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Bad Math

  1. Mar 21, 2010 #1
    In regards to dark energy or dark matter...

    Why does the science community create new science to fit the math rather than fix the math to fit the science? Are we so confident in the math that we have to adjust the science to match? Why are we so confident in the math?

    If galaxies rotate differently than what math would predict, shouldn't the math be adjusted to match the universe rather than adjusting the universe to fit the math? What makes more sense?
     
  2. jcsd
  3. Mar 21, 2010 #2
    Some people are trying to do that, it's called MOND, modified newtonian dynamics. But it doesn't work nearly as well as the standard model approach (unless you only consider galaxies and no galaxy clusters or lorentz invariance) and I think the theory ends up having to introduce dark matter anyway. It works perfectly to explain the observed rotation curve though.
     
  4. Mar 21, 2010 #3
    If you throw out dark energy and dark matter, what other theories out there suffer.
     
  5. Mar 22, 2010 #4

    Chronos

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    Fixing the math is probably a bad idea. 1 + 1 = 2 is easier to accept than claiming 2 is a conspiracy. Without dark matter you run into trouble with virial theory and large scale structure in the universe. Without dark energy, you run into to trouble with SNAP [Perlmutter, et al]. Science follows the trail of observational evidence, even when it leads us to odd conclusions about the nature of the universe.
     
    Last edited: Mar 22, 2010
  6. Mar 22, 2010 #5

    Chalnoth

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    Small correction: SNAP is a future, proposed satellite. But without dark energy, you do run afoul of CMB evidence, Baryon Acoustic Oscillation evidence, and supernova evidence, all from multiple sources.
     
  7. Mar 22, 2010 #6

    Vanadium 50

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    I don't think MOND "fixes the math". There is nothing wrong with the math.
     
  8. Mar 22, 2010 #7
    You threw me a curve. I'd just finished reading about SNAP 10A, the one or only disclosed nucular reactor powered satellite put in orbit, now keeping us company at 700 Km distance.
     
  9. Mar 22, 2010 #8
    Well it fixes the equations instead of believing that the equations are right and fixing the physics. I suppose that's what the OP meant, because I would say math itself can't be fixed, it's the way it is.
    And you can't know weather or not there is something wrong with the equations, just because they haven't been proven false yet. Even Einstein's GR might end up not being the ultimate truth, as it has been with Newton, Schroedinger and so on.
     
  10. Mar 22, 2010 #9

    Chalnoth

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    Well, we know that GR is not completely true. It can't be: it predicts singularities. The question, though, is where GR breaks down. So far all experimental tests of GR have shown it to be quite accurate. For example:
    http://www.nature.com/nature/journal/v464/n7286/full/nature08857.html

    (This paper compares the estimated mass of regions from weak lensing to the estimated mass of the same regions from galaxy velocities, and finds they agree)

    From our understanding of quantum mechanics, we generally expect GR to break down on short scales (such as inside black holes), not long scales. Long-distance modifications are possible, of course, but they're not motivated by theory.
     
    Last edited by a moderator: May 4, 2017
  11. Mar 22, 2010 #10
    We aren't exactly talking about 1+1 here. We are talking about "theoretical" equations that work sometimes but not others. If the equations worked as well as "+" then I would agree with you.
     
  12. Mar 22, 2010 #11

    Chalnoth

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    The thing is, we're now at the point where dark matter has been rather strongly confirmed by a wide variety of pieces of evidence that all point in the same direction. Our studies of dark energy are still rather young, and modifications of gravity are still on the table. More and more data are currently being collected to attempt to distinguish between dark energy and modified gravity.

    I should mention that you don't really have a valid complaint here. The cosmology community is most definitely attempting a very wide variety of approaches for solving the dark matter/dark energy problems. With dark matter, we now basically know the solution. With dark energy, we're still working on it.
     
  13. Mar 22, 2010 #12
    I'm glad to hear that the cosmology community is still considering alternatives.
     
  14. Mar 23, 2010 #13

    Chronos

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    Doh, I meant SNLS [supernova legacy study]. It is true the case for dark energy is less securely established than dark matter, but, is still fairly convincing.
     
