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Message: <blockquote data-quote="Dr. Harry" data-source="post: 2145477" data-attributes="member: 5468">Eyrosian AstronomyHooo-kay, this is a clarification rather than a new contribution, but I thought that I might as well do the math.  The sun, which the Eyrosians call Etat, would be classified by Earth astronomers as an A7V star, which would mean that it has a surface temperature of 7800K, 1.3x that of Sol, a mass of 2.3 solar masses, a total diameter about 1.7x Sol's diameter, and a luminosity about 10x that of the Sun.  In order for Eyros to have a Mediterranean-type climate, and assuming that it is located similarly on the planet, the planet would have to be 3.16 times as far away from Etat as Earth of from Sol.  This would make the year about 4 Earth-Years long, and the size of Etat in the sky would be just over half the apparent size of the Sun.  We could bring the planet in somewhat if high level highly reflective clouds were very common (perhaps this is a magical substance high in the atmosphere) or if the carbon dioxide level of the planet was below Earth's.  If only 4/10's of Etat's radiance reaches the surface, then we could bring the planet in to 2 AU (the Earth-Sol distance) and bring the year down to 696 days (my original estimate was based on a mass 10x the Sun's not brightness 10x Sol's.  My bad.)With the protective layer (which would make the planet quite brilliant from space), then:Etat has its peak wavelength at 371 nm (distinctly bluish)The planet is 2 AU away from Etat.The year is 696 Earth days long.Etat "sleeps" (has a weak quiet period, dimming by about 5%) with a period less than half a day different from the length of the year.  (This would not be strongly noticeable).Has an apparent size about 85% the size of Sol (as observed in the sky; it is really 1.7x the radius of Sol.)What is protecting the planet like this?  Did the lizard folk druids do this over a long period of time a very long time ago to make the planet more habitable for our type of life?  Did they do this by mistake?  Did they do this because they ran out of some resource where they were and decided to change the climate to make their new home as comfy as their old home farther to the north?I wonder if any of this was done in the Vale of Ur ...A single moon will generate tidal effects unless it is very small or very far away</blockquote>

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