massive gravity effects

[GamingGlen]

Its density (to get that gravity) would have to be around 7000 kg/m² (which is not in itself unreasonable for a planet of that size), but itwould be about 18 times more massive than the Earth!

Solid planets conform to a logarithmic scaling law of mass vs radius. If King obeyed that law, it would have 33 earth masses inside its 30,000 km diameter and the gravity would be closer to 6 gees instead of 3 gees. The density would be 14 g/cc instead of 7, so the planet is only half as massive as it should be.

More boondoggle.

Is there an equation for this? The only one I found is linear, so my spreadsheet keeps the surface gravity seemingly low for super Earths (which does keep such planets more viable for adventuring on them).

Doesn't 2300 use beanstalk tech? Would that help to lift stuff off of King?

 

[F33D]

what about battle dress and a grav belt

No grav tech in 2300U.

Then the planet is not going to be exploited in any major fashion. Too deadly for humans and too high G to lift materials in any quantity off of it using rockets. Did the game designers list it as a mining colony or something?

 

[CosmicGamer]

The robots do all the work. Special robots that do the mining then convert into ore carrying vehicles.

Home of the Transformers!

 

[spirochete]

Is there an equation for this? The only one I found is linear, so my spreadsheet keeps the surface gravity seemingly low for super Earths (which does keep such planets more viable for adventuring on them).

There are several equations for this. The simplest is to use a scaling exponent x.
The formula is: r=m^x, where r is radius in earth radii and m is earth masses.

Normally, the mass of a sphere is proportional to its volume, so the scaling exponent x would be the cube root x = 0.3333.
This only holds true for uncompressed bodies with a uniform mass distribution. As the size increases, gravitational compression effects begin to show, and mass becomes concentrated in the planetary core. The exponent reduces to something like 0.27. Over the entire mass range of asteroids to gas giant cores, x = 0.31 to 0.25.

You can find the exponent for any body by log(r)/log(m). Sometimes you find an outlier with an exponent larger than it should be, like Mercury or Aurore. Their scaling exponents are close to 0.33 because of a greatly enlarged core. You can also approximate the scaling exponent for solid bodies using x ~ 0.25 + (16 - TravSize) / 300.

This method isn't perfect. The value of x varies according to the size and mass of the bodies. Other equations are better, but scaling exponent is the simplest.

                             Scaling exponent x
     Class                    Range       Typical
     --------------------------------------------
     Large icy moons      0.239 - 0.242    0.240   Callisto, Ganymede, Titan
     Superterrestrials    0.265 - 0.275    0.270
     Plutinos, KBOs       0.271 - 0.285    0.280   Triton, Pluto, Charon
     Icy moonlets         0.265 - 0.290    0.278   Dione, Rhea, Mimas, Iapetus
     Large Terrestrials   0.257 - 0.283    0.281   Mars, Earth, Venus
     Small Terrestrials   0.292 - 0.298    0.295   Io, Europa, Moon
     Asteroids            0.292 - 0.324    0.309   Pallas, Juno
     Mercurians           0.300 - 0.350    0.332
     Subjovians           0.477 - 0.518    0.496   Saturn, Uranus, Neptune

 

[Wil Mireu]

What spirochete says is generally correct, but there is a complication - a 'superearth' could have a lower than expected density because it has a very high volatile content. Imagine a rocky body with a few hundred (or a thousand) km of high pressure ices and water on top of it - that would lower the bulk density of the planet signficantly. The gravity would be lower too (more like 1.5 to 2.5G).

You could potentially have planets that are 12,000 km in radius but they would be the same (or even lower) density as Earth because of that... but they will not have rocky continents on their surfaces.

 

[rust]

In general I assume that a healthy Earth-normal human on the surface of King is going to be as frail as someone at the extreme edge of old age (say a 90+ year old right now) with severe arthritis: movement is going to be a shuffling, very slow gait and walking across a small room is going to be exhausting. Any kind of fall is potentially very hazardous.

The doctor would certainly not recommend upright positions, and
especially not walking. Under 3 G the blood the heart would have
to pump up to the brain in a body in an upright position would ha-
ve three times its normal weight, something which a heart is not
made for.