  15. Apr 4, 2010 #14
    Really, Really!
    >I'm glad to hear that the cosmology community is still considering alternatives. <
    You should read some of the things people say about such studies! Especially you should do so before screaming "conspiracy!" or "idiocy!"
    For a start, the number of alternatives those guys have come up with in the last few decades have been so numerous that I, as layman, have nearly stopped listening. So forgive me if I find your astonishment odd.

    then again:
    >We aren't exactly talking about 1+1 here. We are talking about "theoretical" equations that work sometimes but not others. If the equations worked as well as "+" then I would agree with you. <
    What is anything but theoretical about "1+1=2"? It is a highly specific statement depending on very limited sets of axioms. It works as a useful model, a practical approximation of certain classes of physical and certain classes of formal relationships. In all other classes it is nonsense. Seen in such a light the maths for the dark matter is neither more applicable nor less: you have your axioms and you apply them and your hypotheses to explain your observations. Then, if things look good you make some predictions and check them against further observations. If things work out, you carry on along those lines, otherwise you reckon that the hypotheses have failed the test of falsification and you try something else.

    Seems good to me. It is much like what we have on Earth. Suppose we have an opaque bag hanging from a balance. The balance registers 1. We drop a ball into the bag and the balance registers 2.
    OK! This looks good! Right! Our advanced mathematicians do a bit of hard work and say that they have a suspicion that 1+1 = 2. But then someone does a bit of work on momentum and mutters things about discrepancies! Idiot!!! So then we take the bag off the balance and the dam' readout says -1!
    Well, good commonsense folks like us aren't going to let nonsense like that lead us by the nose are we??? We'll scrap the 1+1 crap that confuses our observations and change our maths to 1+1=3 (for small values of three of course!) After all, we have the evidence of our sense and our senses! The thing to change is our maths!
    To hypothesise that there was a third ball in the bag in the first place is simply too unrealistic. We should change the maths to match the science, like any sensible man would do.
    So I'm being unreasonable, you say? Well, who am I to argue with common sense like yours?
    And yet, the reasoning of the cosmologists really came down to much the same thing really, Really! They weighed the visible galaxies and found that they were heavier than they had thought. So instead of assuming 1+1=3, they assumed that there were more balls or strings or axions or dark meteors or something else... than they had been able to see through their telescopes. Maybe! Subject to further falsification.
    Then they proceeded to evaluate their alternate ideas in their turn. Sadly, this proved so challenging that they have not yet finished, the ignorant, lazy swabs! Would you believe that the universe doesn't come with little labels saying "Duhhh... Thisyer Dark matter" "Thatther lite matter." "Special discount!"
    John Maynard Keynes said something like: "When the facts change, I change my mind Sir! What do you do?"

    Well, Really? What DO you in particular do?

    Go well,

    Jon
     
    Last edited: Apr 5, 2010
  16. Apr 4, 2010 #15

    DevilsAvocado

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    Bad Argument

    Science is not religion. In science you must know that the theory fits the observations. To believe will not do. A theory is only valid as long as not proven wrong. New theories build on a logical continuum with previous theories, knowledge and observations (i.e. no sane scientist will today start working on a theory with Earth as the center of Universe). Science is an (functional) approximation of nature, and mathematics is just a (extremely well functioning) tool, in that process.

    The basic work for a scientist is to questioning everything – including his own work.

    Therefore this is an extremely bad argument – "we have to adjust the science to match (the math)". Adjust the science? What are you saying? Adjust the observations and data to fit the theory!?

    Well, some criminal tricksters have tried in the history of science, and all have been caught – by reality.

    But if you really believe that global communities of scientists works in a global conspiracy to swindle the public, you must ask yourself the obvious question – Why?

    If you suspect that Dark Matter is a fraud – made-up to fit some "crazy theory" – please investigate how MOND handle this 'little' problem:

    "[URL [Broken] Bullet Cluster[/B]

    hs-2006-39-a-web.jpg [/URL]
     
    Last edited by a moderator: May 4, 2017
  17. Apr 4, 2010 #16

    Vanadium 50

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    I am not a MOND fan. I agree that MOND has problems explaining the unseen mass in the Bullet Cluster. But LCDM has problems in explaining the high collision velocity. There are also BC analogs out there that look very different - Abell 520, for example.

    We should be careful not to read more into a single observation than is there.
     
    Last edited by a moderator: May 4, 2017
  18. Apr 4, 2010 #17

    DevilsAvocado

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    Yes sorry, you are absolutely right.

    My point was that the most 'promising' theory that leaves DM out, do that by doing (IMOO) exactly what the OP dislikes – Wikipedia: "Therefore a “marriage” of MOND with ordinary hot neutrinos of 2eV has been proposed to save the hypothesis"

    . . . ?

    "The important thing is not to stop questioning." -- Albert E
     
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