The Energy Radiation Rate represents the total rate at which an object radiates heat energy out into space.. This property is used to calculate the change in the object's temperature over time.

The Energy Radiation Rate is a read-only property that is continually calculated by Universe Sandbox using the Stefan-Boltzmann law:

$P_{rad} = \sigma T^4,$

where σ is the Stefan-Boltzmann constant and T is the object's Average Surface Temperature.

## Property Details

### Location

For Planetary Body objects, the Energy Radiation Rate property can be found in the Energy Flow section of the Surface tab. For Stars, Black Holes, and Human-Scale Objects, the Energy Radiation Rate property can be found in the Temperature tab.

### Units

Energy Radiation Rate can be viewed using the following units:

• Solar luminosity (L star) = 3.846×1026 W
• Watts (W) is the SI unit for luminosity.

## Simulation Effects

### Surface Temperature

At each simulation time step, the change in the temperature of each point on the object's surface, ΔT, is calculated using the Energy Absorption Rate, Pabs, the Energy Radiation Rate, Prad, the time step, Δt, and the object's Surface Heat Capacity, C, using

$\Delta T = (P_{abs} - P_{rad})\Delta T / C.$