 

[spirochete]

Is there an equation for this? The only one I found is linear, so my spreadsheet keeps the surface gravity seemingly low for super Earths (which does keep such planets more viable for adventuring on them).

The radius-density relationship is better than scaling exponents. You can derive density from radius and vice-versa. Once you have these two values, you can solve for everything else. Where radius r and density d are expressed in earths (radius and density = 1), the radius-density relationship appears to be:

Ln(2d) = Ln(2) × r and 2d = 2^r

Therefore
d = Exp(r × Ln(2))/2 = 2^r/2 and
r = Ln(2d)/Ln(2)

Watery/icy bodies (icy moons, failed cores, oceanic superterrestrials) have 1/3 to 1/6 of this value (Ceres 0.67, Pluto 0.651, Triton 0.649, Titania 0.574, Charon 0.562, Oberon 0.546, Ganymede 0.531, Titan 0.517, Callisto 0.513, Dione 0.508, Umbriel 0.477, Rhea 0.414, Mimas 0.409, Iapetus 0.365, Enceladus 0.343, Tethys 0.339).

With mass m expressed in earth masses,
m = 0.5 Exp( r × Ln(2) ) × r³ = r³ × 2^r / 2

You can derive radius from mass by working this in reverse, but you need a Lambert power log function.
r = 3 LambertW( Ln(2) / 3×CubeRt(2m) ) / Ln(2)

 

[Jeraa]

what about battle dress and a grav belt

No grav tech in 2300U.

Then the planet is not going to be exploited in any major fashion. Too deadly for humans and too high G to lift materials in any quantity off of it using rockets. Did the game designers list it as a mining colony or something?

It is one of the richest deposits of tantalum found so far.

Under ordinary circumstances, neither nation would have considered putting the effort and financial support into solving the problems of establishing a colony in such a harsh environment, but King proved to bear one of the richest deposits of tantalum yet discovered by man. Today it serves as the primary tantalum supply for both nations and produces a small, salable surplus besides. America's place at the cutting edge of warship design is due, in part, to King's reliable tantalum supply; as is Trilon's success in the field of starship development.

 

[F33D]

Under ordinary circumstances, neither nation would have considered putting the effort and financial support into solving the problems of establishing a colony in such a harsh environment, but King proved to bear one of the richest deposits of tantalum yet discovered by man. Today it serves as the primary tantalum supply for both nations and produces a small, salable surplus besides. America's place at the cutting edge of warship design is due, in part, to King's reliable tantalum supply; as is Trilon's success in the field of starship development.

Tantalum makes up ~1.5 ppm of Earth's crust. It'd still be cheaper to extract on Earth over a 3G planet using 2300 tech.

The writers didn't do their homework.

 

[Jeraa]

Its a very specific isotope, Ta-180, which apparently makes up only like 0.012% of the tantalum. So, if my math is correct, thats more like 0.00018 ppm.

 

[Wil Mireu]

As I implied in the Cobalt Mining thread, writers often "don't do their homework" when it comes to mining. Lanthanum in Traveller and Tantalum in 2300AD don't come in "deposits" that are easily accessible. Some research on the interwebs will show where they are found on Earth, and that sort of environment (e.g. hydrothermal veins, pegmatites, metamorphic zones, sedimentary deposits, placer deposits, etc) would be where they are found on other planets too.

 

[rgrove0172]

How effective would simply reducing King's gravity to maybe 2.2 be in fixing some of the problems? First, maybe bringing it more in line with where it could be and more importantly allowing the typical traveller to visit there, the mining operations to be more conventional, and the colonists more human.

 

[Lemnoc]

How effective would simply reducing King's gravity to maybe 2.2 be in fixing some of the problems? First, maybe bringing it more in line with where it could be and more importantly allowing the typical traveller to visit there, the mining operations to be more conventional, and the colonists more human.

It would become a place where adventurers could conceivably adventure. It would also become a concept where you might actually bump into someone from King... part of the problem with the gravity economy as written is the terrible expense, horrible physics (not to mention the physiological horror) of people actually going to and from King. Once in, I don't see anyone actually leaving; it's almost literally a campaign black hole.

