Trillions of Earths

[CraigS]

G'Day Les;

Very cool. I thank you for taking the time to present such a considered case.

I've learned a lot from your terrific posts.

I also respect your final opinion of it all, because you presented it as your opinion.

I think this discussion is influencing my views on it all as well, although my focus is more on how to discuss the topic, given the paucity of empirical data, to make any firm statements, one way or the other.

Your posts serve as a good reminder that so far, what we DO know about what it takes for intelligent life to come about and develop, is quite specific (and keeps growing). The frequency of occurrence of these specific conditions in an infinite universe, leads us to the conclusion that life, (intelligent or otherwise), is probable (ie: probability ~ 1). That's not saying much, because we know we exist !

The second instance of it, is clearly the big question. (That's like stating the glaringly obvious, too … I'm trying hard …)

Personally, I think panspermia or necropanspermia are quite likely, (yep that's an opinion), but there have been some interesting discoveries along these lines lately in support of these views. Possibly even more likely, is that our probes may have transported bacteria or viruses, in some state or another, to the planets we've visited. I'm perplexed about what we'd make of an exo-life finding in our own solar system, particularly if we'd already sent probes to the same location. Also, what might we make of it, if we found bacteria on a passing Asteroid or comet ?

Anyway, I've shared about as much as I'm able to in this thread. It mostly amounts to dimensions of thought about the issue .. which is quite intentional.

Cheers & Regards.

[bojan]

Originally Posted by ngcles

On that basis, again the way I see it, intelligent life is likely to be exceptionally rare and maybe even singular in our galaxy. Agree or disagree with my opinion (that for the last time I point out that I'm not passing-off as “fact”) by all means, but your view like mine is similarly an opinion.

It is an exceptionally interesting topic.



Best,

Les D

Than could be the explanation for Fermi paradox...

[Jason D (Jason)]

A number is a number. It might not mean much.

There are trillions and trillions of sand grains on earth, what is the likelihood to find two identical sand grains – atom for atom? We can safely assume 0%

If I flip a coin 10 times, what is the likelihood I end up with at least one “heads?” ~99.9%

Jason

[CraigS]

Hi Jason;

Thanks for your comments .. I have some questions (as follows) ..

Originally Posted by Jason D

A number is a number. It might not mean much.

Humans make meaning out of everything.
We are meaning adding machines !!

Originally Posted by Jason

There are trillions and trillions of sand grains on earth, what is the likelihood to find two identical sand grains – atom for atom? We can safely assume 0%

Why is it safe to assume this ?

Originally Posted by Jason

If I flip a coin 10 times, what is the likelihood I end up with at least one “heads?” ~99.9%

This is a safe prediction because we know a coin has two sides before we start flipping !

Your former statement however, is definitely 'not safe' !

Cheers

[Jason D (Jason)]

My point of my earlier post is that calculating/estimating probability is highly influenced by the set of assumptions rather than the size of the sample. In my example, I have shown an event with 99.9% probability of occurring with a sample of 10 and another example of an event with ~0% probability of occurring with a sample of trillions and trillions. By the same token, we should not rely on the sample size of planets count to estimate probability of life but rather we need to come up with a good set of assumptions to do so. Unfortunately, coming up with that set of assumptions is highly subjective.

[jenchris (Jennifer)]

If we ARE the only intelligent life in our Galaxy, I find that immensely sad.
To be the only few with the wit to look up and wonder, to look up and weep at the indescribable beauty.

Fortunate even more so that we humble few with telescopes can look further than others and see it first hand.
Of all the worlds in all the galaxy we have to pick one 4 light years from the next one. That's a lot less fun than it could be.

However having beat my breast (metaphorically), I now support my claim with further views that make possibilities seem more likely. We don't have a clue as to ANY of the parameters that support life of any sort. Even Gene Roddenberry knew that. Intelligence may be rare or it may be that we're wierd that only humans have it in spades on this planet.

