User blog comment:MachineGunSuper/My axiom about the biggest number/@comment-32876686-20171130163605/@comment-30754445-20171130183425

Fun fact: Nobody really knows how large Loader's number is. It's so mind bogglingly huge that we don't yet have the tools to estimate it's size. We just know it's really really really big.

This is completely unlike Graham and TREE(3), whose size can be accurately analyzed with the proper tools.