Extraterrestrial life? Maybe we really are alone.

[Falconius]

Its been a while since i posted here, and it is good to be back. I'd like to hear some other opinions on this subject. Two weeks ago i spent some time with the astrological society in the Karoo, observing the stars through the night. The skies was clear and the night was extremely cold (-3deg. celsius). And this subject was mentioned, briefly, and brushed aside.

At this point I find myself leaning more towards a conservative outlook, maybe we are actually alone.

The Mars rock that NASA claimed to have shown signs of life has turned out to be a farce. And Scientists have failed to provide answers (as opposed to a shed load of theories) about the origen of life. In fact there are many scientists who favour the theory that life origenated somewhere else and arrived on Earth with a meteorite. This rather makes it irrelevant how many Earth like planets there are in the universe. It is also a good way of pretending to have solved this problem, by moving it elsewhere. Most of the reasoning I have seen conserning the existence of alien life is centered around the size and age of the universe and propability factors.

But the very same approach can be used to prove the existence of an entire planet made out of cheese.

Anyway, a good old rub your hands together and start typing whatever you think type subject, I hope.

Enjoy.

[Lord J]

So, I recently went to a talk in Phoenix that addressed this topic, amongst others (it was, generally, on life-- what is it?). There was a lot of interesting research thrown around, and some of the most interesting perspectives involved the idea of, if there was alien life, would we know it?

[Edric O]

I don't think there is any other intelligent life in our galaxy (though there may be some in other galaxies). I have never seen any adequate response to the Fermi Paradox: If there is some extraterrestrial intelligence, why can't we see any evidence of its existence, any "footprints" it left behind? Anywhere we look in the sky, all we see are natural phenomena. No evidence at all that anyone up there is doing anything artificial. Earth is leaking radio communications into deep space all the time. Someone looking at our Solar System may not be able to decode our signals, but they would certainly be able to see that they are artificial radio signals of some kind. We don't see that anywhere else.

The most likely reason is because other civilizations simply do not exist. But as for the existence of non-intelligent life... well, that's another story.

[Falconius]

Earth is leaking radio communications into deep space all the time. Someone looking at our Solar System may not be able to decode our signals, but they would certainly be able to see that they are artificial radio signals of some kind.

Good point, Ordos.

The sheer distances involved makes this a rather more involved argument. If a civilization exists in the neigbourhood of Antares they would need to wait 600 years to start watching Magnum P.I. If our civilization was on the one side edge of the Milky Way then another civilization on the opposite edge would only start hearing Elvis sing after 100 000 years. This of course works both ways, so by the time we start tuning into wrmkooos fm these "new friends" of ours could be 50 000 years buried and gone.

But as for the existence of non-intelligent life... well, that's another story..

I'm all ears as to what makes you say this. Do you mean you believe non-Terra live will be found out there? If so, why?

[Edric O]

The sheer distances involved makes this a rather more involved argument. If a civilization exists in the neigbourhood of Antares they would need to wait 600 years to start watching Magnum P.I. If our civilization was on the one side edge of the Milky Way then another civilization on the opposite edge would only start hearing Elvis sing after 100 000 years. This of course works both ways, so by the time we start tuning into wrmkooos fm these "new friends" of ours could be 50 000 years buried and gone.

Yes, but the galaxy is billions of years old. A few hundred thousand years is the blink of an eye by those standards. There is no reason to expect that all galactic civilization would rise and grow within such a short time span. If other civilizations existed in the galaxy, we should expect them to be spread out not only in space, but in time as well. For example, if there were 10 civilizations in the Milky Way, then we should expect the first one to be a billion years old, the second to be 900 million years old, the third to be 800 million years old, and so on...

And the radio communications of any civilization older than one million years should have reached us by now, no matter where this civilization was located in the galaxy. But wait, you might say, if a civilization is too old, maybe they've moved on to some other form of communication not based on the EM spectrum, and the radio tide from them has come and gone before Homo sapiens even existed. Perhaps. But a civilization advanced enough to develop non-EM communications should have left some other visible traces in the sky, like unusual heat signatures (infrared emissions) around their parent star, or ringworlds, or Dyson spheres, or something. The idea that a civilization could be millions of years old and leave no visible clues to its existence is absurd. Such a civilization should be expected to have left behind the equivalent of a giant neon sign saying "WE ARE OVER HERE."

I'm all ears as to what makes you say this. Do you mean you believe non-Terra live will be found out there? If so, why?

