Objects acting under each other's gravity. Test

I want to test the revised script from http://answers.unity3d.com/questions/196749/objects-acting-under-each-others-gravity.html (script from the best answer). I've completed the script, but it doesn't work:

 #pragma strict
 
 var planet : Transform;
 var numberOfPlanets = 10;
 var minimumSize = 1;
 var maximumSize = 10;
 var position = Vector3.zero;
 var planets = new Array ();
 var masses = new Array ();
 var total = Vector3.zero;
 var speed = Vector3.zero;
 static var G = 0.01f; // adjust with try & error
 static var planets = List.<Rigidbody>();
 private var myRigidbody : Rigidbody;
  
 //for testing. Set the z value to give the planet an initial speed along it's z-axis
 public var initialForwardSpeed : Vector3;
 function Awake()
 {
     myRigidbody = rigidbody;
     myRigidbody.velocity = transform.TransformDirection(initialForwardSpeed);
 }
  
 function OnEnable()
 {
     planets.Add(rigidbody);
 }
  
 function OnDisable()
 {
     planets.Remove(rigidbody);
 }
  
 function FixedUpdate()
 {
     var pos = myRigidbody.position;
     var acc = Vector3.zero;
     for(var planet in planets)
     {
         if (planet == myRigidbody)
             continue;
         var direction = (planet.position - pos);
         acc += G * (direction.normalized * planet.mass) / direction.sqrMagnitude; 
     }
     myRigidbody.velocity+= acc * Time.fixedDeltaTime;   
 }
 function calculate ()
 {
     for (k=0;k<numberOfPlanets;k++)
     {
         var indiv = planets [k];
         total = Vector3.zero;
         for(j=0;j<numberOfPlanets;j++)
         {
             var planetRef = planets[j];
             var direction = (planetRef.position-indiv.position);
             total += (direction.normalized * masses[j]) / direction.sqrMagnitude;
             speed[k] += total;
             indiv.transform.Translate (speed[k]);
         }
     }
 }

Error message: Assets/Script.js(13,12): BCE0089: Type 'Script' already has a definition for 'planets'. If I delete a variable, I get much more errors. What should I do?