AFAIK, all this discussion is in the realms of hypothesis. It is. It's just currently the best hypothesis, and it's refined to better match observation over ti

AFAIK, all this discussion is in the realms of hypothesis. It is. It's just currently the best hypothesis, and it's refined to better match observation over time. For example, the impact with Theia was originally thought to be a glancing blow by a planet spinning similarly to earth, but more recent simulations indicate it was a head-on collision and that Theia had relatively little angular momentum. This hypothesis does make predictions about the moon's core that are falsifiable but it may be some time before we figure out a way to make the necessary measurements.