On the subject of a million monkeys.
You do realise of course that the monkeys would get less random over the next few millenia as they begin to understand what they
are typing. This may hinder or help in the accumulation of Shakespeare's works. (And lets face it, there's even a hint that Shakespeare didn't write much of anything - he just took the credit of someone else's work. In which case the million monkeys could do it in about 10 minutes)

Never forget progress.

All those who bought solar panels - who will be regretting it in a year when the new paint-on type come out and cost almost nothing by comparison.

[CraigS]

Hi Jenny;

You don't have to feel sad … you can choose to be sad, or you can choose to be overjoyed at being the first …

We can't change what may be, and we're trying to find out what else there is !

The journey is worth the effort and we may end up being not alone ! We won't know, if we don't look !

The Monkeys Theorem is fascinating. I'm writing a post about it but its very tricky.

Wish me luck.

Cheers

[Robh (Rob)]

Originally Posted by ngcles

....
On that basis, again the way I see it, intelligent life is likely to be exceptionally rare and maybe even singular in our galaxy. Agree or disagree with my opinion (that for the last time I point out that I'm not passing-off as “fact”) by all means, but your view like mine is similarly an opinion.

It is an exceptionally interesting topic.



Best,

Les D

Les,

Thanks for your informed and deliberated viewpoint. I gained a lot out of your extended posts (59 and 60) as they were both informative and interesting.

Regards, Rob

[Robh (Rob)]

Originally Posted by jenchris

On the subject of a million monkeys.
You do realise of course that the monkeys would get less random over the next few millenia as they begin to understand what they
are typing. This may hinder or help in the accumulation of Shakespeare's works. (And lets face it, there's even a hint that Shakespeare didn't write much of anything - he just took the credit of someone else's work. In which case the million monkeys could do it in about 10 minutes)

Jenny,

You could have mentioned they were evolving thoughtwise before I did my head in with all those calculations.
Still it was a fascinating problem and deserved a look in.
As for understanding Shakespeare's works, that could be a problem!

Regards, Rob

[avandonk]

Has anybody considered if there is 'intelligent' life out there they have either died out when their star's life ended or like us they trashed their only home.
We quite cheekily define ourselves to be intelligent or more intelligent than all other life on earth. We are all guilty of using the Earth's resources at a rate that is faster than replenishment. In less than thirty years we will need two Earths just to stay at the then rate of consumption. This is of course impossible. And we think we are intelligent? Our species has only been around for about one million years tops, and just like dumb bacteria are using all the nutrients in the Petri dish as if there is no limit to our growth. When the nutrients run out folks the party is over.

It could be that life appears in the Universe like fireflies that blink only once and then are gone forever. We just may not have any near neighbours that are at our level of development. They are gone long ago or are still at the bacterial stage which seems to be the longest phase in evolution.

Just like Dr Who we have a temporal and spatial dimension to this problem as he had in navigating the Tardis. Where was the Earth relative to 'space time' ten minutes ago let alone centuries ago.

When I look at the Vela SN remnant and the much older Gum Nebula behind it I see our ancestors or at least the same 'stuff' we are made of!

Bert

[CraigS]

Yes Bert;

Interesting.

Humans are part of the nature, and the environment which created us.

I don't see us being separate from it. That rubbish we make perhaps, was always what we were going to do. We might be able to change it ... we might not. What ever the outcome is of this is, it can be factored into what we know supports, (or doesn't support), life. Ie: another variable.

I sometimes wonder about the dinosaur extinction. I find it difficult to accept the meteor impact extinction hypothesis but there again, that's an opinion. One thing's for sure though, they didn't choose pollution as a means to self destruct !

Hang on a minute !! .. Crocodiles are pretty close to what we call dinosaurs, aren't they ? They survived.

Hmm … perhaps we don't know enough about that variable, either (??)

Cheers

[avandonk]

Yes we do crocodiles are not dinosaurs. They are cold blooded and a can go without food for over twelve months. The dinosaurs were warm blooded and needed huge amounts of food. The smaller ones were OK we now call them birds. Our ancestors at that time were similar to shrews. I know this as I was married to a couple of them.

