Originally posted by wolfgang59
The conclusion then is that life did not form.
... or maybe we do not know enough yet?
I think it safe to say life appeared somehow on Earth. It is probably safe to say if we ever find the means to go to other stars we will eventually find life there too. Maybe only microbes but that remains to be seen.
Like the Katz said, space is big and mostly empty but just because we have not found evidence for life doesn't mean there is no life, only that we have not found it yet.
We may find life on Mars, and there are hints of some anomalies in the atmosphere on Venus where presumably it is WAY to hostile for life on the surface by maybe there are microbes of some kind in the atmosphere way above the killing heat and killing atmosphere. Venus is as good a description of hell as we could ask for with the possible exception of the surface of the sun. Atmosphere pressure around that of a full nitrogen bottle, 1500 PSI or so and temperature of around 400 C, not a place to visit.
But above all that there are hints of something going on we may be able to probe someday, collect samples in some kind of fly by and return to Earth.
That would be a kick to find life in the upper atmosphere of Venus.
But we might find it in the future on Mars or even in those underground oceans alleged to exist on some of the moons of Jupiter and Saturn. That will be in the next century or beyond.
We are in no special place in our galaxy and no special place in our universe except our sun happens to be one with 'metals', a lot of stars are low metal stars and any planets around them would also be low in metals needed for trace elements needed for life, at least our style of life.
That said, there are literally billions of suns just like our sun, lots of metallic's to spread around.
It looks certain for long term implications for life elsewhere there would need to be a nice strong magnetic shield around a planet to protect it from the influx of ions and radiation from it's parent star.
Without that you get Mars, where it once had a nice thick atmosphere and liquid water oceans, all that was lost when its magnetic field dried up and all that is left now are bits and pieces of magnetic lines scattered around the planet so the atmosphere and water were stripped away leaving the mess we see now. That does not mean life if it was there, went totally extinct, it might have just gone underground where there is less radiation.
Of course we won't know till we get there and start digging around.
But the fact our sun is a pretty common type in our galaxy and every other galaxy in the universe assures there will be SOME with lucky planets in the right place, goldilocks zone and all that, and a nice fat magnetic shield like Earth or Jupiter.
We may never know that but you never know what is going to happen in science in the next 400 years or so.
We may not even have to visit personally, but send nanotech probes by the millions that does the job of a super telescope and so forth, a lot of sci fi stories have been written on that theme.
Of course I know that is just science fiction for now anyway, but a few hundred years from now? Another story perhaps.
Billions of stars per galaxy, billions of galaxies. Seems a fundamental error to diss the idea of life elsewhere in either our galaxy or the universe.