PHYS 284 Lecture 2: Lesson 2
Document Summary
Observing the night sky from earth: the stars are at vastly different distances from earth, but they appear to be close to each other because we lack depth perception when we look into the night sky. The ancient greeks mistook this illusion for reality, imaging the stars to lie on a greta celestial sphere surrounding earth. Although the idea that earth is in the centre of a giant ball of stars is not correct, we still use the concept of a celestial sphere to help us map the sky, The point in the sky directly above earth"s north pole is called the north celestial pole . The star is currently at the location of the north celestial pole; this star is commonly called the north. The point in the sky directly above earth"s south pole is called the south celestial pole. There is not currently a star at that location, so we don"t have a corresponding south star .
