I hope this doesn't sound out of context, but what will you do if you wake up in the morning and BAM!!! aliens are attacking!!
I agree with our Ninja friend, it's a matter of certainty, humans are already destroying the planet while we don't even know if intelligent extraterrestrial life really exists. Assuming they exist and they know about our existence, then most likely we are too primitive for them to catch their attention.
That we are destroying the planet is not proof that we are more dangerous on a scale, that would put us higher than any aliens. The aliens at least would have proven that they have high tech and could strike us down from far away by dropping stones really fast (it worked against the dinosaurs). That is what I would call dangerous. Also, they might just as well come here with an arch ship and attack us, because they already destroyed their own planet, outscaling us twice.
Oh, and extraterrestial intelligent life does exist. The real question is, if we ever make contact or see proof.
It might just be, that we are among the first to emerge. You need heavy elements to have planets and enough stuff on the planet to do chemistry. Heavy elements are not that old in the universe, you need several generations of exploding stars to make them. But even in interstellar dust clouds we can see organic chemstry happening, including so much amino acids that we can see it with telescopes, so the stuff is all there. You only need some lightning and pre organic soup to form stuff that looks like proto cells. While we are very lucky with our planet, it looks like you will have life everywhere where there is stability for a billion years or three. One of those is bound to be intelligent eventually.
Most are not really aware of that fact, but we have no clue how big the universe is. There is a limit how far we can see, but that is not the end, only the limit of vision. The universe is bigger than that. Wich means, whatever number of planets you probably think you can "roll the dice" to see if there is life, your number is too small.
That we are destroying the planet is not proof that we are more dangerous on a scale, that would put us higher than any aliens. .... Oh, and extraterrestial intelligent life does exist. The real question is, if we ever make contact or see proof.
You say " ...extraterrestial intelligent life does exist" and then say "The real question is, if we ever ... see proof." How can you say something exist but you have no proof (apart from faith)? So... All you said there are assumptions without proof, on the other hand there are real and scientific proofs that we are destroying our planet, therefore that's the real danger, anything "intelligent" happening outside of earth is just indagation.
As for the intelligent alien life, I don't deny but I don't agree, we still don't know. For that I recommend you research about the Fermi Paradox, which points several different explanation about that. One possible reason simply points out that we are indeed alone, therefore your assumption is wrong, but one of my favorites is the Zoo hypothesis that I described in my previous post (it's just my favourite because I find it fun, they all have no proof).
It is not faith. It is numbers.
The Fermi paradox is based on assumptions and those assumptions narrow the question down quite a bit. It basically is: are there colonizing and expanding civilisations in our galaxy that started doing this some million years ago. Of course not, because they did not colonize earth. It only becomes a paradox if you assume space colonizing intelligent life is the norm and life is so common that those civs spawn near each other.
There are at least 100 Billion galaxies that we can see. Even if you postulate that life is so rare, that only 1 in 100 Galaxies has 1 planet that evolves live, you still have a billion tries to evolve intelligence - in the part of the universe that is visible to us. And the current data and lab experiments point to a very much higher chance as 1 in 100 galaxies . The current estimate for earth size planets is 16% per sun. Even if you shave that number for habitable and water and such, as soon as you have organic chemestry happening for a few hundred million years, there will be cells.
The universe is just too big to assume we are alone, but since it is so big, we also might be alone in our neighborhood - yet. And of course, intelligence is not necessary for life, amobea do just fine. And technology does not automatically follow from intelligence, see elephants and octopus or even our cousins, the apes.
So yeah, I do think there is intelligent life out there and it is only a question wether we will see evidence any time soon or not. Best candidate apart from them knocking is atmosphere on exoplanets. But small exoplanets are hellish to detect, let along analyze their atmosphere.
only 1 in 100 Galaxies has 1 planet that evolves live
That's way too opimistic and also you forgot the most important variable: time.
The universe is 13.7 billion years old, and life began 3.8 billion years ago, out of the 3.8 billion years of life we took 3.7999... billion years to evolve to inteligent civilzations, this means life took 73% of the whole universe life time to appear*, that's a huge amount, which points out that yes, life is indeed extremily hard to occour even considering the size of the universe.
*= I put an asterisk in that "appear" because I know life may have already appeared and died, which is pointed out in the great filter theory. Which also postulates that inteligent life strugges to exist for long period of times.
In short, did/will inteligent life ever exist(ed) in a time frame other than ours? OF COURSE.
Does that mean, by any chance, that there could be another inteligent civilization besides us right now? NO, we still don't know about that.
Optimistic? That is quite pessimistic, by a couple of zeros.
Anthropocentric argumentation is flawed. But you can estimate chances for life by numbers that do not depend on our existence. Scientists estimate that there are about 300 000 000 planets in the habitable zone around planets in our galaxy. They exist whether or not we do. Give or take a zero, does not matter.
There are lab experiments that try to simulate conditions on early earth. If you mix the the chemicals and stir, you get small lipid bubbles and amino acids. And they only mixed it obviously for less than hundred years and not for 100 000 000 years. If you can get cells from the makeup of chemicals, you will get cells. It is Murphys Law backward. Abiogenesis occurs because it can.
People do not intuitivly grasp big numbers and chances. In the visible-to-us universe, there are about 10 000 000 000 000 000 000 planets that are in a place around their star to have conditions that allow life as we know it.
One could shift the goal post and speculate, we might be the first techno civilisation in our galaxy. The need for heavier than hydrogen elements certainly limits possible life for the first 10 billion or so years.
Probably we will be the aliens invading other planets.
You are right that I describe conditions for life in general. But here come the numbers I said previously. If the base to start from is so often reached, there is bound to bbe intelligence. Oh, one can shift the goal post to whatever one likes. Even to humanoid. But once you have nerves that can react to stimulus, it becomes advantageous to remember and predict. What ensues is what we call intelligence. It is a prediction machine based on previous experience.
It might just be some of those nieches, a species can gain access to. Like flight. Even mammals learned it. And the pterodactylus and the avian-ancestors independently achieved it. I do not even count insects, because they are so small, flight is almost free.
And we see this for intelligence as well. Talking about higher intelligence. Like tool using or even tool making. Some birds can do that and cephalopods are also very intelligent. It is not a mammal thing. There might even be an incomprehensible swarm intelligence in bees or ants.
But I think the arbitrary goal post would be technology that can lead to space travel. But even here, the universe is very big. We know it can happen, so there is no reason to believe it is a singular event. Whatever unlikelyness you attribute to it due to lack of data, the universe is still quite big.
On the thought about dangerousness, I think, if the aliens would come to us to fight, they would be more dangerous, because they would leave the peacelovers back at home. We on the other hand do have them still here. While we whine about our worst specimen, as a whole we have quite decent members. (And this was actually a "problem" in war, with soldiers intentionally missing when shooting. We do not like to kill very much. Some even so little that they turn vegan)
I have almost know that people do cut trees, destroying fishes home using dynomites, throing trash from the ground plus anything.
