ASTR 1P01 Lecture Notes - Lecture 2: Before Present, Astronomical Unit, Kuiper Belt

• School: Brock University
• Department: Astronomy
• Course: ASTR 1P01
• Professor: Bozidar Mitrovic

Document Summary

Earth spins/rotates around the north-south axis: but spins west-east as a general direction. The direction of the spin is counter-clockwise (prograde from above the north pole---from west to east. The distance between the earth and the moon is 384,500km: how long does it take light reflected off the moon and traveling at a speed of. 384,500km / 300,000km/s = 1. 28 seconds: note: the greater the distance the longer the lookback time. By sending radio pulse (which travels at the speed of light) which is a form of electromagnetic radiation, to the moon and back we can calculate the distance using the speed of light (300,000km/s) The average earth to sun distance is 150 million km (1. 5x108: it is more natural to express the distances in the solar system in terms of earth-sun distance. This is measured the same way as the moon with a radio pulse.