...But OTOH Y2300UMMV, and I actually like King conceptually the way it is, a place of horrors. My campaign has really never spent much time in the American Arm—sketchy worlds, no interesting aliens except through Back Door, kind of a deranged sort of society in my reading.

 

[spirochete]

How effective would simply reducing King's gravity to maybe 2.2 be in fixing some of the problems? First, maybe bringing it more in line with where it could be and more importantly allowing the typical traveller to visit there, the mining operations to be more conventional, and the colonists more human.

Making it 1.5 earth masses and 1.2 gee would put low orbit just within the capability of single-stage vehicles. A 2.3 gee world sounds okay, though I doubt you could find many willing colonists.

The "broken" King sounds sort of interesting as is. They're mining something and sending it aloft at great expense. It's probably tantalum, and I doubt raw ore is being launched, strictly refined product, and only a few times a year.

The locals take the afternoon off on Launch Day and turn out two watch the spectacular launch of the gargantuan vehicle that sends a month or two of production up into space with a Krakatoan roar. Launch Days would be the only opportunity for the characters to leave this hell-hole.

 

[Lemnoc]

interesting to imagine what the King High Port Creche might be like.

Maybe something like 2001’s Station V spinning at 1G for the comfort of most, with a couple of appendages hanging out like hammers at 2G, acclimatization gyms. Perhaps the thing would balance best in two halves, rotating in opposite directions, each with two “hammers” rotated at 90 degrees to each other. The whole thing might take advantage of beanpole tech just to keep from flying apart.

No woman would risk a viable fetus to the stresses of traveling there; and the throw economics off-planet would suggest in-vitro fertilization. So maybe genetic material goes up first, the woman following for implant if/when a zygote is judged viable. Fathers all trapped below, in hell, with commlinks as their only connection to their developing family.

Kind of a house of horrors, but interesting to think about from a sci-fi perspective. You could actually build an adventure around that, at least.

 

[spirochete]

No woman would risk a viable fetus to the stresses of traveling there; and the throw economics off-planet would suggest in-vitro fertilization. So maybe genetic material goes up first, the woman following for implant if/when a zygote is judged viable. Fathers all trapped below, in hell, with commlinks as their only connection to their developing family.

The Colonial Atlas mentions the orbital gestation facility. It's called the "Maternity Boat" or something like that. The moms could only be sent up on the infrequent Launch Days.

 

[Lemnoc]

The Colonial Atlas mentions the orbital gestation facility. It's called the "Maternity Boat" or something like that. The moms could only be sent up on the infrequent Launch Days.

Yes; but as I say, if you were carrying a fetus would you really want to make that trip? I guess it depends on the quality of the high grav DNAM, just how that improves one's ability to endure REALLY high G stresses, but it seems like an unhappy miscarriage waiting to happen. In-vitro may be better... certainly cheaper to send up genetic material first. Mother after.

 

[Wil Mireu]

What if people could remotely operate mining drones from orbit instead of having to go down to the surface? Teleoperation doesn't seem terribly impossible to me, especially if the drones have a bit of intelligence of their own to handle hazard avoidance.

 

[spirochete]

How effective would simply reducing King's gravity to maybe 2.2 be in fixing some of the problems? First, maybe bringing it more in line with where it could be and more importantly allowing the typical traveller to visit there, the mining operations to be more conventional, and the colonists more human.

I remember now that the Bayern's executive officer is a Kingian woman. Looking it up, I see her Strenth stat is 15 and Endurance 9.

The illustration depicts her as an ordinary human, not the heavy-set mask wearing DNAM type. Bayern was probably published before the Colonial Atlas mess. GDW probably imagined King as a moderately high-gravity world, and then came the CA write-up without editorial oversight.

 

[spirochete]

Yes; but as I say, if you were carrying a fetus would you really want to make that trip? I guess it depends on the quality of the high grav DNAM, just how that improves one's ability to endure REALLY high G stresses, but it seems like an unhappy miscarriage waiting to happen. In-vitro may be better... certainly cheaper to send up genetic material first. Mother after.

Yes, most likely in vitro. I still imagine they have a "maternity shot" up to the gestation facility on a special Launch Day, where moms are the only "cargo". It's distopian. It makes the planet even more hellish than it already is.