Well, why not? In the case of non-intelligent life, we have no evidence one way or the other. Our technology is not yet advanced enough to detect signs of life anywhere outside our Solar System. So, the galaxy could be full of non-intelligent life, and we wouldn't know.

I'm going to hold off judgment on this one until we develop a reliable way to test the atmospheric composition of rocky exoplanets. Once we have that, it becomes easy to test for the presence of life. Just look for oxygen. If there are a lot of planets with high concentrations of oxygen in their atmospheres, then life must be common. If not, then it isn't.

[Edric O]

Also, I just realized I jumped straight into the discussion and forgot to say this...

WELCOME BACK! :)

[Falconius]

Thanks Edric, Dune2k is the first Forum i joined online and as such it always revives something deep inside for me. "The gamer must awaken". :D

So, I recently went to a talk in Phoenix that addressed this topic, amongst others (it was, generally, on life-- what is it?). There was a lot of interesting research thrown around, and some of the most interesting perspectives involved the idea of, if there was alien life, would we know it?

This being the "WE ARE OVER HERE" neon sign?

Facinating point. And the connection between this (the 10 civilizations example) and the original topic lies with the theory of evolution. The idea being that life, once started, will inevitably become more and more advanced untill the rise of sentient beings and civilization.

This leaves us with a very complex problem: it is almost possible to calculate a broad picture overview of the time needed from the first basic forms of life right up to the "neon sign" to be received on our side. Our Earth and sun is about a third of the age of the Milky Way, and life is considered to have started in simple cell form after the Earth was about a billion years old. Man arrived about 3.6 billion years after life started (200 000 years ago) and it took us 10 000 years to get from hunter-gatherer to virtual reality. These figures may be very close to the truth, or they may be horribly wrong. But as they stand they do make the amount of time the "neon sign" would need to travel to us seem much less significant than i had originally thought. Eighter we are the first place where life started, or we should have received a multitude of signs by now.

My first point still stands though, we don't know how life started. And untill we do, we have little reason to think it exists elsewhere in the universe.

[Lord J]

Thanks DK :)

I think it actually has more to do with, A: there are rock exchanges with all of the nearby planets of the Solar system, and probably intergalactic exchanges as well. If we discovered a new lifeform, would it differ from life on this planet in terms of the structure of the DNA/RNA? If not, would it actually be extraterrestrial? B: Who knows how extraterrestrial life advanced throughout the universe? Just because primates evolved to use radiowaves on Earth doesn't necessarily mean that all other advanced civilizations would do so. Also, for all we know, very, very advanced civilizations are capable of some sort of radio-dampening/shielding technology that either erased their radio signal histories or shields us from their presence. Future communication is expected to involve optical arrays, which, I think, would remove radio communication from the table and end our broadcasting (I could be very, very wrong about this. I'm just not up on the science). I think (again, I'm not sure) that it is possible that an advanced civilization used radio for a time then switched over to something else a long time ago, and we just missed them.

[Falconius]

A: there are rock exchanges with all of the nearby planets of the Solar system, and probably intergalactic exchanges as well. If we discovered a new lifeform, would it differ from life on this planet in terms of the structure of the DNA/RNA? If not, would it actually be extraterrestrial? B: Who knows how extraterrestrial life advanced throughout the universe? Just because primates evolved to use radiowaves on Earth doesn't necessarily mean that all other advanced civilizations would do so. Also, for all we know, very, very advanced civilizations are capable of some sort of radio-dampening/shielding technology that either erased their radio signal histories or shields us from their presence.

A:Generally accepted theory

After reading this, one has to ask: how different should this mythical point of origen (panspermia) be to Earth for life to have started "over there" before it spread to Earth? I would be very surprised if this life starting conditions cannot be recreated in a lab somewhere.

This may come across as a nasty comment, so sorry in advance, but the belief that we will one day be able to restart the first life is at this point pretty much a faith type statement. Right up there with the statement/theory that God created life. But this last theory won't get any funding for scientists, so it makes more sense for them to continue pretending they will have the answer next week and get funded for life. And from a moral perspective we should support their continued search, of course. But we should also admit that we are at an impasse on some fundamental questions.

B:FTL would seem to be the answer. About the second point i am unsure. You would almost need to time-travel in order to erase/contain the ever expanding signature of the times when your civilization first started to broadcast its presense with radiation. Light is simply a form of radiation our eyes can pic up to allow us to observe our surroundings. In a universe ablaze with radiation the idea of a civilization that does not use it sooner rather than later seems very unlikely.

But still very thought provoking, thanks Lord J.