Aliens

[scorpia]

Maybe time with a trekkie I know is getting to me..... but lately I feel the need to ask; people here only believe things on scientific basis. Well then what of the existance of aliens? There seems to be more than enough proof that life existing on a planet other than Earth is possible. There are plenty of planets in other solar sytems discovered already. And if life could happen here on Earth, it can happen again. So would there be by now sufficient proof for the existance of aliens? Are they really that supernatural?

[otseng]

Is anyone getting a little...nervous about the lack of results from SETI? I remember wondering about this way back in the 70's, but I was told back then to hush up and be patient, they hadn't covered the smallest fraction of the sky or the potential frequencies; wait another 20 years or so, they told me.

Actually, the contrary for me. Not finding any ETI would be what should be expected if one believes in creationism. So, with each passing decade with no evidence of extraterrestrial intelligence, it simply confirms the tenets of creationism.

Well...it's been more like 30, and there hasn't been so much as a peep.

Though I would agree that evolutionists should be starting to get nervous about this. Why should life on earth be the only lucky ones to have evolved from chemical soup? Aren't there billions (or even more) of planets out there? And hasn't evolution had over 10 billion years to work its magic? If evolution is true, surely something else must exist out there. But, curiously, absolutely no evidence of any other life form has materialized.

What are the theological implications?

If we are the only intelligent beings in this universe, the theological implications would be huge. Especially if you combine this with the possibility that we are at/near the center of the universe.

(BTW, I've moved this thread to "Science and Religion")

[Jose]

I dunno, otseng. We're pretty much in the infancy of looking at the rest of the universe. Our search for ETI is pretty much limited to (1) sending out messages we think sound intelligent, and (2) looking to see if anyone else is silly enough to send out miscellaneous messages in random directions hoping that whoever replies is nice. Maybe they think it likely that whoever replies will be predators, and eat them. Maybe they think it likely that whoever replies will bring their version of smallpox to their planet and wipe out everything. Maybe the other guys are way smarter than we are, and have already studied us enough to know that they want us contained on our one planet.

It's hard to conclude that there's no other life on the billions of planets that calculations say must be habitable, when we haven't looked at any of them. All we can say at this point is "we haven't figured out how to detect them yet." As I often say in the lab, "we haven't done the experiment yet," so conclusions are premature.

[QED]

Actually, the contrary for me. Not finding any ETI would be what should be expected if one believes in creationism. So, with each passing decade with no evidence of extraterrestrial intelligence, it simply confirms the tenets of creationism...

...Though I would agree that evolutionists should be starting to get nervous about this. Why should life on earth be the only lucky ones to have evolved from chemical soup? Aren't there billions (or even more) of planets out there? And hasn't evolution had over 10 billion years to work its magic? If evolution is true, surely something else must exist out there. But, curiously, absolutely no evidence of any other life form has materialized.

In order to justify your optimism here, I would ask that you refute the argument I made earlier about the very limited 'window in time' through which we can detect an extraterrestrial intelligence. I went into some detail explaining the technical reasons why the broadcasting of interceptable signas is a primitive phase that would very rapidly be bypassed by technologists yielding to the same universal constraints forced upon everyone by common Physics.

The natural shift away from broadcasting to direct satellite transmissions has occurred in a single human lifetime. This contributes a huge reduction in 'leakage' where high-powered omnidirectional transmitters putting out thousands (and in some cases millions!) of watts of power are replaced by inward pointing satellites delivering only tens of watts.

In a few more human lifetimes I would expect our Planet to return to virtual radio silence compared to the peak of our activity. So the chances of us spotting another civilization going through their primitive broadcast phase is as good as zero. The only thing SETI can hope to detect are deliberate, multi-billion year long projects to establish Electromagnetic calling-cards. And I think Jose covered the reason why this probably won't happen.

[otseng]

I would ask that you refute the argument I made earlier about the very limited 'window in time' through which we can detect an extraterrestrial intelligence.

I don't know if I can "refute" it, but we can discuss it. 8)

I see your point about a possible technological/time mismatch. But, let me approach it from a view of a skeptic.

