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Drake's equation

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46531.  Wed Jan 18, 2006 11:22 am Reply with quote

Yes, the main problem with all current theories of planetary formation and development of life is that they're trying to extrapolate from a graph with a single data point.

And before anyone points out there are nine planets (allegedly), they were all formed at the same time and so really only give us one theory which explains the solar system.

46777.  Fri Jan 20, 2006 7:12 am Reply with quote

Excellent thread. I love those Bracewell-Von Neumann Probes, which somewhat undermine my own intuition (ie, I know nothing at all on this subject) which is that 1) the conditions for life to exist are tremendously rare but must exist in many places nevertheless, and 2) they typically only persist for short periods (long enough for, say, a few thousand years to be the typical maximum duration of a scientifically advanced life form) and 3) the problems of inter-stellar communication are effectively insuperable. If these ideas are right you'd get life forms popping on and off all over the Universe like flash bulbs all the time, but all functionally isolated from each other unless two planets in the same solar system happened to develop intelligent life simultaneously - ie yet another layer of extreme coincidence, and one which has not occurred in our case.

But I do love those Bracewell-Von Neumann Probes.

46813.  Fri Jan 20, 2006 9:03 am Reply with quote

For the more paranoid punter, who thinks that there are lots of alien communications going on, there's this article which explains how they conceal themselves.

There's a book out at the moment (which I cannot seem to find anywhere!) called something like 50 Reasons We Haven't Heard Yet, which gives 50 pretty good reasons for the apparent silence of the galaxy, ranging from "we're first" to "everyone hates us". I flipped through it in the bookshop, and it seemed quite coherent and carefully thought out.

My current favourite theory remains that all sentient life than can create information and communications systems will disappear inside its own internet, and live in a virtual paradise of its own creation, ignoring the physical world, which is rather unforgiving and hostile.

46820.  Fri Jan 20, 2006 9:38 am Reply with quote

Has anyone ever read the great SF book The Star Maker by Olaf Stapledon? This gives an amazing account of the writer's view of a possible Galazy and Universe. Many life forms have arisen among the huge number of stars, all striving for the same goal of spiritual and mental lucidity. This seems extremely relevant to this topic and is quite interesting too.

It might be that an 'awakened' race, having gone through the troubles and hardships that we are now experiencing to reach higher consciousness, has recognised that this process is necessary for the proper formation of intelligent minds, so has deliberately guarded us from any outside interference to see if we have 'what it takes' to be super-intelligent beings, reminding me of the Royal Marines slogan, '99.9% need not apply'

Or, of course, we could just be part of an elaborate computer system, created by pan-dimensional beings that manifest themselfes as white mice, that has been corrupted by the unneeded hairdressers and telephone sanitisers of another world and that will be destroyed 10 minutes before the final, incorrect, readout.

(sorry, Douglas Adams, it had to be done)

Arfur Fuxache
49437.  Sun Feb 05, 2006 8:09 am Reply with quote

Most of the discussion and indeed theorisation makes the assumption that life requires a similar environment to our own and probably carbon based.

What about other life form which could use totally different environments - Makes the "Why aint we seen em" question even more daunting.

But they are here, they live amongst us and hidden from view, and if you look carefully the evidence is here - They move things around that you have put in a "safe place" and they eat socks

49438.  Sun Feb 05, 2006 8:56 am Reply with quote

Arfur Fuxache wrote:

But they are here, they live amongst us and hidden from view, and if you look carefully the evidence is here - They move things around that you have put in a "safe place" and they eat socks

Nurse! Some of the patients are out of bed again.

49472.  Sun Feb 05, 2006 1:45 pm Reply with quote

They eat biros too.

Arfur Fuxache
49493.  Sun Feb 05, 2006 5:32 pm Reply with quote

Hey its difficult posting with crayons

49517.  Mon Feb 06, 2006 5:02 am Reply with quote


Carbon is the only element which has the electronic stability to make long chains of bonds with itself and with the range of other atoms that replicating molecules need. There's nothing even remotely as complex that we've found or can even theorise involving non-carbon based chemistry.

But that's just what we've seen around here, of course. There's quite a good description of possible life in the atmosphere of gas giant planets, where the density is enough to act like a watery medium - essential to allow replicators to get about and compete for the limited resources.

49527.  Mon Feb 06, 2006 5:45 am Reply with quote

What he said.

Carbon based life is all we know about at the moment. We can, therefore, devise tests which prove the existance of carbon based life on other planets and show, here on earth, why these tests must be caused only by carbon based life.

Life forms based on other materials have never been seen here and are, therefore, completely hypothetical. Coming up with a rigorous test to prove the existance of such life, something which can only be caused by such life, is therefore impossible. For this reason, the search for extra-terrestrial life is concentrating solely on carbon based life forms.

49529.  Mon Feb 06, 2006 5:55 am Reply with quote

Wired is running an article on (moderately) plausible carbon lifeforms that we might expect to find on planets with different environmental conditions.

It would be extremely surprising to find anything that looked like us, although some features will almost certainly be convergent. Eyes will exist elsewhere (because light is a channel through which to get information about the world around you), and similarly ears and touch. And if there are eyes, then there will also be coloured animals - sexual selection will use any 'channel' is can to get an organism noticed...

Some kind of gripping hands will allow for tool-making and therefore advanced and intelligent life (tools 'shape' brains). But by this point, it becomes very hard to identify 'intelligent' characteristics in a way that is non-human-centric. Small, abundant insectoid life is probably going to be the most common form we see.

Not that we'll ever get to travel that far without some handy space-bending techniques, mind you...

49547.  Mon Feb 06, 2006 8:37 am Reply with quote

As anyone who has seen Alien can tell you, silicon is a possible base for a life form, but just how useful is it?

Also, it may be that we have missed some other alien race, since the immensity of the universe's life and the comatative previty of civilisations, we could simply be in the wrong place at the wrong time.

49554.  Mon Feb 06, 2006 8:53 am Reply with quote


49555.  Mon Feb 06, 2006 8:55 am Reply with quote


49567.  Mon Feb 06, 2006 10:50 am Reply with quote

Although it's certainly possible that we'll discover some other information channel that we can't currently conceive of, let alone detect, I imagine things like radio will be a common discovery, simply because it's an extension of light - it's the same phenomenon, but at a different frequency.

Radio and radioactivity are found naturally (that's how we stumbled across them) so discovery is just a matter of examining the phenomena sufficiently closely. First notice it, then harness it.

If there were any other effects lurking around us that we could exploit, then we'd have picked up some kind of sign of them, surely. There are no mysterious forces or channels of communication that are currently unexplained.

But, having said that, there might be something like quantum hyperspace tunneling that we could use, which might be instantaneous and render radio useless. That might be why we're not hearing any radio from space - it's been abandoned by advanced races a long time ago (or not discovered yet by others), and we're looking for the equivalent of huge semaphore flags in space...


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