Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

B Speed of Light in Dark Matter

  1. Jun 15, 2018 #26

    Sanborn Chase

    User Avatar
    Gold Member

    Thank you very much for your thoughts; I'm happy I've not irritated you, Mr. Drakkith.
    I've been following the literature about dark matter for a number of years. I understand very little of the technical arguments as mathematically expressed (I wilted shortly after calculus), but the concepts surrounding the mystery of dark matter have continued to amaze me, and I realize its quantification is cardinal to our understanding of our world. I also think it's extremely important to understand its nature, and so far there hasn't been a profound breakthrough. It deserves our closest scrutiny. In my life all too often my ignorance has hidden behind my certainty.
    BTW. I doubt Greg B. wants me cross talking so much. I'll cease and desist as of now.
    Again, thanks for everyone's opinions and thoughts.
     
  2. Jun 16, 2018 #27
    Thanks Drakkith, and I agree. Which makes me wonder... given that researchers are converging towards two very precise, but different, values for a "Hubble constant", would this qualify as a pointer to something that may turn out to be "difficult for the standard model to explain"?

    https://www.scientificamerican.com/...on-universes-expansion-polarizes-scientists1/

    Nigel
     
  3. Jun 17, 2018 #28

    Drakkith

    User Avatar

    Staff: Mentor

    It might. It depends on whether there's a true difference vs a measurement error or something.
     
  4. Jun 17, 2018 #29
    Sorry for expanding this aside, but let me sum up the article.
    1. The expansion rate was 67.3 km/s/Mpc in the early universe
    2. The expansion of the universe is accelerating
    3. Today, the expansion rate is 73.5 km/s/Mpc.
    I fail to see a problem here...?
     
  5. Jun 17, 2018 #30

    Ken G

    User Avatar
    Gold Member

    Acceleration doesn't mean the Hubble parameter should increase. Without acceleration, it should drop with age, and the steepest type of acceleration that is normally treated is one in which the Hubble parameter stays fixed with age, which might be a situation we are now moving toward as dark energy wrests control. But it would be a significant problem for current models if the Hubble parameter increased with age.
     
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook

Have something to add?
Draft saved Draft deleted