(urth) grumble at wolfe comment made attached to guardianarticle

[Gerry Quinn]

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.

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).

- Gerry Quinn

  ----- Original Message ----- 
  From: Jack Smith 
  To: The Urth Mailing List 
  Sent: Wednesday, February 09, 2011 1:47 AM
  Subject: Re: (urth) grumble at wolfe comment made attached to guardianarticle


  "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?"


  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.


  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.

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