The discussion centers on calculating the number of cubic Planck lengths that can fit within the observable universe, emphasizing that the calculation involves dividing the volume of the universe by the volume of a Planck unit cube. Participants note that while strings are theoretically smaller than Planck lengths, they complicate the question since they do not have a defined size. The approximate calculation yields around 9.47 x 10^184 cubic Planck lengths in the observable universe. The conversation highlights the importance of understanding the volume measurements and the theoretical nature of strings in relation to Planck lengths. Overall, the focus remains on the mathematical approach to estimating the volume of the universe in terms of Planck units.