there are a great many experiments in mathematics that require as much computer as can be obtained. if you want to model the universe you need a second universe of equal mass. approximations will be required by people decended from us 10 billion years from now, it simply must be approximated. nevertheless scope needs be maximized for resolution increase in detail. then there are things like just three objects which cannot be solved to begin with, and requires thousands of iterations with even so little material. space trajectories require this, and places that do that have the programs hardwired on chips. you'ld be suprised how much data one can generate. and how much time it takes. the full use of a supercomputer for a year is around standard if one can get that. i mean one single program running that long say at 60% capacity is typical for some models such as the early universe. weather forcasting in america uses three at severe storms center last i heard. (supercomputers) modelling water freezing, explosions, and so forth take a great deal of space. pure mathematics can be hard to separate from that, because they arent real, they are models, and then you have to tune them. different algorithms are more efficient. so sometimes there are researchers, who tell programmers what to do, and that makes up a pretty good team.