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Thread: Parenago Discontinuity

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    Parenago Discontinuity

    Matloff's argument for conscious stars cites an observation that cool, light stars orbit the galactic center slightly faster than hot massive stars.
    Is this an actual datum, and if so, why would that happen?
    http://www.jcer.com/index.php/jcj/article/view/579/595

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    It's a datum, but a product of sampling bias. The explanation is rehearsed, for instance, by Binney in Secular evolution of the galactic disk (160kb pdf).
    The abrupt change in slope at (B-V) = 0.6 is called Parenago's discontinuity, and the natural interpretation of this phenomenon is this. Bluewards of the discontinuity stars have main-sequence lifetimes shorter than the age of the solar neighbourhood, τmax, while redwards of it lifetimes exceed τmax. Consequently, any tendency of the velocity dispersion of a stellar group to increase over time will cause S [random velocity in plane of sky] to increase with B-V at (B-V)<0.6 because in this range the age of the oldest stars contributes to S increases with B-V. Conversely, S should be independent of B-V redwards of the discontinuity.
    Grant Hutchison

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    A glance at the abstract pegged my woowoo meter, and now that Grant has commented on the sampling bias it will take a pretty powerful incentive to get me to read further.

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    Yes, there are many possible reasons to get a correlation between velocity dispersion, or even orbital velocity itself, and the age of the star, and it's easy to get a correlation between age and color. So I'd have to count "sentient stars that like to go fast" as among the all-time least likely explanations for any phenomenon that I have ever seen.

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    Quote Originally Posted by Tom Mazanec View Post
    Matloff's argument for conscious stars...
    Geez, that sounds like Aristotle's idea that things fall because they want to be closer to the earth!
    As above, so below

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    Perhaps worth pointing out that Matloff's phrase, "Parenago's Discontinuity refers to his discovery that cool, less massive stars circle that galaxy's center a bit faster than hot, massive stars" misrepresents Parenago's discovery in two ways.
    1) The "discontinuity" is actually the point at which that correlation stops being true
    2) Parenago's discovery relates to plane-of-sky velocity (ie, relative to the Local Standard of Rest) and not orbital velocity.

    Grant Hutchison

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    Matloff and Alex Tolley discus his hypothesis on Centauri Dreams:
    https://www.centauri-dreams.org/2019...discontinuity/
    I wonder who was first to think of "living" stars? IIRC C. S. Lewis in a Narnia book had a Tinkerbell-like star being punished for some sin. One of the children said that stars are huge globes of fiery gas. Aslan replied "Even in your world, that is what stars are made of, not what they are." Was he before Stapleton?
    SHARKS (crossed out) MONGEESE (sic) WITH FRICKIN' LASER BEAMS ATTACHED TO THEIR HEADS

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    Quote Originally Posted by Tom Mazanec View Post
    Matloff and Alex Tolley discus his hypothesis on Centauri Dreams:
    https://www.centauri-dreams.org/2019...discontinuity/
    I wonder who was first to think of "living" stars? IIRC C. S. Lewis in a Narnia book had a Tinkerbell-like star being punished for some sin. One of the children said that stars are huge globes of fiery gas. Aslan replied "Even in your world, that is what stars are made of, not what they are." Was he before Stapleton?
    C.S. Lewis was already running on that topic/idea back in 1938 with the Space Trilogy. In that series, planets had representative angels. It seems the series was a knock at then current contemporary fiction. As a part of the exercise, Tolkien was supposed to write a time travel story. They were both a part of the Inklings, a group of writers. It seems that Tolkien wrote something, it was only published as fragment by his son.

    The Space Trilogy series was influenced by an older story from the 1920s, but I haven't read that book.
    Solfe

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    I did like the name "Perelandra"

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    Quote Originally Posted by Solfe View Post
    C.S. Lewis was already running on that topic/idea back in 1938 with the Space Trilogy. In that series, planets had representative angels. It seems the series was a knock at then current contemporary fiction. As a part of the exercise, Tolkien was supposed to write a time travel story. They were both a part of the Inklings, a group of writers. It seems that Tolkien wrote something, it was only published as fragment by his son.