From a cosmic perspective, we have only been searching for a very small amount of time, but yet, in the time that we have been looking and listening, we detect no signs of intelligence. What should be the natural conclusion based on evidence so far? People have claimed to have seen ghosts. But why should a skeptic believe ghosts exist if they can't even be captured on camera? Likewise, why should a skeptic believe that aliens exist if there are no evidence for them?

To argue that aliens are "at the wrong place at the wrong time" or "they don't want to taken over by a hostile alien civilization" or "they just don't want to communicate with us" seems to beg the question. These attribute characteristics to justify their silence yet assumes their existence to be true.

So, the main question would be, why should anyone believe aliens might exist if there are no material evidence to support it?

[QED]

All I have done is to demonstrate that even if there are extraterrestrial intelligences, we would not expect to detect them by their EM signals without maintaining a watch-period spanning a considerable length of time. The requisite watch-period would depend on the frequency of new civilizations reaching the same technological level that we are at now. So nobody should regard the absence of evidence as evidence of absence. No doubt a conclusion that will make-up for any other disappointments.

So, the main question would be, why should anyone believe aliens might exist if there are no material evidence to support it?

Well, apart from faith, hunch or wishful thinking, the only reason would be if we understood how life came about naturally on our own planet. If this was understood and if it was known that other planets were out there that could provide the same conditions then we would have good reason to believe in ET.

If we found out that life arose here through supernatural means then we could draw no such conclusion. It would be entirely at the discretion of the supernatural. However, this supernatural force would seem to have a rather peculiar taste for where it decided to put us

Just remember that you're standing on a planet that's evolving
And revolving at nine hundred miles an hour,
That's orbiting at nineteen miles a second, so it's reckoned,
A sun that is the source of all our power.
The sun and you and me and all the stars that we can see
Are moving at a million miles a day
In an outer spiral arm, at forty thousand miles an hour,
Of the galaxy we call the 'Milky Way'.
Our galaxy itself contains a hundred billion stars.
It's a hundred thousand light years side to side.
It bulges in the middle, sixteen thousand light years thick,
But out by us, it's just three thousand light years wide.
We're thirty thousand light years from galactic central point.
We go 'round every two hundred million years,
And our galaxy is only one of millions of billions
In this amazing and expanding universe.

[otseng]

Well, apart from faith, hunch or wishful thinking, the only reason would be if we understood how life came about naturally on our own planet.

However, we don't understand how life came about naturally on our own planet. So, that being the case, how can we explain how life can originate elsewhere?

It appears to me that the belief in ETI would be based on philosophical grounds, rather than any sort of material evidence. The only argument seems to be that since abiogenesis/evolution must be true and that the earth must not be special, then it must occur elsewhere also.

However, this supernatural force would seem to have a rather peculiar taste for where it decided to put us.

Yes, it did have a peculiar taste for where it decided to place us. And a very special place at that.

[teegstar]

For every grain of sand on Earth, it is estimated that there are a few hundred million stars. Nobody can imagine a number that big - its huge, almost infinite

Even if there was only a 1x10^-99999 chance of a life form forming on a planet that had a 1x10^-99999 chance of existing with a sun that had a chance of being 1x10^-99999 the right size, when you multiple that by the sheer number of stars in our univerise, you're gonna end up with a big number.

Having said that, in this day and age, nothing can go faster than the speed of light. They may be out there, but we wont be seeing them anytime soon

EDIT: Changed word galaxy to universe...
EDIT2: Changed 'infinite' to 'reallllly big number'

[McCulloch]

For every grain of sand on Earth, it is estimated that there are a few hundred million stars. Nobody can imagine a number that big - its infinite.

Technically not. Infinite is a mathematical concept which means having no limits or boundaries in time or space or extent or magnitude. Clearly the number of grains of sand on Earth is finite. Multiplying that number by a few hundred million (another finite number) can only yield a finite number.

Even if there was only a 1x10^-99999 chance of a life form forming on a planet that had a 1x10^-99999 chance of existing with a sun that had a chance of being 1x10^-99999 the right size, when you multiple that by the sheer number of stars in our univerise, you're gonna end up with a big number.

