Page 2 of 79 FirstFirst 12341252 ... LastLast
Results 11 to 20 of 784

Thread: The dumb questions thread

  1. Top | #11
    Fair dinkum thinkum bilby's Avatar
    Join Date
    Mar 2007
    Location
    The Sunshine State: The one with Crocs, not Gators
    Posts
    21,154
    Archived
    10,477
    Total Posts
    31,631
    Rep Power
    81
    D'oh. if N=1, of course. Not 0. Bugger.

    Now I guess I have to cite you as a co-author and we share the prize.

  2. Top | #12
    New Member
    Join Date
    Apr 2008
    Location
    St Augustine, FL
    Posts
    19
    Archived
    1,609
    Total Posts
    1,628
    Rep Power
    42
    I may word this poorly, but this IS the dumb question thread.

    As I understand current cosmology, the universe we see around us expanded from an infinitely dense point some 13 billions years ago. It was at that point that space and time as we understand it, began. It would seem to me that we really are not able to describe what was "there" when time began and space started expanding. Yet, it seems physicists, at least some, are boldly stating that the universe came from...NOTHING. I wonder why they make that statement? It might actually be true, but how can they know? I read Kraus' book, A Universe from Nothing where he tries to lay out his ideas for how "nothing" might be unstable. I could take it as conjectural on his part, but a worthwhile thing to consider. But I am pretty sure he calims the universe came from nothing.

    How can they know there was actually NOTHING? I realize why they might say there was no space or time, matter/energy, but how can they know it was not some other heretofore unimagined state which we have not yet contemplated much less discovered and certainly have been unable to model mathematically?

    Like I said, it's a dumb question so try not to pick apart my understanding so much as, if possible, try to explain why some physicists...Hawking, Kraus to name a few seem to be promoting this idea. It seems the Bord, Guth, Valenkin theorem maintains, in Valenkin's words: '[I]f someone asks me whether or not the theorem I proved with Borde and Guth implies that the universe had a beginning, I would say that the short answer is “yes”. If you are willing to get into subtleties, then the answer is “No, but…” So, there are ways to get around having a beginning, but then you are forced to have something nearly as special as a beginning.'

    It would seem at least they'd hedge their bets and acknowledge they don't know what was there, but explain they are studying the plausibility/possibility of a universe coming, literally, from nothing. It seems to me that there might very well turn out that some other region/realm/state existed/exists that IS outside of time and space and does not contain classic forms of matter/energy and they seem to be prematurely excluding this possibility without really knowing. But they are the experts so what am I missing...what does it mean?

    If the question is too involved to explain, at least, point me to a book/website that explains why some physicists are promoting a universe specifically/exactly FROM NOTHING. Thanks
    Last edited by rizdek; 05-15-2014 at 01:18 AM.

  3. Top | #13
    Veteran Member skepticalbip's Avatar
    Join Date
    Apr 2004
    Location
    Searching for reality along the long and winding road
    Posts
    4,731
    Archived
    12,976
    Total Posts
    17,707
    Rep Power
    62
    You are beyond actual physics when you talk about cosmology of “the beginning”. The reason they are saying that the universe came from nothing is because the mathematics works. The universe is still nothing mathematically. Take the mass and energy in the universe as positive energy and the gravity of the universe as negative energy. Add them and you get zero. The beginning was just when the positive and negative energy that amounted to zero separated (because it was unstable?) and we got what we now see. At least that is my understanding of their reasoning.

  4. Top | #14
    Veteran Member credoconsolans's Avatar
    Join Date
    Apr 2005
    Location
    Texas
    Posts
    2,900
    Archived
    9,729
    Total Posts
    12,629
    Rep Power
    55
    Dumb question:

    Is the only reason we think humans originated in Africa is because we find remains there that date back millions of years? And the reason we still find those is because they were preserved because the area dried up and became arid?

    Suppose humans evolved elsewhere outside of Africa, but the environment remained well watered and fertile and destroyed any remains before they could become fossilized?

  5. Top | #15
    Veteran Member Wiploc's Avatar
    Join Date
    Dec 2002
    Location
    Denver
    Posts
    1,861
    Archived
    14,058
    Total Posts
    15,919
    Rep Power
    64
    Quote Originally Posted by credoconsolans View Post
    Dumb question:

    Is the only reason we think humans originated in Africa is because we find remains there that date back millions of years? And the reason we still find those is because they were preserved because the area dried up and became arid?

