more urgent at this point to stress that the mechanism is there and is known; the particulars can be discovered in the (hopefully near) future. My motivation is more philosophical, rather than purely scientific: I want to make these ideas known to non-scientists, who often view life as a miracle (that happened with supernatural intervention). I want to tell them: look, there doesn't have to be any supernatural intervention, it can all happen naturally.

Knowledge of the principle is also important for speculating about the nature of extraterrestrial life. If the chemical nature of matter "affords" (allows) replicators, we expect this to hold not only here, but in the entire universe (assuming the fundamental laws of matter are universal). The possibility for extraterrestrial life then becomes a question of "initial conditions". The principle (i.e., replicators) is analogous to a differential equation that describes an orbit; to have your orbiting object arrive where you want it, following your equation, you need appropriate initial conditions. Most scientists are concerned with the discovery of those conditions, rather than with an explanation of the principle. Regarding extraterrestrial life, however, we should be aware of the fact that it's conceivable that an environment can "solve the equation" (arrive at replicator molecules) starting from different initial conditions than those that prevailed 4 billion years ago on Earth. In this case, we would expect that such replicators would almost certainly have different properties than those we are familiar with (e.g.: no DNA). Or, it may be that chemistry (matter) affords only one solution: the one that leads to DNA. Then all extraterrestrial life would exhibit similar properties. In this case we would expect "mammals" and "birds" and "fish", and so on, everywhere where life appears/appeared in the universe.

What are the readers' opinions on the probability of extraterrestrial life? Sorry, I guess you have already discussed this. I just subscribed today and had no time to read what has been written. My own opinion (which doesn't matter much) is that those initial conditions must be pretty rare, else we should observe the signature of life in the part of the universe that is available to us for observation. But I would be delighted to know the opinion of others.

Thanks,
-Harry Foundalis.

Haglund
2003-Oct-22, 10:41 PM
Hello Foundalis, right now I have one question: do you think that in the forseeable future it will be possible to incorporate this or a similar theory into the theory of evolution? I realize that we might not be able to know exactly what happened on Earth, of course. Anyway, would such a theory be the link between physics and biology? If you know what I mean.

Foundalis
2003-Oct-23, 07:27 PM
Hi Parker,

"Theory"? I am not proposing any theory. What I have in my page is called "armchair philosophy". That doesn't mean it's wrong -- I certainly don't mean to denigrate my own writings (I've yet to see an author who does!). But it definitely is not a theory. A theory is a system of propositions that explain experimental data. I don't have data to explain yet, ergo, no theory. Unless, of course, you consider the fact of the existence of life and its evolution as a single piece of datum, a prospect I think hardly any scientist would agree with.

The ideas in my page, however, *should be* part of the link between chemistry and biology. (I'd prefer to use "chemistry", rather than "physics", as you did, because at the level of very complex organic molecules it is the emergent laws of chemistry that are at work, rather than simply the laws of quantum mechanics; the latter stand at a lower level of description.)

How could one make a theory out of this set of ideas? One could attempt to simulate atoms and molecules in a much more realistic way than the elementary Java applet I present in my page. The more realistic the simulation, the more persuasive the argument. If one could simulate actual molecules in 3-D, and one arrived at real replicators, I guess that would count as "data", and it would be an enormous step forward in the issue of origins of life. Unfortunately, current computer speeds do not allow us to produce any realistic simulation, with the number of molecules that would be required for obtaining any result. Notice that I propose a computer simulation and not a real-materials experiment because in the former one has much more flexibility in toying with values of parameters, trying this, failing, trying that -- it can all be done much faster than real chemicals. Assuming much facter computers, of course.

Haglund
2003-Oct-23, 07:58 PM
What I meant was, can we form a theory that possibly would explain the origins of life similar to what your ideas did? And also, even if we through computer simulations could reach simple lifeforms and DNA, it would still only be one of many possibilities, right? I mean we wouldn't know for sure exactly how it happened, but would it still be enough?

Matthew
2003-Oct-24, 08:46 AM
A lightning bolt could provide the increase in energy to create a 'replicator', but you need only one replicator to replicate, if you have had enough replications by the next lightning strike at least one should survive. Allowing for more replications.


The ideas in my page, however, *should be* part of the link between chemistry and biology. (I'd prefer to use "chemistry", rather than "physics", as you did, because at the level of very complex organic molecules it is the emergent laws of chemistry that are at work, rather than simply the laws of quantum mechanics; the latter stand at a lower level of description.)

I think physics, chemistry and biology need to be used to understand the complexity of life, and how it emerges. Biology is life, the understanding about life.
Chemistry explains how individual molecules interact
Physics explains energy, and is inter-related with chemistry.
I know its a bit basic, but my list above does show that we need all three.

