MultiBody Gravity Calculation (approximate)

using UnityEngine;
using System.Collections;

public class ChangeGravity : MonoBehaviour {


    private Transform moonT;

    public Transform [] GravitySources;


    [SerializeField]
    float gravityScale = 10f;
    Rigidbody2D rb;

    void Awake()
    {
        rb = GetComponent<Rigidbody2D>();
    }

    void FixedUpdate () {

        Vector3 totalGravity = Vector3.zero;

        for (int i = 0; i < GravitySources.Length; i++)
        {
            Vector3 thisGravity = (GravitySources[i].position - transform.position).normalized * gravityScale * Time.fixedDeltaTime
                                                         / (GravitySources[i].position - transform.position).sqrMagnitude;

            rb.AddForce(thisGravity);

            totalGravity += thisGravity;


        }

        transform.rotation = Quaternion.LookRotation(Vector3.forward, -totalGravity);

    }


}