We know how long the day is on Earth and Mars. I presume that 26 hours is the length of the Bajoran day. Is there any canonical references or back materials for other key planets?
planetary rotation rates
- Thread starter Ronald Held
- Start date
I dunno, but this is a good question.
I do not recall that information in the Star Charts outside of the Terran solar system.
Any other sources?
Any other sources?
I'm sure there are a couple of episodes out there where we have inconsistencies in the timing of the scenes unless we decide that the length of day on that planet is "anomalious"...
However, it would be easy to argue that the majority of habitable planets in the Trek galaxy are the result of terraforming performed by preceding advanced humanoid cultures. After all, most of those supposedly have the same biological requirements and preferences, as dictated on them by those meddling proto-humanoids from "The Chase". And the first thing the ancient terraformers probably would alter would be the planet's rate of rotation, and perhaps distance from the star - "fine-tuning" feats easily achieved by standard starship technologies applied on a slightly larger scale... So a 24 hour rotation period might well be the galactic standard!
(Or to be more exact, the "The Chase" humanoids would have built humanoid species that are at home on worlds that have a 24 hour rotation period, even if those worlds had different rates of rotation at those stages of their evolutionary history when no humanoids were dwelling on them. Planets with big moons would have varying rates of rotation, just as Earth does - but the later terraformers would probably prefer planets with stable rates of rotation, fixed at that arbitrary but optimal 24 hours.)
Timo Saloniemi
However, it would be easy to argue that the majority of habitable planets in the Trek galaxy are the result of terraforming performed by preceding advanced humanoid cultures. After all, most of those supposedly have the same biological requirements and preferences, as dictated on them by those meddling proto-humanoids from "The Chase". And the first thing the ancient terraformers probably would alter would be the planet's rate of rotation, and perhaps distance from the star - "fine-tuning" feats easily achieved by standard starship technologies applied on a slightly larger scale... So a 24 hour rotation period might well be the galactic standard!
(Or to be more exact, the "The Chase" humanoids would have built humanoid species that are at home on worlds that have a 24 hour rotation period, even if those worlds had different rates of rotation at those stages of their evolutionary history when no humanoids were dwelling on them. Planets with big moons would have varying rates of rotation, just as Earth does - but the later terraformers would probably prefer planets with stable rates of rotation, fixed at that arbitrary but optimal 24 hours.)
Timo Saloniemi
Timo. I can buy the seeding of planetary environments, but not necessarily the terraforming of the system. Since They were not certain what would evolve to find their message and when, I do not believe they could predict any long term eveolutionary path in detail.
Why not dump the genetic matter on planet with near 24 hour rotation periods and Class M conditions. Plenty of those planets in the Galaxy assuming they had the equivalent of slipstream or transwarp drives.
Why not dump the genetic matter on planet with near 24 hour rotation periods and Class M conditions. Plenty of those planets in the Galaxy assuming they had the equivalent of slipstream or transwarp drives.
Is it necessary to assume that the ancient humanoids had FTL at all? I think it makes much more sense if they didn't, that way no one has to make up an explanation as to how they died out, why they cared more to vaguely continue their genetic line instead of actually saving their civilization--they recognized (or believed) that they could not.
Kind of like the Kataanians from "The Inner Light." They sent their telepathic probe thing because they weren't aware that they could escape and colonize easily with warp drive. The Salome Jensians might have performed their epic task for the same reason. Indeed, there's no particular reason to think that the seeding actually took place in the civilization's lifetime. Like Kal-El, their DNA might have been blasted off into the nethers of space, to a fate unknowable to its long-since-dead progenitor. The time elapsed between departure and planetfall could have been thousands or millions of years.
Or they became the Organians or something. Who knows, who cares.
Edit: also, it occurs to me, if I understand tidal locking, I think we do know the rotation rate of one planet--Remus. It has a day of one Reman year.
Kind of like the Kataanians from "The Inner Light." They sent their telepathic probe thing because they weren't aware that they could escape and colonize easily with warp drive. The Salome Jensians might have performed their epic task for the same reason. Indeed, there's no particular reason to think that the seeding actually took place in the civilization's lifetime. Like Kal-El, their DNA might have been blasted off into the nethers of space, to a fate unknowable to its long-since-dead progenitor. The time elapsed between departure and planetfall could have been thousands or millions of years.
Or they became the Organians or something. Who knows, who cares.
Edit: also, it occurs to me, if I understand tidal locking, I think we do know the rotation rate of one planet--Remus. It has a day of one Reman year.
I always figured the rotation rate was probably one of the (many) criteria that went into any given planet being considered or classified as a 'Class M' planet.
Cheers,
-CM-
Cheers,
-CM-
But they did - that was the point, apparently. They didn't seed life, because life would have emerged anyway. They seeded special life, the sort that would at first evolve in a random fashion but then, suddenly, almost magically, decide to take a sharp turn towards the humanoid form that these, um, Progenitors so loved. On Earth, this happened at least twice: first with the dinosaurs, then with the mammals. On Cardassia, something similar to lizards underwent this treatment. On Antedea, it apparently happened with the fish!
