On May 8, 6:36=A0pm, Peter Knutsen <pe...@[EMAIL PROTECTED]
> wrote:
> It is said that even Hal Clement effed up once, so I feel I ought to ask
> in here, just to be sure:
>
> If a planet has multiple moons, all large enough to be visible, as
> discs, from the surface (through the atmosphere), i.e. unlike the moons
> of Mars, will they all be in the same phase at the same time, i.e. full,
> waning, new, waxing?
>
Yes.
> If not, how does it work. Is there some kind of essay I can read, or a
> brief educational animation I can watch, or something?
>
WTH. I'd write a short article about that.
It's a standard cryptography translation with a period "o". There is
the period of a first object, period of the second object and theirs
crossover. A person that would like to define phases of a non earth
moons, should also define an error factor "r" which would be required
to rigidly specify the full moon phase. Obviously because it's a
trivial cryptography translation, they'd be in the same phase once per
period of the faster moon, which would result for several matches per
night for faster rotating moons. In addition, there might be several
hundred matching phases per night, when the planet would have the
right orientation with respect of the local star.
With definition of full moon as max brightness - (max brightness - max
brightness/20), the full moon matching phases would be much more rare,
as the slower rotating moon would need to be in correct phase as well.
It's somehow simple calculation, when both moons have fairly circular
orbit, it's somehow more complicated with high eccentricity moons, or
crossing orbits.
Or you can simply remember on a situation from Krym books when there
were all three moons in full phase.
|
