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What would you say to this?

  1. Sep 27, 2007 #1
    "Light travels as fast as we can think (process the visual image)."

    What would you say to this? Do you agree?

    Does light only travel as fast as our brains can process the image?
  2. jcsd
  3. Sep 27, 2007 #2
    I don't see why this is in Astrophysics, but...

    Since we can control the creation of single photons, and measure the arrival of single photons, and can therefore calculate the speed at which photons travel...


    To even say that light travels as fast as we can think betrays extremely sloppy thinking, and deliberate word-play designed to sound clever.
  4. Sep 27, 2007 #3
    It's in the Astrophysics section because I created the thread here. If it needs to be moved, I'm sure a moderator will do so.

    Let's say we were to come into contact with another life form, and let's pretend that their brain structure, along with their eyes, were constructed differently to our own. If the other life form was capable of carrying the signals from its eyes to its brain faster than us, then wouldn't it see light quicker than us?

    By the way, I do not appreciate nor understand why you have resulted in posting a rude comment, however I will ignore it.
  5. Sep 27, 2007 #4
    There is a huge difference between the speed of seeing light and the speed of light. That is what I meant by sloppy thinking. Of course if the biology allows faster processing, then the alien will "see" light faster. But that doesn't change anything about the speed of light.
  6. Sep 27, 2007 #5
    I guess I can see what you are saying.

    The alien would see the same light, which is travelling at the same speed, but just before a human.
  7. Sep 27, 2007 #6


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    This doesn't really have anything to do with the speed of light. It sounds like your question is about the biological process by which we process and respond to signals from our eyes. This happens very slowly - a few hundredths of a second. Contrast that with the few nanoseconds it takes light to get from your monitor to your eyes.

    Btw, that first sentence in the OP is in quotes - is it a quote from someone? In any case, genneth is right: is a very poorly constructed sentence/question. Almost to the point of being meaningless. And for that and other reasons, it is the type of thing that sets off my warning bell too.
    Last edited: Sep 27, 2007
  8. Sep 30, 2007 #7
    ...and that's on instinct on a good day. The average person takes on the order of 200ms+ if they have to think make useful sense of what they're seeing.
  9. Oct 2, 2007 #8
    I think I see the gist of your question, but your physiology is not quite right. Your eyes are part of your brain; it's the processing that goes on further in. You might make some point that the speed of light is different through your vitreous humor rather than the alien's but that begs the question of how one would ever know who saw the light faster. Are you arguing that physical reality is what we perceive it to be?
  10. Oct 2, 2007 #9
    CleffedUp is right on the time it takes our brains to become conscious of sensory input. In addition, signals travel on neurons up to 180 mph, I recall.
  11. Oct 4, 2007 #10


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    It wasn't a 'rude' comment, and you shouldn't ignore it; Genneth's response was quite appropriate. The envelopment of your initial statement in quotes indicated (to me, at least) that it was something that someone else told you. I suspect that anything 'disparaging' said about it was directed toward whoever said it initially, rather than toward you.
    Light travels at a uniform speed, period. You'd be hard-pressed to find any two people whose neuronal pathways conduct the resultant signal exactly the same way. That's biology and electrochemistry, not optics. All that you can measure empirically is the response time of the individual brain.
  12. Oct 4, 2007 #11
    Light speed is measured in units of distance divided by units of time. In what units is image processing speed measured? Number of images divided by units of time? If so, then the two speeds are incommensurate.
    Last edited: Oct 4, 2007
  13. Oct 4, 2007 #12


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    As a comment about how science applies to everyday life, the statement has some meaning. It suggests that a person should put things into a little perspective when trying to apply technological advances to the real world. Focus on improvements that will provide a meaningful result. If you could improve the speed of light (or more realistically, reduce the propagational delays in making information appear on a screen), it wouldn't improve a person's life since data flow rate isn't the limiting factor - comprehending the data is.

    An example: The billing department that determines the cost of a chemical down to the thousandths of cents/per gallon based on the ingredients that go into the chemical and the cost of producing it. Then some guy pumps the chemical into a tanker truck until it goes above a certain line - an accuracy that might be within 10 gallons if he's lucky.

    Or: A human that makes three approximations on where a ball happened to be when the ball carriers knee touched the ground - then brings out the chains to determine whether the ball was advanced exactly 10 yards or not (probably one of the most bizarre processes in sports, if you really think about it).

    There's a lot of things in life that don't warrant sweating small details that just get lost in the noise. Focus on things that have a meaningful result. Is it worth making information on a screen update faster than a human can perceive it?
  14. Oct 4, 2007 #13


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    A typical NCAA/NFL ref has eyes calibrated to judge all distances in thousandths of an inch, to the nearest thousandth. C'mon Bob, show some respect! :)
  15. Oct 4, 2007 #14
    What are motion pictures in? 24 frames a second?
  16. Oct 4, 2007 #15


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    24/fps but each frame is shown twice to give 48 images/second.
    At only 24 images/second you are aware of the individual images, below about 16/s it starts to look very jerky.
    This hasn't really anything to do with the speed of the transmission from your eye to brain - it's to do with how your brain processes images.
  17. Oct 4, 2007 #16
    I literally do this every day with my naked eye as part of my job. I'm getting so good at it now I can almost do it blindfolded. Maybe I should apply to be a ref for the NCAA/NFL.
  18. Oct 4, 2007 #17


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    One of the jobs I once had involved peering down into a can of ethanol to make sure it was filled precisely to the proper level. They gave me a pair of standard woodshop goggles to protect my eyes in the event the ethanol splashed out of the can for some reason. That turned out to be a fairly common event.

    Fortunately for me, the cans rattled as they moved down the metal conveyor belt. My ears became so attuned to the proper pitch the rattle of the cans should have that I literally did do the job with my eyes closed most of the time. The sound of a can with too little ethanol stuck out so bad that I could pick it out from among the full cans every time.

    Which would add a whole different twist to the original quote, I guess.
    Last edited: Oct 4, 2007
  19. Oct 4, 2007 #18
    Galileo ran his experiments on the inverse square law before accurate clocks were available. He did it by rolling balls down an incline strung with violin strings (or perhaps lute strings, his father was a music teacher and lute player). When the sound of the ball hitting the strings was regular, he knew the time traveled between them was equal. All he needed to do was space the strings at intervals that would produce that regular sound.

    I've tried to find out if he discovered the law, or merely confirmed what Newton had postulated. I've heard anecdotes either way. Does someone have a good citation?
  20. Oct 4, 2007 #19
    Galileo preceeded Newton, and wouldn't have been confirming or denying anything Newton postulated.

    http://www.mathpages.com/home/kmath121.htm [Broken]

    Regardless, assessing things by the pitch of the sound they make is a fascinating subject.
    I noticed a while back that you can tell when the water begins to run hot from a tap by the change in pitch.
    Last edited by a moderator: May 3, 2017
  21. Oct 4, 2007 #20
    did it ever 'splash' out on your lips?

    From the OP, "as fast as we can think" -----I was thinking the brain can't process even at 24 (48) images a second, so light speed seems faster---what I was going after is that 'photon' reception gets blended in the/'our' brain into what it can handle.
    Last edited: Oct 4, 2007
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