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I Could "reverse entropy stars" exist in our universe?

  1. Apr 19, 2016 #1
    My lecturer claimed that "reverse entropy stars" could exist in our universe.

    One of the examples he gave was that if you exposed some sort of detector in the direction of a hypothesized reverse entropy star, you could determine if it existed by whether it "sucked" photons out of the detector.

    Is it just me or is this all BS?
     
    Last edited by a moderator: Apr 20, 2016
  2. jcsd
  3. Apr 20, 2016 #2
    My guess. BS.
     
  4. Apr 20, 2016 #3

    Drakkith

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    Staff: Mentor

    I'm no expert, but this sounds like the latter option to me. The first 5 pages of a google search for "reverse entropy star" bring up no results relating to astronomy except for this exact thread. Besides, something "sucking" photons out of a detector is nonsense. Photons cannot be "sucked" out of something. They will be emitted from an object through several different mechanisms, none of which can be influenced by a far away star of any type.

    However, it's possible I'm wrong. Perhaps others here will know more about this.
     
    Last edited by a moderator: Apr 20, 2016
  5. Apr 20, 2016 #4

    Ken G

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    Presumably what this dubious lecturer is saying is that stars shine because they are hotter than the 2.7 K cosmic background radiation, and that's why we see them because of normal entropy considerations, but if there existed "reverse" entropy stars, they would instead remove light from the CBR even though they are hotter. One doesn't need reverse entropy stars for that, stars cooler than 2.7 would suffice fine. Of course there is no reason to expect the existence of either type of star, nor would a reverse entropy star do anything to a photon detector that is different from what a very cold star would do. I think that lecturer needs to bone up on not only what physics says, but also what physics is.
     
  6. Apr 20, 2016 #5
    Hi guys

    Thanks so much for replying. It sounds like we all seem to agree that there may be something wrong here. However, in my best effort to not misrepresent his argument, here is a link to a screencap of him discussing the topic with a skeptical student (all names are removed):

    http://imgur.com/Saa6VAX [Broken]
     
    Last edited by a moderator: May 7, 2017
  7. Apr 20, 2016 #6
    He specifically said such a star could "suck out photons from a previously exposed detector". But yes, I agree with what you said 100%.
     
  8. Apr 20, 2016 #7

    Ken G

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    All he is doing is watching the universe with time running backward. It's trivial. But we don't see time running backward, so we do not have reverse entropy stars. I don't even see a lesson here-- yes, we can watch a movie running backward, and it will look like entropy is reversed. This is not what we actually observe, though one can always imagine hypotheticals. What is learned?
     
    Last edited by a moderator: May 7, 2017
  9. Apr 20, 2016 #8
    Is your lecturer referring to a white hole? White holes should decrease entropy, but they're considered more a curiosity of the mathematics than real objects.
     
  10. Apr 21, 2016 #9
    No he definitely isn't referring to a white hole.
     
  11. Apr 21, 2016 #10
    Well he seems to believe that reverse entropy objects could exist in our current universe. Again, I'm no expert but I am sceptical of claims that I can't find any credible backing for.
     
  12. Apr 26, 2016 #11
    In our universe of endless wonders it's not that hard to imagine.... who knows, maybe he has telepathically seen something the rest of us are yet to :biggrin::biggrin::biggrin:?:)
     
  13. Apr 26, 2016 #12

    sophiecentaur

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    Was this lecture on April the First, by any chance?
     
  14. Apr 26, 2016 #13
    I suspect so
     
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