Are we alone?

[xelasnave]

Originally Posted by Max Vondel

Anthropomorphic reasoning doesn't help
Because life is abundant here...doesn't translate to the other places in the universe. Dolphins are intelligent but don't build radio telescopes or space capsules

Yes but who knows what they build on the planet of the dolphins...

[xelasnave]

Originally Posted by deanm

As a molecular geneticist, the fundamental basis of life on earth was the evolution of self-replicating molecules which contain & propagate information.

That's the hard part, but a lot of chemistry can happen over a few billion years.

Once you have self-replicating molecules, the subsequent development of cellular structures, then multicellularity, is pretty straightforward.

So *life* can readily evolve. However, intelligent life is a different proposition.

Dean

Dean

I think I know how an independent environment can be created with a mere droplets of water.
Bert presented some interesting stuff years ago which showed molecules line up at the surface of a small drop of water which I think may be the first step in formation of an "egg" or an independent environment.
It would not be a stretch to imagine other "relevant" molecules getting together at the center. Use my idea if you wish I hope you see the implications.
Alex

[deanm (Dean)]

Alex - you're coming up with your very own 'Drake Equation'!

If the universe is truly infinite, then no matter how low the chances or probability of life evolving around any given star, given the dimension of infinity, this probability becomes an inescapable certainty.

Dean

[GTB_an_Owl (Geoff)]

Dean

you probably don't know how right you might be about Alex and a "Drake Equation"

(and i think this might be a private joke between Alex and myself)

what do you think Alex?

geoff

[OICURMT]

Originally Posted by xelasnave

Probably no one has ever thought about this question so I ask it now

I assume you were not serious about this statement...

Originally Posted by el_draco

chemistry and biology as we understand them

This is the basic problem. Our knowledge is fledgling, consequently, we know little if anything at all when compared to the evolutional history of our planet.

Originally Posted by bojan

believing is one thing, knowledge is another

I love this statement... believing in this context is better known as "faith"... which takes us to a different topic, so I'll stop now.

Originally Posted by AstralTraveller

AFAIK we couldn't even detect oxygen in the atmosphere of an extra-solar planet. It's not so much looking for the wrong telltale sign as not yet being able to detect the most obvious smoking gun. Until we can do that, the best we can say is that they haven't knocked on the door. Of course we haven't knocked on theirs either and we're here (though I'm not all here).

Why would we have to concentrate on Oxygen? Are we, as a humans, stating that all intelligent life *MUST* breath oxygen? What about Groot? "He" takes in CO2 and exhales oxygen! Maybe we should concentrate on CO2, albeit difficult as it's a by-product of volcanism.

Originally Posted by Max Vondel

Anthropomorphic reasoning doesn't help
Because life is abundant here...doesn't translate to the other places in the universe. Dolphins are intelligent but don't build radio telescopes or space capsules

This is the best post in this thread...

Maybe life is abundant. Maybe there are lifeforms that are intelligent, but see no need to "expand to their surroundings" as the famous "Homo Sapiens" do. Maybe *MOST* lifeforms just keep to themselves and don't have the curiousity of humans. Maybe *we* are the outlier in the intelligent universe...

Originally Posted by Max Vondel

However finding microbes is different to finding a space faring communicating civilisation by many orders of magnitude.

Agreed, but life is life and if there is life, there is the possibility of intelligent life. We have a rudimentary form of it here on our planet, and I mean rudimentary, as there are still way too many problems to consider our species truly intelligent.

Originally Posted by xelasnave

Yes but who knows what they build on the planet of the dolphins...

I suspect not submarines...

As for the question about correlating intelligent life with economics... money is a human construct. Other forms of life may not have it or need it. There could be a society of aliens that just get along for the survival of the species, each contributing to the advancement of the "species". The process of Natural Selection may work differently than it does here on earth.

OIC!

[bojan]

Yep, money is a human construct..
In essence it is a tool to measure effort put into some result.

The question should be - how much effort is required for achieving contact (space travel) ?
It shouldn't affect the internal society balance, no mmatter on what that balance is based.

[vlazg (George)]

Why would we have to concentrate on Oxygen? Are we, as a humans, stating that all intelligent life *MUST* breath oxygen? What about Groot? "He" takes in CO2 and exhales oxygen! Maybe we should concentrate on CO2, albeit difficult as it's a by-product of volcanism.


I am GROOT !!!

[xelasnave]

Originally Posted by deanm

Alex - you're coming up with your very own 'Drake Equation'!

If the universe is truly infinite, then no matter how low the chances or probability of life evolving around any given star, given the dimension of infinity, this probability becomes an inescapable certainty.

Dean

Yes the drake equation but I wanted something that anyone could understand and start to comprehend the numbers and of course my numbers are so conservative but enough for folk to get a handle on just how real the chances of life must br.
It is a notion some can not entertain because of the philosophical position and fair enough but to them I suggest a night under the stars with a grain of sand and an arm rest.
Then ask really are we it

Alex

[sn1987a (Barry)]

They don't care what meat thinks

[ross-boughen]

Any one here know of Eduard Albert Meier?

[AstralTraveller (David)]

Originally Posted by OICURMT

Why would we have to concentrate on Oxygen? Are we, as a humans, stating that all intelligent life *MUST* breath oxygen? What about Groot? "He" takes in CO2 and exhales oxygen! Maybe we should concentrate on CO2, albeit difficult as it's a by-product of volcanism.

The reasoning is that planetary atmospheres form with a reducing atm because that's what you get when you condense a proto-planetary disc. On Earth the oxygen is wholly a product of photosynthesis and so proves that the Earth is inhabited (at least by blue-green algae). I understand that there may be planets where chemical energy is obtained by other means but if you see oxygen there is life.

