How the 'verse works.
POSTED BY: meimeiCobb
UPDATED: Friday, April 11, 2008 03:13
VIEWED: 14554
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My husband, the telecomms engineer and non-Browncoat (yeah, right) had a complete meltdown the other day about communications in the 'Verse. Without FTL, you'd never get messages, was the gist of it. (It got technical and scary - I did history.)
Joss puts in some good mcGuffins to make stuff work - positing the tech for gravity is a good one. (maybe it's like Pratchett, and they discovered Devices, or big alien machines a la Total Recall...but that way lies madness and random giggling...y'know, standard AnJlverse stuff...)
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Quote:
Originally posted by mal4prez:
I'm with JSF about orbital stability issues. A second sun would be heavy - much heavier than a planet, even if it's a small star. There's a certain amount of mass required before gravity can start fusion and "light" a star. Wikipedia says the minimum theoretical star mass is 75 times the mass of Jupiter. A body that heavy won't be sitting in a happy orderly orbit. The two suns would rotate around each other, and planetary orbits would be all messed up. Planets passing in between them are likely to get spun off into the Black, or maybe even shattered by gravitational forces. When you start talking three suns - whoa. There won't be many stable orbits, not inside or near these three suns. Stable orbits would be far outside.
Really, I just don't see any kind of pseudo-scientific hand waving that can make Joss's verse work, physically speaking. It's just not realistic. I have to agree with Sigmanunki - Firefly is not hard sci-fi. It'll never be astronomically believable.
If that ever bothers me (and it does cause I'm a physicist and former astrophysics major and a tad anal) I go for engineering solutions. There's more room for fiction there. Maybe the terraforming tech is *so* good that it can minimize or maximum the sun's energy. Big lenses or shields in space, say, that focus or disperse sunlight so that Mercury and Pluto can be equally habitable. And if gravity is a problem - well, gravity is controlled on spaceships, why can't terraformed planets be given earth-normal 1g by giant gravity machines?
I know - it's complete BS. But in the end, I ain't in the FF verse for the science.
(It's still fun to talk about meimeiCobb! I'm not meaning to flame your suggestions. I love science threads.)
I love the discussion. It's nice that someone out there studied the physics of things.
I want to throw out there that I do know there is no logic to the 'verse, that I would probably give myself an aneurysm thinking about the actuality of it all, but if I didn't put some form of logic in there, my brain would have exploded. I need some sort of reason to go off of, especially when I try to figure the order of the planets.
The problem with my theory is that I don't have a map, chart, or even a doodle to back up what I mean. I do have an article though, which is what I based my finding off of. I intended for the second star to be small but hot enough to emit heat to nearby stars, and possibly light. I got the idea from an article, actually.
http://www.daviddarling.info/encyclopedia/A/55_Cancri.html
It's based on a sun-like primary and a red-dwarf secondary star; I figured if I expanded that model, made the distances larger and the suns a bit larger too, it would be able to work. Granted, something of that mass would cause a bizzare orbit unless it was far enough out and it's mass was small enough, but I tried to count on that, though I didn't say. I didn't want to cause people who had no idea what this stuff is a headache.
Then there are the orbits to consider. A planet with a faster orbit has a hotter core and therefore is a warmer planet - the Earth might not be so warm without its volcanoes and its molten rock center. @ jewelstaitefan: You said, "i don't see the velocity of the body along it's orbital path (speed around the sun) as affecting it's temp. Rotational speed, yes. Distance from the Sun. Rotational speed. Size of body/gravitational force." If Mars had a revolving molten core like Earth, it would produce a gravity sufficient enough to sustain an atmosphere, it would be a warm planet that could probably support lots of life. As it is right now, probably not - but that is where the terraforming comes into play. You start up a core in a world and get it going, that's half the battle of making the gravity earth-norm as well as an atmo. As for the planets being burned up, I kind of addressed that earlier, but I'm sure when they account for terraforming that make it so that it's norm for the position in the 'verse, how much light the
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Cool web site. I like the idea of planet with two suns, it makes for fun sci-fi. I just don't see a ton of planets - enough to make Joss's verse - having stable orbits in that environment. And here's another argument against a two star system: not one episode of Firefly showed a planet with two suns!
Quote:Um... huh? Orbital velocity and planetary temperature are completely unrelated.
Originally posted by meimeiCobb:
Then there are the orbits to consider. A planet with a faster orbit has a hotter core and therefore is a warmer planet
Quote:You're speaking some other kind of physics here. The "revolving molten core" has nothing to do with gravity. Gravity is all about mass. It can be hot mass or cold mass or still mass or spinning mass. Don't matter.
If Mars had a revolving molten core like Earth, it would produce a gravity sufficient enough to sustain an atmosphere, it would be a warm planet that could probably support lots of life. As it is right now, probably not - but that is where the terraforming comes into play. You start up a core in a world and get it going, that's half the battle of making the gravity earth-norm as well as an atmo.
