recursal/Fanatic-Fandom huggingface dataset:
Tidal Power

The Tidal Power property of an object represents the rate that energy from tidal heating is added to the object over time. Tidal Power is a **read-only** property that is continually calculated by Universe Sandbox.

## Property Details

### Location

For Planetary Body object, the Tidal Power property is located in the Energy Flow section of the object's Surface tab, when the Energy Absorption Rate property is expanded. For Stars, Black Holes, Fragments, and Human-Scale Objects, the Tidal Power property is located in the Temperature tab.

### Units

Tidal Power 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

### Temperature

Tidal Power is one of several sources of energy that can increase an object's Average Temperature or Surface Temperature.
Add Tool

The Add Tool allows the user to add a new object to the simulation.

## Tool Details

### Location

The Add button is located in the Tools menu. When clicked, the Add Tool menu will appear, displaying a list of objects that can be added to the simulation, sorted by object type, as well as four settings: Still, Orbit, Binary, and Launch.

Certain objects can also be added to the simulation with the Launch setting using the numbers 1-8 on the keyboard.

### Settings

The Add settings determine the initial velocity that the new object will be given when it is added to the simulation.

* Still
	+ The object will be added with zero initial velocity relative to the Simulation Grid.
* Orbit
	+ The object will be added on a circular orbit around the object's strongest attractor in the simulation.
	+ When an object has been selected from the menu but not yet added to the simulation, the orbit will be displayed.
	+ If there are no other objects in the simulation, the new object will be added with zero velocity, as in Still.
* Binary
	+ The object will be added on a circular orbit around the object's strongest attractor in the simulation.
	+ If Balance Motion is on, the other object's velocity will be changed such that the barycenter of the two objects will remain stationary as they orbit.
	+ If there are no other bodies in the simulation, the new body will be added with zero velocity, as in Still.
* Launch
	+ The object will be launched from the location of the camera in the direction that the camera is facing.
	+ If Auto Launch Velocity is on, the launched object will be given a velocity that will put it in orbit around the object's strongest attractor in the simulation.
	+ If Auto Launch Velocity is off, the user can use the Launch Velocity setting to assign a specific initial velocity.
	+ If there are no other objects in the simulation, the new object will be launched with a velocity of 10 km/s.
Radiative Power

The Radiative Power property of an object represents the rate that energy is absorbed by the object over time from sources of light and heat in the simulation, such as nearby stars. Radiative Power is a **read-only** property that is continually calculated by Universe Sandbox.

## Property Details

### Location

For Planetary Body objects, the Radiative Power property is located in the Radiation section of the object's Surface tab. For Stars, Black Holes, and Human-Scale Objects, the Radiative Power property is located in the Temperature tab.

### Units

Radiative Power 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

### Temperature

If the object absorbs more power from external sources than it emits back into space, the Effective Temperature of the object will increase.
Energy Absorption Rate

The Energy Absorption Rate represents the total rate at which energy is added to an object from sources in the simulation, such as stars or tidal friction. This property is used to calculate the change in the object's Average Temperature or Surface Temperature over time.

The Energy Absorption Rate is a **read-only** property that is continually calculated by Universe Sandbox as the sum of the incoming energy rates, or powers, from all sources in the simulation, including Stellar Power, Atmosphere Power, Tidal Power, Supernova Power, and Gas Drag Power.

## Property Details

### Location

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

### Units

Energy Absorption 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, Δ*T*, is calculated using the Energy Absorption Rate, *Pabs*, the Energy Radiation Rate, *Prad*, the time step, Δ*t*, and the object's Surface Heat Capacity, *C*, using

Δ
# T
(

P

a
b
s

−

P

r
a
d

)
Δ
T

/

C
.

{\displaystyle \Delta T = (P\_{abs} - P\_{rad})\Delta T / C. }
Tidal Stress Direction

The Tidal Stress Direction represents the direction of the tidal force vector representing all the tidal forces acting on the object. This force is a 3D vector, and the Tidal Stress Magnitude property represents the magnitude of the vector. Tidal Stress Direction is a **read-only** property that is automatically calculated by Universe Sandbox.

## Property Details

### Location

The Tidal Stress Direction property is located in the Tidal Effects section in the Motion tab of the object's properties panel.

### Units

Tidal Stress Direction is a unitless 3D vector with a magnitude of 1.
Getting Started

This page is a guide for getting started in Universe Sandbox.

## Tutorials

To get familiar with the basics of Universe Sandbox, try browsing the tutorials in Home > Guides > Tutorials.

These will show you the basics of the interface, introduce you to various tools and settings, and give you some ideas for starting your journey of astronomical creation and destruction.

