Time passed....
When the Travelers from Outer Space took the capsule back to their ship and opened it, they found the contents in perfect order. Even the reel
of magnetic tape had not succumbed to the centuries.
In due course, the Travelers examined the tape, divined its purpose, and constructed a machine that would play back the recording.
Out of a million evolutionary possibilities in a Universe of planets, the chances of two intelligent races being even roughly similar are astronomically remote.
A being develops sense organs for no other reason than to make it aware of its environment. The simplest primitive being's awareness of its environment centers around food, its means of survival. It develops organs and appendages that will enable it to ferret out, obtain and ingest its food. As the food differs, so, then, does the eater.
The Travelers had no ears or eyes, as such. They had other organs for other purposes, but the net result was that they "saw" and "heard" quite as well—even better—than Earthmen.
Perhaps that explains why the Travelers gleaned so much more from the tape recording in the Twentieth Century capsule than its originators had planned or intended.