Probability on Finding a Habitable Planet and Other Life in the Universe

No.

I think we should stop referring to a singular universe. The argument for a multi-verse is very strong indeed..perhaps just as strong as the argument for more habitable planets in this 'verse'.

I don't think the evidence for a multiverse is strong at all. It may be interesting, but not necessarily strong.

However, the sheer size of the known universe, the number of stars in it, and the ratio of stars with planets orbiting in a zone where water could exist as a liquid alone is staggering.

I would suggest to you that one universe is probably more than enough room for life in multiple places. Obviously, we are proof that it is possible for life to exist. It seems only a small stretch that there would be others.

No argument from me on the existence of other life..wouldn't take much to improve on ours (intellectually, anyway)

I don't think water is necessarily a pre-requisite though....other life may be far superior and less dependent than ours, on naturally occurring compounds.

Maybe their bodies manufacture those necessary compounds as part of their living process, just as we breathe, and extract oxygen.

Maybe you can squeeze blood from a stone after all....

There are some things to consider when looking at potential abilities of 'superior' life forms.

1) All life in this universe needs to obey the Physical Laws. Chemistry will follow the same rules everywhere.

2) The most versitale elements to make the backbone of complex molecules are the Group 14 Elements, Carbon, Silicon, Tin, Lead, out of all of these, Carbon is the 'best suited' to make complex compounds with, as it's 'lightness' relative to the others makes it more likely to form the rings and chains needed for these molecular 'backbones.'

3) Carbon-based molecules seem to work best when suspended in water than in other liquids.

Therefore, the most likely forms of life in the universe will be based o carbon, and will be water-dependent to some degree.

References for Carbon Group (Group 14): http://en.wikipedia.org/wiki/Carbon_group#Biological_role

I accept that as a definite maybe.

As far as SETI is concerned, if we don't look, we will never see whatever is or might be out there. Think of it like the Lottery. My chances of winning are infinitesimal, but if I don't buy a ticket, my chance of winning is zero.

Is this anyhow some sort of statistical stuff or a theory which Drake has to prove still a billion years to come?

It's almost a certainty that other planets exist with conditions that we think are necessary to support life as we know it. But they are very, very, very far away. The real question (to me anyway) is whether it will ever be possible to travel such vast distances in a reasonable amount of time. The energy required to accelerate a modestly-sized ship to half the speed of light is almost incomprehensible, even for a ship powered by nuclear fusion. (Not to mention the deceleration (negative acceleration) that would be necessary upon arrival.) Energy breakthroughs of several orders of magnitude would be necessary to even conceive of such space travel.

Somewhere in the Universe the formula developed by other lifeforms might be P = 1/(∞ - 1) = >0, therefore SETI might here from them.

Re 4 and 10.

4: Blake seems to have missed a factor for simultaneous existence. Life 'as we know it' that fit the current formula could have come and gone - unless L is a very long time to allow overlap.

10: I read a sci-fi story 60 years ago where humans evolved by developing machines that had computer brains that evolved to be self-reproducing - the story ends at the 'birth' of a machine. But if these machines inherited hostile human characteristics they might have tried to wipe out other life forms (hints of 'Terminator' and 'The Matrix' for adventure and entertainment).

But nowadays I guess it would be possible to imagine development forced along Von Neumann lines using some friendly materials.

4.Blake ?

10. Sorry, can't engage. 60 years ago I was out playing in the mud and dirt (actually undertaking a scientific evaluation of the hardiness and durability of my toys).

Finally, upon independent 3rd party, testing, it turned out that my backside might have been hardier than my tip-truck or my trike!

Sorry. 4: should be Drake - senior moment - regrettably too often nowadays.

Looking over the website of the National Space Academy, under "LIfe in Extreme Environments", it looks as if the potential for opportunities in the number of potential habitual planets is much greater than previously thought.

habitual ≠ habitable

Thank you. As my wife has repeatedly said, "if you could type, you would be dangerous.."

Just because a habitat can support life does not necessarily mean it will lead to intelligent life.

I think the prospect for intelligent life is going to be orders of magnitude lower than the ability to support life at any level.

You are probably right, but, the possibilities become greater. More or less what I am referring to. If Creationism isn't taken into effect, how long does life take to go from a single celled organism, to a texting teenager (Minus the teenage years)?

Now that is funny! Thanks!!

I think the chances are 100% that if we find life in the universe, it will be of a more primitive state. My reasoning:

1) More advanced life will discover us before we discover them.

2) Given mankind's track record, they will do all they can to avoid discovery.

As Calvin Would Say