The antimaterial world is mentioned here, and in addition information is given that in the antimaterial world there is no "seasonal" fluctuation. Everything there is permanent, blissful, and full of knowledge. But when we speak of it as a "world," we must remember that it has forms and paraphernalia of various categories beyond our material experiences.
The material body is destructible, and as such it is changeable and temporary. So is the material world. But the antimaterial living force is nondestructible, and therefore it is permanent. Expert scientists have thus distinguished the different qualities of the material and antimaterial particles as temporary and permanent respectively.
The discoverers of the two forms of matter have yet to find out the qualities of antimatter. But a vivid description is already given in the Bhagavad-gītā as follows. The scientist can make further research on the basis of this valuable information.