Explaining the origin of life and how possible it is, now seems so much more complex! :(

kashi
2003-Oct-24, 10:07 AM
Harry,

Welcome to the forum! There have been lots of posts related to the likelihood of extraterrestrial life occurring. This topic discusses possible reasons for why life is apparently not very common in the universe:

http://www.universetoday.com/forum/index.p...p?showtopic=843 (http://www.universetoday.com/forum/index.php?showtopic=843)

It links to a great article from the Scientific American.

Kashi

Haglund
2003-Oct-24, 03:33 PM
Something from MIT regarding self replicating molecules:
http://web.mit.edu/newsoffice/tt/1990/may09/23124.html

EagleUK
2003-Oct-24, 08:18 PM
It occurs to me as more reasonable that life would arise where a more benevolent and sustaining energy was available. As several of you mentioned earlier, the lightning scenario has a greater capacity to destroy than to create.

Perhaps if we look at the example of the deep sea "smokers" discovered in recent years in our own oceans. An energy source like this could provide a suitable environment over an extended period of time, acting as a safe haven for the incubation of life, far from the harmful effects of cosmic radiation and countless environmental pressures on the surface.

There must be countless planets in our galaxy, let alone the universe, where these conditions exist. When I look at the Milky Way, I am reminded of a huge coral reef that could be teeming with life. Just because we haven't discovered the signs yet doesn't mean that they don't exist. For a start, any civilization that is advanced enough to generate enough interstellar noise to attract attention must quickly realize that to do so risks inviting the wrong kind of attention (babe in the woods). So there's probably a small window of time before that civilization learns not to broadcast its presence. If we look at every example that nature provides on this planet, this sems to be the case. A few life forms rule, most others hide. Why should the galactic "jungle" be any different?

The other thing to consider is the approach that we have chosen. The SETI/Phoenix project, however laudable, is more about a search for extraterrestrial astrophysicists than anything else. How many of our broadcasts are at the 21 cm "watering hole"? I suspect that the "I Love Lucy" approach would be much more fruitful. Focus on high traffic wavelengths where the signal density could be much greater.

My two cents worth...

kashi
2003-Oct-24, 11:59 PM
EagleUK, I would argue that the reason that some animals hide in the jungle, is because they have evolved to do so as a means for survival. It is likely the most extraterrestrial civilisation have not evolved in this way, as they probably havne't encountered life outside their planet.

kashi
2003-Oct-25, 12:10 AM
Great article Parker! Do you think that's the mystery of the origin of life solved?

Matthew
2003-Oct-25, 06:15 AM
I don't think the mystery of life has been solved yet Kashi. The article is dated 9/5/1990, if they had found the origin of life, would we be discussing the topic currently? But it does add a new dimension to the topic. 'Replicators' can exist.

kashi
2003-Oct-25, 09:13 AM
hmmm...I was thinking about this. These aminoesters (or whatever they're called) don't sound like they have the ability to "evolve", and become better, more sophisticated replicators. They would need to have an evolutionary capacity to be even considered as a potential origin of life.

Haglund
2003-Oct-25, 09:45 AM
Personally I think that science has come a little closer to the mystery of origin of life, but there is much to do still. I am sure we can understand how it might have happened, and not too far into the future either.

Matthew
2003-Oct-26, 03:43 AM
We may come up with a hundred possibilities of the formation of life on Earth. Which one is true? We may never know. Maybe life was never born here, but was brought here (maybe by aliens, maybe may a mere asteroid).

Haglund
2003-Oct-26, 09:31 AM
Originally posted by matthew@Oct 26 2003, 03:43 AM
We may come up with a hundred possibilities of the formation of life on Earth. Which one is true? We may never know. Maybe life was never born here, but was brought here (maybe by aliens, maybe may a mere asteroid).
True, it will be very difficult to actually say exactly how life arose on this planet, but I think that we can come really close to a good theory on how it happened in general, so to speak.

Foundalis
2003-Oct-26, 05:11 PM
There must be countless planets in our galaxy, let alone the universe, where these conditions exist. When I look at the Milky Way, I am reminded of a huge coral reef that could be teeming with life. Just because we haven't discovered the signs yet doesn't mean that they don't exist. For a start, any civilization that is advanced enough to generate enough interstellar noise to attract attention must quickly realize that to do so risks inviting the wrong kind of attention (babe in the woods). So there's probably a small window of time before that civilization learns not to broadcast its presence. If we look at every example that nature provides on this planet, this sems to be the case. A few life forms rule, most others hide. Why should the galactic "jungle" be any different?

