AS101 Lecture Notes - Lecture 1: Minute And Second Of Arc, Big Bang
Document Summary
Earth has a diameter of 13000 km. 1 au is the distance of the earth to the sun (150,000,000 km) The known universe is around 7 billion ly across. The estimated age of the universe is 13. 8 billion years since the big bang. Around 3000 individual stars are visible with the naked eye. The distance between the earth and the moon is around 384,000 km. The precessional period for the earth is about 26,000 years, all the while maintaining its. Astronomers measure distances across the sky as angles in units of degrees, arc minutes and arc seconds. A zenith is the point in the sky directly overhead to your position. Your meridian is the line going from due north, through your zenith and finishing due south. While stating size or the distance between two objects we use degrees.
