Did you go back in Psych?

Your observation about ships passing in the night rings true. Several people have modeled the SETI contact probabilities for coexistent civilizations depending on assumptions about the mean inter-civilization distances, and the longevity term (L) in Drake’s Equation.

Turns out with the limited reach of our current listening systems (Arecebo, Allen Telescope), that you could have an L over a 100 thousand years and still not detect each other. And our L (duration of a technological civilization able to communicate electronically) is about 100 years so far. Argument SETI researchers make to keep at it.

But I wonder who will fund that work after we descend into the New Dark Age abyss?

Anyway,
Good to hear from you.

DHQ

Vulcanis here, still alive and well. Unfortunately the trappings of postgraduate study have eaten up alot of my previously spare time. Juggling work, the purchase of my first home, practicum placements, coursework and thesis writing is proving to be a challenge! I will endeavour to start some more discussions in the near future.

It is depressing when one contemplates that we may truly be alone. However, the enormously vast timeframes involved with evolution and the age of the universe itself can act as a ‘reality kick to the head’ if required.

Quite possibly there have been countless intelligent civilisations out there that have come to rise and pass all within the relatively short span of a few million years. Our tiny chronological footprint stamps almost no bearing upon the universe, in the grand scheme of things.

Hyper-advanced civilisations could have existed at the same time as the neanderthals – transcending this existence and heading towards the next just as we were taking our first baby steps towards ‘humanness’. In the same vein, a tiny blue spot millions of light years away could just now be evolving towards multicellular life, coming to the ‘intelligent’ phase just as we are nearing the end of our species’ existence.

Like ships passing in the dead of the night, perhaps there are/have been other civilisations out there, but cosmic circumstance has thus far, prevented us from connecting.

Talk more soon,

Vulcanis

I’m inclined to agree with you. I think humans are alone in the universe. There is probably a lot of life out there (of the microbial variety) because it seems to be able to grow anywhere, hot springs, a mile under the ice in greenland, etc.

But intelligence? Why do we need to be so smart? We might be better adapted to surviving on planet earth if we weren’t so smart: more like the earlier hominids a couple of million years ago (e.g., Homo Erectus). The mutations that led to Cro Mangons may ultimately prove to result in an evolutionary dead end and the demise of the planetary ecology, as well as us.

SETI has found no indications of anyone out there. Only searching for 50 years, but it is a data point. I think we should continue looking, but the null hypothesis seems to be more confirmed every year that goes by without some indications on non-human intelligence in the universe.

We may be the smartest thing the universe has produced.
Not sure whether I’m proud or terminally depressed by that.

Hang in there

DHQ

All that science blows your mind.

Take care,

DHQ

Evolutionary pressures combined with random genetic fluctuation probably played a large part in the emergence of our species. There are also the variables involved with the formation of Earth, and in turn, the solar system. As DHQ mentioned, our collection of planetary bodies is relatively old in the history of the cosmos, formed from a second generation of exploding stars (making our own star Sol part of the relatively young Population I group). Older stars from Population II contained an intermediate amount of heavy metals, thus indicating that life could have been possible earlier in the life-cycle of the Universe (heavier elements are essential for life as we know it).

Not to mention the differing environmental influences on the development of life. Would a more competitive environment (perhaps one where two or more intelligent species coexisted) result in a faster growth of life? I suppose it would be quite a delicate balance whereby ultra-competitive environments would be just as detrimental to life as banal environments.

Thanks all for the great discussion thus far.

The current image of the evolution of the universe (subject to change!) is that it all stared in the Big Bang about 13.7 B years ago. The creation event generated mostly hydrogen and helium, with only a smattering of elements of higher atomic number.

The larger nuclear species (carbon, oxygen, nitrogen, etc.) needed for life as we know it (emphasis) are created in stellar explosions (supernova). So the first generation of stars that formed the first galaxies that began about 1-2 billion year after the Big Bang, had no heavy elements that could have yielded life. That first generation had to go through their life cycle (a few billion years) and explode spewing out the heavier elements needed for life.

Then a second generation of stars could form, and there would be both H and He in the gas/dust clouds, and also the heavier elements made by the explosions of the first generation supernovas. Pretty convoluted, but best guess is that it was several billion years after the BB before the necessary materials were available to make organic life.

Then it takes several billion years (based on planet earth history) before higher forms of life can evolve in planetary systems where the lower forms of life can get started.

So how long after the BB before we could have intelligent biologicals somewhere? Maybe 5-8 billion years. The solar system looks like it got started about 4.5 B years ago, so it might be composed of materials from the second generation of supernovas. We are potentially very late commers in the galaxy. There could be some very old societies out there. Or they could all be “come and gone”.