## Exploring the Included Simulations

Universe Sandbox includes hundreds of built-in simulations to explore.

Go to Home > Open to browse a list of included simulations. You can filter the list by selecting a category, such as Collisions, Explosions, Historical, Exoplanets, and Galaxies.

## Creating a Star System

Custom simulations can be very simple or very complex, and can vary widely, but a good place to start by with creating your own star system.

Here's a simple list of steps to get you started:

1. Select Home > New to load an empty simulation
2. Open the Add tool from the Tools menu in the bottom bar, and select a star
3. Click in the simulation to add your star
4. Select a planet from the Add tool menu
5. Add your planet to the simulation

Your planet will automatically begin orbiting your star. Next, try adding moons, rings, and asteroids.

Learn more in the Add Tool tutorial: Home > Tutorials > Add Tool

## Viewing & Changing Properties

Universe Sandbox allows viewing and editing dozens of properties for every object in a simulation. To view properties for any object, right-click on it, or click on it once and then click on its mini-info panel on the right side.

Try changing a property and seeing how it affects your simulation. For example, in the default Solar System simulation, increase the mass of the Sun and see how it increases its gravitational influence and pulls in the planets.

## What if... Experiments

If you've explored the included simulations and created some custom systems and now don't know what to do, try to think of a "What if..." experiment. This is a great way to come up with an idea for a new simulation you can create, or an idea for how you can change an existing simulation to see unexpected and interesting results.

First, think of a question, like "What if the Sun disappeared?"
Show Magnetosphere

The Show Magnetosphere property determines whether the object's magnetosphere will be displayed. The magnetosphere is the region of space in which particles will be affected by an object's magnetic field. The size of the magnetosphere is represented by the Magnetosphere Size property.

## Property Details

### Location

The Show Magnetosphere property is located in the Magnetic Fields section at the end of the Composition tab in the object's properties panel. This property is only visible for Planetary Body objects.
Camera Azimuth

The **Camera Azimuth** of an object represents the rotation of the camera around the object in space. When Camera Azimuth is zero, the camera's position shares the same x-coordinate as the object's position. This is a **read-only** property that is automatically calculated by Universe Sandbox.

## Property Details

### Location

The Camera Azimuth property is located in the Camera Relative section of the Motion tab of the object's properties panel.

### Units

Camera Azimuth is an angle, and can be viewed using the following units:

* Radians (rad)
* Degrees (°) = (180/π) rad

Camera Azimuth is defined in the range 0-360°, or 0-2π rad.
Tidally Lock

The Tidally Lock action will set an object's Rotational Period equal to its Orbital Period. As a result, one side of the object will always face towards its Orbital Parent, while the opposite side will always face away.

## Property Details

### Location

The Tidally Lock button can be found at the end of the Rotation section of the Motion tab in an object's properties panel.
Galaxy Mass

The Mass property of a Galaxy object represents the total mass of all the objects that make up the galaxy, including the Black Hole and any Galaxy Nebulae. The gravitational force exerted on other objects in the simulation by the galaxy's Black Hole will depend on this total mass.

## Property Details

### Location

The Mass property of a galaxy can be found at the top of the Galaxy tab in the properties panel, just under the galaxy's name.

The Mass of a galaxy 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
Stats Menu

The Stats Menu displays statistics about the currently opened simulation. It can be opened by clicking on Objects or Simulated in the Sim menu on the bottom bar.

The Stats Menu displays the following information:

* Object Count
	+ The total number of objects in the simulation
* Simulated
	+ The number of objects being actively simulated
* Non-Simulated
	+ The number of suspended objects not being actively simulated
* Attracting
	+ The number of attracting objects exerting a gravitational force
* Non-Attracting
	+ The number of objects not exerting a gravitational force
* Decals
	+ The number of impact decals used in the simulation
* Star Count
	+ The number of Star objects in the simulation
* Mass
	+ The total mass of all objects in the simulation
* Velocity
	+ The magnitude of the sum of the Velocity Vectors of all objects in the simulation
* Momentum
	+ The magnitude of the sum of the Momentum Vectors of all objects in the simulation
* Mass Lost
	+ The total amount of mass lost to the simulator during the simulation
* Momentum Lost
	+ The total amount of momentum lost to the simulator during the simulation
Auto Orbit

The Auto Orbit action will change the selected object's Velocity Vector to place the object in a circular orbit around its Orbital Parent or, if no Orbital Parent is assigned, around its Strongest Attractor.

## Property Details

### Location

The Auto Orbit button can be found at the bottom of the Overview tab of an object's properties panel, in the Actions section of the Motion tab, or in the Actions tab.
Density

The Density of an object is its mass per unit volume. All objects in Universe Sandbox are assumed to have uniform density.

