Are WE the only life in the Universe?

[maddog]

I just went and researched back and found last time Telemad had posted here was last

September. Sad, cause I had wished he might read my belated response the following quote.

 

IF life arising spontaneously is as highly improbable as I believe it is, then having the one instance of life we know of could be argued to make it less likely that the same low-probability event occurred a second time somewhere else.

 

Elsewhere you had some kind back-of-envelope calculation that in essence said probability of

life arising in the universe to be zero. Maybe you don't do math. If really zero we wouldn't

be here. Duh. So I guess your earlier probability of 10e-120 was some approximation to 0

or what. We don't really know the probability of the genesis of life in the universe. I would

only be able to guesstimate it to be >0. Now with recent discovery of more and more

organic compounds found in space (last years was discovered some kind of aldehyde that

is a relative to some of the amino acids in DNA). Another point is we have determined over

130 planets revolve around other stars in our galaxy. Add to that the new relevation of

anerobic life near steamvents in the ocean. All of these attenuate the Drake equation.

You are welcome your belief.

 

The probability of life existing in the universe is 1. Here we are. Drake's equation is about elsewhere in the universe.

 

I was talking about the notion of intelligent life in the universe. Even so, whether we exist

as life doesn't effect the equation at predicting life elsewhere. The theme question was

whether we the only one => why I was discussing Drake equation. Two turns of the

roulette wheel, the second turn is not effected by the outcome of the first. So the probability

of the genesis of life given a set of conditions is not one either. This value would imply

intergalactic space and near the surface of a black hole are teaming with life. Not that I

am denying either. Current evidence that this not likely. So more than zero and less than

one. It is the same as once you flip the coin does not change the probability of the coin

toss. This is the same before. You just know the outcome.

 

Now one more point that I have not seen discussed in the thread so far is what if one of

16 or so basic constants were slightly different. Could life have arisen (including us). There

are some examples where (universe created) where changing a value prevents atoms from

forming, quark-gluon plasma never cools off, I forget all the ones mentioned. I think

Brian Greenes book Elegant Universe goes into it. Another book About Time (I forget author)

goes into details. What was interesting is that most of the parameters have a very small

window that works such that if probability were free over all of them say 1:1e22 were

the odds at acheiving a stable life producing universe. [check my numbers I just remember

it being large]

 

Maddog

[infamous]

I think I gotzya Irish, maybe we need to kick this off by trying our best to define life as we each understand it. I'm sure there are many ways to come at this question, but let me make a feeble attempt to start things off. In my humble opinion, life is very simply, the ability to reproduce offspring by sharing cellular material. I may be wrong, but I don't think that a virus can qualify for this distinction. Maybe someone would like to add to this however, can a virus qualify as life?

[Fishteacher73]

I'm new to the board, so If I re-tread over ground that has been discussed, I apologize. I haven't been able to make it through all the threads...

There has been some discussion on what level the driving force is behind "life", and therefore a debate(Which this seems to be) over what constitues life.

The opinion that I find most compleling is that DNA is the "stuff" of life. All these fine complex organisms are just various vehicles to perpetuate the molecule. Meaning that "life" is here to promote DNA, not the other way around. Amino acids were here and began to settle in specific paterns in charged clays, slowly begening to formation of our nuleotides and their pairing. The egg came before the chicken. The elegance and simplicity of this concept is possibly the most compelling aspect of this theory. Occam's razor. This also alllows one to see a purpose in life without theological implications and puts life all on the same playing field. No one type is more important than the other (although some are more profecient).

[lindagarrette]

Good analysis, fishteacher. It makes sense to me that all life forms in the universe would have to follow the same pattern of DNA/RNA evolution. If there were any other combination possible, then it surely would have developed here on earth where conditions are primo. That leads me to conclude there is no ET.

[infamous]

Good analysis, fishteacher. It makes sense to me that all life forms in the universe would have to follow the same pattern of DNA/RNA evolution. If there were any other combination possible, then it surely would have developed here on earth where conditions are primo. That leads me to conclude there is no ET.

