Are WE the only life in the Universe?

[TeleMad]

Its called the Drake Equation...For someone who acts as all knowing as you seem to act I would think you would know this.

 

I've known about it for years, thank you very much.

 

Fishteacher73:

N = R* X fp X ne X fl X fi X fc X L

 

where:

 

...

 

fl is the fraction of the above which actually go on to develop life

...

 

The equation based on current estimates is thus:

 

... fi = 1×10-7 ...

 

 

Exactly what empirical evidence shows that the value 1 in 10 million is the correct value? Why couldn't it be 1 in a billion? Why couldn't it be 1 in a trillion? Why couldn't it be 1 in a googol?

 

In fact, that variable's value can't be based on empirical evidence because we know of only about 200 total planets, fewer than 10 that we have actually landed craft on to see if we find any life, past or present.

 

The Drake Equation is fun to play around with, but does not produce any kind of an accurate result because several of the terms are not themselves accurate, with some being much more uncertain than others.

[Fishteacher73]

Uncertainty implies a +/-, these equations could be possible quite low as well. The values used in my claculation are the low end of the spectrum and still come up with a decent possibilty. I feel that it would be erroneous to conclude that since we have only observational evidence of about 200 planets there are no more. By the same reasoning it would be ill advised to extrapolate that the universe as a whole matches the small area that we can actually observe. Hence why I atributed to the values the lowest estimates that are currently agree upon generally. Even with the low-balling the possiblity comes up that there is reasonable conclusion to say that other life should exist out there.

 

All of these assumptions are also based on the idea that life must evolve on a planet much like Earth (Carbon based RNA/DNA containing organisms). There could be a vast array of life forms that are based on a completely different set of requirements.

[Freethinker]

I had posted info on this book before. This thread?

 

But new posters, so worth repeating.

 

A great book on this subject is:

 

Probability 1: Why There Must Be Intelligent Life in the Universe by Amir D. Aczel

 

It takes the Drake Equation, breaks each variable down and provides "reasoned" numbers to sub. (reasoned? Logical? that's another thread...)

 

Would I be giving the ending away to say the results are "1" (100%)?

[alxian]

did anyone mention europa in this thread?

[maddog]

I had posted info on this book before. This thread?

But new posters, so worth repeating.

A great book on this subject is:

Probability 1: Why There Must Be Intelligent Life in the Universe by Amir D. Aczel

It takes the Drake Equation, breaks each variable down and provides "reasoned" numbers to sub. (reasoned? Logical? that's another thread...)

Would I be giving the ending away to say the results are "1" (100%)?

This depends on how you define it. The book Carl Sagan and IL. Silkhovsky (I think his spelling),

"Intelligent Life in the Universe". This book is a bit older so does not have added correlation with new

data about planets around other stars.

In this book the answer would not be "1.0". Because this would imply EVERY star in the universe has

intelligent life. This is the statistical probability that any one star would have life or not. I suppose

you could argue the cumulative statistical probability that the universe has life to be "1.0" assuming

that you think there is Intelligent life on Earth ? ;)

 

Maddog

[pgrmdave]

He at the very least assumes himself to be intelligent ;)

[maddog]

He at the very least assumes himself to be intelligent :D

My answer to that could start a whole new thread...! ;)

 

Maddog

[TeleMad]

The values used in my claculation are the low end of the spectrum and still come up with a decent possibilty.

 

No, the one value you used can't be said to be on the low end of the spectrum because we have no idea whatsoever what the true value is. It could be 1 in a trillion...it could be 1 in a googol.

 

Fishteacher73: I feel that it would be erroneous to conclude that since we have only observational evidence of about 200 planets there are no more.

 

That there are no more what? Planets? If so, that's not at all what I said.

 

Fishtecher73: Hence why I atributed to the values the lowest estimates that are currently agree upon generally.

 

Which doesn't change the fact that the number I questioned could be 1 in a googol.

 

What empirical evidence do you have that shows that can't be the case? None.

 

Fishteacher73: Even with the low-balling the possiblity comes up that there is reasonable conclusion to say that other life should exist out there.

