1. Ms. Fauss 7 th Grade

2.  Galaxy: a large group of stars, gas, and dust held together by gravity.  Earth and the solar system are in a galaxy known as the Milky Way.  Might contain as many as one trillion stars  Countless other galaxies exist separated by millions of light years.

3.  Spiral Galaxies (The Milky Way is a Spiral Galaxy):  Have spiral arms that wind outward from the center  Arms consist of bright stars, dust and gas  The sun and the rest of the solar system are located near the outer edge of the Milky Way Galaxy.

4.  Elliptical Galaxies:  Shaped like large three dimensional ellipses  Many are football shaped but others are round  Some are small while others can be so large that several Milky Way sized galaxies could fit inside of it

5.  Irregular Galaxies:  Many different shapes  Smaller than the other types of galaxies The two Magellanic Clouds (or Nubeculae Magellani) are a duo of irregular dwarf galaxies visible from the southern hemisphere, which are members of our Local Group and may be orbiting our Milky Way galaxy

6.  Steady State Theory: The universe has always been the same as it is now. However, the universe is expanding and creating new matter, therefore it is different than in the past.  Oscillating Model: The universe began with expansion. Over time expansion slowed as the universe contracted. Scientists hypothesize that it expands and contracts in a cycle.  Big Bang Theory: The universe started with an enormous explosion, and matter began collecting in clumps. It has been expanding in all directions ever since.

7.  Evidence (Edwin Hubble 1929) showed that all galaxies beyond the Local Group are moving away from Earth.  This means the universe is expanding.  It is unknown whether the universe will continue to expand forever.  If enough matter exists, gravity might halt expansion.  However, studies of distant supernovae indicate that energy (dark energy) is causing the universe to expand faster.