Questions: Need help with the Science of Science Fiction

[Mage]

Hello everyone,

I was wondering if anyone in the know could help me with the rational and scientific parts of the game.

Basically, I want to set a Traveller campaign on a single planet. I want the planet to be absolutely massive, and habitable to humans as we know them, you and I, the Terran kind. This will be for my own campaign.

So, I want a large planet. Would a larger planet have greater gravity due to its mass? Would this affect a species living here? Or would its proximity to the sun have a greater bearing on gravity. If the proximity to the sun or star (depending on star type) affected the planet in other ways, how would this in turn affect days, nights, calendars, and the environemnt?

Basically, I want an even larger version of earth, but do now the science behind it or required to try to make it as real as possible. I want it to be big, maybe the size of Jupiter (even though it is a gas giant and not a planet per se).

Please help! Thanks!

 

[far-trader]

Jupiter size but Terran type is screaming artificial world to me. Though the inhabitants may not know it if sufficiently primitive.

It would have to be practically hollow to not have too high a gravity. Definitely artificial. With artificial means installed in the hollow core to set up other required elements like a magnetic field.

Of course such a world is ripe with mystery and exploration potential. What's inside? How do we get inside? Who built it? Why?!

And the construction of such a world would probably mean the entire natural solar system (except the star) was used in the construction one way or another. Possibly even requiring importation from other nearby solar systems. Meaning it may be a bit of a distant island cut off from other systems by a gulf of strip mined solar systems (possibly even including the stars themselves for fuel and energy).

Sounds like a fun setup

 

[Lemnoc]

I doubt you could size a rock world up to the Jovian realms without it being fearsomely lethal with radiation from its core, to say nothing of its deadly Gs.

You could probably spin up a world several times the diameter of Earth that humans could still suffer and groan on if you assumed it was made primarily of lighter elements like lithium and was therefore metals-poor. Ceramics might take the place of metals in many applications.

EDIT: Solve the radiation / radioactives issues by assuming a dead core like Luna, therefore little tectonics or earthquakes or volcanoes. But also no Heaviside layer and little protection from solar radiation.

If you assumed it was less of a water world than Earth, you could have HUGE extended land masses, with rivers and seas that could dwarf those on Earth. A nation like New New Texas could have big bragging rights there. :lol:

IIRC Jack Vance posited something like this with his Big Planet series of stories.

 

[Mage]

@ far-trader

Wow, that was quite informative, and it blew my mind a little :shock: . A hidden world beneath the 'real' one. That is pretty awesome.

On the other end of the spectrum, how would this work for a 'real world' that is not artificial?



@ Lemnoc

I am not sure what you mean by the Jovian realms. This will not be set in the Traveller universe. A lot of the stuff you are saying is kind of going over my head a little, if you wouldn't mind explaining it a little bit more, please

 

[Jeraa]

I am not sure what you mean by the Jovian realms. This will not be set in the Traveller universe. A lot of the stuff you are saying is kind of going over my head a little, if you wouldn't mind explaining it a little bit more, please

"Jovian" is another name for gas giants, like Jupiter. (Jupiter was named after the god of the same name, who was also called Jove. Similar things to the planet Jupiter are therefor "Jovian".)

 

[Mage]

I am not sure what you mean by the Jovian realms. This will not be set in the Traveller universe. A lot of the stuff you are saying is kind of going over my head a little, if you wouldn't mind explaining it a little bit more, please

"Jovian" is another name for gas giants, like Jupiter. (Jupiter was named after the god of the same name, who was also called Jove. Similar things to the planet Jupiter are therefor "Jovian".)

Oh, I did not realize that, I thought it was a Third Imperium reference.

 

[Easterner]

Earths surface area: 148,300,000 million sq km
Earth surface, no water: 509,000,000 million sq km

Jupiter: 62,179,600,000 BILLION km2

Jupiter is made of ammonia and hydrogen, light gases no solids and it has gravity 254% of earths. No solid surface that size would have lesser gravity. A hollow artificial world would.

Unless for some reason you want a planet with a pop measured in thousands of googles I see no reason for such a planet size. (You haven't told us why) Any world of large size artificial or natural would be extremely short of metals as dense elements increase gravity. That lowers Tech level progress. Mass population can mean starvation/cannibalism issues particularly if no large bodies of water.

