ASTR 1013 Lecture Notes - Lecture 1: Astronomical Unit, Solar System
110 views1 pages
ASTR 1013 1st Lecture
+Astronomical unit (AU)= mean earth to sun distance= 1.5x10^8
+Speed of light (c) = 3x10^5 km/sec
+Light year (LY)= distance light travels in one year
+Parsec (pc)= distance at which 1 AU subtends 1/3600 degrees= 3.3LY
1.2
+Solar system= 11 light hours
+Typical distance between 2 stars ~ (about) 1LY
+Large star clusters ~10^2 LY
+Large Galaxies ~10^5 LY
+Clusters of galaxies~10^7 LY
+Clusters of clusters of galaxies and empty voids between~10^8 LY
1.3
+Speed planets orbit the sun~10Km/sec
+Speed of stars around center of galaxy, or galaxies within a galaxy cluster~10^2Km/sec
1.4
+Science: The hunt for deeper understanding of, and new knowledge about the physical
universe
+Newton’s formulas are great for low speed and low mass, general relativity is for high speed
high mass
+Astronomy’s distinction: studies conditions that don’t exist on earth
+Why astronomy?: fundamental knowledge, application (over time), intellectual curiosity and
pleasure, and it teaches a respect for truth and accuracy.
find more resources at oneclass.com
find more resources at oneclass.com