Sci-fi novelist's plea for help

  • Thread starter ann-omaly
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  • #26
ann-omaly
Tidal locking of the moon to the planet doesn't mean the sun wont rise and set. The so-called "dark side" of the moon does see the light from the sun as it orbits the earth. If you have body tidally locked to a large planet, the planet will always be in the sky, but the sun will still rise and set. To what extent each will be present will depend on the location on the satellite.

Check out this basic animation and watch the moon as it orbits the earth
http://jove.geol.niu.edu/faculty/stoddard/JAVA/moonphase.html [Broken]
Travis, observing the animation you provided: daylight on our moon lasts about two weeks in a single location--? I think my character's moon will need to rotate.
 
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  • #27
DaveC426913
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Travis, observing the animation you provided: daylight on our moon lasts about two weeks in a single location--? I think my character's moon will need to rotate.
Daylight lasts half of a body's day. The Moon's day is a month long, so its day is two weeks.

Your Moon could have a shorter day by being closer to its planet. Or its planet could be more massive.

But you can't go too far, or you'll get problems with tides, quakes and, ultimately, disintegration.
 
  • #28
ann-omaly
Daylight lasts half of a body's day. The Moon's day is a month long, so its day is two weeks.

Your Moon could have a shorter day by being closer to its planet. Or its planet could be more massive.

But you can't go too far, or you'll get problems with tides, quakes and, ultimately, disintegration.
Dave, now it looks to me that my character needs to be on a planet. I can give her bright light at night via several moons that show simultaneously for a few days. Thanks.
 
  • #29
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But you lose your "large object in the sky" effect. If you had two planets of similar size locked to eachother, you could have something approaching your conditions, depending on her location on the planet. Since you will have librations so your large planet in the sky will still move around throughout the day (not to mention the filtered effect when the star's light is dominant).

Point is, if you just mention these things, eg. "She looked up in the sky and saw a big freaking planet that is always there", People are going to make up their own minds on why. As long as you don't give numbers, nobody can really prove you wrong as long as what you propose is feasable.
 
  • #30
Ryan_m_b
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Dave, now it looks to me that my character needs to be on a planet. I can give her bright light at night via several moons that show simultaneously for a few days. Thanks.
If the moons are low enough (like Phobos) they will orbit every few hours.

But you lose your "large object in the sky" effect. If you had two planets of similar size locked to eachother, you could have something approaching your conditions, depending on her location on the planet. Since you will have librations so your large planet in the sky will still move around throughout the day (not to mention the filtered effect when the star's light is dominant).

Point is, if you just mention these things, eg. "She looked up in the sky and saw a big freaking planet that is always there", People are going to make up their own minds on why. As long as you don't give numbers, nobody can really prove you wrong as long as what you propose is feasable.
Indeed. The character could even wonder about the strangeness of it, this is a SF novel after all. It could turn out that the giant moon in the sky is pretty much hollow and put there by ETs nan as a night light.
 

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