re: Scientists estimate 100 Billion civilizations have evolved prior to us

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I'd be interested to see how long it takes to establish a form of communication if we were in fact able to contact other beings.
Maybe they can't hear or see, so the only form of contact that's basically universal is touch. And even that's debatable. It would be extremely interesting to see how we'd establish a form of trust and peace

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Unless we're wrong about the impossibility of faster-than-light travel (and in any event it would take us a very long time to achieve it even if it is possible), there would be almost no chance for meaningful communication unless they were pretty much right next door in a cosmic sense, and that would be WAY more unlikely than two next door neighbors each separately winning separate powerball lottery jackpots.

Much more likely is that they would be thousands or even millions of light years away, meaning any communication we sent would take millenia to get there and any response they sent would take millenia to get back. By the time we received their response, we'd be lucky if anyone then alive even remembered that we sent the original message in the first place. And that exchange would be just the initial "hello".

The good news is that peace would likely not be a problem, given the apparent virtual impossibility of traveling the necessary distances to attack each other.

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It's likely that we're the first sentient species in the Milky Way

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I'm not saying it's not, but how can we conclude that it's "likely"? I would think that, at best, we can only say it's a realistic possibility in the sense that the numbers (as in the cited study) don't have to be too outrageous for it to be true.

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The universe is boundless. Chances are there is a planet the same distances from a star that has the same elements in it's atmosphere to make life possible

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And I'd bet the Aggies on that planet can't beat LSU in football, either.

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But now we know there may be an infinite number of universes.

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Or at least uncountable. In 1995, Edward Witten proposed M Theory which describes a multiverse composed of uncountable universes existing on branes. It seems crazy upon first read, but is logical as you get to understand it.

Humans are just too obsessed with the idea of beginnings, endings and infinity. To continue advancing in our understanding of existence I think we need to throw out our human constructs. They're obviously not reality.

I'm thinking this more and more.

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I'm not saying it's not, but how can we conclude that it's "likely"? I would think that, at best, we can only say it's a realistic possibility in the sense that the numbers (as in the cited study) don't have to be too outrageous for it to be true.

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The study lists a possible 100 billion civilizations have existed. There are an estimated 100 billion Galaxies.

So, 1 civilization per Galaxy would be an average. That's very simplistic, of course.

I prefer to use the only firm evidence we have in predicting the potential of intelligent life elsewhere. We evolved here on earth.

After the Milky Way Galaxy formed about 13 billion years ago, stars and their systems came and went. As they went supernova, they formed the elements of which we are composed and spewed them into the Galaxy.

About 4.5 billion years ago our Sun and many other stars formed together in our neighborhood of the Milky Way. This area happened to now be rich in the elements necessary for life.

Life began very quickly on earth after it coalesced from the leftover dust circling the new Sun. After less than a billion years, single-cell organisms formed on the planet that was rich in the basic elements of life and, all-importantly, water.

Confoundingly, it took another 3 billion years for complex life to evolve and almost the complete history of the solar system for humans to come onto the scene. Some scientists think that oxygen levels had to rise to a level that collagen,
the main structural protein found in animal connective tissue, was stable; this allowed the simple cells to aggregate into more complex multicellular organisms.

So, again using our one example, we can see that it took about 9 billion years for the Milky Way Galaxy to create the elements of life in dense areas. Then it took another 4+ billion years for intelligent life to evolve in one of those regions.

You might ask, "Isn't it equally likely that life arose on similar planets in other element-rich areas of the Milky Way?" It absolutely is.

Life may be ubiquitous wherever conditions are good for its evolution. However, the discussion is about the prevalence of intelligent life.

Evolution is driven by environmental pressures to adapt and mutations. While the former may be fairly predictable, the latter is completely random.

Was it environmental pressures or a mutation that sparked the growth of the human brain? Arguments are ongoing for both ideas.

Oh, I was just extrapolating on that 100 billion civilizations number. While the article's premise is entertaining, and is a bit more advanced than Drake's Equation, it's still a wild guess in my opinion.

We still don't know enough about the Universe to make these kinds of estimates reliable, although I'm very glad there's enough interest in the scientific community to keep them coming. As long as we think there's a decent chance that other civilizations exist, we'll keep looking for them.

I shared my estimate, which is coincidentally similar, based on what we know about our own situation. Of course this may be off wildly, too, especially if we evolved our unique brain due to environmental pressures.

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For some reason as we separated from apes we stopped growing hair which allowed us to develop sweat glands. With sweat glands we could cool ourselves without panting.

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Yes, research shows that that is why we lost our hairy bodies. We sweat prolifically and have a large area over which evaporating water cools us.

But why did we evolve this feature? Apparently, early humanoids began to rely on running down their prey over a long distance.

Prey animals could easily outrun our ancestors over short distances. However, we could maintain a cool stamina over long distances.

Our quarry would sometimes die from heat exhaustion before we caught up with it. That evolutionary change was a distinct advantage and resulting generations became great runners.

So, on the plains of Africa humans evolved into lithe, hairless creatures that had lots of meat available for consumption. That's why we don't have the pot bellies of our primate cousins. Meat is very high in energy and we no longer had to have big stomachs for storing large amounts of plant material for digestion.

Most scientists also think that this is one of the reasons why our brains grew larger and larger. We had to out think our quarry, so those with bigger areas of their brains that dealt with reasoning of this sort were more likely to succeed in killing prey and passing on their genes to their progeny.