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

Why sun looks bigger in the evening?

  1. Jan 31, 2006 #1
    why sun looks bigger in the evening? although it's closer to the earth during noon?
     
  2. jcsd
  3. Feb 1, 2006 #2

    tony873004

    User Avatar
    Science Advisor
    Gold Member

    It's not significantly closer to Earth during noon. Your eye could never percieve the difference.

    I would have to guess its for the same reason as the Moon illusion. When the Moon is low, you have foreground to compare it to. That sets up an optical illusion that deceives you into thinking that it is bigger.

    The Moon's horizon and overhead distances are slightly greater than insignificant, with it being bigger overhead. But the difference is still small enough that the optical illusion overwhelms it.
     
  4. Feb 1, 2006 #3

    mathman

    User Avatar
    Science Advisor
    Gold Member

    One thing I've noticed is that if you lie on the ground looking straight up at the sky, things overhead (clouds particularly) look closer than when you are standing up.
     
  5. Feb 1, 2006 #4

    Labguy

    User Avatar
    Science Advisor

    I believe that only happens because you (any person) are on the ground looking up from being too stoned to stand....:rofl:
     
  6. Feb 2, 2006 #5

    mathman

    User Avatar
    Science Advisor
    Gold Member

    Didn't you ever picnic in the park with your girl friend?
     
  7. Feb 3, 2006 #6

    Labguy

    User Avatar
    Science Advisor

    Yes, many times but I don't recall ever looking UP.
    :biggrin: ..:biggrin: ..:biggrin:
     
  8. Feb 4, 2006 #7

    turbo

    User Avatar
    Gold Member

    This is true. If you will Google on fovea, you will see how the non-uniformity in the eye and the non-uniformity in the visual cortex work together to give us a magnified and sharpened image in the center of our field of view. This effect is especially pronounced in birds of prey, who often have to locate their food from very high up.
     
  9. Feb 5, 2006 #8

    Chronos

    User Avatar
    Science Advisor
    Gold Member
    2015 Award

    In a word, refraction. The earth's atmosphere magnifies the image.
     
  10. Feb 5, 2006 #9

    Thats just a function of positioning.
     
  11. Feb 5, 2006 #10

    turbo

    User Avatar
    Gold Member

    Not enough for you to notice, and the effect is in the wrong direction, anyway. When you are looking straight up, you are looking through the least amount of atmosphere possible. The apparent largeness and sharpness of things in the center of our field of view is due to the physiology of the eye and to the manner in which the eye is wired to the visual cortex.
     
  12. Feb 6, 2006 #11

    Chronos

    User Avatar
    Science Advisor
    Gold Member
    2015 Award

  13. Feb 6, 2006 #12

    SpaceTiger

    User Avatar
    Staff Emeritus
    Science Advisor
    Gold Member

    If you're looking at the sun close enough to notice this, you should see an eye doctor. :yuck:
     
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook

Have something to add?



Similar Discussions: Why sun looks bigger in the evening?
Loading...