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Why Haven't the Arms of Spiral Galaxies Wound Up After All This Time? (forbes.com)

Posted by timothy on from the rigor-mortis dept.

StartsWithABang writes: When you take a look at a spiral galaxy in the night sky, it seems obvious that the stars on the inner parts of the galaxy are going to orbit in less time than the stars in the outer part. This turns out to be true, something we've figured out even though the timescales for galaxies to complete a full revolution are far longer than we've ever been able to observe. But one thing that doesn't happen is that the arms don't "wind up," meaning that the galaxies don't see the spiral patterns intensify as they age. Even though we first observed spiral structure in galaxies back in the mid-1800s, we didn't understand what the cause of this effect was for over 100 years. Yet now, not only do we understand it, but we can explain why galaxies will never wind up over time, and how this effect is true with or without dark matter.

4 of 94 comments (clear)

  1. Actual Link by cfalcon · · Score: 5, Informative

    Actual Link (warning: still Forbes): http://www.forbes.com/sites/st...

  2. This is clearly corruption by DNS-and-BIND · · Score: 5, Interesting

    An account repeatedly posting links to the same website, forbes.com. That website is full of ads, which are being shown to the audience that clicks through from Slashdot. The content is scienc-y stuff that would attract an audience's like Slashdot. I don't know what the ad was because the adblocker caught it, all I got was a forbes.com landing page and a famous quotation. Then I clicked to enter the article and was directed to http://www.forbes.com/sites/et... which is a "4-0-Forbes" error which means 404 not found.

    The fact that this is happening again and again is no coincidence. There is clearly collusion and someone is getting paid. A shockingly low amount, I suspect. Or a favor is being repaid, or other non-monetary gain. But damn there are too many ads going off for it not to be. On the other hand, I don't really know how successful the operation is. You have to question the wisdom of an operation that doesn't even bother disguising the posting account, and then markets to the one audience in the world that is most enthusiastic about ad-blockers.

    --
    Shutting down free speech with violence isn't fighting fascism. It IS fascism!
  3. But can we explain by thegarbz · · Score: 5, Interesting

    Why slashdot insists on linking to every single article posted by Startwithabang on the incredibly shitty advert infested Forbes?

  4. Better source than Forbes - PBS (Phil Plait) by donkeyb · · Score: 5, Informative

    Phil Plait's excellent series of PBS shorts explains all this in a better fashion (I think), and he doesn't spam himself all over slashdot, so is more deserving of our time :) Galaxies part 1 is here: https://www.youtube.com/watch?... Part 2 is linked from there. :)