Rotation and Gravity

How to use this calculator:

Mass, Density, Radius Radius, Rotational Velocity, Rotational Period Acceleration of Gravity
  1. Enter two of these values: Mass, Density, and Radius of planet. Press the yellow "find missing value" button to get the third value.
  2. Satisfied? Follow one of the two methods below to get the rotational velocity and period of your planet. Otherwise, click any of the clear buttons to clear the data in one or all fields.
  3. I want to enter my own values for rotational velocity or period.
    • Enter the rotational velocity or period in their respective input areas.
    • Press the red "find missing value" button to get the third value.
    I want the computer to output the rotational velocity and period for me.
    • Click the "Generate" button to generate those values from the outsourced formula.
    • Pressing this button will calculate the rotaitonal velocity and period of your planet from the outsourced formula.
    • To change mass, density or radius, simply remove that value by clicking its respective "clear" button. Then, change the other values. Go to step 2.
  1. Enter two of these values: Radius of planet, Rotational Velocity and Rotational Period. Press the red "find missing value" button to get the third value.
  2. Satisfied? To get the other data for the planet, fill out one more value in the "Mass, Density, Radius" section. Press the yellow "find missing value" button to get the third value in that section.
    • If you aren't satsifed with any of the data values, click any of the clear buttons to clear the data in one or all fields.
    • To change radius, rotational velocity, or rotational period, simply remove that value by clicking its respective "clear" button. Then, change the other values. Go to step 1.
  3. To get the amount of gravity on your planet, make sure you fill out the mass, density and radius of the planet. From that data, the gravity of your planet will be generated.
  1. Enter two of these values: Mass, Density, and Radius of planet. Press the yellow "find missing value" button to get the third value.
    • This will generate the gravity of the planet at the planet's radius.
  2. To figure out the speed of gravity at different heights above the center of the planet, change the value of the radius while keeping the values of density and mass the same.
    • The "radius" is the distance from the center. Changing it would calculate the amount of gravity at different distances from the center of the planet.
    • Gravity of Earths at various heights
    • The gravity of a planet of M Earth masses at 1 earth radius is M times the gravity of Earth.

Important Details

Siderial v. Syndonic Periods
Mass, Density, Radius Rotational Velocity and Period Gravity
Mass (Earths) Density Radius

Clear Mass
kg/m3 Earths


Clear Density
Meters Earths


Clear Radius
Velocity (m/s) Rotational Period (hours)

Clear Velocity

Clear Rotation Period
m/s2 Earths


Clear Gravity

Equation

Randy Evangelista, Electrical Engineer, Backyard Astronomer Quora Page

Planet Mass
(Earths)
Density
(kg/m^3)
Rotational Velocity % Error
Actual Formula
Earth 1 5514 465 466 0.215
Mars 0.107 3983 241 241 0.000
Jupiter 317.957064 1326 12600 12596 0.032
Saturn 95.16 687 9870 9868 0.020
Uranus 14.54 1270 2590 2589 0.039
Neptune 17.15 1638 2680 2525 5.784
For Jovian Planets (Mass >10 Earths), this formula is used: For Terrestrial Planets (Mass <= 10 Earths), this formula is used:
Densities of Solids - Engineering Toolbox Star Wars Planets Star Wars Planets