| Comments from "Ole Rømer og den
bevægede Jord - en dansk førsteplads" by Jan Teuber
in the book "Ole Rømer -
videnskabsmand og samfundstjener", Gads Forlag 2004
and Erling Poulsen: Here are told
that Rømer has "devised", the article are written by
somebody else.
Here the reader
must get the impression that it will take light a
little less than a second to travel the Earth
diameter, this are about twenty times less than what
are written later.
If the Earth
moves 210 diameters in 42½ hours then it will move
4.94 diameters in one hour and the circumference of
the orbit must be 43300 diameters, the radius of the
orbit are then 6900 Earth diameters, but from Rømers
notebook and from his letters to Huygens we know
that he used a distance Earth-Sun of 12000 Earth
diameters.
Here we learn that if it takes light one second to
travel one Earth diameter (which is very wrong) then
it will take 3½ minutes to travel 210 diameters (we
learn that 210 seconds equals 3½ minutes, very
interesting) and we learn that if two such intervals
are added we get nearly half a quarter of an hour.
This cryptic part is difficult to
understand but an interpretation could be that the
proportion between the velocity of light and the
velocity of the Earth is like (40 revolutions of Io
seen from one side of the Earth orbit + 40 seen from
the other)*42½*60 to 22, this gives 9300 very near
today's value 10000.
If we
use this value then we get: Earth velocity = 2π/365.25/24/60
= 1.195*10-5 AU/min; light 9300 times as
fast = 0.111 AU/min or 9 min./AU; on August 23rd
1676 the distance Earth-Jupiter were 4.408 AU, on
November 9th the distance were 5.526 AU,
increase 1.118 AU
(WinStars 2 is used, but it can be calculated by
help of Kepler's laws), therefore it will happen 9*1.118
=10 minutes later.

This article must have been
written by a not so clever scientific journalist.
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