GetRootGameObjects for unloaded scenes?

Hi, I have an editor extension that I have been working on that I am using for serilization purposes, and to get references for objects. Basically I have an ID library and some Monobehaviors I have, have an ID attached to them. So I am looking for a way to look through all scenes that are in the build (I do this through a World Asset that has other information about the scene) and get all IDs from objects but GetRootGameObjects seems to only work for loaded scenes. So I am wondering if there is a different solution?
Also this is the code I am using:

Code (CSharp):

1. List<World> worldsInProject = new List<World>(Resources.FindObjectsOfTypeAll<World>());
2. List<GameObject> allObjects = new List<GameObject>();
3.  
4. foreach (World w in worldsInProject) {
5. allObjects.AddRange(SceneManager.GetSceneByName(w.WorldScene.name).GetRootGameObjects());
6. }

And the error I am getting is "The Scene is Invalid"