Here is a proof that the universe is finite in size. [Ref] means the details are in the reference mentioned at the end.
Life on earth is periodic. We take birth, grow to a matured state, decay to death, remain dead for some time, and then reincarnate [Ref] with a new life. Thus we have a living period and also a dead period.
Since every object in the universe is created by its own individual soul [Ref], every object in the universe will behave in the same was as humans do. Thus all objects will have a living period and also a dead period.
Since summation of periodic waves will also be a periodic wave, the entire universe will also be periodic, with a living period and a dead period. Thus the universe is eternally existent, with no beginning and end times.
Finally, since the dead period of the universe is finite, therefore all objects inside the universe must die during that finite time interval. Therefore the number of the objects in the universe must be finite and therefore the size of the universe must be finite also. For more details see the following article: