Originally posted by Plankowner:
</font><blockquote>quote:</font><hr />Originally posted by Laryssa:
Why wouldn't people live on it? If you can live on the Moon, living on the surface of a big ocean should be no big deal.
I would think that gravity would have a lot to do with it. SURE, you can put grav plates on everything, but no matter what TL you are dealing with, it will get very expensive, very quickly. Floating cities are nice for the tourist trade and to make sure the Plebes know who is REALLY in charge, but to consider every single house, every single street etc, to be grav plated will not allow much for true economics of scale.
Size C would imply a surface gravity of about 1.5 assuming Earth Normal Density. Not very comfortable on a continuing basis. I would rather live that world's moon, which would make the moon the Main World, not the Ocean World. You could easily include this idea into any existing Traveller campaign by picking a smallish sized world and saying it orbits one of these Ocean Giants. </font>[/QUOTE]One of the erroneous assumptions of Traveller is assuming that all planets have the same density, and they don't. Saturn for example is less Dense than Water and has a gravity of around 1g more or less, if it had the same density as Earth, I think it would have a gravity of around 70g. This is one of the reasons why I include a separate gravity statistic in my UWP listings, I don't derive the gravity purely as a function of size as compared to Earth.
It just so happens that water is less dense than rock, if you can a planet where a significant portion of its makeup is water, you can have a planet that is less dense than Earth and which would have a lower surface gravity than what its size would be.
One way of thinking about a gas giant is as a fluid world. The gases as you go deeper into a gas giant's atmosphere actually become liquid when the pressure becomes thick enough. The planet Neptune is actually though to have an ocean of water deep under its atmosphere, oddly appropriate given its name. A water world can be though of as another type of gas giant.
Now if you have a certain type of gas giant, one with a breathable standard, or Dense atmosphere and a water mantel, you can actually have people living on a floating platform on the surface of the Ocean. The ocean would go down several thousand miles toward the core of the planet. You could not reach the core of this planet via submarine, because at a certain pressure water actually turns into a kind of ice, even at room temperature, this ice is denser than water but sill less dense than rock, so it would go down quite aways until it meets a rocky core of even denser material.
This "Gas Giant" has circulating ocean currents, and there is enough water volume in this to actually create a nagnetic field. If things are just right and the planet it proportionally made of the right material, you could have a planet with a gravity of 1.0 at the ocean's surface. If the planet's atmosphere is Dense High, you could still have microorganisms maintianing the atmosphere in a hot water ocean, and humans can establish a "cloud city" at a higher more temperate elevation where the atmosphere is breathable. This is the sort of gas giant that the Star Wars planet Bespin might be. A normal gas giant with a hydrogen-Helium atmosphere could not be breathable, but if the gas giant some how did not accumulate these gases yet somehow retained heavier gases, it could have a hydrogen-oxygen atmosphere. Escape velocity is a function of a planet's mass and diameter. if the Escape velocity is lower than the average molecular velocity of hydrogen gas at room temperature, then the hydrogen could have escaped. Its very important that this excess hydrogen escapes, because so long as hydrogen is around, you can't have free oxygen in the atmosphere, it will combine with hydrogen to form water and become part of the hydrosphere. So at some point in the planet's history, it must have lost all its excess free hydrogen so you can have free oxygen. Having retained helium is not such a proble since it is a noble gas.