## Property Details

### Location

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

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

### Units

Density can be viewed and edited using the following units:

* Grams per cubic centimeter (g/cm3) = 1000 kg/m3
* Kilograms per cubic meter (kg/m3) is the SI base unit for density
* Hydrogen molecules per cubic centimeters (H2/cm3) = 1.67×10-24 kg/m3

## Simulation Effect

### Mass and Radius

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

# M

4
3

π

R
3

ρ
.

{\displaystyle M = \frac{4}{3}\pi R^3 \rho.}
Photo Tool

The Photo Tool takes one or more screenshots of the simulation and saves it to the user's device.

## Tool Details

### Location

The Photo button is located in the Tools menu in the bottom bar. When clicked, a menu with several buttons will appear.

### Settings

The Photo Tool has a number of actions that appear as buttons in its settings menu.

* Show Last Screenshot in Folder
	+ Opens the folder on the user's device where screenshots are stored, with the last screenshot selected
* Open Last Screenshot
	+ Opens the last screenshot in an image viewer
* Open Screenshot Folder
	+ Opens the folder on the user's device where screenshots are stored
* Screenshot Settings
	+ Opens the Photo tab in the main Settings menu
* Take Screenshot Set
	+ Takes a series of screenshots as the simulation runs
	+ This action can also be performed by pressing F8 on the keyboard
* Take Screenshot
	+ Takes a single screenshot
	+ This action can also be performed by pressing F12 on the keyboard
Magnetic Field

The Magnetic Field property represents the strength of the object's magnetic field.

## Property Details

### Location

The Magnetic Field property is located in the Magnetic Fields section at the bottom of the Composition tab in the object's properties panel.

### Units

Magnetic Field can be viewed and edited using the following units:

* Tesla is the SI unit for magnetic field strength.
* Gauss = 10-4 Tesla
Optimize Simulation Speed for Water

The Optimize Simulation Speed for Water action will set the current Target Simulation Speed to the Water Stable Simulation Speed, increasing the stability and accuracy of the object's vapor flow and liquid flow simulations.

## Property Details

### Location

The Optimize Simulation Speed for Water button can be found in the Advanced Simulation section at the bottom of the Surface tab in the object's properties panel.
Fireworks Tool

The Fireworks Tool launches multicolored fireworks from a selected object.

## Tool Details

### Location

The Fireworks button is located in the Tools menu in the bottom bar. When clicked, a menu will appear displaying several settings.

### Settings

There are a few settings that determine the appearance of the fireworks.

* Fragments
	+ The number of particles that make up each firework
* Auto Velocity
	+ When this setting is on, the launch Speed will be 10 km/s.
	+ When this setting is off, the user can set the Speed.
* Speed
	+ The speed at which the fireworks are launched from the object.
Supernova Drag Heating

One of the effects that Universe Sandbox uses to calculate the temperature of an object is supernova drag heating, which is produced by the friction between the object and any supernova clouds passing by the object.

## Related Properties & Settings

### Properties

* The rate at which energy is added to the object from passing supernova clouds is shown in the Gas Drag Power property.
* The amount of heating depends on the Maximum Cloud Radius and Cloud Mass properties of the expanding supernova.
* The amount of heating also depends on the object's Radius.
* Supernova drag heating will affect an object's Average Temperature or Surface Temperature.

## Models

At every time step of a simulation where a supernova has occurred, Universe Sandbox checks whether any of the supernova clouds have reached the object. If so, the amount of energy produced by friction is calculated based on the object's size, the supernova cloud's density, and the relative velocity between the object and the cloud. The rate at which energy is added to the object via friction with passing clouds is represented by the Gas Drag Power property. The Gas Drag Power is included in the Energy Absorption Rate, which is used to calculate the change in temperature for the object.
Spiral Galaxy

A Spiral Galaxy is a type of Galaxy object representing a specific spiral-type galaxy, or a new spiral galaxy created by the user. Spiral galaxies are characterized by a central bulge of older, redder stars and an extended flat disk of younger, brighter stars. The disk often exhibits a spiral structure with stars and gas concentrated in a number of bright arms curving around the galaxy. Opaque dust orbits in the regions between the spiral arms, and is responsible for the dark "dust lanes" seen when viewing spiral galaxies like the Milky Way edge-on.

## Related Properties and Settings

### Properties

* The Galaxy Type is located in the Galaxy tab of the Galaxy's properties panel. When the type is set to one of the spiral types, the following properties will appear:
* The Spiral Arms property determines the number of spiral arms.
* The Pitch Angle property affects how tightly the arms are wound, and depends on the specific spiral type.
* The Spiral Arm Noise property affects how cleanly the arms appear.
* The appearance of an individual Galaxy Nebula object is controlled by the Gas Fraction, Star Fraction, Dust Fraction, and Average Star Temperature properties in the Nebula tab of the nebula's properties panel.