Quote:I'm happier to stick with fudging future engineering rather than inventing new physics. It's highly likely that mind-blowing technology will be invented over the next 500 years, (assuming we get rid of our present Idiots in Charge
The 'verse bible doesn't make sense to me and I have to find out how to make it work.
) but physics stays the same. Not that fiction can't get around the laws - FTL communications (SpaceAngl: have you read Simmon's Hyperion?) or giant sunlight lenses or gravity generating machines, for instance.-----------------------------------------------
hmm-burble-blah, blah-blah-blah, take a left
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I agree with orbital veloctiy and planet temp being unrelated - don't see the relationship.
Regarding Mars, if I understand some things, the Sun is getting larger, and will eventually consume Earth. Therefore is is now hotter than it was before. Mars has water, right? Mars has evidence of a major collision, a large asteroid, right? The Asteroid belt, which some theorize was a planet, or unformed mass, may have broken upn and impacted Mars, destroying it's atmo - with the Sun hotter than when Milky Way was formed, Mars was unalbe to recover it's atmo.
Just a posibility, to ap[pl to your verse operation.
Also, the largest bodies will be in the middle of the orbital rings - Jupiter and Saturn are the largest, with progressively smaller bodies as one gets farther or closer to the Sun. Gas bodies are there for mass - I don't see them providing heat for neighboring bodies.
Planets orbit around the Sun. Moons orbit around planets which orbit around the Sun.
I didn't see a reason that terraforming would not work in closer or farther bodies. The greenhouse gasses that trap in the atmo would need to be different, is all. The photosysthesis is from the Sun's radiation - and PE generates heat. Our at,mo also diffuses the sun's energy, deflecting most of it off, except for direct penetration. Remember that Earth would be comletely uninhabitabel without atmo.
Perhaps think of atmo as our Thermal battery, or charger. It soaks up energy on the light-side and discharges energy/heat during the dark-side cycle. Notice that it is cooler from dawn til noon, but heating up. It is then hottest a couple hours after Sun peak, and reamins hotter as the Sun goes down, and is not coolest at midnight, but several hours later (like 0400), until just before dawn agian.
Give the other planets atmo, and "ADJUST" the plantlife for more or less heat generation (think "more rainforest" for cooler planets), and regulation should be achievable.
The light factor available at a distance is the square root of the comparative distance. However this difference is negligible. How much of the sun's energy are we getting? Surely you understand that Jupiter is getting more, and likey also Saturn, because they have more surface area facing the Sun, although they are farther. Mercury and Venus have smaller surface area and might get less total radiation than Earth. If they were larger, they would have burned up with the amont of Sun energy hitting a larger surface.
Distance does not diminish the power of the radiation - space is a vacuum, how much dissipation of energy do you really think occurs in space? Something needs to be there to absorb that energy. I don't see an unshielded astronaut on Neptune surviving exposure to the Sun. They would need atmo to diffuse or shielding to deflect the energy.
Anybody know enough to reject these ideas? I would like to know if they are not scientifically valid.
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Quote:Since you ask... This looks to be funner than work.
Originally posted by jewelstaitefan:
Anybody know enough to reject these ideas? I would like to know if they are not scientifically valid.
Quote:The sun is indeed gradually heating and becoming brighter. It lives in a state of balance between the collapsing force of gravity and the outward pressure of fusion in its core. As there's less and less fuel to burn, it burns hotter to maintain the balance. I don't think it's getting larger so much - that will happen suddenly (on the cosmic time scale), when it uses up all its core's hydrogen and starts fusing hydrogen in its shell. Then it'll be a red giant, and things will look very different!
Regarding Mars, if I understand some things, the Sun is getting larger, and will eventually consume Earth.
Before that though, the gradual heating doesn't make the solar system more or less habitable. Certainly it moves the "habitable zone" ( http://en.wikipedia.org/wiki/Habitable_zone#Circumstellar_habitable_zo
ne) out toward Mars rather than at Earth, but it doesn't put a significantly larger portion of the solar system in the happy temperature zone.
Quote:I think you misspeak here - the sun is in the Milky Way Galaxy. It didn't exist when the Milky Way was formed.
Mars has evidence of a major collision, a large asteroid, right? The Asteroid belt, which some theorize was a planet, or unformed mass, may have broken upn and impacted Mars, destroying it's atmo - with the Sun hotter than when Milky Way was formed, Mars was unalbe to recover it's atmo.
Anyhow, I'm sure Mars has been hit by stuff, same as Earth has. But it'd be hard for a body to hit Mars, then retreat to where the asteroid belt is now. Impossible, really. The rubble of the collision would have stayed in Mars's orbit.
