Re: [Space] How much does a Gas Giant heat it's moons?
 

They also occasionally block sunlight from the other, so it's likely a wash, and in any case most of the time the effect is negligible.

Re: [Space] How much does a Gas Giant heat it's moons?
 

Cool, thanks. I was afraid my double planet system had even one more hassle than those I already knew about.

Re: [Space] How much does a Gas Giant heat it's moons?
 

So if I've got a moon of .56 Earth diameters (.23 radius) orbiting 61.07 Earth diameters from a Gas Giant the Blackbody temperature of the moon is increased by 4% of the Gas Giant's temperature? Is that correct? And how do I calculate the temperature of the gas giant?

Re: [Space] How much does a Gas Giant heat it's moons?
 

No, for several reasons. First, we need the radius of the gas giant. Second, you actually add T^4 from all sources and then take the 4th root, so if the secondary heat gave a temperature of 4% of the primary, the actual increase is (1 + .04 ^ 4)^1/4 - 1, or 0.000064%

Re: [Space] How much does a Gas Giant heat it's moons?
 

Not so often though, unless they're orbiting perfectly flatly in the equatorial plane. Look at how uncommon eclipses are for the Earth and moon to block sunlight from each other.

For a moon around a gas giant, however, it is more likely. You'd have to figure out the axial tilt of the gas giant and then the semi-major axis and eccentricity inclination of the moon's orbit to see how long it spends under occultation.