## Models

The structure of a spiral galaxy is very complex compared to irregular or elliptical galaxies, and therefore requires the most complicated model. The bulge of the galaxy is simulated as an E0 elliptical galaxy, which circular but randomly oriented orbits and a low Average Star Temperature.

The orbital elements of nebulae in the disk of the galaxy are carefully calculated to orient the orbits to create the spiral arm structure according to density wave theory. The Gas Fraction, Star Fraction, and Dust Fraction of an individual Galaxy Nebula object within the galaxy varies as the nebula orbits around the galaxy, enhancing the appearance of the spiral arms as well as the dust lane when the galaxy is viewed edge-on. The Average Star Temperature of nebulae in the disk of a spiral galaxy is higher than the nebulae in the bulge, representing the recent star formation in the spiral arms that tends to create younger, hotter stars.

Spiral galaxies are simulated with the following subtypes:

* S0: Also known as a lenticular galaxy, this type of galaxy has a central bulge and an extended disk, but does not have spiral arms. The Spiral Arms property of an S0 galaxy will automatically be set to 0. This galaxy type is simulated with a bulge that extends 30% of the way from the center to the outer radius of the galaxy.
* Sa: Has a Pitch Angle between 10-15 degrees and a bulge that extends 25% of the way from the center to the outer radius of the galaxy.
* Sb: Has a Pitch Angle between 15-25 degrees and a bulge that extends 20% of the way from the center to the outer radius of the galaxy.
* Sc: Has a Pitch Angle between 25-30 degrees and a bulge that extends 15% of the way from the center to the outer radius of the galaxy.
Kinetic Energy

Kinetic energy is the energy possessed by an object that is moving. The kinetic energy can be calculated from the object's mass, *M* and the magnitude of its velocity, *V*, also known as its speed, using the following equation:

# E

1
2

M

V
2

.

{\displaystyle E = \frac{1}{2}M V^2.}

Since energy can be neither created nor destroyed, the velocities of objects involved in processes like collisions can be calculated based on the exchange of kinetic energy between objects, or the transition between kinetic energy and other types of energy.
Life Simulation

Currently, Universe Sandbox does not simulate the evolution of life. However, it does calculate some properties related to how suitable an object's surface would be for life.

## Related Properties & Settings

### Properties

* The Earth Similarity and Life Likelihood properties of an object are listed in the Comparisons section of the Composition tab of the object's properties panel.

### Settings

* The Habitable Zone for a star can be displayed using the Habitable button in the View menu in the bottom bar, or by using the Habitable Zones setting in the full View Settings Menu.
Pitch Angle

The Pitch Angle property of a spiral galaxy is a measure of how tightly the galaxy's spiral arms are wound. In Universe Sandbox, the structure of a spiral galaxy is a logarithmic spiral, such that a in a galaxy with Radius *R* and pitch angle *P*, at a point where the spiral arm is some distance *D* from the central Black Hole of the galaxy, the arm will have turned around the Black Hole by an angle of *θ*, where *θ* is given by

# θ

log
⁡

(
D

/

R
)

tan

−
1

⁡

P

.

{\displaystyle \theta = \frac{\log{(D/R)}}{\tan^{-1}{P}}.}

Spiral arms in galaxies with larger pitch angles will be more loosely wound than spiral arms in galaxies with smaller pitch angles.

## Property Details

### Location

The Pitch Angle property is located in the Spiral Section of the Galaxy tab of the galaxy's properties panel. This section is only visible for spiral galaxies.

### Units

Pitch Angle can be viewed or edited using the following units:

* Radians (rad)
* Degrees (°) = (180/π) rad
Avarice Chapitre 2 (Boss)

## Grottes

### Toutes les vagues de Boss

Monstro
Dodu
Fistule
Dégoulis
### Vague 1 spécifiquement

Le Duc des Mouches
Gémeaux
Dégoulis

Paresse
Luxure
Colère
Envie
Orgueil
### Vague 2 spécifiquement

La Carcasse
La Flaque
Boris Jr.

