The Radius of an object is the distance from its center to its surface. Most objects in Universe Sandbox are represented as spheres, so the Radius property serves as a simple representation of an object's size.

## Property Details

### Location

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

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

### Units

Radius can be viewed and edited using the following units:

• Milky Way Galaxy radius (milky way) = 5.5×104 light year
• Parsec (parsec) = 3.08568025×1016 m
• Light-year (light year) = 9.46073047×1015 m
• Astronomical Unit (AU) = 1.495978707×1011 m
• Solar radius (sun) = 6.955×108 m
• Lunar distance (lunar dist) = 3.844×108 m
• Light-second (light sec) = 2.99792458×108 m
• Jupiter radius (jupiter) = 6.9911×107 m
• Earth radius (earth) = 6.37101×106 m
• Moon radius (moon) = 1.7371×106 m
• Kilometer (km) = 1000 m
• Meter (m) is the SI base unit for length
• Centimeter (cm) = 0.01 m
• Millimeter (mm) = 0.001 m

## Simulation Effects

### Collisions

The radius of an object is used to determine when two objects are colliding.

### Mass and Density

Objects in Universe Sandbox are simulated as spheres of uniform density, so the radius of an object, R, is related to its mass, M, and density, ρ, by 