- A galaxy is a giant cluster of stars, gases, and dust held together by gravity
- The galaxy that we live in is the Milky Way Galaxy
- There are 3 different types of galaxies, Elliptical, Spiral, and Irregular
- The Milky Way Galaxy is a Spiral Galaxy
- Some galaxies occur alone or in pairs
- The observable universe may contain more than 100 billion stars
- Some galaxies are really close to each other and after millions of years, can merge together.
- A Quasar is distant bright object in the universe that almost look like stars.
- The origin of galaxies is where gas and dust are pulled together by gravity to create a nebula, it becomes really hot and then a star is born
- There is an infinity number of stars in the universe and each star is really hot, like our sun.
Nebula
- A nebula is hydrogen, helium, dust, and other ionized gasses to form an intersellar cloud.
- Materials such as gas and dust, clump together and eventually form stars when they are big enough.
- Remaining materials are believed to create planets.
- Nebulae are sometimes formed from supernova explosions.