Steve (EagleUK), here is a thought that seems unsettling to me.

First, even if there is only a small window of time before a civilization thinks it's better to keep quiet, the sheer number of civilizations implied by the analogy of a coral reef means that, statistically, we should be able to receive *some* signals, from those small windows. We ourselves, are prime examples that this can happen. On November 16, 1974, we broadcasted a message towards star cluster M13, some 25,000 light years away, in the constellation of Hercules. If a statistical sample of size one (i.e., "we") says anything, it is that this can at least happen -- the probability is nonzero.

And second, the universe didn't come into existence at the same time like our planet. The former existed probably for 8 to 9 billion years *before* any sign of life appeared on Earth. Of course, just because the universe got started so long time ago, doesn't mean there could be habitable planets from the beginning. A sufficient number of supernova blasts should already have occured before a planet with the composition of Earth could be constructed. But still, there is plenty of time before we humans appeared. It is reasonable to accept that if there are more than one civilizations in our galaxy, we are not the first. If a number of other civilizations have passed through this window of time where they carelessly broadcasted their presence, as we did, their signals should be travelling in space. Once a signal sent, our current understanding of physics says that it cannot be intercepted (and "cancelled") by the sender of the message. Of course, we can always appeal to unknown parts of physics, but if we are to make a rational discussion, I think we should restrict ourselves to what we know; else anything is possible, and there is no point in arguing against anything.

So, if a number of such signals are traveling in our "coral reef", I'm tempted to ask Enrico Fermi's question: "Where are they?"

Cheers,
-Harry Foundalis.

Haglund
2003-Oct-27, 10:54 AM
It may very well be that not the entire milky way is suitable for life, some mean that life would be very rare in the center of the galaxy because the stars are too close to each other. Also, it is difficult to detect radio leakage from internal communications, as it's very weak.

Victoria
2003-Dec-23, 04:07 AM
What about magnetic reaction? Does a core reflect energy? A few thoughts I question.

Matthew
2003-Dec-24, 01:27 AM
The magnetic field that the earth emits, deflects things. Eg. the solar wind, most of that is deflected.

Littlemews
2003-Dec-24, 02:14 AM
Originally posted by matthew@Dec 24 2003, 01:27 AM
The magnetic field that the earth emits, deflects things. Eg. the solar wind, most of that is deflected.
What happen when there is a crack on the atmosphere

damienpaul
2003-Dec-24, 03:28 AM
i think that may have no effect on the magnetic field, although it'd be a dang nuisance!

GOURDHEAD
2003-Dec-24, 07:36 PM
Quite a number of carbon bearing molecules and an even larger quantity of water molecules have been discovered in various molecular clouds within the galaxy. As a proto-stellar cloud begins to contract to become one or more stars and planets it likely passes through pressure and temperature states that allow a wide variety of chance contacts and associations of these constituents. Depending on the relative affinities of these members for each other, amino acids, proteins, and perhaps RNA/DNA level molecules can aggregate and, though less likely, become alive. If so, the planets of such a system would be seeded as they form.

Whatever the mechanism, there is no reason to assume that the proto-solar cloud was sufficiently different from others to either generate or host living organisms more or less so than others. My guess is that life can and did originate in several isolated environments. If panspermia obtains, its chief contribution is to add commonality to the structure of living organisms at the carbon and water level. The most fit among these will (did) dominate and permeate the galaxy.

They&#39;ll show up; I hope we&#39;re ready&#33;&#33; <_<

damienpaul
2003-Dec-25, 03:31 AM
Very interesting posting gourdhead, you make a good point that it seems reasonable to expect that somewhere else ther eis a chance that life have have propogated. A question I have, is when a star goes nova and blasts its excrement out and about, this too is laden with heavier molecules, surely this mechanism would have a similar effect?

GOURDHEAD
2003-Dec-26, 06:54 PM
:rolleyes: That&#39;s how the elements that make up the heavier molecules got into the proto-stellar cloud. Chances of even microbes surviving novae or supernovae environments are very small indeed--perhaps not impossible. By the time the sun goes novum, our descendants and those of our current microbes and other relatives will probably prosper in the outer regions of the solar system. Timing is extremely important and, on some scale, of the essence. :huh:

Faulkner
2003-Dec-27, 09:08 AM
Chances of even microbes surviving novae or supernovae environments are very small indeed

I disagree. Life can exist ANYWHERE - with oxygen, without oxygen, high pressure, low pressure, toxic gases, ultra-high radiation, etc etc... We find it happening on Earth, doesn&#39;t that mean it extends to outer space too?? Life is EVERYWHERE throughout the cosmos, it&#39;s obvious.