DHQ

Re: Gene’s comment about the time delay in detection. You are correct in your analysis that the ET originators of a transmission may not be there any more by the time we get their missive. If the senders are 500 light years away, 500 years will have passed by the time the message arrives in the solar system. A lot of water could have passed under the bridge, and the transmitting society may be gone, or transformed beyond recognition. Based on our history, the transmitting ET society may have transmogrified so much that it no longer even cares about talking to the stars, and will have forgotten it even sent a message out after 500 years.

We are unlikely to hear any RF transmitter further out than 10000 or 20000 LY, thus back in time no more than 20,000 years. Problem is not the power of their transmission, but the limitations of our best RF telescopes (Aricebo, Paul Allen Telescipe, etc.) to detect faint signals. Thus we are not listening back to the Big Bang (13.7 Billion years ago) when looking for ET’s noise making. Just relatively recent stuff. The Murchison Wide-Field Telescope being constructed in Australia (see Sci American article a couple of months ago) will only hear TV/Radio class emissions out to about 200 LY.

As you recall, one of the parameters in the “Drake Equation” is L, the estimated lifetime of a technological civilization. Obviously, non-technological ET civilizations are of little interest (e.g., like the Ancient Egyptians) until we can physically visit them. Only a technological civilization approximately like ours would have discovered electromagnetic communications, and thus be detectable by the basic SETI search protocol. Given our own future uncertainties (e.g., The Singularity, global climate change inducing civilizational collapse, nuclear war, etc.), the issue of how long an ET civilization might remain in a state where it could generate and hear high energy RF radiation is clearly important.

Since all of the parameters in the Drake Equation are just multiplied together, L gets no more or less weighting than the values of the other parameters, except that the variables dealing with astronomical uncertainties (like R, the rate of formation of suitable stars) may be less uncertain today (after decades of research) than L. If you look at analyses like the one I mentioned that Jill Tartar did, it is clear that assumptions about the value of L turn out to drive your conclusions (whether optimistic or pessimistic) about ET search success. The reason is that L has one of the largest uncertainty bands of any of the parameters in the Drake estimate. The astronomically-oriented parameters have much smaller error bars, based on research over the years.

L remains anyone’s guess. We still have only one exemplar (humans), and our L today (the period of time we could listen to or transmit RF radiation across interstellar distances) is certainly less than 100 years. So when L = 10,000, or 100,000 years is hypothesized in a Drake calculation, we are really being optimistic. Do civilizations like ours last a million years, or only 250?

If ET techno-civilizations are rare in the galaxy, then they have to last a long time to have some reasonable probability of overlapping in time with us. If they are plentiful, then we probably will overlap even with some short-lived ET societies, before they self-destruct.

I don’t remember what Dr Tartar assumed here in the 2002 analysis for the value of L. But obviously, L and fc (the number of techno-civilizations in the galaxy) have to play off each other to get to N (the Drake estimate of communicating civilizations in the galaxy). But in other papers I’ve read, it seems that any L less than 10,000 years gives you very pessimistic estimates: a very low probability that any communicating civilization would overlap with humans in the entire galaxy at the present time. L has to be upwards of 100,000 or even a million years before the probabilities look encouraging. Another reason for wondering if anyone is really out there transmitting.

However, plenty of RF noise makers around planet Earth, at least for now.

DHQ

I must admit I have not heard of the Baha’i faith, however I have read the Wikipedia page now that you have introduced it. Baha’i is described there as a relatively modern faith, beginning in the 19th century. Is it an offshoot from Islam? I found its belief in and support of a world government particularly refreshing.

In regards to your question of ‘hearing back in time’, I am not sure of the answer, there are alot of unknown factors involved. Firstly, science has not completely explained the necessary factors involved in creating life, nor the time periods involved. How did the ‘primordial soup’ of basic chemicals take that great step into multicellular life? The main theories posit a wide range of possible catalysts for this reaction; anything from electrical discharges from lightning to the organisational properties of clay (crystalline molecular structure arranges chemical elements into useful matrices). Secondly, the age of the civilisation would depend upon the distance to the transmission origin. A planet 1000 light years away would thus be at a point 1000 years in the past; by the time the signal reaches us they could be extinct.

Perhaps extra-terrestrial life occurs in waves; intelligent life has not been around very long on our planet compared to the cosmic timeframe involved. Alien civilisations that emerged millions of years earlier could have been born, matured and faded away due to natural calamity or a product of their own progression. Perhaps this is a universal law of the Universe; civilisations can only advance to a certain point before the planet is no longer able to save them. The pace of technological advancement and potential solutions is less than the rate of planetary decay.

Humanity could already be in its twilight years.