# orbit/sol

`import "github.com/matjam/bunyip/orbit/sol"`

Package sol holds real-world constants for games set in our solar system. The orbit package itself is unit-agnostic and works with any masses, any gravitational constant and any scale of distance and time, so a fictional system needs nothing from this package.

## Constants

<a id="AU"></a>

<a id="Day"></a>

<a id="Year"></a>

<a id="EarthRadius"></a>

<a id="MoonRadius"></a>

<a id="SunRadius"></a>

<a id="SunMass"></a>

<a id="EarthMass"></a>

<a id="MoonMass"></a>

<a id="MarsMass"></a>

<a id="JupiterMass"></a>

<a id="MuSun"></a>

<a id="MuEarth"></a>

<a id="MuMoon"></a>

<a id="MuMars"></a>

<a id="MuJupiter"></a>

<a id="MoonDistance"></a>

```go
const (
	AU          = 1.495978707e11 // astronomical unit in metres
	Day         = 86400.0        // day in seconds
	Year        = 365.25 * Day   // Julian year in seconds
	EarthRadius = 6.371e6
	MoonRadius  = 1.7374e6
	SunRadius   = 6.957e8

	SunMass     = 1.98892e30
	EarthMass   = 5.9722e24
	MoonMass    = 7.342e22
	MarsMass    = 6.4171e23
	JupiterMass = 1.8982e27

	// Standard gravitational parameters (G times mass), m³/s².
	MuSun     = 1.32712440018e20
	MuEarth   = 3.986004418e14
	MuMoon    = 4.9048695e12
	MuMars    = 4.282837e13
	MuJupiter = 1.26686534e17

	MoonDistance = 384400e3 // approximate mean Earth-Moon distance in metres
)
```

Distances in metres, masses in kilograms, time in seconds.