- Aratus applied the mythical name Ἠριδανός (Eridanos) to this constellation although many other authorities, including Ptolemy in the Almagest, simply called it Ποταμός (Potamos), meaning river. Eratosthenes had another identification: he said that the constellation represented the Nile, ‘the only river which runs from south to north’. Hyginus agreed, claiming that the star Canopus lay at the end of the celestial river, in the same way that the island Canopus lies at the mouth of the Nile. However, in this he was wrong, for Canopus marks a steering oar of the ship Argo and is not part of the river. Hyginus had evidently misunderstood a comment by Eratosthenes, who had simply said that Canopus lay ‘beneath’ the river, meaning that it was at a more southerly declination.
- Arrow of time (Wikipedia)
The arrow of time, also called time’s arrow, is the concept positing the “one-way direction” or “asymmetry” of time. It was developed in 1927 by the British astrophysicist Arthur Eddington, and is an unsolved general physics question. This direction, according to Eddington, could be determined by studying the organization of atoms, molecules, and bodies, and might be drawn upon a four-dimensional relativistic map of the world (“a solid block of paper”).