Bert

[jenchris (Jennifer)]

Couple !!

Future eating is what humans do best - Easter Island - The Aztecs; they all removed what gave them their ecology -
I think we're likely to do a similar thing when the third world gets hacked with USA taking all the big cherries for itself.

Then we'll have a major disease outbreak or an engineered one.
This may reduce the population or annihilate it.
Think Drax!

Eugenics - eek

[CraigS]

Originally Posted by avandonk

Yes we do crocodiles are not dinosaurs. They are cold blooded and a can go without food for over twelve months. The dinosaurs were warm blooded and needed huge amounts of food. The smaller ones were OK we now call them birds. Our ancestors at that time were similar to shrews. I know this as I was married to a couple of them.

Bert

Hmm .. some debate over the years about warm-bloodedness of dinosaurs, eh ?

I think I may have met a shrew or too, also.

Cheers

[CraigS]

Hmm .. interestingly, we might be able to make definitive statements about the proportions of 'intelligent species' at certain definitive points in the evolutionary scale.

But why be concerned with 'intelligence' ?

This kind of equates to the T-Rex having big teeth, as his main weapon.

So, intelligence should lead to greater longevity than big gruesome, scary teeth ! And that's in spite its relatively miniscule proportions !

Things aren't looking too good here, Jenny !

There again, aliens might consider our intelligence to be nothing more than a bee sting (perhaps not even that).

Cheers

[avandonk]

I have 'tame' magpies, possums, rainbow lorikeets, crimson rosellas, currawongs etc. I call it tame because they have no fear of me. Apart from bribing them with good food I never attempt to touch them. They are wild animals and should stay that way.

These animals over many years have worked out my movements to the point where if I have been to the butchers in the case of the magpies and currawongs they are waiting for fresh minced steak at the back door. The older magpies come inside and sit on the kitchen table demanding food much to my dogs dismay!

Even these birds have an ability to learn and adapt.

We are not that special.

Bert

[CraigS]

I agree that we're not special .. so neither is intelligence .. just another weapon.

Interesting your story about maggies. We've just had one which built its nest at ground level, in our garden ! We've been watching the young one, the mother and the father, cope with other marauding predators (cats, us) etc.

No matter how many times we walk by the nest, the mother perched above, still sounds out the warning, despite our non-interference with the young one.

They might have some 'intelligence' but they don't seem to relate non-interference, (ie: safety), with passing humans.

Its kind of threat-aversion instinct at odds with a dumb choice of nest location.

Another type of intelligence !!

The numbers just changed again !

Cheers

[ngcles]

Hi Bert & All,

Originally Posted by avandonk

These animals over many years have worked out my movements to the point where if I have been to the butchers in the case of the magpies and currawongs they are waiting for fresh minced steak at the back door. The older magpies come inside and sit on the kitchen table demanding food much to my dogs dismay!

So did they learn this all by themselves? No! In fact unwittingly you (as an intelligent being) have been teaching them -- and it took them "many years" to learn to repeat a simple behavioural pattern.

By the rewards given out, you have unwittingly taught them when to expect a possible reward, how to act if they want a reward or to increase the probability of a reward. If there was no teacher, how long would it have taken them to learn and display that behaviour? Answer: Likely never. How many of these birds have been independently able to teach this information to other birds (that are strangers to you), so that they come along display a pattern of behaviour to provoke a reward. I can confidently predict the answer is none.

Originally Posted by avandonk

Even these birds have an ability to learn and adapt.

Yes of course they do -- but given their limited (and limiting) physiology and quite small brains, they need a teacher to learn this type of behaviour! Otherwise their learning capacity and learning speed is extremely limited.

Originally Posted by avandonk

We are not that special.

Yes you are, we are the only "conscious" teachers on the planet! That makes us very special indeed.


Best,

Les D

[avandonk]

You mean Les that all this time they are not my friends?

I am shocked!

Of course you are quite correct. It takes a long time and selective breeding to make a wild animal as domesticated as the dog.


