Re: Gravity Forces

Newsgroups	sci.physics
Date	2015-08-05 18:23 -0700
References	<1a4b8db5-f17c-4973-8685-9e95f2b4fbd3@googlegroups.com> <12b0db7f-327e-4506-9919-135ed7381014@googlegroups.com> <iNadnSC6oYJHPl_InZ2dnUU7-WudnZ2d@giganews.com>
Message-ID	<8fdd5135-e1be-471a-9609-1fc2e465c770@googlegroups.com> (permalink)
Subject	Re: Gravity Forces
From	Enomis Skating <anomis.edenomis@libero.it>

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Il giorno giovedì 6 agosto 2015 02:01:33 UTC+2, Sam Wormley ha scritto:
> On 8/5/15 6:47 PM, reber g=emc^2 wrote:
> > A photon has infinitly weak gravity
> 
>    Do not be silly, reber, depending on wavelength the Energy
>      E = hc/λ

Or, depending on frequency: E = hf

>    One can use E = mc^2 to determine equivalent mass.  

As it stands, for a photon it means that m = hf/c^2 which is not zero. 
So either E = mc^2 is not general or the photon is not massless.

>    It is not
>    infinitely small and does exert a tiny gravitational force as
>    it whizzes by.

Caution is needed when teaching, and much more so when popularizing science.

regards
Angelo

Thread

Gravity Forces "reber g=emc^2" <herbertglazier0@gmail.com> - 2015-08-05 11:32 -0700
  Re: Gravity Forces Sam Wormley <swormley1@gmail.com> - 2015-08-05 13:53 -0500
    Re: Gravity Forces HVAC <Mr.HVAC@gmail.com> - 2015-08-06 06:26 -0400
  Re: Gravity Forces "hanson" <hanson@quick.net> - 2015-08-05 12:48 -0700
  Re: Gravity Forces "reber g=emc^2" <herbertglazier0@gmail.com> - 2015-08-05 16:47 -0700
    Re: Gravity Forces Sam Wormley <swormley1@gmail.com> - 2015-08-05 19:01 -0500
      Re: Gravity Forces gilber34 <invalid@invalid.com> - 2015-08-05 19:35 -0500
        Re: Gravity Forces "reber g=emc^2" <herbertglazier0@gmail.com> - 2015-08-05 18:10 -0700
          Re: Gravity Forces "hanson" <hanson@quick.net> - 2015-08-05 19:50 -0700
          Re: Gravity Forces gilber34 <invalid@invalid.com> - 2015-08-05 23:12 -0500
      Re: Gravity Forces Enomis Skating <anomis.edenomis@libero.it> - 2015-08-05 18:23 -0700
    Re: Gravity Forces Sam Wormley <swormley1@gmail.com> - 2015-08-05 19:07 -0500
      Re: Gravity Forces "reber g=emc^2" <herbertglazier0@gmail.com> - 2015-08-05 17:34 -0700
        Re: Gravity Forces Sam Wormley <swormley1@gmail.com> - 2015-08-05 20:07 -0500
    Re: Gravity Forces HVAC <Mr.HVAC@gmail.com> - 2015-08-06 06:28 -0400
  Re: Gravity Forces Sam Wormley <swormley1@gmail.com> - 2015-08-05 19:10 -0500
    Re: Gravity Forces "reber g=emc^2" <herbertglazier0@gmail.com> - 2015-08-05 17:37 -0700
      Re: Gravity Forces gilber34 <invalid@invalid.com> - 2015-08-05 23:20 -0500
    Re: Gravity Forces R Kym Horsell <kym@kymhorsell.com> - 2015-08-06 00:43 +0000

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