Re: [asa] George & heliocentricity

Bernie -

There is no question that there is a reference frame in which any particle is at rest, it's "proper frame" or "rest frame" to use the language of relativity. (In fact there is an infinite number of such frames which are related to one another by purely spatial rotations.) Bernie Dehler's proper frame is the one that you instrinctively use when you consider yourself to be at rest. However, you don't have to use that frame - you can use one moving past the earth at high speed without jumping into a spaceship.)

This is also true of the earth to the extent that we can consider it a particle - i.e., that we can neglect its spatial extension (as we usually too when talking about orbital mechanics) and its rotation. As I've pointed out, you run into problems with trying to use a frame that rotates with the earth but with appropriate limitation we can - & do - use such a frame.

So the existence of the rest frame of any particle isn't - or shouldn't be - in question. The further question, however, is whether all reference frames are equally valid for the description of physical phenomena. General relativity says they are - that's why it's general relativity. It is true that reference frames, aka space-time coordinate systems, generally aren't valid over the whole of space-time. That's the same sort of limitation as the fact that the usual latitude-longitude systems on the earth's surface break down at the poles (because there the longitude can have any value).
  
Shalom
George
http://home.roadrunner.com/~scitheologyglm

  ----- Original Message -----
  From: Dehler, Bernie
  To: ASA list
  Sent: Monday, July 13, 2009 1:06 PM
  Subject: RE: [asa] George & heliocentricity

  George said:
  "We do not know that the earth is not at rest, only the obvious fact that there are reference frames in which the earth is not at rest."

  I think this is in error, and I hope to follow up with it if I have time. I could be wrong. But this looks like something very critical that has to be understood by all parties for a solid foundation on which to build a scientific worldview of the world.

  Right off the top of my head, this seems like a quick response:

  You say "there are reference frames in which the earth is not at rest .." Agreed. However, can you provide one reference frame which suggests the earth IS at rest?

  If you can't find a reference frame to show the earth is at rest, but find many that it is not at rest, then it should be deduced that it is not at rest, correct?

  Another pithy response would be appreciated- thanks.

  .Bernie

------------------------------------------------------------------------------

  From: George Murphy [mailto:GMURPHY10@neo.rr.com]
  Sent: Friday, July 10, 2009 7:29 PM
  To: Dehler, Bernie; ASA list
  Subject: Re: [asa] George & heliocentricity

  Bernie -

  No, I'm afraid you do not understand what I mean by relativity. There is no such thing as absolute rest or absolute motion. We do not know that the earth is not at rest, only the obvious fact that there are reference frames in which the earth is not at rest. But in a reference frame fixed to the earth it is at rest, & that frame is as good as any other.

  And please do not quote me as saying that the statement "the earth is the center" can be disproved observationally unless you add my qualification that it really doesn't make sense today to speak of the center of the universe at all.

  Shalom
  George
  http://home.roadrunner.com/~scitheologyglm

  ----- Original Message -----

  From: "Dehler, Bernie" <bernie.dehler@intel.com>

  To: "ASA list" <asa@calvin.edu>

  Sent: Friday, July 10, 2009 7:40 PM

  Subject: RE: [asa] George & heliocentricity

> Hi George-
>
> Thanks for clarifying and for your pithy answer. So your answer is 'yes' it can be disproven.
>
> You then say:
> "But the real question today - when it makes
> little sense to speak of any "center" of the universe - is whether or not
> one can legitimately say that the earth is at rest. I.e., is a fixed-earth
> reference frame as good in principle as a fixed-sun one? & the answer to
> that is an unambiguous "Yes.""
>
> That is interesting. However, in reality, we also know that both the Earth and Sun are not at rest. So if someone hypothesized that either is at rest, we could disprove that scientifically also, correct?
>
> And I do understand/agree with what you mean by relativity, reference frames, etc.
>
> ...Bernie
>
> -----Original Message-----
> From: George Murphy [mailto:GMURPHY10@neo.rr.com]
> Sent: Friday, July 10, 2009 4:23 PM
> To: ASA list; Dehler, Bernie
> Subject: Re: [asa] George & heliocentricity
>
> Yes, I did answer it as clearly as possible in posts of 26 & 29 June. Just
> as a matter of geometry the sun is, roughly, at the "center" of the solar
> system & the earth isn't. But the real question today - when it makes
> little sense to speak of any "center" of the universe - is whether or not
> one can legitimately say that the earth is at rest. I.e., is a fixed-earth
> reference frame as good in principle as a fixed-sun one? & the answer to
> that is an unambiguous "Yes."
>
> Shalom
> George
> http://home.roadrunner.com/~scitheologyglm
>
> ----- Original Message -----
> From: "Dehler, Bernie" <bernie.dehler@intel.com>
> To: "ASA" <asa@calvin.edu>
> Sent: Friday, July 10, 2009 5:50 PM
> Subject: [asa] George & heliocentricity
>
>
>> Hi George-
>>
>> I'm not sure if you even clearly answered this question... and I'm really
>> curious. A pithy answer would be great.
>>
>> Question:
>> Suppose someone has this hypothesis:
>>
>> The Earth is the center of the universe.
>>
>> Do you think this can be scientifically disproven?
>>
>> I would appreciate it if your answer began with a 'yes' or 'no.'
>>
>> I think heliocentricity is a great analogy for many things, so I want to
>> make sure I understand you completely.
>>
>> ,,,Bernie
>>
>>
>>
>> To unsubscribe, send a message to majordomo@calvin.edu with
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Received on Mon Jul 13 14:27:33 2009