The plan seems to be "to find intelligent civilizations, look for Earth-like planets that can harbor life." How terribly narrow minded.
> you'd think the chance that there is intelligent extraterrestrial life in our galaxy seems enormous
"And the Earthling rocket ships departed Planet X3, having found no life, only an advanced civilization of extraterrestrial robots."
> Another study out of the University of British Columbia looked at the number of sun-like stars in the galaxy and estimated that one in five of them could have an Earth-like planet
On Earth, Life has embarrassed us by being found in the most inhospitable, acidic, saltiest, hottest places. And then embarrassed us again, by turning up in the cold black energy-poor ocean depths, sipping sulfur from vents. Life is surely bigger than Earth-like planets. And Intelligence is surely bigger than Life.
In Sagan's book Contact, the hard problem was not finding intelligence, but recognizing it. By the end, we learn that the arrangement of the stars and the digits of pi itself carry a message. This is the level of thinking that our search calls for.
> On Earth, Life has embarrassed us by being found in the most inhospitable, acidic, saltiest, hottest places. And then embarrassed us again, by turning up in the cold black energy-poor ocean depths, sipping sulfur from vents.
And yet, all life on Earth has the same basic structure. The most likely reason for this is that life only originated once, and in one "place". This observation significantly reduces the probability we should ascribe for life to appear, and/or the specificity of the conditions required. For example, we know for sure that a planet like the Earth today is completely inhospitable to the emergence of life (there has not been an abiogenesis event for billions of years).
The other option is that life has emerged in many places/times on Earth, but with the exact same structure. While unlikely, this would suggest that life must have a very specific structure, that at least on Earth-like planets we should also expect RNA and DNA based life at least. This would also suggest that the likelihood of other kinds of life existing is smaller than initially could have been conceived. And even with this assumption, it would still not be clear that life is appearing on Earth today anymore, as the life forms we've looked at seem to have a phylogenetic link with other life (though our methods may be weak if the possibility of abiogenesis were correct). And even if abiogenesis was still occurring on Earth, it would have to be in some remote place in extreme conditions, as we have tried in all regular places with no success.
Overall, my belief is that the emergence of life is likely a vastly improbable event, and that we shouldn't expect to "see" a living (or formerly living) being that is not related to life on Earth in the lifetime of the Earth.
> And Intelligence is surely bigger than Life.
This seems a mystical belief, given all we know of the world.
> This seems a mystical belief, given all we know of the world.
if you assume that intelligence comes from the brain and if you assume that the brain is just a very highly optimized computer, there's no need for an intelligent entity to be alive. it just needs an adequate computer to exist.
Sure, but the computer must have been built by some form of life ultimately (possibly through a long line of other computers). If your point was only that artificial life created by a form of life could vastly outlast that form of life, then I agree that that is a very good point.
There are certain realities that limit where life can be established and flourish, and while different kinds of life might be possible, they're extremely unlikely due to basic physical/chemical constraints, amount of other elements in the universe compared to hydrogen and carbon and oxygen, etc. And even the most inhospitable place on Earth is pretty okay by galactic standards - Earth's magnetic field, characteristics of our star and our planetary configuration being the main reasons.
I don't think your advanced civilization of extraterrestrial robots is doing enough work to establish this particular point.
That said I would think looking for earth like planets is not so much just for finding life, but also for the point of making it easier to recognize it as life, and finally hopefully having enough points in common to communicate.
> you'd think the chance that there is intelligent extraterrestrial life in our galaxy seems enormous
"And the Earthling rocket ships departed Planet X3, having found no life, only an advanced civilization of extraterrestrial robots."
> Another study out of the University of British Columbia looked at the number of sun-like stars in the galaxy and estimated that one in five of them could have an Earth-like planet
On Earth, Life has embarrassed us by being found in the most inhospitable, acidic, saltiest, hottest places. And then embarrassed us again, by turning up in the cold black energy-poor ocean depths, sipping sulfur from vents. Life is surely bigger than Earth-like planets. And Intelligence is surely bigger than Life.
In Sagan's book Contact, the hard problem was not finding intelligence, but recognizing it. By the end, we learn that the arrangement of the stars and the digits of pi itself carry a message. This is the level of thinking that our search calls for.