    Suppose humans evolved elsewhere outside of Africa, but the environment remained well watered and fertile and destroyed any remains before they could become fossilized?
    I recommend the book Guns, Germs, and Steel. It's been too long since I read it, so I can't explain or even remember the answer to your question. But I do remember that it persuaded me that they know what they're talking about.

    Plus its a great read.

  6. Top | #16
    Elder Contributor Keith&Co.'s Avatar
    Join Date
    Apr 2006
    Location
    Far Western Mass
    Posts
    15,507
    Archived
    24,500
    Total Posts
    40,007
    Rep Power
    72
    Quote Originally Posted by credoconsolans View Post
    And the reason we still find those is because they were preserved because the area dried up and became arid?
    You do know we find fossilized fish, right?

  7. Top | #17
    Veteran Member
    Join Date
    Sep 2006
    Location
    Connecticut
    Posts
    2,132
    Archived
    1,715
    Total Posts
    3,847
    Rep Power
    51
    Quote Originally Posted by credoconsolans View Post
    Dumb question:

    Is the only reason we think humans originated in Africa is because we find remains there that date back millions of years? And the reason we still find those is because they were preserved because the area dried up and became arid?

    Suppose humans evolved elsewhere outside of Africa, but the environment remained well watered and fertile and destroyed any remains before they could become fossilized?
    Genetics. If you look at mitochondrial DNA, you see that the older DNA appears in populations in East Africa. There is also much greater genetic diversity in Africa, supporting the fact that humans originated there.

    Of course, it's possible that an earlier group moved to Africa and then died out completely elsewhere without leaving DNA or fossil evidence, but that's unlikely to the extreme.

  8. Top | #18
    Veteran Member Wiploc's Avatar
    Join Date
    Dec 2002
    Location
    Denver
    Posts
    1,861
    Archived
    14,058
    Total Posts
    15,919
    Rep Power
    64
    Quote Originally Posted by beero1000 View Post
    Genetics. If you look at mitochondrial DNA, you see that the older DNA appears in populations in East Africa.
    That confuses me. How can some Human DNA be older than others? And how would we know?



    There is also much greater genetic diversity in Africa, supporting the fact that humans originated there.
    Okay, this part makes sense.

  9. Top | #19
    Veteran Member jonatha's Avatar
    Join Date
    Sep 2002
    Location
    Kentucky
    Posts
    1,757
    Archived
    3,551
    Total Posts
    5,308
    Rep Power
    64
    Quote Originally Posted by Wiploc View Post

    That confuses me. How can some Human DNA be older than others? And how would we know?


    You look at lots and lots of humans' genes.

    Assuming that mutations occur at a relatively constant rate (or occur at the same rate everywhere and everywhen regardless of whether it's constant), the genes that have the most mutations on them are older than the ones that don't.

    (Most mutations means the largest number of distinct DNA sequences for a particular gene in your big collection of that gene from lots of humans....)

  10. Top | #20
    Veteran Member
    Join Date
    Sep 2004
    Location
    California
    Posts
    3,631
    Archived
    4,797
    Total Posts
    8,428
    Rep Power
    59
    Quote Originally Posted by credoconsolans View Post
    Dumb question:

    Is the only reason we think humans originated in Africa is because we find remains there that date back millions of years?
    No. Before we ever found any, Darwin said we probably originated in Africa and advised fossil hunters to look there, because our nearest relatives are chimps and gorillas and they live in Africa. (Not a dumb question, by the way. It was highly controversial among anthropologists pretty much all the way until Piltdown Man was proven to be a hoax.)

    Suppose humans evolved elsewhere outside of Africa, but the environment remained well watered and fertile and destroyed any remains before they could become fossilized?
    Depending on the time frame you care about, that's kind of what happened -- the long transition from monkey to ape happened in Asia, and then some apes moved to Africa. That counts as human evolution too, no?

Similar Threads

  1. Quick Questions Thread
    By Kharakov in forum Mathematics
    Replies: 10
    Last Post: 01-14-2019, 02:15 AM
  2. The dumb statement's thread
    By Kharakov in forum Logic and Epistemology
    Replies: 22
    Last Post: 02-23-2018, 01:35 AM
  3. Really dumb questions
    By Davka in forum Natural Science
    Replies: 9
    Last Post: 12-26-2014, 10:36 AM
  4. Dumb Questions
    By spikepipsqueak in forum Natural Science
    Replies: 3
    Last Post: 12-22-2014, 08:46 PM

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •