[geocentrism] Re: The Sun/ Comment & question
- From: "Philip" <joyphil@xxxxxxxxxxx>
- To: <geocentrism@xxxxxxxxxxxxx>
- Date: Sun, 8 Aug 2004 08:27:54 +1000
Thanks for that Alan. Another similar question. How do they calculate the
mass of the sun with any degree of accuracy. And the earth for that matter,
as the composition of the interior is only presumed, as indeed all the
heavenly bodies.
Philip.
----- Original Message -----
From: "Knarr" <knarrrj@xxxxxxx>
To: <geocentrism@xxxxxxxxxxxxx>
Sent: Saturday, August 07, 2004 1:14 PM
Subject: [geocentrism] Re: The Sun/ Comment & question
----- Original Message -----
From: Alan Griffin
To: geocentrism@xxxxxxxxxxxxx
Sent: Thursday, July 29, 2004 6:10 PM
Subject: [geocentrism] Re: The Sun
On 29 Jul, Jack Lewis <jandj.lewis@xxxxxxxxxxxxx> wrote:
> Dear Alan, I hope that you are still on-line to the forum. Please could
> you point me in the right direction to find out how the distance to the
> Sun was measured? Perhaps your brother could be helpful here? Jack Lewis
Roger says that it was done by parallax from opposite sides of the
earth using the earth's diameter as a reference. The transits of Venus in
the 17th and 18th centuries gave it accurate to 1%.
The relative distances of all the planets is known very accurately
by measuring their periods, so it only needs one distance to be measured
accurately to know all the others. The planetoid Eros was found in 1901,
and being nearer to the earth gave a more accurate distance.
Nowadays the distances are known extremely accurately by laser
ranging, as they can bounce a radar beam off Venus, and time it. Since the
velocity of light is known to 9 places of decimals, this is a pretty
accurate way of measuring!
Does this help?
Alan Griffin
----------------------------------------------------
Dear Alan,
The velocity of light is not known. Only the reflected speed of light
is known. Can you name one place where the speed of light was measured
directly? The constancy of the speed of light , also, is a theoretical
assumption. This point(s) was covered in some depth in Robert Lavaggi's book
Einstein On The Carpet.
Perhaps you could help me. I have been trying to find out if the
orbital speed of a satellite, the speed necessay to keep it in a stabil
orbit, would alway be the same at a given distance from the earth
regardless of the satellites mass.
Thank you, Ronald Knarr
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