See: http://en.wikipedia.org/wiki/Dyson_sphere
Even more surface area but natural ecology kept intact.
Dyson Sphere at 1 AU: 272 quadrillion km2, or about 550 million times the surface area of the Earth

Can't go wrong with that, there are variants including Dyson Ring and Dyson Bubble.

TRAV NOTE:
IIRC if I recall correctly there is an incomplete Dyson Sphere in Vargr space.

 

[Mage]

@ Easterner

I simply want a large planet to set a traveller campaign in, as opposed to various solar systems and the like which require a lot of time and effort, but I want a very large planet with plenty of space, and room for possibilities.

Regarding earth and being so water filled, would gravity be affected on our planet if there were less water on its surface?

 

[Jeraa]

The Earth has a surface area of 510,072,000 square kilometers, and is a Size Code 8 world. A Size Code A world (The largest in the world generation rules) has a surface area of 803,840,000 square kilometers, or roughly 1.5x Earth.

Thats total surface area, not counting water.

 

[Mage]

Thanks for the info, I do not have the rulebook on hand at the minute.

 

[Easterner]

Water is heavy, metals are heavier. The denseness of planets composition affects gravity. But a Jupiter size planet will be tough if 50Kg on earth weighs 350Kg there.

 

[Mage]

@ Easterner

Ok, I will rephrase my question. Lets say present day earth, 50% of its water disappears. Aside from the massive environmental side effects that I do not want to go into, what affect would this have on our current gravity in the short term (1 - 100 years) and long term future?

 

[Jeraa]

Gravity is based on mass. And even though a majority of the Earths surface is covered by water, that water only makes up about 1/4400 of the Earths mass. Removing the water won't make much (if any) difference.

 

[rust]

Basically, I want an even larger version of earth, but do now the science behind it or required to try to make it as real as possible. I want it to be big, maybe the size of Jupiter (even though it is a gas giant and not a planet per se).

Whether this idea would be useful despite its many plausibility
problems would depend on what you intend to achieve with it,
and whether it would really work that way. For example, with
an average Traveller technology the fact that the planet is so
much bigger than Earth would not make a lot of difference for
travel and trade, the time required to travel to some remote
location with a suborbital craft would hardly increase enough
to make the planet "feel real big" for the players.

 

[far-trader]

The more I think on it Mage what might work better for your needs is not a single super planet but a many worlds system. Probably a dispersed multi sun system. Suggested as an option...

Something like a trinary (3) star system with each star having several small to average worlds. I can see having 6 close to Terra type worlds easily with some basic terraforming, and perhaps many more marginally so, smaller and less hospitable but still near shirtsleeve survivable, and possibly some moons around the gas giants. Think colder all the time and perhaps needing breathing support but not full vacc-suits. The system could support 10s of billions of people and still have wilderness areas.

Spreading the planets around gets the same effect as a large world, or better since travel times will be at least week long between the closest, months between farther ones, and if you eliminate jump drives players are stuck with slow travel and fast communication. No outrunning their deeds.

 

[Captain Jonah]

No one has yet mentioned how advanced the players are going to be.

Several options.

As Far trader says, many worlds around the sun. These have been pulled into the habitable zone and used to be the larger moons of the gas giant. Add some terra-forming and there they are.

If the players world is lower tech the worlds could be connected by transport portals, strange ruins with pairs of white crystal pillars. Local scientists think they are ceremonial, for those 1 in a million people who retain that DNA tag from the original colonising effort by the ancient aliens they can be activated and used.
A government searches its people and assembles teams of people with the DNA tag. These ad hoc groups are sent forth to explore and exploit.

Higher tech there are radio signals coming from several of the other worlds and the secret project to reverse engineer the gravatic drive found as wrecks in that alien hanger under the polar ice cap is producing workable units. Time to explore

Traveller level you have firefly.

Second option. Why does the world have to be a planet.

How about a ring world, incredibly ancient. Formed by shattering every world in the system and pulling them and every asteroid within a LY inwards to form a thin ring round the sun. Works best with a red dwarf as the ring is much smaller.
Imagine a ring as wide as the earth and a thousand earths long. Some parts have vast metal reserves, others have none at all but have much richer stores of rare earths or lighter elements.

Now separate those earth sized areas by the failing Gravity generators left by the builders. In a few thousand years they will fail completely and the ring will begin to disintegrate.