 

It's nice that a calculation based on a complete unknown shows that. Now, show us some real science that does.

[ldsoftwaresteve]

Hi, this topic is the most dear to me of many so I'm driven to throw in my two cents worth.

 

Let me provide some observations of my own. I can't provide any source for them except that they come from me, from my own contemplations, etc.

 

The first is that, to me at least, the entire discussion of life seems to always imply a sort of 'un-naturaleness' with regard to life. The silliest example I can think of are the proposed theories that say that life originated 'elsewhere' and was deposited on earth. To me, that is used to slip the responsibility of understanding what life is or at best, just postpones dealing with it. All such theories are weak, to say the least, since we have ample proof that life originates here all by itself. And by extension, it's probably safe to say that we'll find it everywhere we look.

 

No, I'm convinced that life exists wherever it can. And if I'm correct, then when conditions are right, life will begin given time enough for it to do so.

 

That implies something about the nature of existence and that life is just part of it. Natural, normal, and most likely necessary for some really wierd reason and by that I don't mean to imply a religious connection. I mean necessary for mechanical reasons.

 

In a particular temperature range, given the confluence of the right components and enough time, I suspect that life spontaneously erupts. I suspect that someday we'll be able to see it happen right before our eyes. We'll watch genetic material come into existence from what at first appears to be nothing - but on closer examination we'll find that it was triggered by an as yet unknown property of the component materials.

 

That will be the point at which we really start understanding what's going on.

 

That's enough for now. I've got to work.

[sage]

hwy is that the same question has been asked for ages and we have not been able to find an answer...................... for more than half a century peolpe has been looking up for ufos from other planets..........................does anyone sincerely want(not believe!!!!!) any extraterrestrial life.................i am another of those men who do not worry about these thing while we have a lot to worry about our own planet..............why waste all the money spent for projects like SETI ................ there is a good lot many people out here who are terribly in need of help ...........................in such a case theis is just a waste of time

 

if as we imagine, they have a superoir race, superior technology to us they will find us ....................and if they are not as good as us ,time has not reached to talk to them......................lare we the only life in this universe-----------lets make sure noone will have to say "is there life left in this universe

[Fishteacher73]

It's nice that a calculation based on a complete unknown shows that. Now, show us some real science that does.

 

To extrapolate values from resonable assumptions is not a complete unknown. While the precision of such estimates is questionable, I feel the accuracy is reasonable.

 

We have evidence that life can exist (We're here). It is a very good bet that there are decent number of planets with similar circumstances such as the Earth. As I stated earlier, this is assuming that there are no other possible variants of life-basis. There may be a form that thrives in a situation very different from the conditions here on Earth. Those possiblities are virtually ignored when looking for possible life locations (We focus on Earth-like planets).

 

I have supported my POV, you seem to oppose it. Do you have any hard science that supports your POV, TeleMad?

[alxian]

so no one has yet mentioned europa in this thread?

[TeleMad]

To extrapolate values from resonable assumptions is not a complete unknown.

 

You've got it backwards. Relying on a complete unknown, as you are doing, is not extrapolating from reasonable assumptions.

 

You have yet to provide a single fact that shows the number you chose to use is correct, or that 1 in a googol is wrong.

 

 

Fishteacher73: We have evidence that life can exist (We're here). It is a very good bet that there are decent number of planets with similar circumstances such as the Earth.

 

Which means squat if the actual probability of an Earth-like planet giving rise to life is 1 in 10^60, or 1 in a googol.

 

Fishteacher73: As I stated earlier, this is assuming that there are no other possible variants of life-basis. There may be a form that thrives in a situation very different from the conditions here on Earth. Those possiblities are virtually ignored when looking for possible life locations (We focus on Earth-like planets).

 

And they should be ignored. The Drake Equation is already next to useless: adding in science fiction speculation would only do it more harm.

 

Fishteacher73: I have supported my POV...

 

No you haven't. You said that if we do the math, we'd see that it is inevitable that there is other life out there. You have not supported that position, except with unsupportable guesses. Until you can show that the variable of interest is what you claim, I and others can do the math and get a near 0 probability of there being any other life anywhere in the universe.