The Progenitors didn't need to predict the future, as they more or less made it. They had control of evolution down pat, down to the smallest biochemical details, as evidenced by the "message" (or advanced and adaptive software lifeform) coded into the building blocks of life. Humanoid lifeforms are their constructs - so humanoid planets could be, too. However, the bulk of terraforming would no doubt have been the work of later generations of species, all of which would have the same biological requirements (except where the Progenitor programming went astray and produced some alien aliens for a change) and probably also the same urge to spread out to the stars.
Probaby not. But then again, discovering FTL seems like an inevitable development in the Trek universe, akin to discovering electricity. And you yourself said that it's difficult to invent a reason for the Progenitors "suddenly" disappearing or dying out, so they probably had plenty of time to discover everything there was to discover, and then evolve to a more divine form of existence - another seemingly inevitable development in the Trek universe...
Timo Saloniemi
I may buy into their vast genetic skills, but not their terraforming abilities or needs to.
But the episode already establishes that the Progenitors wanted to create humanoid life, and that they did succeed. That requires them to be able to regulate the evolution of lifeforms. And that, in turn, is a trivial skill if one had biochemistry so down pat that one can insert software into biochemicals that then goes on to survive billions of years of mutation.
So, what in the above speculation goes beyond what was established in "The Chase"?
If anything, it would be inane to think that "natural" evolution could ever result in genetically compatible humanoids all across the galaxy. "The Chase" avoids that pitfall nicely enough, and gives a good rationale for why things would be as they are in the Trek universe.
Timo Saloniemi
So, what in the above speculation goes beyond what was established in "The Chase"?
If anything, it would be inane to think that "natural" evolution could ever result in genetically compatible humanoids all across the galaxy. "The Chase" avoids that pitfall nicely enough, and gives a good rationale for why things would be as they are in the Trek universe.
Timo Saloniemi
There is some physics behind this... the sort of thing that generally gets ignored in "sci-fi writing" but is reasonable and logical, nevertheless.
I'll spare the math here, but let's just say that, for a planet the same size as earth, in the same size orbit around the same size sun, the length of the day should be nearly identical. (I'll leave the moon out of it, but that's also a major issue.)
There are lots of examples of this sort of thing in real science which tend to get ignored. For instance, realize that Mars is less massive than Earth. We have strong reason to believe that Mars once had liquid water, which also means that it had a much more dense atmosphere than it has today. The thing is, with the lower gravity, the eventual reduction in atmosphere was inevitable (and thus explaining why the sole remaining water on Mars exists in solid form, subsurface).
A smaller, lower-gravity world simply will not retain an atmosphere as effectively as Earth does. A larger, higher-gravity world will inevitably have a different atmospheric mix.
Put an Earth-sized planet further away from the same size sun, and it's going to be much, much colder. Put it the same distance from a larger and/or hotter sun and it'll be much, much hotter. Common sense, but easy to "overlook" when writing Sci-fi.
Basically, for a planet to be habitable by humans on a long-term basis, it needs to be almost identical in mass (and nearly identical in size) to Earth... not just to get the 1g gravity, but also to retain the proper atmosphere.
It needs to collect the same amount of heat from the sun, in the same general wavelengths. This means a yellow sun, by definition pretty much the same size as ours and which, in the sky, will look almost identical to our own.
It's far more reasonable to put "Star Trek" episodes on planets which look a lot like Earth than to put them on planets with giant purple suns and 1/5g gravity. That stuff may seem "cool," and I'm sure that such planets exist... but the odds of them being "human-friendly" are extraordinarily slim.
No, worlds where humanity would settle would be those few worlds which would be "like Earth." And because of the various factors involves all being interrelated (day-length based upon planetary mass/density and sun-orbit path/rate, for instance) it's likely that an "Earth colony day" will be very close to 24 hours and a year will be very close to an "earth year."
Cary, your explananations are a little simplified. the initial rotation of the Earth was the net result of its formation by planetesmals. the presence of a large moon changes the rotation history over that with no large moon(by mass). For that object(in a similar orbit and stellar mass) the long term results would be to have the rotation rate and orbital rate the same(or close to it) due to tidal inteactions with its star.
the atmospheric composition is important as is the distance to the star and orbital parameters in determing its thermal properties.
Lower mass worlds will not retain the similar earth composition atmosphere at the same mean temperature for the same duration of time.
I am just adding some detail, not "slamming" Cary.
the atmospheric composition is important as is the distance to the star and orbital parameters in determing its thermal properties.
Lower mass worlds will not retain the similar earth composition atmosphere at the same mean temperature for the same duration of time.
I am just adding some detail, not "slamming" Cary.
No problem... I wanted to keep it as simple as possible (hit the concept, not dwell on individual details) for the benefit of the non-technically-inclined.
I'd like to add that atmospheric composition--which is important like Ronald said--is, however, largely decided by the biosphere on a planet that has one, as well. Which is good for us, because we didn't start with an atmosphere that was particularly breathable to folks like ourselves. 
Not my speciality, but it would depend on the type of life and waste products it expells. Also for how long life had been around when the planet was "discovered".
The Bajoran day may be 26 hours long, but we have no idea how long a Bajoran hour is.
