NATS 1740 Lecture Notes - Lecture 16: Harlow Shapley, Spiral Galaxy, Drake Equation

• School: York University
• Department: Natural Science
• Course: NATS 1740
• Professor: Radu Campeanu

Document Summary

Give some statistics based on the keppler observations. Describe the colonization of our solar system. What are the challenges in the colonization of our galaxy. Billions of stars form galaxies, which for the old astronomy were the nebulae (some nebulae are actually supernova remnants). For hundreds of years stars and nebulae were the fixed constellations while the planets were the moving cosmic objects. Determining the distance to galaxies became possible only after 1923 by measuring the distance to specific stars inside those galaxies. The observations with non-optical telescopes uncovered a world of galaxies far more violent than the world of stars. Galaxies can have different shapes: oval, s, spiral, iregular. The sun is a medium star in our galaxy, a medium size spiral galaxy known also as the. We are in the orion arm , slightly above the galactic plane.