raycasthit.normal sometimes returns zero

Hello, so here is my story, my "player" shoots a blast, the "blast" object has a trigger and when it is shot and hits an object with tag "enemy", it adds a force to the object relative to the normal of the hit.

 void OnTriggerEnter(Collider col)
         {
             if (col.gameObject.tag == "enemy")
             {
                 RaycastHit hit;
                 Physics.Raycast(transform.position, col.gameObject.transform.position, 
                     out hit, DistanceToEnemy(col.gameObject));
                 Debug.Log("Distance To Enemy: " + DistanceToEnemy(col.gameObject));
                 col.gameObject.GetComponent<GetHitEvent>().GetHitEffect(gameObject, hit.normal);
                 Destroy(gameObject);
             }
         }

and here is the GetHitEffect(GameObject, Vector3) function code

 public void GetHitEffect(GameObject blastObj, Vector3 hitAngleVector) //hitAngleVector is the hit.normal
     {
         GetComponent<Rigidbody>().freezeRotation = false;
         GetComponent<Rigidbody>().AddForce(-hitAngleVector * 6, ForceMode.Impulse);
     }

so my problem is that when i fire a blast object and it hits the enemy, sometimes, the hit.normal is zero and i get no force on the object, but other times it calculates the hit perfectly fine.

your help is immensely appreciated.