Re: [Off-topic] Requests author discusses MentalHealthError exception

From	Gregory Ewing <greg.ewing@canterbury.ac.nz>
Newsgroups	comp.lang.python
Subject	Re: [Off-topic] Requests author discusses MentalHealthError exception
Date	2016-03-04 19:34 +1300
Message-ID	<djsojkF3b2hU1@mid.individual.net> (permalink)
References	(7 earlier) <56d7a130$0$1611$c3e8da3$5496439d@news.astraweb.com> <mailman.132.1456972516.20602.python-list@python.org> <Xo_By.1410878$QP2.1092239@fx42.am4> <mailman.157.1457028277.20602.python-list@python.org> <101Cy.1411363$QP2.758114@fx42.am4>

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alister wrote:
> On Thu, 03 Mar 2016 11:03:55 -0700, Ian Kelly wrote:
> 
>>On Thu, Mar 3, 2016 at 10:21 AM, alister <alister.ware@ntlworld.com>
>>wrote:
>>
>>Antimatter has positive mass.
> 
> Are you sure?
>  mix 1 atom of hydrogen + 1 of anti hydrogen & you end up with 0 mass

That's not because anti-hydrogen has negative mass, though.
It's just because photons happen to have zero mass. (You're
assuming here that photons are the only products, which is
not the only possible result, but it's one of the possibilities.)

Mass on its own is not a conserved quantity. The thing that's
conserved is total energy. Mass is just the energy something
has when it's standing still, so if the anti-hydrogen had
negative mass, it would also have negative energy when at
rest, and you would get a total of zero energy out of the
reaction. This is not what happens.

As far as I know, there are no negative masses anywhere in
any of our current theories of physics, nor have we observed
anything that would suggest the need for such a thing.

