UNIT 1: the Universe & Galaxies

The Universe & Galaxies SOL 14

Fundamental Concepts and Skills Reading 1. Many types of observations are needed to better Chapter 28 understand our universe.  Much of our information about our galaxy and the universe comes from ground-based observations, using optical and radar telescopes as well as spectroscopes.  The Hubble Space telescope has greatly improved our understanding of the universe because it is located above the earth’s atmosphere.

2. Define a light year as the distance light travels in one year. It is Chapter 28 the most commonly used measurement for distance in astronomy.

3. Explain that the Big Bang Theory and the solar nebular theory Chapter 28 are the best current hypotheses for the origin of the universe and origin of the solar system respectively.

4. Recognize that the Big Bang Theory states that the universe began Chapter 28 12-15 billion years ago as a dense sphere that expanded and eventually condensed into galaxies.

5. Understand that : Chapter 28  Galaxies are collections of large numbers (billions) of stars.  Identify the basic types of galaxies as spiral (have arms), elliptical (round or oval shaped), and irregular.

6. Understand that :  Stars have a finite lifetime and evolve over time. Chapter 28  The mass of a star controls its evolution, length of its lifetime, and ultimate fate.  Stars form by condensation of interstellar gas.

7. The sun, like other stars, consists largely of hydrogen gas. Its energy comes from nuclear fusion of hydrogen to helium. Chapter 28

8. The solar system is located in the Milky Way Galaxy. Chapter 28