1. Limited time only! Sign up for a free 30min personal tutor trial with Chegg Tutors
    Dismiss Notice
Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Question about Light/dark energy

Tags:
  1. May 9, 2014 #1
    First off I claim no expertise in this subject matter, and this is a result of pondering dark energy.

    When light strikes our eyes(or equipment) how do we perceive its location relative to us?

    is it just in the exact opposite direction of lights angular impact with the plane whether that is equipment or eyes?

    If that's the case when you curve or bend light wouldn't we perceive an object to be in a spot in which it is not?

    The final question is if this were the case could it be possible that the galaxies are not actually accelerating away, but the light emitted from them is getting bent/curved on its way to our plane leading us to believe that movement is different then whats actually happening?
     
  2. jcsd
  3. May 9, 2014 #2

    phinds

    User Avatar
    Gold Member
    2016 Award

    Yes, that is exactly how General relativity was confirmed some 100 years ago.

    "tired light" is a tired theory, totally discredited.
     
  4. May 9, 2014 #3

    HallsofIvy

    User Avatar
    Staff Emeritus
    Science Advisor

    I'm not sure what you mean by this.

    When light "strikes our eyes" it location is in our eyes! If you mean "how do we perceive the origin of the light", then it I in a straight line from our eye. Of course, our eye is not capable of determining whether light has changed direction as, for example, by passing through a prism or by reflecting off a mirror. Nor can it determine how far away a single ray of light originated.

    Yes, of course. When you look at yourself in a mirror, you know you are not in the mirror, don't you?!

    No, computations about the speed at which stars and galaxies are moving have been done taking all known changes to the path of the light into account. It is certainly conceivable that there are other un-known changes- no one claims such calculations are perfect.
     
  5. May 9, 2014 #4
    So correct me if I'm mistaken, but tired light deals with photons collisions casing a decrease in energy => effecting wave length?

    I'm also working with the concept of dark energy being a 'pressure' that's force is greater then the force of gravity from the center of mass of the universe => acceleration different then what was expected..

    With that said I guess a more clear way of explaining my question is..

    Could there be a curvature in space time between us and these distant galaxies? Would this curvature cause an increasing curve/bend of light as the light emitted from galaxies move closer to this 'field'. This curvature then would cause us to perceive an increasing change of position relative to time.. which would explain what the phenomenon we call dark energy. There is no force exceeding that of gravity, but just an unaccounted for source of gravity.. Perhaps dark matter. I just thought that perhaps there is no dark energy force, but just an unforeseen interaction between dark matters gravity and light.

    I appreciate the response, and forgive me my errors... I'm new to this frontier, and I don't know all the rules yet

    Edit.. Sorry I was typing my response before I saw the second reply
     
    Last edited: May 9, 2014
  6. May 9, 2014 #5

    phinds

    User Avatar
    Gold Member
    2016 Award

    Since there IS no "center of mass" of the universe, any theory predicated on that is automatically flawed. The universe HAS no center. I recommend the link in my signature.
     
  7. May 9, 2014 #6
    Thanks for the link, I'll check it out when I have time... Sorry if what I was asking was nonsense.. I just thought the simpler explanation of this acceleration isn't some unknown we call dark energy, but just dark matter curving light. The COM of the universe really in the end had nothing to do with what I was putting forth, and that's my fault for not being more clear. Anyways thanks for the information, and I appreciate your responses
     
  8. May 9, 2014 #7

    phinds

    User Avatar
    Gold Member
    2016 Award

    I don't mean this in any rude way at all but something you might think about asking your self when you come up with such ideas is, do I REALLY believe that all the thousands of professional physicists who have thought about this are so stupid that it never occurred to them?

    Thinking outside the box is to be admired, but it IS a good idea to know what's IN the box first.
     
  9. May 9, 2014 #8
    Phind's has already pointed out the mistakes in your questions, and pointed you out to his excellent Balloon analogy, I'm going to recommend some further reading material so your not poring over the web with its numerous misconceptions in numerous popularizations.

    here are numerous articles designed to clear any misconceptions you may have

    http://tangentspace.info/docs/horizon.pdf :Inflation and the Cosmological Horizon by Brian Powell
    http://arxiv.org/abs/1304.4446 :"What we have leaned from Observational Cosmology." -A handy write up on observational cosmology in accordance with the LambdaCDM model.
    http://arxiv.org/abs/astro-ph/0310808 :"Expanding Confusion: common misconceptions of cosmological horizons and the superluminal expansion of the Universe" Lineweaver and Davies
    http://www.mso.anu.edu.au/~charley/papers/LineweaverDavisSciAm.pdf: [Broken] "Misconceptions about the Big bang" also Lineweaver and Davies
    http://arxiv.org/abs/1002.3966 "why the prejudice against a constant"
    http://arxiv.org/abs/gr-qc/0508052 "In an expanding universe, what doesn't expand? Richard H. Price, Joseph D. Romano
    http://arxiv.org/abs/1301.0219What's [Broken] in a Name: History and Meanings of the Term "Big Bang" Helge Kragh
    http://arxiv.org/pdf/0906.1442v1.pdf Is it possible to see the infinite future of the Universe when falling into a black hole?

    my signature has a site

    http://cosmology101.wikidot.com/main

    where you can find numerous articles designed to teach cosmology,
     
    Last edited by a moderator: May 6, 2017
  10. May 10, 2014 #9
    In fact I have thought about that but..

    A. if every person on the verge of discovering something did think that way nothing would be discovered.
    B. An original thought isn't indicative of the stupidity of others, but perhaps indicates a fresh/different perspective helping.
    C. The only thing I lose when I voice these theories is to hear no... If I could possibly, albeit remote and extremely unlikely, help further the scientific frontier then I'm obligated to voice them.
    D. I believe a more scientific society is something to strive for, and when individuals are told that they should know more before they voice a query is counterproductive to that idea. They feel dejected, and become sequestered from science.

    So in the end I don't think that line of reasoning holds any water.

    I do agree that it would behoove me to know more about the basics, but I also think that its possible that living and learning inside the box could bias your ability to recognize whats outside of it. You cant reconcile it with whats inside so you dismiss it because of its foreign nature.
     
  11. May 10, 2014 #10

    phinds

    User Avatar
    Gold Member
    2016 Award

    That's reasonable, and looking back I see that you did not state your theory as a fact but rather were just asking a question. We have SO many folks come here and do exactly that (state some half-backed idea as their newly discovered fact) that I got a bit oversensitive to your post. My apologies.
     
  12. May 10, 2014 #11
    I completely understand, and its water under the bridge. I just appreciate the feedback so I can stop having this idea kick around in my head :)
     
  13. May 10, 2014 #12

    phinds

    User Avatar
    Gold Member
    2016 Award

    Did you check out my balloon analogy page? Several people here helped me get it right.
     
  14. May 12, 2014 #13
    Yeah I checked it out and it taught me a bit, and brought to light an easy way to view a complex idea. I appreciate the time that you put into it..

    One question I have about it though is why up to the 1990s did we expect the expansion rate to be slowing down? Was it theorized that eventually the gravitational pull between near galaxies would pull them together, and eventually this would result in a single body of mass after a great amount of time (Big Crunch)?
     
  15. May 12, 2014 #14

    phinds

    User Avatar
    Gold Member
    2016 Award

    Yes, exactly. There was also the possibility that it would reach steady state and not collapse but I've never understood that one since it seemed like an expectation of a system staying in unstable equilibrium forever.
     
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook




Similar Discussions: Question about Light/dark energy
  1. Dark energy question (Replies: 21)

Loading...