-- 
Greg

Thread

[Off-topic] Requests author discusses MentalHealthError exception Steven D'Aprano <steve@pearwood.info> - 2016-02-27 20:37 +1100
  Re: [Off-topic] Requests author discusses MentalHealthError exception Mark Lawrence <breamoreboy@yahoo.co.uk> - 2016-02-27 09:50 +0000
  Re: [Off-topic] Requests author discusses MentalHealthError exception Ethan Furman <ethan@stoneleaf.us> - 2016-02-27 14:06 -0800
  Re: [Off-topic] Requests author discusses MentalHealthError exception Jason Friedman <jsf80238@gmail.com> - 2016-02-27 17:00 -0700
  Re: [Off-topic] Requests author discusses MentalHealthError exception Larry Martell <larry.martell@gmail.com> - 2016-02-29 11:21 -0500
  Re: [Off-topic] Requests author discusses MentalHealthError exception Ian Kelly <ian.g.kelly@gmail.com> - 2016-02-29 09:47 -0700
  Re: [Off-topic] Requests author discusses MentalHealthError exception Ben Finney <ben+python@benfinney.id.au> - 2016-03-01 03:56 +1100
    Re: [Off-topic] Requests author discusses MentalHealthError exception Rustom Mody <rustompmody@gmail.com> - 2016-02-29 09:08 -0800
      Re: [Off-topic] Requests author discusses MentalHealthError exception Ben Finney <ben+python@benfinney.id.au> - 2016-03-01 04:33 +1100
        Re: [Off-topic] Requests author discusses MentalHealthError exception Rustom Mody <rustompmody@gmail.com> - 2016-02-29 09:54 -0800
      Re: [Off-topic] Requests author discusses MentalHealthError exception Larry Martell <larry.martell@gmail.com> - 2016-02-29 17:40 -0500
      Re: [Off-topic] Requests author discusses MentalHealthError exception Mark Lawrence <breamoreboy@yahoo.co.uk> - 2016-02-29 23:29 +0000
      Re: [Off-topic] Requests author discusses MentalHealthError exception Joel Goldstick <joel.goldstick@gmail.com> - 2016-02-29 18:33 -0500
      Re: [Off-topic] Requests author discusses MentalHealthError exception Steven D'Aprano <steve@pearwood.info> - 2016-03-02 04:05 +1100
        Re: [Off-topic] Requests author discusses MentalHealthError exception Rustom Mody <rustompmody@gmail.com> - 2016-03-02 09:02 -0800
          Re: [Off-topic] Requests author discusses MentalHealthError exception Steven D'Aprano <steve@pearwood.info> - 2016-03-03 13:27 +1100
            Re: [Off-topic] Requests author discusses MentalHealthError exception Chris Angelico <rosuav@gmail.com> - 2016-03-03 13:35 +1100
              Re: [Off-topic] Requests author discusses MentalHealthError exception alister <alister.ware@ntlworld.com> - 2016-03-03 17:21 +0000
                Re: [Off-topic] Requests author discusses MentalHealthError exception Ian Kelly <ian.g.kelly@gmail.com> - 2016-03-03 11:03 -0700
                Re: [Off-topic] Requests author discusses MentalHealthError exception alister <alister.ware@ntlworld.com> - 2016-03-03 20:20 +0000
                Re: [Off-topic] Requests author discusses MentalHealthError exception Ian Kelly <ian.g.kelly@gmail.com> - 2016-03-03 13:33 -0700
                Re: [Off-topic] Requests author discusses MentalHealthError exception William Ray Wing <wrw@mac.com> - 2016-03-03 18:02 -0500
                Re: [Off-topic] Requests author discusses MentalHealthError exception alister <alister.ware@ntlworld.com> - 2016-03-04 14:05 +0000
                [Still off-top] Physics [was Requests author discusses MentalHealthError exception] Steven D'Aprano <steve@pearwood.info> - 2016-03-04 11:04 +1100
                Re: [Still off-top] Physics [was Requests author discusses MentalHealthError exception] Oscar Benjamin <oscar.j.benjamin@gmail.com> - 2016-03-04 10:19 +0000
                Re: [Still off-top] Physics [was Requests author discusses MentalHealthError exception] Marko Rauhamaa <marko@pacujo.net> - 2016-03-04 12:38 +0200
                Re: [Still off-top] Physics [was Requests author discusses MentalHealthError exception] Dan Sommers <dan@tombstonezero.net> - 2016-03-04 13:10 +0000
                Re: [Still off-top] Physics [was Requests author discusses MentalHealthError exception] Oscar Benjamin <oscar.j.benjamin@gmail.com> - 2016-03-04 17:35 +0000
                Re: [Still off-top] Physics [was Requests author discusses MentalHealthError exception] André Roberge <andre.roberge@gmail.com> - 2016-03-04 11:12 -0800
                Re: [Still off-top] Physics [was Requests author discusses   MentalHealthError exception] Gregory Ewing <greg.ewing@canterbury.ac.nz> - 2016-03-05 15:51 +1300
                Re: [Still off-top] Physics [was Requests author discusses MentalHealthError exception] Chris Angelico <rosuav@gmail.com> - 2016-03-05 14:13 +1100
                Re: [Still off-top] Physics [was Requests author discusses MentalHealthError exception] Marko Rauhamaa <marko@pacujo.net> - 2016-03-05 10:31 +0200
                Re: [Still off-top] Physics [was Requests author discusses MentalHealthError exception] Oscar Benjamin <oscar.j.benjamin@gmail.com> - 2016-03-05 13:11 +0000
                Photon mass (was: [Still off-top] Physics) Thomas 'PointedEars' Lahn <PointedEars@web.de> - 2016-03-05 16:38 +0100
                Re: [Still off-top] Physics [was Requests author discusses MentalHealthError exception] Gene Heskett <gheskett@wdtv.com> - 2016-03-05 10:15 -0500
                Photon mass (was: [Still off-top] Physics) Thomas 'PointedEars' Lahn <PointedEars@web.de> - 2016-03-05 16:46 +0100
                Re: Photon mass (was: [Still off-top] Physics) Gene Heskett <gheskett@wdtv.com> - 2016-03-05 12:36 -0500
                Re: Photon mass (was: [Still off-top] Physics) Dennis Lee Bieber <wlfraed@ix.netcom.com> - 2016-03-06 12:16 -0500
                Re: Photon mass (was: [Still off-top] Physics) Larry Martell <larry.martell@gmail.com> - 2016-03-06 09:21 -0500
                Re: [Still off-topic] Physics Steven D'Aprano <steve@pearwood.info> - 2016-03-06 16:36 +1100
                Re: [Off-topic] Requests author discusses MentalHealthError   exception Gregory Ewing <greg.ewing@canterbury.ac.nz> - 2016-03-04 19:34 +1300
                Re: [Off-topic] Requests author discusses MentalHealthError   exception Marko Rauhamaa <marko@pacujo.net> - 2016-03-04 08:52 +0200
            Re: [Off-topic] Requests author discusses MentalHealthError exception Rustom Mody <rustompmody@gmail.com> - 2016-03-02 19:57 -0800
              Re: [Off-topic] Requests author discusses MentalHealthError exception Ian Kelly <ian.g.kelly@gmail.com> - 2016-03-02 23:44 -0700
              Re: [Off-topic] Requests author discusses MentalHealthError exception Steven D'Aprano <steve@pearwood.info> - 2016-03-04 02:50 +1100
              Re: [Off-topic] Requests author discusses MentalHealthError exception Mark Lawrence <breamoreboy@yahoo.co.uk> - 2016-03-03 16:21 +0000
      Re: [Off-topic] Requests author discusses MentalHealthError exception Anders Wegge Keller <wegge@wegge.dk> - 2016-03-03 08:23 +0100
    Re: [Off-topic] Requests author discusses MentalHealthError exception Paul Rubin <no.email@nospam.invalid> - 2016-02-29 16:35 -0800
      Re: [Off-topic] Requests author discusses MentalHealthError exception Ethan Furman <ethan@stoneleaf.us> - 2016-02-29 16:54 -0800
  Re: [Off-topic] Requests author discusses MentalHealthError exception Larry Martell <larry.martell@gmail.com> - 2016-02-29 17:36 -0500
  Re: [Off-topic] Requests author discusses MentalHealthError exception Larry Martell <larry.martell@gmail.com> - 2016-02-29 17:38 -0500
    Re: [Off-topic] Requests author discusses MentalHealthError exception Steven D'Aprano <steve@pearwood.info> - 2016-03-01 23:13 +1100
      Re: [Off-topic] Requests author discusses MentalHealthError exception "Sven R. Kunze" <srkunze@mail.de> - 2016-03-01 17:49 +0100
  Re: [Off-topic] Requests author discusses MentalHealthError exception "Mario R. Osorio" <nimbiotics@gmail.com> - 2016-02-29 20:11 -0800
  Re: Photon mass (was: [Still off-top] Physics) Gene Heskett <gheskett@wdtv.com> - 2016-03-06 16:46 -0500
  Re: Photon mass (was: [Still off-top] Physics) Larry Martell <larry.martell@gmail.com> - 2016-03-06 17:51 -0500

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