Could we detect the oxygen in Earth's atm from the distance of an exoplanet? I suspect not. So if we couldn't detect life on Earth from several light years distance why would we think we can detect it on an exoplanet?

Originally Posted by deanm

As a molecular geneticist, the fundamental basis of life on earth was the evolution of self-replicating molecules which contain & propagate information.

That's the hard part, but a lot of chemistry can happen over a few billion years.

Once you have self-replicating molecules, the subsequent development of cellular structures, then multicellularity, is pretty straightforward.

So *life* can readily evolve. However, intelligent life is a different proposition.

Dean

My understanding is that the development of life might be pretty 'easy' but developing photosynthesis may be the big stumbling block. I recall hearing that the evolution of photosynthesis is very unlikely. Something about it requiring the appearance of two unlikely chemical pathways at the same time. This explains why things like vision, hearing and all forms of locomotion have evolved multiple time but photosynthesis only evolved once. It could well be that there are many planets where rudimentary life has developed but hasn't progressed much because there is no mechanism to capture solar energy. So they may have a few 'worms' hanging around deep sea vents but no phyto-plankton in the oceans, no land plants and no higher organisms harvesting the trapped solar energy.

Of course people will argue that alien life may use a different chemistry and I accept that. However the chemical pathways should at least be viable. Mythical beings who are powered by endothermic reactions are just that - mythical. In the meanwhile we should consider what we can predict based on the biochemistry we know.

BTW were you bored today Alex?? Thought the pot needed some stirring?

[xelasnave]

Originally Posted by GTB_an_Owl

Dean

you probably don't know how right you might be about Alex and a "Drake Equation"

(and i think this might be a private joke between Alex and myself)

what do you think Alex?

geoff

Yes indeed Geoff.
How many beers can you handle at the Drake Pub and still grab the pool que by the right end.
Its been a while since I have been over and there is a new public who I have yet to meet.
I have been in Sydney looking after my father and I miss the place and the people.
Alex

[OICURMT]

Originally Posted by AstralTraveller

The reasoning is that planetary atmospheres form with a reducing atm because that's what you get when you condense a proto-planetary disc. On Earth the oxygen is wholly a product of photosynthesis and so proves that the Earth is inhabited (at least by blue-green algae). I understand that there may be planets where chemical energy is obtained by other means but if you see oxygen there is life.

Thinking out of the box... 'cuz I like to

What about direct coalesence of Oxygen into an atmosphere around a planet after the accretion phase of development?

http://www.space.com/12494-oxygen-mo...-herschel.html
http://sci.esa.int/herschel/49009-ox...-orion-nebula/

Alternatively, maybe there is life in the Orion Nebula and free-floating algae is everywhere!!! (ok ok ok ... it's evening and I'm drinking )

[deanm (Dean)]

" I recall hearing that the evolution of photosynthesis is very unlikely".

Hmmm.. my gutters need cleaning: photosynthesis still going strong here!

Many microbes use various wavelengths of sunlight to do their version of photosynthesis.

For electron transport, some use metals (even halogenated metals), some use sulphides, chlorinated species and the like.

Life will always achieve whatever is biologically possible.

Dean

[xelasnave]

David I was not bored or stirring the pot.
Well I am always a little bored I guess but it only occurred to me after the op that folk may hold views such that speculation about life may not be acceptable.
I dont wish to upset people but it seems I do at times and maybe this is one of those times.
Nevertheless it would seem odd that given the size of the Universe, even if only finite it is still huge, to believe there is no life anywhereother than Earth.

There are billions of gallaxies and each galaxy has billions of suns moons planets etc.
so if one wishes to think there could be no life anywhere but Earth they are welcome to do so in my book... I dont need to argue against their belief and I hope to receive tolerance of my belilef... Which is life will be out there and beings greaterthan we can imagine probably commonplace.
Now if the Universe is infinite other life will be infinite... And as infinite goes inteligent life will be infinite... Infinite think about the implication...
Personally I believe the Universe probably is infinite if not bigger.
Alex

[deanm (Dean)]

"Personally I believe the Universe probably is infinite if not bigger. "

Go on Alex: twice as big as infinite?!

THREE times as big as infinite?!

Yikes! Infinity might be bigger than anyone imagined!

Dean

[xelasnave]

Originally Posted by deanm

"Personally I believe the Universe probably is infinite if not bigger. "

Go on Alex: twice as big as infinite?!

THREE times as big as infinite?!

Yikes! Infinity might be bigger than anyone imagined!

Dean

My attempt to make folk focus on the concept of infinity.
Thanks for your input it will help.
Question... Can we talk about probability in infinity or is it simply pointless cause infinity destroys the concept of probability?
Alex

[deanm (Dean)]

"Can we talk about probability in infinity or is it simply pointless cause infinity destroys the concept of probability?"

What an interesting concept, Alex!

If the probability of an event has any magnitude above zero, then infinity dictates that the event must happen.

And not just once: this once-in-a-trillion-googleplex-biannual event must recur an infinite number of times.

Infinitely.

So, Alex - I believe you are correct:

Infinity abolishes probability.

Dean

(But I'll toss ya for it..!!)

[OICURMT]

Originally Posted by deanm

"Personally I believe the Universe probably is infinite if not bigger. "

Go on Alex: twice as big as infinite?!

THREE times as big as infinite?!

Yikes! Infinity might be bigger than anyone imagined!

Dean

I remember as a kid saying how much I loved my mother... I described it as "I love you to inifinity!", to which my sister said "Mom, I love you infinity times infinity!"...

[raymo]

If the universe began with the big bang, and is still expanding[even accelerating its rate of expansion] then by definition it can't be infinite.
raymo