That's mentioned on the "Conclusions" page of TFA:
> Large-scale simulation: So far, we have only focused on systems with a few objects. What about large-scale systems with thousands or millions of objects? Turns out it is not so easy because the computation of gravity scales as
. Have a look at Barnes-Hut algorithm to see how to speed up the simulation. In fact, we have documentations about it on this website as well. You may try to implement it in some low-level language like C or C++.
> Large-scale simulation: So far, we have only focused on systems with a few objects. What about large-scale systems with thousands or millions of objects? Turns out it is not so easy because the computation of gravity scales as . Have a look at Barnes-Hut algorithm to see how to speed up the simulation. In fact, we have documentations about it on this website as well. You may try to implement it in some low-level language like C or C++.