Two things: 1) Our knowledge of physics is still very small. ~20% of the universe is 'dark matter'. All we really know about it is that it falls down. It outwe

Two things: 1) Our knowledge of physics is still very small. ~20% of the universe is 'dark matter'. All we really know about it is that it falls down. It outweighs the stuff you, I, and the all the stars in existence are made out of by ~4x. The other ~75% of the universe is 'dark/negative energy'. We know even less about it beside that it seems to fall ... up (?). And it's the super majority of what we know it out there. Give it another 200 years, and even this understanding is going to be embarrassingly outdated. Any other civ that is just 10k years ahead of us is going to be working in physics that we can't even imagine. 2) That leads to the larger issue: Time. The difference in our lives and the lives of the earliest humans is literally astronomical, in that we have people living up in space now. That same rate of difference separates us from any neighbors out there. Their understanding of our universe is likely to be so vast that we're essentially amoeba to them. Though intelligent life may exist out there in bushels, we're still infants in what 'intelligent' means. We may be surrounded by olde gods rendering us effectively alone all the same, and those gods themselves surrounded by yet grander deities rendering them alone as well.