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

Some relaxation

  1. Jan 23, 2007 #1
    Does " What you don't see with your eyes, don't invent with your mouth" does work in special relativity?:rofl:
  2. jcsd
  3. Jan 26, 2007 #2
    Your post is a bit vague - you must have something specific in mind!
  4. Jan 26, 2007 #3


    User Avatar
    Staff Emeritus
    Science Advisor

    Abstract concepts are very useful in relativity, as elswhere. This is what I assume is meant by "don't see with your eyes" - abstractions.

    But sometimes people incorrectly carry over abstract concepts that used to work in Newtonian theory to relativity. This can be a problem.

    Discussing everything in terms of observations (i.e. no abstractions, take everything down to the lowest level of what is actually measured and directly observed) is more work, but is one way (and one of the better ways) of avoiding or sidestepping the trap of incorrrect abstract concepts, if all parties are sufficiently dedicated, patient, and have enough time.
  5. Jan 26, 2007 #4
    believe what you see?

    When I posted the thread I did not have a clear answer to the question proposing it only for relaxation. Pervect's answer is interesting. In between I remembered an old question in special relativity: Can we see the Lorentz contraction? As far as I know there are authors who consider that we are not able to see it (Terrel?) and others who consider that under certain circumstances we can. Are thought experiments a way to make abstract concepts more palpable?
  6. Jan 27, 2007 #5
    Thanks. Do you mean by abstract "instantaneous velocity", "instantaneous frequency"...? Using photographic detection or radar detection we can compare (see) the snapshots or the radar screens of two observers in relative motion. Such approaches ensure the fact that we believe what we see?
  7. Oct 23, 2010 #6
    Re: believe what you see?

    The not being able to see (or photograph) the Lorentz length contraction of a moving object only applies to the case of a perfect sphere. The length contraction of a long rectangle or rod for example can be photographed. The demonstration that the the length contraction of a sphere cannot be visually photographed is seized upon by too many to imply (incorrectly) that length contraction cannot be seen in ANY object and that length contraction is an illusion.

    Oops, just noticed this is a very old thread. Sorry! Stumbled across it when searching for something else.
    Last edited: Oct 23, 2010
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook