- #71
surajt88
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.They were debating the possibility of finding intelligent life elsewhere in the universe. And Sagan, speaking from the point of view of an astrophysicist, pointed out that there are innumerable planets just like ours. There is no reason they shouldn’t have developed intelligent life. Mayr, from the point of view of a biologist, argued that it’s very unlikely that we’ll find any. And his reason was, he said, we have exactly one example: Earth. So let’s take a look at Earth. And what he basically argued is that intelligence is a kind of lethal mutation. And he had a good argument. He pointed out that if you take a look at biological success, which is essentially measured by how many of us are there, the organisms that do quite well are those that mutate very quickly, like bacteria, or those that are stuck in a fixed ecological niche, like beetles. They do fine. And they may survive the environmental crisis. But as you go up the scale of what we call intelligence, they are less and less successful. By the time you get to mammals, there are very few of them as compared with, say, insects. By the time you get to humans, the origin of humans may be 100,000 years ago, there is a very small group. We are kind of misled now because there are a lot of humans around, but that’s a matter of a few thousand years, which is meaningless from an evolutionary point of view. His argument was, you’re just not going to find intelligent life elsewhere, and you probably won’t find it here for very long either because it’s just a lethal mutation. He also added, a little bit ominously, that the average life span of a species, of the billions that have existed, is about 100,000 years, which is roughly the length of time that modern humans have existed
I think exactly this time span shows the success of intelligence in terms of reproduction and survival of individuals.We are kind of misled now because there are a lot of humans around, but that’s a matter of a few thousand years, which is meaningless from an evolutionary point of view.
True but that is why bigger animals are more vulnerable. Relatively small disturbances in a trophic web can cause them to go extinct.mfb said:If you see "existence of species" as "success", the number of living animals does not matter. Humans exist, and as long as they do Earth is a species with (quite) intelligent life.
Big animals are less numerous - that is not a matter of intelligence, but a simple scaling with available food, the ability to travel and so on.
Bacteria can go from 1 to 7 billion in a matter of days. Point being that "success" has very different meanings and IMO when we talk about the success of intelligent beings we aren't talking abut their numbers or how fast their population doubles.mfb said:I think exactly this time span shows the success of intelligence in terms of reproduction and survival of individuals.
And compared to other big animals, humanity is less vulnerable.Ryan_m_b said:True but that is why bigger animals are more vulnerable. Relatively small disturbances in a trophic web can cause them to go extinct.
The interesting point in the human population growth is not the growth itself, it is the self-made rapid increase in food production and habitable areas.Bacteria can go from 1 to 7 billion in a matter of days. Point being that "success" has very different meanings and IMO when we talk about the success of intelligent beings we aren't talking abut their numbers or how fast their population doubles.
Do these numbers have any scientific background (if yes: source?) or did you just make them up? They look quite specific.Scitech said:As it would only take 3 million years may to colonize the Milkyway
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thus the likely hood of any two civs being in close radio or physical contact goes up approx 100 fold.
Why? I have doubts, can you explain this?No doubt genesis is clumpy too, life will spawn near to other within its local 'birth clump'
I would not use the number as an upper limit then.Scitech said:3 million years , is an oft quoted number for star hopping across the galaxy, you could do it in less, you could do it in more, but its a good mid point time-wise without making to many assumptions that stretch credibility or feasibility
The universe is clumpy, but different clumps are often quite similar, so you don't expect that some clumps have a higher probability to get life than other, similar clumps.The universe is clumpy at all scales, look out the window or thru a microscope, thus it stands to reason that as galaxies are clumpy and not random that some of those clumps will be more favorable to genesis than others
Neither is the detection of gravitational waves, but I do not expect that this will help to establish colonies.Fact 1 , we know for 100% sure that high yield fusion is not trivial
There are so many possible reasons, some of them are listed here. The evolution of life and a powerful energy source are just 2 points in the list. Other reasons why we did not see extraterrestrial life are listed here, for example.Fact 2, where are they ?, If life is not miraculous then there must be 1000s if not millions or billions of civilizations in the universe.
The number of species or living creatures is not (directly) related to the probability that life appears at all.D English said:It would be shortsighted to think there's no life out there. I dare say there are billions of life-forms on the Earth itself. This shows how prolific life is. Only one life form is capable of contemplating this.
So mathematically, it is a sure bet that life is out there.
How did you get that number?But also mathematically, it is a sure bet that 99.99999% of that life is not intelligent- as we define it.
I wonder how non-fragile life would look like then. How can life be more robust than "survived every threat in the past 4 billion years"?Life as we know it is very fragile as well.
mfb said:I wonder how non-fragile life would look like then. How can life be more robust than "survived every threat in the past 4 billion years"?
Life is inherently hardy even if individual species and ecosystems aren't.enceladus_ said:The dinosaurs are extinct, are they not? My point is, it isn't hard for us to be wiped out. In fact, once the Sun begins its red giant death march, all life on this planet will be dead. That will be in a long time, but it is conceivable that life in the past was wiped out due to cosmic events, which would give the impression of their being no life in the present.
Ryan_m_b said:Life is inherently hardy even if individual species and ecosystems aren't.