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Neil DeGrasse Tyson headed down same loony road as Carl Sagan?
On Wednesday, September 26, 2018 at 6:52:19 AM UTC-6, Martin Brown wrote:
On 26/09/2018 12:11, Gary Harnagel wrote: On Tuesday, September 25, 2018 at 2:01:11 PM UTC-6, Paul Schlyter wrote: And how do you know that intelligent civilisation will not self-destruct within a few millennia or so? Out of MILLIONS of civilizations, all that's needed is ONE to survive. We don't know of any other ET civilisations though. As yet we haven't found life arising independently on another planet either That's because we haven't looked except in a very few places. Wanna bet on the oceans of Enceladus? although there may be hints of life having been on Mars back when it had liquid water. (it may still be there deep in underground rocks or dormant as cysts) I wouldn't consider proof of life elsewhere in the solar system as proof of interstellar life. It could have come from earth. Anyone with a grasp of probability theory and no preconceived notions would disagree with you. No, they would disagree with you. I have a grasp of probability theory and I disagree with YOU. You have a rather weak grasp of probability theory You are very funny :-)) and an even weaker grasp of the Drake equation. Planets now appear to be far more common than was once thought but a lot of them are hot Jupiters tidally locked to their parent star (a side effect of present experimental methods which are particularly good at detecting planetary transits and Doppler shifts as the hefty planet orbits its parent star close in). And you seem to be very weak on present theory that posits Jupiter having started out close to Sol. Comparatively few have been found in the Goldilocks zone (although that may be a selection effect of present observational techniques). Indeed. We should be looking at OLD G and K-type stars for old civili- zations. Tabby's Star may qualify although it's a 6-billion-year-old F-type. You do need a sufficient base of actual data to be able to say anything about the probability, otherwise you are just guessing. We have actual data on one civilization. YOU are just guessing about its longevity, but that's irrelevant because an example of one AND proof that almost every star has planets (via Kepler), it is a VERY good "guess" that life has developed elsewhere. It is certainly possible. But whether or not it is common for life to evolve beyond the single celled stage is still an open question. "Life will find a way.” -- Michael Crichton One awkward upper bound on the timescale that a technological civilisation can operate without having to develop space faring technology is the time it takes to exhaust the finite resources of their home planet. As I said, it only takes ONE civilization to make it. It can then spread to other galaxies in a few million years, a very short time in the universe.. You are the one who is biased here, not me, :-)) since I have not claimed any probability figure about that. THAT is YOUR bias speaking. We just know too little to be able to do that reliably. Just the sheer numbers of planets in the universe shred that assertion. If intelligent life was really common in our galaxy then there should be some residual signals for our radio and optical astronomers to see. Not necessarily. The time that a civilization uses radio technology may be quite short. Consider our own civilization. It's mostly beamed or fiber. That or we would have seen self replicating probes by now a la Fermi paradox. Not if there is an over-arching civilization that has already been here. And why isn't theology an exact science like physics? Why aren't our most powerful computers running simulations of God? There, now you have some things to think about... I thought. You got nuttin'! We don't know enough about how life started to do believable simulations. We don't even know if it started here. The chemists and molecular biologists are slowly getting closer to finding out answers. The tricky step is more likely to be the point where single celled simple life makes the transition to complex multicellular organisms. Science is always a step by step refinement from present knowledge by way of experiments. https://www.the-scientist.com/featur...-complex-42874 What they find will be way more convincing than a "Just So" story. -- Regards, Martin Brown Indeed. But haven't complex organic molecules been found in the solar system? |
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