 

Fishteacher73: Do you have any hard science that supports your POV, TeleMad?

 

Trying to switch things around? No, let's stick to the current topic. We'll worry about my position after you actually support yours - or admit what you said is not correct, whichever comes first.

[ldsoftwaresteve]

Personally, I like both arguments. If life is an accident, then I agree with one side. If not, I agree with the other.

 

If there is a causal relationship between unknown properties of matter and life, then life is not an accident and wherever the right conditions exist, life follows.

 

If life is an accident, a freak in the universe, then the odds of discovering it elsewhere are not good. One in a million or one in a million squared, w/e, it's still not good.

 

Since we don't know the answer to this it seems pointless to argue about the odds, don't you think? When we can observe 'distant shores', then we'll know.

 

Here are some other paths to walk down in the meantime: 1. What is the difference between 'Plant' life and 'Animal' life, really? 2. Do all lifeforms percieve? 3. Could living things be classified in terms of their perceptive abilities? 4. If there is a causal relationship between unknown properties of matter and life, what are the implications?

 

Without life, the universe has no meaning.

[pgrmdave]

Telemad, I think that what you are saying is that the values for the Drake equation are so arbitrary as to make it useless, right? Well, consider the number of stars in the galaxy, about 100,000,000,000. There are an estimated 200,000,000,000 galaxies in the universe. That means that there are, assuming that our galaxy is typical, about 20,000,000,000,000,000,000,000 stars in the universe. I'm not sure of the numbers, but I've read that roughly 10% of stars are assumed to have terrestrial planets. That brings the number down to 2,000,000,000,000,000,000,000 stars with earth like planets. Now the math becomes fuzzier - Is our solar system typical? If it is, then we can proceed, if not, then we need to find out why. However, with at least 2,000,000,000,000,000,000,000 planets, the chances of life forming would need to be .0000000000000000000005% for us to be the only planet with life. While I think that it is possible, I do not believe that it is probable for us to be the only planet with life.

[TeleMad]

I did read the rest of your post. It sounded like - and in fact was - unsupported personal speculation. Let's see, there's methane in Titan's atmosphere - guess that means there's life there. When you do come up without something a little more convincing, let me know (I won't hold my breath).

 

Well, we've visited - even landed a craft on - Titan now, so, where's the life?

[TeleMad]

Telemad, I think that what you are saying is that the values for the Drake equation are so arbitrary as to make it useless, right?

 

For anything other than having fun, basically, yeah.

 

pgrmdave: Well, consider the number of stars in the galaxy, about 100,000,000,000. There are an estimated 200,000,000,000 galaxies in the universe. That means that there are, assuming that our galaxy is typical, about 20,000,000,000,000,000,000,000 stars in the universe.

 

Okay, let's suppose there are 2 x 10^25 stars and each one has a total of 500 planets and moons. We won't worry about things like the fraction of stars that can produce Earth-like planets: we'll accept all stars and all planets and all moons as being appropriate. That would bring the total number of celestial bodies to 10^28. Huge number, isn't it. Now suppose that each of those celestial bodies gets a trillion trillion trillion trillion - that 10^48 - shots are originating life. That would come to a staggering 10^28 * 10^48 = 10^76 shots at generating life in this system of celestial bodies. Wow!

 

But now what if the probability of life arising in a "single shot" is 1 in 10^120? See how much bigger the exponent is on that number than on the number of possible shots? It is so much larger that life's arising indepdently twice on these celestial bodies should be rejected. And what empirical/scientific evidence do we have that the "single shot" probability of life arising by a prebiotically plausible mechanism can't be as small as 1 in 10^120? None. In fact, some evidence (based on the closest things to an RNA replicase yet produced by directed evolution) supports the notion that it could be that small.

 

Some people get too excited when they think about the number of celestial bodies on which life might arise that they are blinded to the fact that there being other life in the universe depends critically on how probable life's arising under prebiotic conditions is: a number they ignore.

 

The output of the Drake equation depends on what value one assigns to this most uncertain parameter.