ASTR 101 Lecture Notes - Lecture 1: Winter Solstice, Solar Time, Equinox
Document Summary
Astronomical scales are very hard to grasp, sun is 93 million miles away from the earth, galaxies: scale is way larger (100,000 light years, or 1000 quadrillion kilometers). What is a light year: the distance light takes to travel 1 year, speed of light: c = 300,000 km per second, 3 x 10^5 km per second, or 3 x 10^8. Light year (ly) m per second: seconds in a year: 1 year | 365 days |24 h | 60 min | 60 sec | = pi x 10 ^7 seconds, or 3. 14 x 10^7 seconds. 1 year | 1 day| 1 hour | 1 min : d = v x t. = 3. 1^5 km/s x pi x 10^7 seconds. Celestial sphere: north and south: celestial pole, equator, the world moves to the right. Seasons: the distances between the earth and sun decides the temperature/season along with the solstice/equinox, ex: winter/summer solstice vs. vernal/autumnal equinox, vernal equinox: mar.