A note about the belt: current threory says that the belt is a planet that never formed because Jupiter's gravity was always disturbing things. Which is in line with my argument that two suns wouldn't make for a stable planetary system. If the body in Jupiter's orbit had 75 times the mass, its gravity might have kept Mars and perhaps even Earth and Saturn from forming. The area of the solar system available for stable planetary formation and orbit would be greatly limited.
Quote:I agree that gas giants don't provide heat. Jupiter and Saturn don't even heat their own moons, how could they heat distant planets?
Also, the largest bodies will be in the middle of the orbital rings - Jupiter and Saturn are the largest, with progressively smaller bodies as one gets farther or closer to the Sun. Gas bodies are there for mass - I don't see them providing heat for neighboring bodies.
However, there's no rule about where the big bodies need to be. A different solar system doesn't need to mirror ours, with the big planets at a certain distance. There may be a limit as to how close in they can be and still have a stable system of many planets, but Jupiter could certainly be further out.
Quote:I agree. It's just a matter of imagining the right technology.
I didn't see a reason that terraforming would not work in closer or farther bodies.
Quote:Whoa! It's not neglible - it's a big deal! It's much more important than the relative planetary sizes. Sure, Earth is larger than Venus and has more area facing the sun, but it also has more area to be heated. It's *rays per area* that matters, and it really does matter. Why is winter on Earth colder than summer? Cause the winter hemisphere is tilted away from the sun and get less rays per area.
The light factor available at a distance is the square root of the comparative distance. However this difference is negligible.
Quote:Sorry, but this is completely bogus! Mercury receives a helluva lot more solar energy than Jupiter. Nearly 20
How much of the sun's energy are we getting? Surely you understand that Jupiter is getting more, and likey also Saturn, because they have more surface area facing the Sun, although they are farther.
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Quote:
Originally posted by mal4prez:
Back to Joss's verse... I think the best way to go is to take Joss's drawing in the BDM as the way it is, and come up with technology that makes that system work. Alternately, do the "official" RPG thing and spread the planets over a few systems that are close to each other. Or, as I've done in my fics, just ignore the problem. It takes 8 hours to get from Planet A to Planet B and 3 days to get from Planet B to planet C. Planet A is hot and dry, Planet B is lush, cause that's just how they are. No explanation needed.
Damn. I'm out of stuff. Guess I have to work now. I tell you, the science you get paid to do is a lot less interesting than sci-fi...
You know, that is a very valid point, and your soothing tone has calmed the inner OCD in me. I guess you don't have to exactly figure it to make it work, you just need cool stuff to make that other stuff seem less important.
But all that said, and granted, we shouldn't look at the maps they gave us too closely, but even still it's something to consider.
Notice how toward the right of the image there is a bright, bright spot and little bits floating around it. What is that supposed to be if it's not a sun? It's bright just like the one in the middle. And granted, we never saw a second sun in the shows, but there should be a bit of realism thrown in there that they either don't see the smaller sun that far away and only get the second sun, or visa versa. There's a clever explanation, I'm sure, I just can't think of it at the moment.
http://www.leavemethewhite.com/
caps/albums/movies/serenity/
Serenity_0007.jpg
(COPY THE URL & PASTE IT INTO YOUR BROWSER)
Also, about Jovian planets and their heating, and how they do radiate a small amount of heat out to their moons. (I don't think I said planets, and if I did I meant worlds - since moons are also worlds in the 'verse.)
http://64.233.179.104/scholar?hl=en&lr=&q=cache:jc66Q17QyAwJ:www.cs.be
rkeley.edu/~samw/projects/ay249/z_heat_sources/Paper.doc
"As seen from the volcanoes on Io, it is clear that there is significant energy is being transferred via tidal interactions between giants and their moons. The amount of energy dissipated as thermal energy is proportional to the phase angle between the moon and the tidal bulge."
And Mal, I agree, it's always more fun to do the Sci-Fi than the actual Sci.
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Quote:16 Cygni B, part of the 16 Cygni Trinary system has been shown to have a gas giant in orbit. 55 Cancri A, part of the obviously named 55 Canri Binary system has shown to have a number of orbital bodies.
Originally posted by mal4prez:
I'm with JSF about orbital stability issues. A second sun would be heavy - much heavier than a planet, even if it's a small star. There's a certain amount of mass required before gravity can start fusion and "light" a star. Wikipedia says the minimum theoretical star mass is 75 times the mass of Jupiter. A body that heavy won't be sitting in a happy orderly orbit. The two suns would rotate around each other, and planetary orbits would be all messed up. Planets passing in between them are likely to get spun off into the Black, or maybe even shattered by gravitational forces. When you start talking three suns - whoa. There won't be many stable orbits, not inside or near these three suns. Stable orbits would be far outside.