If ET does't exist then we have been wasting a huge amount of money and human resources trying to prove otherwise. I believe that your opinion might be in the minority, that does't make you wrong Linda, just outnumbered.

[Fishteacher73]

It does seem that ET life is inevatable conclusion by just doing the math. Whether that organism is intelligent seems to be hanging point for many. (I mean come on, its hard enough to find intelligent life here on Earth...). The emergence of an "intelligent" (here again this is a term that can spawn a bit of debate) organism is dependent upon a huge series of random events(This is in addition to the vast series of random events that must occur to spark life). Some believe that intelligence is the inevitable conclussion of a life form that's sole purpose is to survive and that this form is mutable to the external forces acting upon it. One could counter this idea by noting that the most prolific life-forms are not "intelligent." From bacteria to arthropods, there's not a whole lot of introspection in these guys, but they are EVERYWHERE. One possiblity is that there just hasn't been enough time on the evolutionary clock for more intelligent organisms to evolve. The converse, is that we are just a random variant soon to be swept into the fossil record. Gia tried man...hope she kept the recipt.

 

Even if one were to concede to the exestence of intelligent ET, the sheer magnitude of the universe makes it impossible with our understanding of physics to contact or to be contacted by any of these life-forms in any sort of timely manner. We may recieve a communicaions transmission but it will be centuries old(If we are lucky).

[maddog]

In my humble opinion, life is very simply, the ability to reproduce offspring by sharing cellular material. I may be wrong, but I don't think that a virus can qualify for this distinction. Maybe someone would like to add to this however, can a virus qualify as life?

 

What I understand life is defined as a structure that self replicate to propagate itself. Thus a

virus can qualify as life. Defining it as "ability to reproduce offspring by sharing cellular material", would imply that all asexual cell division as in mitosis of Bacteria is not life. Of

course I have heard (from an article a couple years ago in Sci Am) where Bacteria of the

same species can trade genes. So maybe that qualifies as "sharing material". Of course

also my definition could be applied to computer viruses.

 

This is a bigger question: Is "digital life" of errantly rampant software like a computer virus

life ? :hihi:

 

Maddog

[maddog]

It makes sense to me that all life forms in the universe would have to follow the same pattern of DNA/RNA evolution. If there were any other combination possible, then it surely would have developed here on earth where conditions are primo. That leads me to conclude there is no ET.

 

1. With only the Earth's version of life based on DNA/RNA is not sufficient justification to

conclude that this is the only method to base life on. We don't yet know what else one

could base life on. Speculation at best.

 

2. Not nessecarily. Other combinations of life base on other things could have been killed

off earlier in the origin of the earths history. We have no fossils of the earliest microbes. So

we don't fully know what was here per se (except for what we see around us now).

 

3. The was a leap of logic I missed here ... Nothing different than DNA'RNA type life could

form ==> Life elsewhere cannot form ?

 

Elucidate, please ? :hihi:

 

Maddog

[Fishteacher73]

While the actual mechanics/chemical of RNA/DNA may vary, it seems to me that there must be a basic template on which each version of life would derive from. I feel I mis-spoke when referring to RNA/DNA as the driving force of life. I think limiting of the concept of life to only concern genetic material (In the strictest of terms meaning the series of combinations of our 5 basic nucleotides) is a bit "Earthoocentric." Just as we concede that while life as we know it is carbon based, Si based life is a posibiity, a variation of DNA/RNA "source code" surely could exist.

 

I think life truly needs to be defined as an entity that can replicate and has the ability (not that it actually has to) to change over time, thus allowing for more apt forms as the envronment changes.

 

I would be inclined to include digital viruses because although they do not contain genetic material, they have an analog RNA/DNA which is the source code of the program. I am not a programmer, so I don't really know if there "mutations" in the code across "generations" of the virus. Whithout this ability, it simply is a machine.

[Stargazer]

Good analysis, fishteacher. It makes sense to me that all life forms in the universe would have to follow the same pattern of DNA/RNA evolution. If there were any other combination possible, then it surely would have developed here on earth where conditions are primo. That leads me to conclude there is no ET.

