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Thread: Our galaxy is bent

  1. #1 Our galaxy is bent 
    ox
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    https://www.bbc.co.uk/news/world-us-canada-49182184

    Apart from tugs from other galaxies, what could cause this?


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  3. #2  
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    Quote Originally Posted by ox View Post
    https://www.bbc.co.uk/news/world-us-canada-49182184

    Apart from tugs from other galaxies, what could cause this?
    If you don't include collisions in tugs, then the former.


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    Maybe Lisa Randall can provide an explanation for your question.

    The important part for you is from 30 min mark (approx).

    Probably better watching full video though to understand her theory better.

    https://www.youtube.com/watch?v=G3cjgHxBwnw
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  5. #4  
    ox
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    Why should dark matter bend the galaxy?
    Her theory of mass extinctions could also be explained by a passing star getting too close to the Oort Cloud.
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    I think the theory is that the DM disk is thinner than the disk of the matter we know in the Galaxy. So the gravity of the DM disk pulls the matter we know around. Causing a warping of the disk.

    It's not my theory. I don't agree with all she says. It was a reply that i thought fit the OP.

    Mass extinction could be explained by other means. But. This too is one of the other means.

    Where is this "passing star" that gets to close to the oort cloud come from? Or, going to?

    The video i posted is her theory only.

    Take it as you wish.

    Nothing is proven.
    Last edited by callsmayberecorded; August 4th, 2019 at 04:08 PM.
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  7. #6  
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    Quote Originally Posted by callsmayberecorded View Post
    Where is this "passing star" that gets to close to the oort cloud come from? Or, going to?
    https://www.space.com/22538-nemesis-star.html
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    Cool thanks
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  9. #8  
    Brassica oleracea Strange's Avatar
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    Our galaxy is bent
    Well, it is certainly very queer.
    ei incumbit probatio qui dicit, non qui negat
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  10. #9  
    Brassica oleracea Strange's Avatar
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    Quote Originally Posted by callsmayberecorded View Post
    I think the theory is that the DM disk is thinner than the disk of the matter we know in the Galaxy.
    Dark matter is distributed spherically around the galaxy, not as a disk.
    ei incumbit probatio qui dicit, non qui negat
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    Thanks Strange.

    Not saying i agree with the video.

    I put it up 'cos it was relevant to the question.

    With DM not proved directly. Only through anomalies.

    It's all just theories.

    But the observed anomalies don't make it look disk shaped.
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  12. #11  
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    Quote Originally Posted by callsmayberecorded View Post
    With DM not proved directly. Only through anomalies.

    It's all just theories.
    “Just theories”? So really well supported by large amounts of evidence? Yes.
    ei incumbit probatio qui dicit, non qui negat
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    “Just theories”? So really well supported by large amounts of evidence? Yes.

    Which would be indirect evidence/proof?

    How is that different from "
    With DM not proved directly. Only through anomalies."?

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  14. #13  
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    Quote Originally Posted by callsmayberecorded View Post
    “Just theories”? So really well supported by large amounts of evidence? Yes.

    Which would be indirect evidence/proof?

    How is that different from "
    With DM not proved directly. Only through anomalies."?

    Well, in science nothing is ever "proved". And I don't really know what "direct" detection of dark matter would mean. I assume you mean an experiment that detects the particles it is made of, and gives us more information about them. As with neutrinos, this would almost certainly be an "indirect" detection. We would be able to see them with our own eyes or touch them. But I have no idea what people mean by "direct detection"; it seems pretty meaningless to me. We can already detect dark matter; we know a lot about its properties, distribution and history (it has been present in the universe in the same proportion and for as long as normal matter).
    ei incumbit probatio qui dicit, non qui negat
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    science is trying to directly detect DM in experiments like Alice, Atlas, Xenon gas exp, WIMP etc.

    They haven't been successful at doing so. That way.
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    Quote Originally Posted by callsmayberecorded View Post
    science is trying to directly detect DM in experiments like Alice, Atlas, Xenon gas exp, WIMP etc.
    Not really.
    For example:
    Atlas:
    Since dark matter is dark, it will not interact significantly with instruments made of ordinary matter. For this reason, the underlying signature of dark matter production at the LHC, used by all ATLAS searches, is the presence of invisible particles in proton-proton collisions. - snip - Therefore, if we add up the transverse momenta of all the visible particles produced in the collision and find it not to be zero, then this could be because we have missed the momentum carried away by invisible particles.

    I.e. an indirect detection. (From here).
    Xenon gas experiment:
    In order to discern WIMPs from neutrons, the number of single interactions must be compared to multiple events. Since WIMPs are expected to be so weakly interacting, most would pass through the detector unnoticed. Any WIMPs that interact will have negligible chance of repeated interaction. Neutrons, on the other hand, have a reasonably large chance of multiple collisions within the target volume, the frequency of which can be accurately predicted. Using this knowledge, if the ratio of single interactions to multiple interactions exceeds a certain value, the detection of dark matter may be reliably inferred.
    I.e. an indirect detection. (From here). (That's also WIMP "detection").
    No idea what Alice is.
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    No idea what Alice is
    Neither have these guys...

    https://www.youtube.com/watch?v=CsrfovOPcjk
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  18. #17  
    Brassica oleracea Strange's Avatar
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    Quote Originally Posted by Dywyddyr View Post
    No idea what Alice is.
    That is probably A Large Ion Collider Experiment at CERN: https://home.cern/science/experiments/alice

    Not directly looking for dark matter, but I guess there is a chance it could find something novel that could provide an explanation.
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  19. #18  
    Genius Duck Moderator Dywyddyr's Avatar
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    Quote Originally Posted by Strange View Post
    Not directly looking for dark matter
    That would explain why I didn't find it: I Googled "Alice dark matter" and it came up with nothing.
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  20. #19  
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    Quote Originally Posted by Dywyddyr View Post
    Quote Originally Posted by Strange View Post
    Not directly looking for dark matter
    That would explain why I didn't find it: I Googled "Alice dark matter" and it came up with nothing.
    Nothing suitable for work, anyway
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  22. #21  
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    Quote Originally Posted by callsmayberecorded View Post
    And which particular link from there discusses direct detection of DM?
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