How long does a epoch last?

An epoch typically refers to a specific period of time used in various contexts, such as in machine learning or geology. In machine learning, an epoch is one complete pass through the entire training dataset, and its duration depends on the size of the dataset and the processing power of the hardware used. In geology, an epoch can last millions of years, marking a subdivision of a geological period. Therefore, the length of an epoch varies widely based on the context in which it is used.