Your argument would be more convincing, if you actually did the multiplication. (Number of Stars in the universe) × (Odds of suitable Planet) × (Odds of life forming on suitable planet) × (Odds that life on the suitable planet would have evolved to advanced stages of technology) × (Odds that the life with the advanced stage of technology have not used that technological advancement to destroy themselves) etc. Remember to use margins of error, since each of these numbers is necessarily a guess. Simply stating that a very large finite number multiplied by very small numbers yields a large number does not quite do it.

Having said that, in this day and age, nothing can go faster than the speed of light. They may be out there, but we wont be seeing them anytime soon

So, adjust your calculation to take into account only those planets likely to have produced and sustained advanced technological forms of life within the time frame dictated by the age of the universe (estimated) and the speed of light. I suspect that once you have completed your calculations properly that the accumulated margins of error would be of such a degree that your conclusion would be meaningless.

[teegstar]

[quote] Your argument would be more convincing, if you actually did the multiplication. [/qupte]

I think its called the Drake equation and it is a pretty impractical equation (but still relevant) - I was never actually out to solve the equation and put in some numbers.

My emphasis was, that there are so many stars out there, that the chance will always be high just because of the sheer number of stars (and in turn, solar systems) that exist. If you want to be technical and give dictionary definitions of the word infinite, then you're welcome to do so but please dont use it as a cheap shot against my post. I think it was pretty obvious that my point was a larger than imaginable number and in future I'll be sure that I specify this.

The more places you have to dig at, the more chance you have at finding gold. You dont need a rocket scientist to tell you that.

[Jose]

So, the main question would be, why should anyone believe aliens might exist if there are no material evidence to support it?

Strictly speaking, no one should believe it--in the true sense of the word "believe." However, based on statistical calculations, as teetgstar has pointed out, it is reasonable to conclude that it is likely that life exists elsewhere. It's not "belief" but "logical inference."

We can use the same argument (as you know) for the existence of god, ghosts, and Santa. Yet, there are those who persist in believing in them to greater or lesser degree, in the absence of evidence or statistical calculations that point to likelihood.

However, we don't understand how life came about naturally on our own planet. So, that being the case, how can we explain how life can originate elsewhere?

We can explain it exactly the way we explain our own origin. We know what types of elements exist, and we know that some of the types of compounds that (Terran) life uses can be produced under the anoxic conditions of ancient earth. We know that chemical reactions can occur, and can be self-organizing, and that surface catalysis can encourage certain types of reactions to proceed at much faster rates than they normally would. [blah, blah, blah...this is a topic for the Abiogenesis thread.]

While you are technically correct that we don't know all of the details of how life originated by natural means, this does not make it impossible or even implausible. We cannot rule it out on the basis of insufficient understanding. The best we can do in that regard is say "I, personally, am unwilling to accept it because I don't understand it." Unfortunately, this logic leads to the conclusion that humans cannot be alive, cannot reproduce, cannot think, and cannot develop from a fertilized egg--because we don't understand all of the details of any of these processes. Yet, we accept them fully in the absence of understanding. Sure, we can observe them directly, so we know that they happen--but it's not scientifically valid to use different standards for different questions. Either we understand it fully, or we don't. If we don't, then we work from the information we have, and search for the best experiments to do next to increase our understanding.

So, alien life on other planets is as likely as life on our own planet. [The fact that life exists here doesn't change the likelihood of its developing; it may be highly unlikely, but it happened.] It seems to me that it is highly unlikely that alien life will closely resemble our form of life either morphologically or chemically. It will have some overall similarities--the need for energy, for chemical building blocks, and for some kind of information-transfer from generation to generation, etc. Beyond that, we're at the level of wild imagination.

I'd say that what it boils down to is one's personal willingness to accept logical inferences from the available information--not as "fact" but as "hypothesis" or "theory." If there are, say, religious constraints against accepting such inferences, then we should accept that these are our personal constraints--and argue that it will take exceptionally strong arguments, supported by irrefutable data, to make us view the issues differently.