These gravity fields cut the ring into sections by causing intense storms where the gravity fields between the generators meet with 300mph storm winds, sand and dust storms that sandpaper through steel in minutes and fields where the gravity fluctuates from -5G up to 50G making any attempt to cross these zones fatal.

For earlier tech games someone has just discovered a strange network of tunnels deep under a coal mine, clearly artificial but not made by any man. Several of these tunnels seem to go under the barrier between worlds.

Pre gravatic civilisations could know about the barriers and have put satellites over the gravity zones but have just discovered the tunnels or developed advanced enough genetic science to be able to identify the DNA tag needed to use the pillars.

Or perhaps that secret reverse engineering project has started building gravatic drives able to get over the barriers which the local rocket tech could not.

 

[alex_greene]

Ah, a BDO.

If the world was hollow (and you could touch the sky ... ) with a surface large enough to accommodate life and civilisation, yet still only have a 1G surface pull, guaranteed it will have to be hollow. But how much of the interior is hollow, and how thick is the outer crust (and how much of it can be mined for mineral resources?)

Life would not have evolved on the surface of this artificial world, but would have to have been put there. So there would have been other protections, too, to keep the atmosphere intact (the gravity field could do that) and to deflect solar radiation (which would require an artificial magnetosphere and ozone layer artificially maintained somehow).

Would there be taboo places where, if a character wanders into those places he is never seen again? (access ports to the interior - once inside, the character can never go back to tell people of his findings ...) The characters, all surface dwellers, could be drawn to this by some simple circumstance such as, oh, a local ruler's daughter having entered the taboo place and disappeared forcing the ruler to send his best men (or just some condemned men his people wouldn't mind never seeing again) to retrieve her.

You can have the environment colour the language, for instance by having the language have no words for "moon," "earthquake," "volcano," "eclipse" or "tide."

 

[Lemnoc]

From the sounds of it, Mage, I think you're looking at a Ringworld. Could have trillions of area the size of the Earth, all accessible at interplanetary distances, with centrifugal "gravity" roughly that of Earth. Shared atmosphere. Could be high-tech, lo-tech, both, whatever. Primary energy source would likely be sunlight falling on all that area, since you would not have access to radioactives. Maybe fusion from seawater.

In OTU, I believe the Ancients constructed in the Leenitakot system in the Hinterworlds.

 

[pasuuli]

Alternate suggestions, to take or leave.

Have a rosette of five earth-sized worlds, sharing their orbit at equidistant points around the primary.

Have a Ringworld. That'll give you more room than you know what to do with!

 

[Solomani666]

@ Easterner

I simply want a large planet to set a traveller campaign in, as opposed to various solar systems and the like which require a lot of time and effort, but I want a very large planet with plenty of space, and room for possibilities.

Regarding earth and being so water filled, would gravity be affected on our planet if there were less water on its surface?

What Tech Level are we talking about?

A single planet can be as big of small as you want it to be depending in the transportation system available and the detail you have outlined for the planet.

Examples:

* In 1800 the world was HUGE, but now with planes, trains and cars, not so much so.

* If you are willing to put in the detail than a single city such as New York can be VERY LARGE.
You can spend a full year of your life wandering around NYC and still not see all their is to see.

* Now take Coruscant from Star Wars. Just slightly smaller than Earth, but with the entire surface being one huge city, with the multiple levels and multiple sub levels, it becomes HUGE ON A GALACTIC SCALE if you are willing to detail the area the characters happen to be in.


Here is an idea to instantly make your world bigger... Government Type 7.
You can divide the world into 20 or so independent city-states each with it's own culture and varied tech level.
Separate some by wilderness and roaming tribes of outsiders.
Of course most of the city-states will always be, warring, back stabbing, stealing, aligning, and blackmailing each other, sabotaging, etc.
Now all you need is an area the size of England. The rest can be explored later.
Now come up with a resource in short supply to keep everybody at each other throats.
The city-states will be sending out exploration teams to find more of the scarce resource.
Hard to keep secret, and hard to protect so far from home.


In summary, what I mean to say, is that it isn't the physical size of the planet, it's the amount of detail and 'stuff' you put into it. Even in present day Earth there are still a few Tech Level 0 and 1 societies that have never had contact with the rest of civilization. And there are still many places that still have not been explored.

Hope this helps.