chapter 1

4 Pages
Unlock Document

University of Toronto St. George
Astronomy & Astrophysics
Clifford Orwin

Our place in the Universe(Chapter 1) Geocentric - Cannot feel the constant motion of Earth as it rotates on its axis and orbits the sun Cosmic Address - Our place in the universe Solar System (e.g.. Earth) - Consist of the sun and all the objects that orbit it (planets, their moons and smaller objects including rocky asteroids and icy comets). Milky Way Galaxy - disk shaped collection of stars (100 billion stars) - 1 of the 2 largest among the 40 galaxies in the LOCAL GROUP Galaxy - island of stars (few 100 million to trillion or more stars) Galaxy Clusters - galaxies with more than a few dozen members (very dense) - arranged in giant chains with huge voids between them SuperClusters - area where galaxies and galaxy cluster are most tightly packed Asteroid - small rocky object that orbits a star. Part of a category called small solar system bodies Comet - Small ice rich object that orbits a star. Part of a category called small solar system bodies - Our solar system is located a little more than halfway from the galactic center to the edge of the galactic disk. Denition of of OUR UNIVERSE: - Sum total of all matter and energy, encompassing the supercluster and voids and everything within them. Our Place in the UNIVERSE: - We live on a planet orbiting and avg. star among more then 100 billion stars in the Milky Way Galaxy. Big Bang (the rate at which galaxies are moving apart) and Expanding Universe - The Universe is expanding----the avg. distance between galaxies is increasing in time - Expansion began 14 billion years ago - Force of gravity has drawn matter together causing matter within to clump together resulting into galaxies and galaxy clusters Stars and planets are formed by: - collapse of clouds of gas and dust
More Less

Related notes for AST101H1

Log In


Don't have an account?

Join OneClass

Access over 10 million pages of study
documents for 1.3 million courses.

Sign up

Join to view


By registering, I agree to the Terms and Privacy Policies
Already have an account?
Just a few more details

So we can recommend you notes for your school.

Reset Password

Please enter below the email address you registered with and we will send you a link to reset your password.

Add your courses

Get notes from the top students in your class.