I am still amazed how carefully they scrutinise me from about two feet away. Then happyly eat out of my hand.

bert

[snas (Stuart)]

So, Craig, as you requested, here are my thoughts, as a biologist, on the biology of the Universe. Please note that these are my thoughts are quite obviously not related to any direct observation leading to hypothesis etc, merely my own personal thoughts. Some is based on observation etc.

Reviewing what I have written below, I guess I need to point out that when I refer to "life", I am mostly referring to "animal" like life as compared to plants, algae etc.

The Earth is in the "so called" Goldilocks zone. Goldilocks for life on Earth, but not Goldilocks for life on, say Eridanus. One would imagine that life on Eridanus, if it did exist, may well have trouble in surviving on Earth. Or, maybe not. There may well be life forms in the Universe that could not possibly survive on Earth or survive in a different planet in the same zone as Earth.

I think (would like to believe, but being a very non-religious type, I steer away from the concept of evidence free belief) that life is, more likely than not, common throughout the Universe. But not to the extent of occurring on, say, even 0.001% of planets.

I think that if there is a planet on which conditions are suitable, life will, at some point in that planet's life, arise and evolve. This thought is based, to an extent, on Paul Davies' suggestion that it seems possible that life may have arisen and become extinct a number of times during the "early period of bombardment". If life arose on Earth on more than one occasion, it would therefore appear that life will form if conditions are suitable.

I think that life throughout the Universe (given the existence the same set if Laws of Physics throughout the Universe) is likely to have certain similarities. For example, what is the prime aim of a living organism? Answer; to reproduce more organisms similar to itself. Therefore a reproductive system is required. Asexual reproduction is inherently a poor form of reproduction due to the lack of mixing of genetic information. Life on Earth consisted of simple, single celled organisms with very little variety for a very long time. The lack of genetic variation leads to a reduced ability to adapt to changes in the local environment, and hence reduced survival ability. It was only once sexual reproduction with sharing of genetic information appeared in life on Earth that life was able to firstly improved its survivability and also to develop into far more complex, multicellular life forms. Therefore, while I think that the majority of life in the Universe is likely to be quite simple, I believe that any complex, multicellular and, by extension, any "intelligent" life is likely to use some form of sexual reproduction associated with some sort of genetic information sharing.

Similarly, the complex life form needs a mode of getting from A to B. Getting from A to B therefore requires some sort of rigid body structure such as a bony (on Earth at least) internal skeleton or a chitin (on Earth at least) external skeleton. Then a means of causing the rigid support structure to move (called muscles on Earth) is required. Using muscles requires energy, so a means of capturing, ingesting and metabolising food into useable energy is also required. I'm not saying that these systems must be exactly as they are on Earth, but the basic set of plans requires what I have described above in order to work.

All up, I would not be surprised at all to see that a complex, multicellular life form in another part of the Universe has numerous basic similarities to life on Earth.

Of course, I could be very, very wrong. In fact, if someone was to discover life elsewhere that did prove me very, very wrong, I would be ecstatic.

Regarding Earth; there are some important things that make Earth a suitable place in which life might arise.

The 23 and a bit degree tilt of the Earth's axis is very important for life on Earth as it leads to us having seasons. The resulting change in weather patterns though the course of a year and also the continually changing day lengths in turn leads to the pituitary glands of pretty much every mammal, and quite a few non-mammals, to produce the hormones essential for effective reproduction. If the Earth had zero axial tilt, would reproduction be possible? I imagine, based on the "life will find a way" theory, that, yes, it would. But would reproduction be as efficient as it is here on Earth?

Having the Moon be the mass that it is, the distance from Earth that it is and having the 29 day lunar cycle that it does leads to tides here on here. Tides lead to the existence of an intertidal zone which may very well have played a major part in complex life being able to leave the oceans and colonise the land.

And of course, orbiting the Sun is far better for us than orbiting many other kinds of stars.

Anyway, Craig, you asked for my biologist's view. Here it is. And again, I am very happy to be proven wrong in any of the above thoughts as said proof will mean we have discovered life elsewhere. I just hope that happens in my life time.

Stuart