Gravity
- Thread starter Peleliu
- Start date
Very few of the Traveller world generators include the gravity generating formula. The problem is the density of the material in the world can vary and thereby give different values for gravity
wiki.travellerrpg.com
Has a range of values for each planet size
Planetary Size - Traveller
Has a range of values for each planet size
CT Book 1 (1977) pg 33 has a formula for calculating the weight a character can carry based on planet size alone.
T5 Book 3 pg 251 has a gravity table also based on planet size alone.
I'm using that in an app I'm working on right now to calculate encumbrance reductions to characteristics.
T5 Book 3 pg 251 has a gravity table also based on planet size alone.
I'm using that in an app I'm working on right now to calculate encumbrance reductions to characteristics.
well, just because they can lift 2x as much does not necessarily mean they can carry 2x as much if those are big things. And inertia still rules
Pg 251? Tucked away in the animal creation section? What an odd organizational choice.
P.S.
I finally found some reference to gravity and density on a page 56 table in the world mapping section. A better place to put it is probably with the system creation rules similar to MegaTraveller's World Builder Handbook.
MT:WHB (page 60) has a formula for gravity...
G=M x (64/R2)
Where G is gravity (in Gs) M is mass (in Earth's) and R is UWP size (0.6 for R)
Not sure if CT Grand Census or Grand Survey (fro mwhere I've heard most info for MT:WHB is taken) also have it...
G=M x (64/R2)
Where G is gravity (in Gs) M is mass (in Earth's) and R is UWP size (0.6 for R)
Not sure if CT Grand Census or Grand Survey (fro mwhere I've heard most info for MT:WHB is taken) also have it...
With T5 you have to search the PDFs using keywords to find anything!
Timerover51
SOC-14 5K
It looks like the T5.10 table on page 251 is assuming that the density of the planet is the same as Earth, which is 5.51 grams/cubic centimeter. If you change the density compared to Earth, you change the surface gravity. Mercury is considerably smaller than Mars, but because of its higher density, its surface gravity is the same.
Given the same density, the surface gravity scales directly with the diameter.
given the same diameter, gravity scales directly with the density.
So G's at surface = D×S/44 where D is density in g/cc and S is size digit.
And while indeed, Mars gravity is comparable to Mercury, it's Mars that's the outlier for rocky, not Mercury, but ceres and vesta both are light rocky bodies, too.
https://starchild.gsfc.nasa.gov/docs/StarChild/teachers/densities.html .
https://spacemath.gsfc.nasa.gov/Pluto/PlutoA.pdf .
given the same diameter, gravity scales directly with the density.
So G's at surface = D×S/44 where D is density in g/cc and S is size digit.
And while indeed, Mars gravity is comparable to Mercury, it's Mars that's the outlier for rocky, not Mercury, but ceres and vesta both are light rocky bodies, too.
Planet or Dwarf Planet | Average Density (gm/cm3) | Type |
|---|---|---|
Mercury | 5.4 | Rocky Planet |
Venus | 5.2 | Rocky Planet |
Earth | 5.5 | Rocky Planet |
Mars | 3.9 | Rocky Planet |
Jupiter | 1.3 | Gas Giant |
Saturn | 0.7 | Gas Giant |
Uranus | 1.3 | Ice Giant |
Neptune | 1.6 | Ice Giant |
Ceres | 2.2 | Astroid Belt Dwarf Planet |
Pluto | 2.1 | KBO Dwarf Planet |
Haumea | 3.0 | KBO Dwarf Planet |
Makemake | 1.8 | KBO Dwarf Planet |
Eris | 2.5 | KBO Dwarf Planet |
Vesta | 3.5 | Asteroid Belt Asteroid |
https://starchild.gsfc.nasa.gov/docs/StarChild/teachers/densities.html .
https://spacemath.gsfc.nasa.gov/Pluto/PlutoA.pdf .
mike wightman
SOC-14 10K
Don't suppose you could add surface gravity and diameter to that table 
not with my current level of lazyDon't suppose you could add surface gravity and diameter to that table
Timerover51
SOC-14 5K
Here is the information for the planets in metric units.Don't suppose you could add surface gravity and diameter to that table
Planetary Fact Sheet
nssdc.gsfc.nasa.gov
For English units, which would give a Traveller-style diameter, see the following.
Planetary Fact Sheet - U.S. Units
nssdc.gsfc.nasa.gov
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