Colère
Gourmandise
### Vague Cauchemar spécifiquement

Larry Junior
Le Duc des Mouches
La Carcasse
La Flaque
Boris Jr.
Pendouille
Grande Gueule

Paresse
Colère

Bumbino
## Catacombes

### Toutes les vagues de Boss

L'Évidé
Dodu
Pin
Fistule

Colère
### Vague 1 spécifiquement

Le Duc des Mouches
La Veuve
Rondouillard
Polycéphale
Dégoulis

Paresse
Luxure
Avarice
Envie
### Vague 2 spécifiquement

La Carcasse
La Flaque
L'Œuf Clair
Boris Jr.
Le Misérable
Grande Gueule

Gourmandise
### Vague Cauchemar spécifiquement

Monstro
La Flaque
L'Œuf Clair
Gémeaux
Boris Jr.
La Veuve
Le Misérable
Pendouille
Grande Gueule
Polycéphale
Bumbino

Paresse
## Grottes Inondées

### Toutes les vagues de Boss

Pin
Fistule
Dégoulis
P'tite Corne
Toutânhaillons
Phararond

Colère
### Vague 1 spécifiquement

Larry Junior
Monstro
Dodu
Le Duc des Mouches
Gémeaux
La Veuve
Rondouillard
Polycéphale
Dégoulis

Paresse
Luxure
Avarice
Envie
Orgueil
### Vague 2 spécifiquement

L'Évidé
Monstro
Dodu
La Carcasse
La Flaque
L'Œuf Clair
Boris Jr.
Le Misérable
Grande Gueule
La Souillure

Gourmandise
### Vague Cauchemar spécifiquement

Larry Junior
Monstro
Le Duc des Mouches
La Carcasse
La Flaque
L'Œuf Clair
Gémeaux
Boris Jr.
La Veuve
Le Misérable
Pendouille
Grande Gueule
Polycéphale
La Souillure
Bumbino

Paresse
Magnetic Fields

Some large objects, like certain stars or planets, generate a magnetic field that can influence particles in the space around the object, including incoming stellar wind. Universe Sandbox can simulate these magnetic fields by displaying the field's magnetic axis or the object's magnetosphere, the region around the object where particles will be affected by its magnetic field.

## Related Properties & Settings

### Properties

* Properties related to magnetic fields are located in the Magnetic Fields section of the Composition tab of an object's properties panel.

## Models

Any Star, Planetary Body, or Human-Scale Object can have a simulated magnetic field, although only certain stars and planets will have non-zero magnetic field strengths based on the Universe Sandbox database, which also includes Magnetic Pole Angle values for some Solar System planets.

The magnetosphere of a Planetary Body object can also be displayed on-screen. The size of the magnetosphere is calculated from the magnetic field strength and the stellar wind pressure from any stars in the simulation.

A Neutron Star or White Dwarf with a non-zero magnetic field will become a Pulsar, emitting two beams of light along its magnetic field axis. The size of these beams depends on the magnetic field strength.
Selected Cell Liquid Water Mass

The Liquid Water Mass property indicates the mass of the liquid water in the selected cell.

## Property Details

### Location

The Liquid Water Mass property is located in the Selected Grid Cell section of the Surface tab in the object's properties panel.

### Units

Liquid Water 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
Argument of Obliquity

The Argument of Obliquity property of an object represents the orientation of the object's rotation axis around a reference axis determined by the Rotation Relative to property. If Rotation Relative to is set to the Simulation Grid, this reference axis is the y-axis of the Simulation Grid. If Rotation Relative to is set to the Orbital Plane, the reference axis is the object's orbital axis, defined by its Inclination and Longitude of the Ascending Node.

When the Argument of Obliquity is zero and the Obliquity is 90°, the object's rotation axis will lie in the reference plane, pointed in the direction of the positive x-axis of the Simulation Grid (if Rotation Relative to is set to the Simulation Grid) or the direction of the orbit's apocenter (if Rotation Relative to is set to the Orbital Plane). Non-zero Argument of Obliquity values represents how far the rotation axis is rotated from this direction.

When the Obliquity of an object is zero, its Argument of Obliquity is undefined and this property will be **read-only**.

## Property Details

### Location

The Argument of Obliquity property is located in the Rotation section of the Motion tab of an object's properties panel.

### Units

Argument of Obliquity is an angle, and can be viewed or edited using the following units:

* Radians (rad)
* Degrees (°) = (180/π) rad

Argument of Obliquity is defined in the range -180° to 180°, or -π to π rad.
Keyboard Controls

A keyboard can be used to control the camera, display settings, Simulation Speed, and to add or delete objects in the simulation. These keyboard controls can be changed in the Input tab of the global Settings in the Home menu.

