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Galaxies
vocabulary for galaxies chap 22 lesson 4
| Term | Definition |
|---|---|
| galaxy | Huge collections of stars |
| universe | made up of hundreds of billions of galaxies |
| spiral | a type of galaxy with a bulging central disk of stars with spiral arms that radiate from it |
| elliptical | a type of galaxy that has either a football or basketball shape |
| irregular | a type of galaxy that does not have any clear shape, contains lots of gas and dust |
| Hubble's Law | a theory that says objects moving away from each other have a relationship with their distance |
| milky way | The galaxy that planet Earth is in |
| big bang theory | the universe began from one point billions of years ago and has been expanding ever since |
| doppler shift | the shift to a different wavelength on the electromagnetic spectrum |
| dark matter | matter that emits no light at any wave lengeth, makes up 90% of the universe |
| local group | The cluster of 30 galaxies that the Milky way is a part of |