In fact there are a number of stable orbits of Binary systems, the two most stable are orbits around a single star, or a larger wider orbit around both. It is possible to have a figure of eight orbit around both stars, orbiting one in a single orbit, then switching to the other and back again, but this is at best semi-stable, and will quickly end with a cosmological planet cannon.
EDIT:
Of course the planets have to form, and this is going to be less likely with the two stars orbiting each other. Of course it says nothing for captured bodies, but captured bodies are even less likely.
The problem is that both stars will 'shepherd' each others acreation disk, moving stuff about, swallowing it, even spitting it out the system completely. A similar system on a less dramatic scale is at work on the asteroid belt, there are gaps caused by Jupiter, where it has shifted asteroids to different orbits, or gone all Shoemaker levy on there arses. Most binary systems have eccentric orbits, with eccentric orbits there's not much shepherding orbits for bodies to exist in, it's either very close to one star or the other, or very far from both.
However I believe both stable orbits (around single stars, and around both) have associated habitable zones.
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Quote:Well, that's not actually heat being radiated to the planet. What's happening is as the planet orbits Jupiters gravity is 'coming at it' from different directions. One moment it's pulling from this side, then the other, causing the planet to flex and change shape, bulging on the side facing Jupiter. This constant dynamic action causes heat from friction within the planet itself, just like rubbing your hands together.
Originally posted by meimeiCobb:
Also, about Jovian planets and their heating, and how they do radiate a small amount of heat out to their moons. (I don't think I said planets, and if I did I meant worlds - since moons are also worlds in the 'verse.)
http://64.233.179.104/scholar?hl=en&lr=&q=cache:jc66Q17QyAwJ:www.cs.be
rkeley.edu/~samw/projects/ay249/z_heat_sources/Paper.doc
"As seen from the volcanoes on Io, it is clear that there is significant energy is being transferred via tidal interactions between giants and their moons. The amount of energy dissipated as thermal energy is proportional to the phase angle between the moon and the tidal bulge."
More insane ramblings by the people who brought you beeeer milkshakes!
No one can see their reflection in running water. It is only in still water that we can see.
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Citizen - sure there can be planets in binary systems. But what's suggested here is a particular situation where both suns contribute heat in a way that makes mamy, many planets habitable. The stars can't be too far away from the planets involved.
But the star's gravity presents a problem. I can't possibly explain well without drawing pictures and bringing in numbers, but I think it's inescapable that a second star which contributes useful amounts of heat will also cause orbital instability. If you move the second star away enough so it won't mess up planetary orbits, it won't give enough heat. So you make it bigger to get more heat, but now its gravity is a problem again.
I'm not saying this intuitively. I did look at the numbers a bit. A very little bit. Back of the envelope like. Just rough estimates of heat versus distance versus gravity perturbations.
I have to say though - the figure eight orbit... Whoa! Cool. I like this a lot! How good would that be as sci-fi? You have a year around a blue star than a year around a yellow.
Hey - actually, Joan Vinge's novels Snow Queen and Summer Queen used this kind of solar system. The social and political situation on this planet was determined by its orbit. For ~100 years it goes around a cool, stable star and space traffic comes and goes. That's winter. Then for ~100 years it goes around a hot, unstable star - summer. The folks on the planet are fine in summer, but no ships can go near it. I just loved that.
EDIT TO REPLY TO YOUR EDIT: 
But is the habitable zone in a binary system that much bigger than a single star system? *scratches head*
Meimei - have you heard of Lagrangian points? It's one way to get more bodies into a solar system. ( http://en.wikipedia.org/wiki/Lagrangian_point)
Oh, and which image do you mean? The one you included isn't working for me.
-----------------------------------------------
hmm-burble-blah, blah-blah-blah, take a left
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Quote:I know what you mean, but there's all sorts of possibilities. Binary stars in close regular orbits with planets orbiting both (but what advantage that would have over a single system I'm not sure, and haven't the time to check off hand), Stars in regular orbits that are further away from each other, allowing planets to orbit both. The advantage wouldn't be anyone body getting heat from both, perhaps, but that there'd be two sets of habitable zones. I'll take a better look at it later, when I'm not out the door to work.
Originally posted by mal4prez:
But the star's gravity presents a problem. I can't possibly explain well without drawing pictures and bringing in numbers, but I think it's inescapable that a second star which contributes useful amounts of heat will also cause orbital instability. If you move the second star away enough so it won't mess up planetary orbits, it won't give enough heat. So you make it bigger to get more heat, but now its gravity is a problem again.
Quote:The problem with Lagrange points is that they're not stable in themselves, things tend to 'fall' out of them over time.
Meimei - have you heard of Lagrangian points? It's one way to get more bodies into a solar system. ( http://en.wikipedia.org/wiki/Lagrangian_point)
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