Chronology Current Month Current Thread Current Date
[Year List] [Month List (current year)] [Date Index] [Thread Index] [Thread Prev] [Thread Next] [Date Prev] [Date Next]

Re: [Phys-L] Sun going around the Earth?



From the point of view of making a reasonably simple analysis one prefers
the Copernican version, and it makes sense to our minds. But I would like
to know, in short, what the philosopher was arguing.

John M. Clement
Houston, TX


Hi!

In 2003 January, I asked a similar question in this list
which was based on a quotation from Fred Hoyle (translated
from Finnish back to English :-)):

"Today [1973] we cannot claim in any physically meaningful
sense that Copernican theory [i.e. the Earth revolves around
the Sun; not other way round] would be right and Ptolemy's
theory would be wrong. These two theories have no difference
whatsoever from the point of view of physics."

Interestingly, some years ago the same discussion appeared in
a Finnish journal for advancement of science: a philosopher
(phenomenologist with no background in academic physics) had
a dispute on the Earth revolving around the Sun with a
distinguished cosmology professor (well over 200
peer-reviewed publications in physics, many papers involving
relativity). The physics professor provided an insightful
analysis in terms of physics - well in line what John D. has
said about the topic - and then explained *in what sense* he
thinks that it is quite proper to say that the Earth revolves
around the Sun: any observer approaching the solar system
would see that the Earth revolves around the Sun. As for
another example, sometimes cosmologists prefer to use a
coordinate system attached to the microwave background
radiation (interestingly, this is a kind of a privileged
coordinate system in the Universe!); the Earth revolves
around the Sun in this as well. He also pointed out that while the
forces between the Sun and the Earth are symmetric, the
accelerations due to the forces are not (the Sun in MUCH
heavier than the Earth).

Of course, he stressed that you can choose any coordinate
system to do physics you wish and that there is no "right"
coordinate system, but there is a price to pay if choose unwisely.

Perhaps unsurprisingly, his arguments did not convince the
philosopher.

Regards,

Antti

--
**************************************************************
****************************
Viesti on tarkastettu roskapostinsuodatus- ja
virustorjuntaohjelmistolla.
Tarkastuksesta huolimatta noudata asianmukaista varovaisuutta
liitetiedostoja avatessasi.
**************************************************************
****************************



_______________________________________________
Forum for Physics Educators
Phys-l@www.phys-l.org
http://www.phys-l.org/mailman/listinfo/phys-l