it's the reoccurring floods, every time this cataclysm happens the weight of everything doubles. all life keeps getting smaller and smaller over time.

before the next flood comes fire, it's how giant fossils are made. it's like how a diesel engine works when the pressure goes up.
i'm guessing TPTB are larping an antimatter comet so as not to spoil their globe hoax; we live in an enclosed realm where life keeps getting smaller and smaller due to successive pressure increases.