Mass

Mass is a property of physical objects that determines the strength of an object's gravitational force on other objects. The mass of an object also determines how it will respond when an external force is applied (such as a collision, or the gravitational pull of a nearby object).

Location
The Mass property of an object can be found near the top of the Overview tab in the property panel, just under the object's name. If the object has a Composition tab, the Mass will also be listed under the Cumulative Properties category in that tab. For a Galaxy Nebula object, the Mass is located near the top of the Nebula tab.

The Mass of an object is also displayed in its mini-info panel.

Units
Mass can be viewed and edited using the following units:


 * Milky Way Galaxy mass (milky way) = 1.5×1012 sun
 * Solar mass (sun) = 1.9891×1030 kg
 * Jupiter mass (jupiter) = 1.8986×1027 kg
 * Earth mass (earth) = 5.97219×1024 kg
 * Moon mass (moon) =  7.349×1022 kg
 * Earth ocean mass (ocean) = 1.4×1021 kg
 * Earth atmosphere mass (atmosphere) = 5.158×1018 kg
 * Kilogram (kg) is the SI base unit for mass
 * Gram (g) = 1×10-3 kg
 * Milligram (mg) = 1×10-6 kg

Gravity
The mass, M, of an object determines the gravitational force that the object exerts on other objects in the simulation, as well as the force that will be exerted on it. If two object have masses M1 and M2, the distance between the objects is d, and the gravitational constant of the simulationis G, then the gravitational force between the objects is


 * $$F = G\frac{M_1 M_2}{d^2}. $$

Collisions
The mass of an object will determine the outcome of a collision with another object, including the resulting velocities due to momentum conservation, the production of fragments, and the amount of heat produced by the collision.

Radius and Density
Objects in Universe Sandbox are simulated as spheres of uniform density, so the mass of an object, M, is related to its radius, R, and density, ρ, by
 * $$M = \frac{4}{3}\pi R^3 \rho.$$