Click on the screen to change the speed from 1 frame per second (the sky will take 24 minutes to show 24 hours) to 24 frames per second (the sky will take 1 minute to show 24 hours.
Unix Time shows a 24 hour time lapse of the sky, with one minute of real time taking one second. A long number is overlayed on the sky showing the current time in unix time, the number of seconds since midnight, 1st January 1970. Every second this number increments by 1. Unix time can be seen as the birth of modern computing, an alternative epoch to the Gregorian.