Welcome to Stars Galaxies and the Universe Summer

Welcome to Stars, Galaxies, and the Universe Summer 2004 • Initial pleasantries, who I am, who you are • This should be the most interesting course you take in college • Example 1(very basic): the star Xi Bootes in the night sky • Example 2: Arcturus as an alien star! (What’s that mean? ) • Example 3: the texture of the universe and the presence of the dark matter (state of the art, up-tothe minute research results).

Example 1: Xi Bootes (see it tonight)

Some of the facts about Xi Bootes • • • A binary star Components G 5 V and K 4 V stars Apparent magnitudes 4. 8 and 7. 0 Separation of pair = 6. 4 arcseconds A good lab project!

All the above meaningless gibberish now, but By the end of the semester, you will recognize that this tells you: (1) The types of stars (the brighter one is like the Sun) (2) The distance to the system (3) The fact that it verifies the “mass luminosity relation” (4) The distance between the two stars

Arcturus (bright star overhead) as an immigrant from another galaxy The Milky Way (and other galaxies) catch and devour small galaxies

The form (or texture) of the universe as a whole (? !) • We will learn that the Milky Way is a system (galaxy) of about 200 billion stars • Galaxies are sprinkled through space at a density of about one every megaparsec or so. • Let’s see how they are distributed on extremely large scales. • In the last few years, new data has been arriving to illuminate this (and not only from the HST!)

The Sloan Digital Sky Survey- on its way to measuring 1 million galaxies “Frothy” nature of galactic matter “DARK MATTER”

A better look

This summer, we’ll learn about all of this, but first…. Details from the Syllabus