We’re literally looking for evidence that there was carbon life on the planet next door. When you consider that, just in the image provided, there are at least 1B x 1B solar systems. 1e18. Or about as many solar systems as there are grains of sand on the planet earth.
> We’re literally looking for evidence that there was carbon life on the planet next door.
And we haven't found any.
> I personally think it’s hard to say that in all likelihood we’re alone.
We simply have no idea. None of our model work at that scale, especially not our intuition or our "statistical" models (we have 1 data point, and it mostly is incomplete). It's like looking at an enormous pile of snow and saying "there must be gold in there, my friend found gold while digging in africa, surely this pile of snow is big enough to contain at least a bit gold".
I wouldn't be surprised if life evolved somewhere else, maybe hundreds of time (either in the past, present or in the future), I just don't see how you can claim with absolute certainty that it happened and that we're not alone.
Saying with absolute certainty that we're not alone is a guess, just like saying we're certainly alone, we don't have the tools to determine it. If someone shows me an advanced math equation and ask me to solve it I'd say "I don't have the tools" not "it's probably 2"
> If only carbon based life is possible and it needs liquid water then, afaik, most of these stars don't have a planet susceptible of hosting life as we know it, and even for the ones with the right conditions we might be a bit early or a bit late.
My point is, there are likely millions or even billions of planets in that photograph alone, with the perfect conditions for sustaining human life.
I can’t say with certainty that there is life, but by God would it surprise me if there weren’t.
Considering that the building blocks of life have been detected on random asteroids arriving on planet earth (https://www.nasa.gov/press-release/goddard/2019/sugars-in-me...), and the capacity for intelligence to evolve in distinct branches of our own DNA (https://www.nature.com/articles/nature14668), I personally think it’s hard to say that in all likelihood we’re alone.