How do you draw such a conclusion?

[maddog]

I think limiting of the concept of life to only concern genetic material (In the strictest of terms meaning the series of combinations of our 5 basic nucleotides) is a bit "Earthoocentric." Just as we concede that while life as we know it is carbon based, Si based life is a posibiity, a variation of DNA/RNA "source code" surely could exist.

 

Yes, I think it possible other chemical reactions can take preeminance give the right

environment of pressure, tempurature, constituents of the atmosphere or fluids present.

Sagan later in his life started speculating that low enough temperature in water/ice, the

presence of a mixture of ammonia and methane can form long polar bonding like it does

with molecules of nearby water (H2O).

 

Si it turns out has not the number of different possible bonding types that Carbon has. It

was never said was this at all tempuratures and pressures (say near freezing water or

alcohol) ?

 

I think life truly needs to be defined as an entity that can replicate and has the ability (not that it actually has to) to change over time, thus allowing for more apt forms as the envronment changes.

 

Real viruses and Bacteria do this as well as plants and animals. I forget the type of life

that has been found in steam vents in the ocean (I think they might mutate as well).

 

I would be inclined to include digital viruses because although they do not contain genetic material, they have an analog RNA/DNA which is the source code of the program. I am not a programmer, so I don't really know if there "mutations" in the code across "generations" of the virus. Whithout this ability, it simply is a machine.

 

I not inclined to think of "digital life" as actually life. I realized when I posted earlier that

such an example met my criteria so I had add it in. I think my definition was flawed. :hihi:

However, the have many renditions where mistakes happen in viruses, so yes, they have

mutations (check with Symantec or NAI). :rant:

 

Maddog

[pgrmdave]

I was tempted, at first, to say that life is anything that strives to reproduce itself, but then I realized that there could be robots which reproduce themselves and I would not consider them alive. I am loathe to have too narrow a concept of life, lest we someday meet an alien and have to sit down and explain to him that, despite everything he knew, he really wasn't alive, but too wide of a concept becomes impossible to deal with. It is simple enough on earth to say that there is only biological life, but what if some day computers become consious, can reproduce, need to take in and expel energy...would we tell them that they are not alive? Especially when condsidering ET, a broad idea of life is often preferable.

[maddog]

It is simple enough on earth to say that there is only biological life, but what if some day computers become consious, can reproduce, need to take in and expel energy...would we tell them that they are not alive? Especially when condsidering ET, a broad idea of life is often preferable.

 

Regarding mechanical conciousness, like you I am hesitant consider so. However, in some

future technology may advance enough (like in the movie AI) where we would have to

redress the issue.

[Tormod]

what if some day computers become consious, can reproduce, need to take in and expel energy...would we tell them that they are not alive?

Interesting question. I don't think I would. If something is self-aware to the point of being conscious that something other than it has the ability to turn it off, I'd say it is alive.

[syntax]

Aren't there some rules regarding what constitutes life?

 

Something about being able to reproduce, requiring a source of energy and such?

[infamous]

Aren't there some rules regarding what constitutes life?

 

Something about being able to reproduce, requiring a source of energy and such?

Maybe we can boil it down a little and describe life as a form of self determinism. By this I mean, some control of its elementary functions in spite of external influences.

[infamous]

Not impossible, but improbable....there's a big difference.

 

Now, as far as using a single existence of something that is improbable to argue that there must be other examples of the same thing, here's a thought experiment. Thoroughly shuffle a normal deck of playing cards and then deal them out to yourself one card at a time; keep track of each card you receive, in the order you receive them in. What is the probability that that exact sequence of cards would have occurred? Less than 1 in 10^67. But it did occur. You seem to be claiming that we should assume that that same sequence has happened other times because we know it happened once. But probabilitistically speaking that is a very unreasonable argument. The better position is that yeah, it is highly improbable and it did occur, but it has probably occurred only once: the one example we know of.

Say TeleMad; did you here the one about these two amoeba, they were creeping along at their amoebic pace when one asked the other, do you think we are alone in the universe. The other responded, must be, I don't see any more around here, do you?