Assigning a gameobject to another

Is there a way to assign a gameobject to another?

Like:

Code (CSharp):

1. public GameObject empty;
2. void OnCollisionEnter(Collision collision)
3. {
4. if(collision.gameObject satisfies a certain criteria)
5. {
6. empty=collision; //error line
7. }
8.  
9.  
10. }

I want to work with the collided object in my update function. But since OnCollisionEnter() is only called when there's a collision, I need to 'store' my collision gameobject in another public gameobject so that I can use it in my other functions like Update etc.

 

http://docs.unity3d.com/ScriptReference/Collider.OnCollisionEnter.html

empty = collision.collider.gameObject;

 

you can skip the collider step, collision.gameobject

http://docs.unity3d.com/ScriptReference/Collision.html

 

I see, thanks :'P