02 BBC Maravillas del Universo [Wonders Of The Universe] - Stardust [BDRip 1080p x264 AC3 Dual Spa-Eng].mkv

Brian uses the glacier as a metaphor for the arrow of time. We take it for granted that events happen in a given sequence; snow falls, ice forms, the glacier inches down the valley where eventually huge chunks of ice fall into the lake and melt away into nothing. But why do events always happen only in one direction? Why do we never see things happen in reverse?