It would be interesting to see the response on Planet Earth when these Mars probes "finally" detect microbic life on Mars (or Titan...or...?). It would disintegrate ALL western religion, wouldn&#39;t it?&#33; (= ie human beings aren&#39;t special...life can evolve everywhere...etc...)

Maybe it would be time then (hypothetically speaking, of course) for governments to finally declare religion as a MENTAL ILLNESS (long overdue&#33;).

(...Or maybe...just maybe...that&#39;s why we "mysteriously" lose contact with these probes...?)

kashi
2003-Dec-27, 09:24 AM
Remember the rules Faulkner. I love this topic so I&#39;m not going to close it but please try to stay away from religion and politics as this only makes people angry.

Faulkner
2003-Dec-27, 09:32 AM
Agreed, Kashi. But I DO have to say that any discovery of life OUT THERE is gonna cause HAVIC on this planet&#33;

Sorry...I&#39;ll try my hardest to stay away from religion...and politics...etc...Just seems that our Universe is so intimately tied up with it all&#33; Ha&#33;

Onya Kashi. I take heed of your warning&#33; B)

kashi
2003-Dec-27, 10:07 AM
I agree with you. This would create some conflict. But this has been going on for centuries. Look at what happened when we discovered that the Earth wasn&#39;t flat, that we weren&#39;t the centre of the solar system, that the universe was expanding...

Anyway...enough&#33;&#33;

Chook
2003-Dec-28, 03:49 AM
Hey (Stirrer) Faulkner:
"Life is EVERYWHERE throughout the cosmos, it&#39;s obvious."

Obviously you are wrong&#33;

Life hasn&#39;t been yet found "out there" where we have BEEN; and you can&#39;t categorically claim that life is where ya ain&#39;t been yet.

Can you?
:rolleyes:

kashi
2003-Dec-28, 05:43 AM
This doesn&#39;t make him obviously wrong anymore than it makes him obvious. It is speculative and I don&#39;t think he intended for you to take him that seriously Chook.

Faulkner
2003-Dec-30, 12:55 PM
Hey, I&#39;m not trying trying to stir anyone. I DO think life is abundant throughout the universe. Who were those scientists who threw some ammonia & hydrogen & methane & stuff in a test-tube, popped a cork in it, shook it up, zapped some electricity through it, ... and came up with some organic molecules?? Maybe if they&#39;d left it to brew they would&#39;ve grown some octopuses&#33; I just think there may be some fundamental FORCE in the universe (yes, a physical, material, gluonic FORCE) that pushes the raw sub-atomic matter into LIFE. I would want to kill myself if I thought Planet Earth was the sole bastion of life in the universe. That would mean there was no God, that it was a total random fluke in this insignificant corner of the cosmos. I much prefer to believe the universe is teeming with creatures with self-awareness. If humanoids are the pinnacle of Creation, then bloody hell, I&#39;m defecting back to the Apes&#33;

QJones
2003-Dec-30, 11:11 PM
Um, just quickly, any religion that can&#39;t incorporate extra-terrestrial life isn&#39;t a well-thought out religion. I believe that all the "major" religions can easily incorporate XT life, considering they&#39;ve incorporated dinosaur fossil evidence. Well-constructed religions have no obvious &#39;proof&#39; that they&#39;re wrong, and the religious leaders are often intelligent enough to iron out any potential faults.

I also agree that there is a force that drives the creation of life. For example, because of life, there is now proof of life on both our Moon and on Mars. In fact, there&#39;s now proof of life outside our solar system (Voyager). Sure, the life was terrestrial in origin, but much of the nature of life is to spread. Pretty soon, there will be proof of life, and maybe actual life (though terrestrial in origin) on all the planets in our system. I&#39;m also pretty sure that I&#39;m going to see such an age.

Victoria
2003-Dec-30, 11:42 PM
Beautifully Said. :)

Littlemews
2003-Dec-30, 11:48 PM
Beautifully Said. #2

Josh
2003-Dec-30, 11:52 PM
How about we keep clear of the religion talk and get back on topic... Thanks.

damienpaul
2004-Jan-04, 02:39 AM
where can i find this info about proof of life from voyager QJones?

Victoria
2004-Jan-04, 06:34 AM
V"oyager", was taht the plane flown around the world?

damienpaul
2004-Jan-04, 11:45 AM
through the solar system actually

Victoria
2004-Jan-04, 02:06 PM
How many planets was it able to study? Was Uranus observed? Congrats to U.S. for their success of Spirit.

damienpaul
2004-Jan-05, 11:33 AM
voyager 1 studied jupiter and saturn and its moons, voyager 2 studied all the outer planets (except pluto) someone please correct me if i am wrong...