    The Space Trilogy series was influenced by an older story from the 1920s, but I haven't read that book.
    Lewis did come up with the concept of a spaceship that sails on sunlight, which probably quite by accident turned out to have some merit in real technology. And he noted that artificial gravity might result in curved floors that had 90 degree corners with "vertical" walls... even if he got it inverted compared to centrifugal artificial gravity.
    "I'm planning to live forever. So far, that's working perfectly." Steven Wright

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    Odd as it might seem (some of my colleagues wonder how I keep both sets of books without them annihilating) there was a correspondence between C.S. Lewis and Arthur C. Clarke (in which Lewis genuinely espouses the idea of the extent of interplanetary space as "God's quarantine rules".) The surviving letters are collected, with early fiction by each, in the book From Narnia to a Space Odyssey : The War of Ideas Between Arthur C. Clarke and C.S. Lewis. (Without the stories, there wouldn't really be enough for more than a pamphlet, because they're letters).

    Each wrote early, little-anthologized stories that might have been done by the other.

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    Quote Originally Posted by publiusr View Post
    I did like the name "Perelandra"
    Oddly, I hated that name. I do love C. S. Lewis though. I read all of his Narnia books to the kids.
    Solfe

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    Quote Originally Posted by ngc3314 View Post
    Odd as it might seem (some of my colleagues wonder how I keep both sets of books without them annihilating) there was a correspondence between C.S. Lewis and Arthur C. Clarke.
    That reminds me of an article from 1985 by Charles Krauthammer

    Science has thoroughly desacrilized the universe. It is in the language. When in the last election Walter Mondale warned against militarizing "the heavens," the usage seemed quaint. After Neil Armstrong and George Lucas, what's up there now is simply "space." The heavens were a place for angels, gods and portentous messengers. Space is home to extraterrestrials, the Force and now snowballs cruising through emptiness.

    https://www.washingtonpost.com/archi...=.6f31887c0fca

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    I would counter that perspective in this way. We essentially invented the word "sacred" to distinguish religion from other ways of giving sense or value to things. If you can see why there is sense or value in it, then it isn't sacred, that word is reserved for the things that are not afforded sense or value by reason, but by religion. This may sound anti-religious on my part, but it isn't-- I am simply talking about the meaning of the word, a word I neither invented nor defined. So to say that science "desacrilized" the universe is not saying anything more than the fact that religion got there first. Had science come before religion, then the sense and value of studying "the heavens" would simply come from science. We would look to the heavens because of the majesty of it, the amazing physical properties abounding there, the remarkable scales and multitudes of happenings that is deep space-- all completely accessible by the scientific method. Had science gotten there first, and religion later, then it would have been religion that "sacrilized" the heavens, which would have only meant it insisted on providing sense and value to the heavens based on religious doctrine rather than scientific study. I can happily leave it up to the reader, as Krauthammer also did, as to whether or not they think that is a good thing. I am merely putting his words into the proper context-- all he is talking about is which happened first, and nothing else.

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    Quote Originally Posted by Solfe View Post
    The Space Trilogy series was influenced by an older story from the 1920s, but I haven't read that book.
    Olaf Stapledon's Star Maker (1937) had chapters about sentient stars that objected (i.e., went supernova) because of having too many planets placed around them by overpopulated sentient beings. It's "Stars and Vermin".
    There is something fascinating about science. One gets such wholesale returns of conjecture out of such a trifling investment of fact.
    Mark Twain, Life on the Mississippi (1883)

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    Quote Originally Posted by Ken G View Post
    I can happily leave it up to the reader, as Krauthammer also did, as to whether or not they think that is a good thing. I am merely putting his words into the proper context-- all he is talking about is which happened first, and nothing else.
    That's fair.

    BTW I wonder if it was C.S. Lewis who gave us the character of Hannibal Lecter . He just called him Screwtape

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    Quote Originally Posted by publiusr View Post
    That's fair.

    BTW I wonder if it was C.S. Lewis who gave us the character of Hannibal Lecter . He just called him Screwtape
    Hannibal Lector was a psychopath. Screwtape was a demon. You might as well ask if Herman Melville gave us the character of Dr. Richard Kimble but called him Moby Dick. There would only be a dozen creations of fictional characters.
    SHARKS (crossed out) MONGEESE (sic) WITH FRICKIN' LASER BEAMS ATTACHED TO THEIR HEADS

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