Brittle Hollow

So if we're only witnessing the 22 minutes before each planet is lost to supernova, holllows lantern has only just begun to destroy Brittle Hollow - right? It happens every loop, sure but for x amount of years before the loop began Brittle Hollow was presumably a solid planet not being destroyed by the lantern.

Is there any explanation for why these random 22 minutes before supernova causes Hollow's Lantern to start flinging rocks over?

I understand something like the hourglass twins would repeatedly swap the sand back and forth even pre-loop, but with Brittle Hollow it makes no sense that it could keep falling in on itself and being blown out into the galaxy via black hole and then putting itself back together in orbit repeatedly. Is it just happenstance? Is it a cosmic phenomenon caused by the end times and I'm looking too far into it?

Also the lantern presumably didn't spit lava out and refill with lava naturally /before/ the loop right? So how could the Nomai have explored inside one of their active volcanoes while it was still filed with lava?