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<DIV><FONT size=2 face=Arial>I forgot about that.</FONT></DIV>
<DIV><FONT size=2 face=Arial></FONT> </DIV>
<DIV><FONT size=2 face=Arial>But one or both could have an elliptical
orbit.</FONT></DIV>
<DIV><FONT size=2 face=Arial></FONT> </DIV>
<DIV><FONT size=2 face=Arial>Again, I don't know whether precession would make
this unrealistic or not. And 35000 leagues is incredibly, dangerously
close for two Earth-sized planets.</FONT></DIV>
<DIV><FONT size=2 face=Arial></FONT> </DIV>
<DIV><FONT size=2 face=Arial>But in terms of basic mechanics, a series of
conjunctions should be possible (for story purposes, I think it would probably
be sufficient if the series lasted a few centuries).</FONT></DIV>
<DIV><FONT size=2 face=Arial></FONT> </DIV>
<DIV><FONT size=2 face=Arial>- Gerry Quinn</FONT></DIV>
<DIV><FONT size=2 face=Arial></FONT> </DIV>
<DIV><FONT size=2 face=Arial></FONT> </DIV>
<BLOCKQUOTE
style="BORDER-LEFT: #000000 2px solid; PADDING-LEFT: 5px; PADDING-RIGHT: 0px; MARGIN-LEFT: 5px; MARGIN-RIGHT: 0px">
<DIV style="FONT: 10pt arial">----- Original Message ----- </DIV>
<DIV
style="FONT: 10pt arial; BACKGROUND: #e4e4e4; font-color: black"><B>From:</B>
<A title=jack.smith.1946@gmail.com
href="mailto:jack.smith.1946@gmail.com">Jack Smith</A> </DIV>
<DIV style="FONT: 10pt arial"><B>To:</B> <A title=urth@lists.urth.net
href="mailto:urth@lists.urth.net">The Urth Mailing List</A> </DIV>
<DIV style="FONT: 10pt arial"><B>Sent:</B> Wednesday, February 09, 2011 3:29
AM</DIV>
<DIV style="FONT: 10pt arial"><B>Subject:</B> Re: (urth) grumble at wolfe
comment made attached to guardianarticle</DIV>
<DIV><BR></DIV>I like this explanation, but I don't think it would work.
For bodies in orbit around a central body, the orbital period is
directly proportional to the distance or radius from the central body.
So if Green orbits in 6/7 of a Blue year, then Green must be 6/7 of
Blue's distance from the sun. If Blue is 90 million miles from the sun,
then Green must orbit at 77 million miles radius, which makes Green 13
million miles from Blue at closest approach. But we know that at
conjunction the 2 planets are only 35,000 leagues (105,000 miles) apart (In
Green's Jungles, ch. 15).<BR><BR>
<DIV class=gmail_quote>On Tue, Feb 8, 2011 at 9:38 PM, Gerry Quinn <SPAN
dir=ltr><<A href="mailto:gerryq@indigo.ie">gerryq@indigo.ie</A>></SPAN>
wrote:<BR>
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<DIV><FONT size=2 face=Arial></FONT> </DIV>
<DIV><FONT size=2 face=Arial>It can work if they have circular orbits
that are quite close together, so that Green orbits their star in 6/7
of a Blue year. Green will go around the star slightly faster than
Blue, so that Blue is falling further and further behind. After 6 Blue
years, Blue will have made 6 orbits, while Green will have made 7 and caught
up on Blue from behind.</FONT></DIV>
<DIV><FONT size=2 face=Arial></FONT> </DIV>
<DIV><FONT size=2 face=Arial>I don't know if two large planets with such
similar orbital radii would be stable, but anyway it would fit the
conjunction schedule, and Green would be a bit hotter than Blue (their
temperatures would also depend on atmospheric composition).</FONT></DIV>
<DIV><FONT size=2 face=Arial></FONT> </DIV><FONT color=#888888>
<DIV><FONT size=2 face=Arial>- Gerry Quinn</FONT></DIV></FONT>
<DIV class=im>
<DIV><FONT size=2 face=Arial></FONT> </DIV>
<BLOCKQUOTE
style="BORDER-LEFT: #000000 2px solid; PADDING-LEFT: 5px; PADDING-RIGHT: 0px; MARGIN-LEFT: 5px; MARGIN-RIGHT: 0px">
<DIV style="FONT: 10pt arial">----- Original Message ----- </DIV>
<DIV style="FONT: 10pt arial; BACKGROUND: #e4e4e4"><B>From:</B> <A
title=jack.smith.1946@gmail.com href="mailto:jack.smith.1946@gmail.com"
target=_blank>Jack Smith</A> </DIV>
<DIV style="FONT: 10pt arial"><B>To:</B> <A title=urth@lists.urth.net
href="mailto:urth@lists.urth.net" target=_blank>The Urth Mailing List</A>
</DIV>
<DIV style="FONT: 10pt arial"><B>Sent:</B> Wednesday, February 09, 2011
1:47 AM</DIV>
<DIV style="FONT: 10pt arial"><B>Subject:</B> Re: (urth) grumble at wolfe
comment made attached to guardianarticle</DIV>
<DIV><BR></DIV><SPAN
style="BORDER-COLLAPSE: collapse; FONT-FAMILY: arial, sans-serif; FONT-SIZE: 9px">"BTW,
is there a consensus on the exact relation of the planets Blue and Green?
Do they orbit one another as a single system, or do they orbit the sun on
opposite sides, as do Earth and Gor?"</SPAN>
<DIV><SPAN
style="BORDER-COLLAPSE: collapse; FONT-FAMILY: arial, sans-serif; FONT-SIZE: 9px"><BR></SPAN></DIV>
<DIV><SPAN
style="BORDER-COLLAPSE: collapse; FONT-FAMILY: arial, sans-serif; FONT-SIZE: 9px">They
can't orbit each other or orbit on opposite sides of the sun because Blue
and Green are farther apart and then get closer at conjunction.
Conjunction occurs every 6 years (OBW, Ch 7), and Blue's year seems
to be about the same as a year on the Whorl.</SPAN></DIV>
<DIV><SPAN
style="BORDER-COLLAPSE: collapse; FONT-FAMILY: arial, sans-serif; FONT-SIZE: 9px"><BR></SPAN></DIV>
<DIV><SPAN
style="BORDER-COLLAPSE: collapse; FONT-FAMILY: arial, sans-serif; FONT-SIZE: 9px">I'm
not sure how Blue and Green move to produce this conjunction. If
they are about the same distance from the sun but in different orbital
planes, they could at times be closer or more distant but conjunction
would occur twice a year. Perhaps Blue's orbit is circular and
Green's is more eliptical, resulting in the 6 year interval, but I haven't
been able to figure how this would
work.<BR></SPAN><BR></DIV></BLOCKQUOTE></DIV></DIV><BR>_______________________________________________<BR>Urth
Mailing List<BR>To post, write <A
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clear=all><BR>-- <BR>Best wishes,<BR>Jack<BR>
<P>
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