- #1
ISAWHIM
Good morning. Just a fair warning, my posts are novel-like in length. (Appropriate, since I write novels.)
I am actually doing research for a current fiction book I am writing, and I am looking for any possible oversights or considerations that I may have overlooked. Just take into account that this is a fiction book, which I simply wish to have as much "reality" in, as possible. (I know it's an oxymoronic and ironic statement.)
Here is the situation. This planet was previously inhabited, and has been colonized by humans. The planet they adopt, is one of two, within a "orange/red star" goldilocks zone. One was shifting out of the habitable zone, thus being too difficult to "manage" or "sustain". The other, which was chosen, had just entered this zone, a few billion years ago. Thus, was more sustainable and would be sustainable longer.
The calculations I have, which are hardly relevant to the story, but to those who scrutinize the facts, they would be... (Gotten through trial and error on several planetary simulator programs, and facts from WiKi, which fit the original concept of the story.)
The star is a K/M class star, with a temperature of 4200K and a solar mass of about 0.21 (More red than orange, but a brighter red.) It has aged well, with low flare-bursts, and one perpetual "flare" at each solar axis. (Part of the reason it is slightly brighter.) The sun-spots avoid the equatorial plane of the sun, favoring the rotational poles, and thus, has less variance of darkness and suitable UV radiation.
The planet they colonize, has these attributes. The AU distance is 0.4->0.5, with a relative earth-mass value of 0.4->0.5. Thus, it is rather small, and about as close as mercury is, to our sun. The planet, unlike mercury but as planets of this region would be expected to do, has a rotation that makes it always face the sun on one side. It also has no moving surface/plates, and only one massive volcanic exposure, from the offset molten core, which faces the solar side. The dark side gets heat through the green-house effect, though it is thinner atmosphere, and underwater boiling jets from the fresh-water oceans. There is little rain, and moderately even and constant winds. There is, however, a lot of snow-fall before the solar-south. This would have left the air at the south completely dry, except the room-temp humidity from the cavernous depths, transfers steam and humidity from the sea-vents. (Think of it as home insulation. The spongy non-molten side of the planet acts as insulation and distribution for heat. It also makes that side of the planet face away from the pull of the sun, being the gravitational top.)
The part that I could not simulate was the following... But here I have taken the freedom of fictional creative writing, to justify what I can not apply physics to. (But I would rather have physics involved here, where possible.)
The planet has two moons. One half as large as our moon, so it is similar in scaled distance and orbit, except that it has a wobble to it. It travels around the planet from solar-north to solar-south, along the sun-facing axis. The wobble is caused by the odd rotation and also the secondary disruptive pull of an equatorial micro-moon. This second smaller moon rides just above the thin atmosphere, close to the planets surface. Though this is un-natural by "our physics on earth", for this planets unique composition, it is acceptable.
Now the specific thing I was having issues with, is the speed of the smaller moon. The size of the planet is about half the mass of Earth 0.4->0.5, but this still leads me to believe that this smaller mass moon, about the size of Connecticut, would have to be traveling unusually fast. Too fast for the fiction in the book. (Part of the reason the fiction counters that unrealistic speed.)
I assume, that the moon with relative scale to ours, would be traveling 2x our speed, since the planet and the moon is 50% the mass. Thus both forces of pull would be halved, thus speed would be doubled, for orbit stability? (Like how closer planets to the sun, even larger in mass, are faster in orbit.) This leads me to estimate that the smaller moon, being smaller and closer to the planet, would have to be traveling nearly 1000x that speed. Or, since it is lighter, would it be traveling 1000x slower, or the same, at this closer distance to this lower mass body?
If it is any matter... the mini-moon also has nearly no rotational speed on its own axis. It is rotating, but literally at a walking speed. (Eg, if this were a merry-go-round, you could walk onto it, or off of it, without trouble. Or an escalator belt.)
I am actually doing research for a current fiction book I am writing, and I am looking for any possible oversights or considerations that I may have overlooked. Just take into account that this is a fiction book, which I simply wish to have as much "reality" in, as possible. (I know it's an oxymoronic and ironic statement.)
Here is the situation. This planet was previously inhabited, and has been colonized by humans. The planet they adopt, is one of two, within a "orange/red star" goldilocks zone. One was shifting out of the habitable zone, thus being too difficult to "manage" or "sustain". The other, which was chosen, had just entered this zone, a few billion years ago. Thus, was more sustainable and would be sustainable longer.
The calculations I have, which are hardly relevant to the story, but to those who scrutinize the facts, they would be... (Gotten through trial and error on several planetary simulator programs, and facts from WiKi, which fit the original concept of the story.)
The star is a K/M class star, with a temperature of 4200K and a solar mass of about 0.21 (More red than orange, but a brighter red.) It has aged well, with low flare-bursts, and one perpetual "flare" at each solar axis. (Part of the reason it is slightly brighter.) The sun-spots avoid the equatorial plane of the sun, favoring the rotational poles, and thus, has less variance of darkness and suitable UV radiation.
The planet they colonize, has these attributes. The AU distance is 0.4->0.5, with a relative earth-mass value of 0.4->0.5. Thus, it is rather small, and about as close as mercury is, to our sun. The planet, unlike mercury but as planets of this region would be expected to do, has a rotation that makes it always face the sun on one side. It also has no moving surface/plates, and only one massive volcanic exposure, from the offset molten core, which faces the solar side. The dark side gets heat through the green-house effect, though it is thinner atmosphere, and underwater boiling jets from the fresh-water oceans. There is little rain, and moderately even and constant winds. There is, however, a lot of snow-fall before the solar-south. This would have left the air at the south completely dry, except the room-temp humidity from the cavernous depths, transfers steam and humidity from the sea-vents. (Think of it as home insulation. The spongy non-molten side of the planet acts as insulation and distribution for heat. It also makes that side of the planet face away from the pull of the sun, being the gravitational top.)
The part that I could not simulate was the following... But here I have taken the freedom of fictional creative writing, to justify what I can not apply physics to. (But I would rather have physics involved here, where possible.)
The planet has two moons. One half as large as our moon, so it is similar in scaled distance and orbit, except that it has a wobble to it. It travels around the planet from solar-north to solar-south, along the sun-facing axis. The wobble is caused by the odd rotation and also the secondary disruptive pull of an equatorial micro-moon. This second smaller moon rides just above the thin atmosphere, close to the planets surface. Though this is un-natural by "our physics on earth", for this planets unique composition, it is acceptable.
Now the specific thing I was having issues with, is the speed of the smaller moon. The size of the planet is about half the mass of Earth 0.4->0.5, but this still leads me to believe that this smaller mass moon, about the size of Connecticut, would have to be traveling unusually fast. Too fast for the fiction in the book. (Part of the reason the fiction counters that unrealistic speed.)
I assume, that the moon with relative scale to ours, would be traveling 2x our speed, since the planet and the moon is 50% the mass. Thus both forces of pull would be halved, thus speed would be doubled, for orbit stability? (Like how closer planets to the sun, even larger in mass, are faster in orbit.) This leads me to estimate that the smaller moon, being smaller and closer to the planet, would have to be traveling nearly 1000x that speed. Or, since it is lighter, would it be traveling 1000x slower, or the same, at this closer distance to this lower mass body?
If it is any matter... the mini-moon also has nearly no rotational speed on its own axis. It is rotating, but literally at a walking speed. (Eg, if this were a merry-go-round, you could walk onto it, or off of it, without trouble. Or an escalator belt.)