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View Diary: A Perspective on Life on Earth (74 comments)

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  •  I'm not sure if rareness is irrelevant (4+ / 0-)
    Recommended by:
    atana, rovertheoctopus, binkycat, jabney

    It may matter a lot if it happens twice in this galaxy or a hundred times or ten thousand times. I suspect the core of the galaxy is too chaotic, with too much radiation and exploding stars and close encounters between systems. I could be completely off on that, I'm a chemist, not an astrophysicist, but looking at the images of the big clusters towards the center makes me think that it is hard to get a few hundred million years of peace in there without something coming along to change your obit or throw crap at your planet.
    I'm curious now as to how many intersystem encounters are estimated to have occurred in our history. I'm sure someone has to have done a paper or model for it.
    It takes about 250 million years for us to orbit the galaxy once, so we have done it about 18 times since the Sun's ignition.
    In any event, do we meet up with something else, or forever stay isolated? I guess that is why it seems relevant to me. If each galaxy only gets a few shots at this, in a given period of time, we probably ought to try to make the most of it. I mean, we probably ought to anyway, but especially if it is as hard to get to us as it appears to me :)
    I think that we don't have evidence of alien life or visitation does mean we are kind of isolated. If you look at where we are at now, technologically, it is reasonable to assume that within, say, 200 years, we will know which stars have potentially habitable planets without our region of the galaxy. If any other species has even a 1000 year jump on us in terms of scientific development, which is nothing in terms of evolutionary time, they have known for a long time that the Earth exists, and is a prime piece of real estate for visiting and/or colonizing. If we found an Earth-like planet we could reach within a few hundred years, I'm pretty sure we would make the effort.
    Or maybe we are just the first locally of many that may come afterwards. Maybe there are dozens of sentient species still working out agriculture or whacking each other with sticks and flint within a few thousand light years.

    •  Stars don't have to stay at fixed distances (0+ / 0-)

      from the galactic center throughout their lives. The sun's composition is a little higher in metals than other stars in this region, suggesting it may have formed closer to the center and migrated outwards.

    •  Plus, Earth is home (1+ / 0-)
      Recommended by:
      binkycat

      I don't know about you, but I tend to get emotionally invested in places I've been in for a long time, and it's fair to say that I've lived on Earth my whole life, and I want to keep it that way. I've become quite fond of the fauna and foliage we've been neighbors with for hundreds of thousands of years. Maybe one generation, if our species comes out of the incoming changing climate alive, when the Sun is a red giant and set to die out another 4.5 billion years from now, we'll have an eye on a livable planet. For now, I like home. I'm just human!

      "Growth for the sake of growth is the ideology of the cancer cell." ~Edward Abbey ////\\\\ "To be a poor man is hard, but to be a poor race in a land of dollars is the very bottom of hardships." ~W.E.B. DuBois

      by rovertheoctopus on Thu Nov 29, 2012 at 12:55:13 PM PST

      [ Parent ]

    •  Yes. There may be intelligent life (1+ / 0-)
      Recommended by:
      BPARTR

      elsewhere but it may not be possible for us to interact or even know of its existence because of space-time. The stars we see are like recordings. The light we see is sometimes older than our planet.

      For if there is a sin against life, it consists perhaps not so much in despairing of life as in hoping for another life and in eluding the implacable grandeur of this life. - Albert Camus

      by Anne Elk on Thu Nov 29, 2012 at 02:37:19 PM PST

      [ Parent ]

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