NATS 1880 Lecture Notes - Lecture 11: Local Group, Photon, Virgo Supercluster
2 Nov 2017
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Document Summary
Cosmic address (earth address) - smallest to largest. We live in a planet - called earth. Earth is in a planetary system (a planetary system is a set of gravitationally bound objects in orbit around a star) - called solar system with sun in the centre (not all planetary systems have one star) Solar system with billions of other stars, planets and are located in a galaxy - called. Milky way galaxy is part of a smaller group of galaxies - called local group. Local group is a member of a larger group of galaxies - called local supercluster. Universe is the sum total of all matter and energy. Recall: astronomical unit (au) is the distance between earth and sun = 150 million km. The distance that a photon of light can travel in one year, which is 9. 46 trillion km. Like planetary system but has more than 1 star in it.
