The planets' trajectories don't have to be nice and regular as that of the Earth, but can WE complex, wild, and apparently random.
Needs to be changed to
The planets' trajectories don't have to be nice and regular as that of the Earth, but can BE complex, wild, and apparently random.
The planets' trajectories don't have to be nice and regular as that of the Earth, but can WE complex, wild, and apparently random.
Needs to be changed to
The planets' trajectories don't have to be nice and regular as that of the Earth, but can BE complex, wild, and apparently random.