Re: [lojban] Re: Lojban Kids Show - location

[CosmicRay <cr@cosmicray.co.uk>]

On 22 Jul 2010, at 15:06, Pierre Abbat <phma@phma.optus.nu> wrote:

> On Thursday 22 July 2010 08:22:09 CosmicRay wrote:
>> OK we've had two compelling votes to place Lojgugde at Earth-Moon L4/L5,
>> which for all practical reasons are ideal.  Can anyone tell me how
>> frequently and for how long Lojgugde at one of these points may be in
>> Earth's or the Moon's shadow?  The Moon's orbital period is ~27 days and is
>> off Earth's equatorial axis by ~5°.
> 
> Lojgugde would be in the Earth's shadow as often as the Moon is eclipsed, 
> which is about twice a year, and in the Moon's shadow as often as an eclipse 
> of the Sun passes through the middle of the Earth, which is somewhat less 
> often. (There may be five solar eclipses in a year, but they pass over 
> different parts of the Earth.) Both occur when the Sun passes through the 
> plane of the Moon's orbit. L4 is eclipsed by the Moon 1/6 through a lunation 
> (starting at the dark, not new, moon) and by the Earth 1/3 through a 
> lunation. L5 is eclipsed by the Earth 2/3 through a lunation and by the Moon 
> 5/6 through a lunation.

Thank you again for a full and considered answer, that's perfect :-)

> 
>> From the story's perspective it's less ideal; placing the station at those
>> points would make it visible to the naked eye at certain times.  When the
>> station is just past parallel to, through to behind the Earth (relative to
>> the Sun) and back again, the spinning mirrors would glint, causing a
>> pinpoint of flashing light in the sky with a frequency of about 30 seconds.
>> For a little under half its orbital period the flash may be visible from
>> Earth at dawn and dusk and would certainly be easy to see at night.
> 
> The mirrors are aimed to reflect sunlight into the station's windows and onto 
> the opposite land. They wouldn't be visible from Earth.

I thought this initially too, but how about when they're opened out to simulate night and to allow excess heat to radiate out?

Also would the windows allow light through in only one direction?  Probably not, so light reflecting from the internal land strips is still likely to reach Earth, if somewhat dimmer than from the mirrors.

> Other surfaces of the 
> station could be covered with matte solar panels or some such.

Very true.

> By the way, how did you get a line beginning "From " past the mail server 
> without it adding a greater-than sign?

I didn't know it was sensitive to that, are you sure?

> 
kozmikreis

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