## Camera Controls

* A moves the camera left
* C lands the camera on the selected object
* D moves the camera right
* E rotates the camera clockwise
* F moves the camera down
* Q rotates the camera counterclockwise
* R moves the camera up
* S moves the camera backwards
* W moves the camera forward
* up/down arrow keys zoom in and out on the camera-locked object
* left/right arrow keys rotate the camera around the camera-locked object or the camera itself

## Display Controls

* G toggles the displayed Simulation Grid on and off
* H toggles the displayed Habitable Zone on and off
* I toggles displayed icons on and off
* L toggles the displayed labels on and off
* O toggles displayed orbits on and off
* T toggles displayed trails on and off

## Simulation Speed Controls

* , decreases the Simulation Speed
* . increases the Simulation Speed
* Spacebar pauses the simulation

## Object Controls

* 1–8 launch the objects labeled with these hotkeys
* Backspace/delete removes the selected object from the simulation

## Other Controls

* F2 will toggle translation mode on and off if the Help Translate toggle is on
* F8 will take a set of screenshots
* F10 will take a single screenshot
* F12 will record up to 30 seconds of screenshot video as an animated gif
Surface vs Sea Level

The Surface vs Sea Level setting determines which temperature map will be used to calculate the Avg Temperature, Min Temperature, and Max Temperature properties in the object's properties panel: the Surface Temperature or the Sea Level Temperature.

## Property Details

### Location

The Surface vs Sea Level setting for a Planetary Body can be found in the Temperature section at the top of the Surface tab.
Mass Loss Total

The Mass Loss Total property of an object represents the total mass that the object has lost due to evaporation or stellar winds since the start of the simulation, or since the last time the Reset Mass Loss Total action was applied. Mass Loss Total is a **read-only** property that is automatically calculated by Universe Sandbox.

## Property Details

### Location

The Mass Loss Total property of an object is located near the end of the Cumulative Properties section of the object's Composition tab.

### Units

Mass Loss Total can be viewed 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
Selected Cell Elevation

The Elevation property indicates the height of the selected cell.

## Property Details

### Location

The Elevation property is located in the Selected Grid Cell section of the Surface tab in the object's properties panel.

### Units

Elevation 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
Energy Radiation Rate

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 Average Temperature or Surface 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

r
a
d

=
σ

T
4

,

{\displaystyle P\_{rad} = \sigma T^4, }

where σ is the Stefan-Boltzmann constant and *T* is the object's Average Temperature or 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, Fragments, 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, Δ*T*, is calculated using the Energy Absorption Rate, *Pabs*, the Energy Radiation Rate, *Prad*, the time step, Δ*t*, and the object's Surface Heat Capacity, *C*, using

Δ
# T
(

P

a
b
s

−

P

r
a
d

)
Δ
T

/

C
.

{\displaystyle \Delta T = (P\_{abs} - P\_{rad})\Delta T / C. }
Star Fraction

The Star Fraction property of a Galaxy Nebula object represents the fraction of the object's mass that is present in stars, relative to the amount of mass in gas or dust. The Star Fraction affects the object's appearance, as stars will appear as points of light in the nebula. The Star Fraction, Gas Fraction, and Dust Fraction values will always sum to 100%.

The Star Fraction is automatically calculated by Universe Sandbox based on the Galaxy Type and the nebula's position within the Galaxy. However, the user can change the Star Fraction, which will automatically turn off the Enable Nebula Evolution toggle for the individual nebula.

## Property Details

### Location

The Star Fraction property is located in the Content section in the Nebula tab of the nebula's properties panel.

### Units

Star Fraction is a unitless property between 0 and 1, but it can be viewed and edited as either a fraction or a percentage.
Semi-Major Axis

The Semi-Major Axis of an object's elliptical orbit is the distance from the center of the ellipse to the most distant point in the orbit. In other words, the Semi-Major Axis is half the distance between the pericenter and apocenter of the orbit. Semi-Major Axis is a way to represent the size of an orbit; objects with a smaller Semi-Major Axis will orbit closer to their Orbital Parent than objects with a larger Semi-Major Axis.

The Semi-Major Axis of an object with a hyperbolic trajectory is negative.

Semi-Major Axis is one of the six orbital elements that described an object's orbit.

## Property Details

### Location

The Semi-Major Axis property is located in the Orbital Elements section of the Motion tab of an object's properties panel, if that object has an Orbital Parent.

### Units

Semi-Major Axis 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
City Lights Appearance

The City Lights Appearance control contains settings for the on-screen appearance of an object's city lights.

The checkbox on the left of the control determines whether the city lights of the object are displayed. The color setting on the right of the control sets the color of the city lights.

## Property Details

### Location

The City Lights Appearance control is located in the Layers section of the Visuals tab of an object's properties panel.

### Settings

The displayed city lights have three settings that control their appearance, listed below the City Lights control in the Visuals Tab.

#### Illuminate

The Illuminate setting determines the condition under which the city lights are displayed. If Always is selected, then the city lights will always be visible on the night side of the object. If the other option, If Habitable, is selected, then city lights will only appear on the night side if liquid water exists on the object's surface.

