GALAXIES Pages 639-642

Galaxies large groups of stars (approx. 100 billion) bound by gravitational attraction- rotates around a center PLUS: nebulae, planets, dark matter (90%), space, etc..

CENTER OF GALAXIES Supermassive black hole

Supermassive black hole https://www.youtube.com/watch?v=kq4u7Sv7GT4

Milky Way Barred spiral galaxy About 100,000 light-years wide Sun is 30,000 light-years from the center Rotates every 200 million years around “galactic center”

Milky Way

Face-on view of the Milk Way Galaxy

Edge-on view of the Milk Way Galaxy

Andromeda (M31) A large galaxy neighbor 2,200,000 ly Can see with naked eye

Clash of Andromeda and Milky Way https://www.youtube.com/watch?v=mchzu-eB_wg

Types of Galaxies

NGC 3384 M105

Spiral galaxies NCG 6946 30% of all galaxies Older in center; younger in arms NCG 6946

A barred spiral galaxy

Elliptical galaxy 60% of all galaxies Contain older stars

Merger of two Spirals to form an Elliptical

M104 (The Sombrero Galaxy)

Irregular galaxy 10% of all galaxies Contain young stars

Hubble’s Law Farther galaxies are moving away faster than closer galaxies

http://hyperphysics.phy-astr.gsu.edu/hbase/astro/hubble.html#c3

Raisin bread analogy of an expanding universe

What does this support? EXPANDING UNIVERSE!

Local group Local Group Milky way and it’s nearest galaxies Contains at least 28 galaxies

What pattern do galaxies form in the universe?

AMAZING FACT Our known Universe (are there more?) contains at least 1,000,000 billions ( Thats One Million, Billions) of other Galaxies...like our own Milky Way. Life?

What is your galactic address? Smallest to largest:

Power of Ten http://micro.magnet.fsu.edu/primer/java/scienceopticsu/powersof10/index.html

Galaxy Song https://www.youtube.com/watch?v=XNj-_705LcA https://www.youtube.com/watch?v=vIy76M-4txo&t=11s