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> our planet is a bit older than the average But our galaxy and solar system is relatively young compared to the universe. Plus the universe is massive. There'

> our planet is a bit older than the average But our galaxy and solar system is relatively young compared to the universe. Plus the universe is massive. There's approximately 10 billion galaxies in the observable universe with and average of 100 billion stars per galaxy. At that scale the processes that created life on Earth would have happened countless times before. The building blocks for life are common in the universe but weren't common on the early, inhospitable Earth. It was brought to our planet from comets which is where the Earth's water came from. https://helios.gsfc.nasa.gov/qa_star.html#howmany https://helios.gsfc.nasa.gov/qa_star.html#howmany https://en.wikipedia.org/wiki/Panspermia https://en.wikipedia.org/wiki/Panspermia

ahje 7y ago
I'm not an expert, but didn't it take quite some time for stars to create heavier elements like iron, go nova, spread the star-stuff across the Universe, and then repeat until we have the current mix of light/heavy elements? Combine that with: * The fact that life on Earth was possibly dependent on life from other planets to form. * Has had multiple near-total extinction events during it's time. * We're outright dependant on fossil fuels left over from previous cycles in order to get to where we are now. * Our own species have been close to extinction multiple times far before we reached our current technological level. * Our own emissions most likely blends with the background noise and are probably not detectable that far out. * It's taken us countless millennia just to get to the point where we're approaching a technology level that will allow a fraction of our population to scan parts of our closest galactic neighbourhood for disproportionately large signal sources that happens to be on the bands we find to be most convenient. To me, it sounds like it's quite plausible that we could be amongst the first to spread on an interplanetary scale (assuming we actually manage to do that), or that something happens and we go back to pre-industrial levels, leaving the aliens on the next habitable planet wondering why the level of noise from group of stars a few hundred light-years away suddenly grew quieter.

ahje 7y ago

I'm not an expert, but didn't it take quite some time for stars to create heavier elements like iron, go nova, spread the star-stuff across the Universe, and then repeat until we have the current mix of light/heavy elements? Combine that with: * The fact that life on Earth was possibly dependent on life from other planets to form. * Has had multiple near-total extinction events during it's time. * We're outright dependant on fossil fuels left over from previous cycles in order to get to where we are now. * Our own species have been close to extinction multiple times far before we reached our current technological level. * Our own emissions most likely blends with the background noise and are probably not detectable that far out. * It's taken us countless millennia just to get to the point where we're approaching a technology level that will allow a fraction of our population to scan parts of our closest galactic neighbourhood for disproportionately large signal sources that happens to be on the bands we find to be most convenient. To me, it sounds like it's quite plausible that we could be amongst the first to spread on an interplanetary scale (assuming we actually manage to do that), or that something happens and we go back to pre-industrial levels, leaving the aliens on the next habitable planet wondering why the level of noise from group of stars a few hundred light-years away suddenly grew quieter.