#### Light Map

The Light Map setting determines the distribution of the city lights. If Earth is selected, the Earth's city lights map is displayed on the objects surface. If Procedural is selected, a randomly generated city lights map is used instead, and the Random Seed setting becomes visible.

#### Random Seed

The Random Seed setting is an integer representing the randomly generated city lights map used when Light Map is set to Procedural. The dice icon to the right of the text box can be clicked to generate a new Random Seed.
Tidal Force

The force of gravity depends on the distance to the object that is exerting the gravitational force. On a large object orbiting closely to its orbital parent, the force of gravity on the side of the object closer to its parent will be significantly larger than the force on gravity on the more distant side. This difference in forces will tend to deform the object, causing it to bulge and stretch. This stress is called the tidal force, as the tidal force from the Moon is responsible for the ocean tides on Earth. In extreme cases, this deformation can cause an object to break apart, a process known as Roche fragmentation. If the tidal force in an object changes over time, the changing deformation in the object will cause internal friction and produce tidal heating.

## Related Properties & Settings

### Settings

* Roche fragmentation can be toggled on and off in the Create Fragments in the full Sim Settings Menu.
* Tidal heating can be toggled on and off in the Thermodynamics section of the Sim Settings Menu.

## Models

Universe Sandbox calculates the tidal force acting on an object with a mass of *M* and radius *R* due to another object with mass *M*i at a distance of *d* in a simulation with a gravitational constant of *G* using

F

i

=

2
M

M

i

G

d

3

2
R
.

{\displaystyle F\_{i}={\frac {2MM\_{i}G}{d^{3}}}2R.}

The total tidal force is calculated by adding the forces from all the other objects in the simulation.

1. ↑ Venn, K., (2013) Tidal Heating. *Astr201 Maths Notes*.
Galaxy Tab

The Galaxy tab in an object's properties panel displays the properties of a Galaxy object, including galaxy-specific properties. Motion-related properties, such as Distance, Speed, etc., are based on the properties of the galaxy's Black Hole.

* Properties
	+ Name
	+ Radius
	+ Mass
	+ Age
	+ Distance
		- Position Vector
	+ Speed
		- Velocity Vector
	+ Relative to
	+ Distance to You
	+ Galaxy Type
	+ Star Count
	+ Simulated Nebula
	+ Enable Nebula Evolution
* Spiral
	+ Spiral Arms
	+ Pitch Angle
	+ Spiral Arm Noise
* Elliptical
	+ Elliptical Ratio
* Colors
	+ Color Mode
		- Color
* Actions
	+ Black Hole
		- Select
		- Remove
	+ Delete Galaxy
Star Count

The Star Count property of a Galaxy Nebula indicates how many individual stars the nebula represents. The Star Count property of a Galaxy object indicates how many individual stars the entire galaxy represents.

Star Count is calculated from the nebula's mass, and assumes that the stars within the nebula have a mass distribution represented by a single power law with index 2.35, and that 10% of the total mass of the nebula is represented in stars.

## Property Details

### Location

The Star Count property for an individual Galaxy Nebula object is located in the Content section of the Nebula tab in the nebula's properties panel. The Star Count property for a Galaxy object is located at the bottom of the Properties section of the Galaxy tab of the galaxy's properties panel.

### Units

Star Count is a unitless value, but it can be viewed and edited using the following orders of magnitude:

* quadrillion = 1015
* trillion = 1012
* billion = 109
* million = 106
* thousand = 103
* value is the full number representing the property
Radius

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

# M

4
3

π

R
3

ρ
.

{\displaystyle M = \frac{4}{3}\pi R^3 \rho.}
Argument of Pericenter

The Argument of Pericenter of an object's orbit is the angle between the orbit's ascending node (the point where the object crosses from below the reference plane to above the reference plane) and the orbit's pericenter (the point where the object is at its closest distance to its Orbital Parent). In Universe Sandbox, the reference plane is the x-z plane of the Simulation Grid.

For an object on circular orbit (with an Eccentricity of zero), the Argument of Pericenter is undefined and the property will be **read-only**. The Argument of Pericenter is also known as the argument of periapsis.

Argument of Pericenter is one of six orbital elements that describe an object's orbit.

## Property Details

### Location

The Argument of Pericenter property is located in the Orbital Elements section of the Motion tab of an object's properties panel, if that object has an Orbital Parent.

### Units

Argument of Pericenter is an angle, and can be viewed or edited using the following units:

* Radians (rad)
* Degrees (°) = (180/π) rad

Argument of Pericenter is defined in the range 0-360°, or 0-2π rad.
Attracting

Attracting objects exert a gravitational force on attracted objects in the simulation, affecting the motion of the attracted objects. Most object types in Universe Sandbox are attracting, but some are not for performance reasons.

