galaxies pages 639-642. galaxies def: large scale groups of stars (approx. 100 billion) bound by...
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GALAXIESGALAXIES
Pages 639-642Pages 639-642
GalaxiesGalaxies
Def: large scale groups of stars (approx. Def: large scale groups of stars (approx. 100 billion) bound by gravitational 100 billion) bound by gravitational attraction- rotates around a centerattraction- rotates around a center
Also contain nebulae, planets, dark matter Also contain nebulae, planets, dark matter (90%), space, etc..(90%), space, etc..
Is the center of every galaxy a Is the center of every galaxy a supermassive black hole?supermassive black hole?
Small Magellanic Cloud
Nearest galaxy 150,000 lyNearest galaxy 150,000 ly
Andromeda (M31)Andromeda (M31)
A large galaxy neighborA large galaxy neighbor2,900,000 ly2,900,000 ly
Milky WayMilky Way
• StructureStructure• Barred spiral galaxy Barred spiral galaxy
• About 100,000 About 100,000 light-years widelight-years wide
• Sun is 30,000 light-Sun is 30,000 light-years from the center years from the center
• Rotates every 200 Rotates every 200 million years around million years around “galactic center”“galactic center”
Milky WayMilky Way
Face-on view of the Face-on view of the Milk Way GalaxyMilk Way Galaxy
Edge-on view of the Edge-on view of the Milk Way GalaxyMilk Way Galaxy
Galaxy SongGalaxy Songfrom Monty Pythonfrom Monty Python
http://www.youtube.com/watch?v=vIy76M-4txo&feature=related&safety_mode=true&persist_safety_mode=1&safe=active
Types of GalaxiesTypes of Galaxies
M105
NGC 3384
Elliptical galaxyElliptical galaxy
60% of all galaxies60% of all galaxiesContain older starsContain older starssmallsmall
LMC
Large Magellanic cloud
NCG 6946
Spiral galaxiesSpiral galaxies
30% of all galaxies30% of all galaxiesOlder in center; younger in armsOlder in center; younger in arms
A barred spiral galaxyA barred spiral galaxy
Merger of two Spirals to form an Elliptical
Irregular galaxyIrregular galaxy
10% of all galaxies10% of all galaxiesContain young starsContain young stars
M104 (The Sombrero Galaxy)
Hubble’s LawHubble’s Law
Galaxies are receding at a speed Galaxies are receding at a speed proportional to their distanceproportional to their distance
Farther galaxies are moving faster than Farther galaxies are moving faster than nearby galaxiesnearby galaxies
http://hyperphysics.phy-astr.gsu.edu/hbase/astro/hubble.html#c3
Raisin bread analogy of an Raisin bread analogy of an expanding universeexpanding universe
What would cause this?What would cause this?
EXPANDING EXPANDING UNIVERSE!UNIVERSE!
Cosmological red Cosmological red shift- supports thisshift- supports this
Local groupLocal group
Local Group Local Group • Milky way and nearest Milky way and nearest
galaxiesgalaxies• Contains at least 28 Contains at least 28
galaxiesgalaxies
What pattern do galaxies form What pattern do galaxies form in the universe?in the universe?
AMAZING FACTAMAZING FACT
Our known Universe contains at least Our known Universe contains at least 1,000,000 billions ( Thats One Million, 1,000,000 billions ( Thats One Million, Billions) of other Galaxies...Billions) of other Galaxies...like our like our own Milky Way.own Milky Way. There is no doubt that There is no doubt that there are other vast Universes in there are other vast Universes in existence on top of our Universeexistence on top of our Universe
What is your galactic addressWhat is your galactic address
Power of TenPower of Ten
http://micro.magnet.fsu.edu/primer/java/http://micro.magnet.fsu.edu/primer/java/scienceopticsu/powersof10/index.htmlscienceopticsu/powersof10/index.html