Attracted object types include:

* Stars
* Planetary Bodies
* Human-Scale Objects
* Black Holes

Non-attracted object types include:

* Fragments
* Volatiles
* Galaxy Nebulae
* Supernova Clouds
Elevation Span

The Elevation Span of an object represents the difference between the highest and lower elevation. This property is automatically calculated by Universe Sandbox.

## Property Details

### Location

The Elevation Span property of a Planetary Body can be found in the Elevation section of the Surface tab.

### Units

Elevation Span can be viewed 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
Show Magnetic Axis

The Show Magnetic Axis property determines whether the axis of the object's magnetic field is displayed. The angle of the magnetic field axis relative to the object's rotation axis is set by the Magnetic Pole Angle property.

## Property Details

### Location

The Show Magnetic Axis toggle is located in the Magnetic Fields section at the bottom of the Composition tab in the object's properties panel.
Minimum Temperature

The Minimum Temperature of a Planetary Body object represents the lowest surface temperature present on the object's Temperature map.

While the user can change the Minimum Temperature in the properties panel, it is continually recalculated as time passes in the simulation.

## Property Details

### Location

The Minimum Temperature property of an object can be found near the top of the Surface tab.

### Units

Minimum Temperature can be viewed and edited using the following units:

* Kelvin (K) is the SI base unit for temperature
* Degrees Fahrenheit (°F)
* Degrees Celsius (°C)

Conversions between these three units are as follows:

°C = K - 273

°F = (9/5)°C + 32
Volatile

A Volatile in Universe Sandbox is a simulated object representing a cloud of gas and vapor emitted by evaporation. Volatiles are produced by heating a Planetary Body. In astronomy and planetary science, the term volatile refers to elements, molecules, or compounds with low boiling points, which tend to vaporize easily. These include hydrogen, water, carbon dioxide, and methane.

## Characteristics

Volatile objects have the following characteristics:

* They are not affected by gravity, so they are neither attracted nor attracting.
* They have no calculated orbital elements, and their orbit will not be displayed.
* They do not collide with other objects, instead passing right through them.
* Their temperature is only represented by a single Temperature property, rather than surface temperature vs. effective temperature.
Atmosphere Density

The Atmosphere Density of an object is the mass per volume of the object's atmosphere at the surface.

## Property Details

### Location

The Atmosphere Density property is located in the Atmosphere section of the Surface tab of the object's properties panel. This section is only visible for Terrestrial Planets.

### Units

Atmosphere Density can be viewed and edited using the following units:

* Grams per cubic centimeter (g/cm3) = 1000 kg/m3
* Kilograms per cubic meter (kg/m3) is the SI base unit for density
* Hydrogen molecules per cubic centimeters (H2/cm3) = 1.67×10-24 kg/m3

## Simulation Effects

### Surface Pressure

The Atmosphere Density is related to the surface pressure, *P*, and temperature of the object, *T*, by the following equation:

# ρ

P

R

s
p
e
c

T

{\displaystyle \rho ={\frac {P}{R\_{spec}T}}}

where *Rspec* is the specific gas constant for dry air, 287 J/(kg K).
Speed

The Speed of an object is the rate at which the object's position is changing with time, relative to a reference point determined by the object's Relative to property. In terms of vector mathematics, the Speed is the magnitude of the object's Velocity Vector.

## Property Details

### Location

The Speed property for an object can be found in the Overview tab, or near the top of the Motion tab. For Galaxy objects, the Speed property is located in the Properties section of the Galaxy tab, and refers specifically to the Black Hole's Speed. For Galaxy Nebula objects, the Speed property is located in the Motion section of the Nebula tab. In the Motion tab, the Speed property can be expanded to show the object's Velocity Vector.

The Speed is also displayed in an object's mini-info panel. This Speed is always displayed relative to the Simulation Origin.

### Units

Speed can be viewed or edited using the following properties:

* The Speed of Light (lightspeed) = 2.99792458×108 m/s
* Kilometers per Second (km/s) = 1000 m/s
* Meters per Second (m/s) is the SI unit for speed
* Kilometers per Hour (km/h) = 0.2778 m/s

## Simulation Effects

### Motion

An object will a constant speed, *V*, will move a distance *D* in a period of time *T*, where

# V

D
T

.

{\displaystyle V = \frac{D}{T}.}

However, in the presence of forces like gravity, the speed of an object is usually not constant, and its motion is more complex.

### Collisions

The speed of an object affects both its momentum and kinetic energy, which determine the outcome of a collision with another object.