8th Grade-Ch. 4 Sec. 4 Star Systems & Galaxies

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YouTube video-Bill Nye Galaxies song

http://www.youtube.com/user/NyeTunes#p/u/47/0S9bvhtUGis

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Discover Activity-Why Does Discover Activity-Why Does the Milky Way Look Hazy?the Milky Way Look Hazy?

1. Using a pencil, carefully poke at least 20 holes close together in a sheet of white paper.

2. Tape the paper to a chalkboard or dark-colored wall.3. Go to the other side of the room and look at the paper.

From the far side of the room, what do the dots look like? Can you see individual dots?

Think It Over1. Making Models How is looking at the paper from the

far side of the room like trying to see many very distant stars that are close together? How does your model compare to the photograph of the Milky Way below?

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The Milky Way

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There are more stars in There are more stars in the sky than all the the sky than all the

grains of sand on all the grains of sand on all the beaches in the world.beaches in the world.

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binary (double) star system

2 stars

triple star system 3 stars

eclipsing binary system in which 1 star blocks the light from another

star system=

• group of 2 or more stars

• located by observing effects of star’s gravity-

• 2nd star makes 1st star move back & forth

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binary starsbinary stars

Hubble image of the Sirius binary system, in which Sirius B can be clearly distinguished (lower left).

http://en.wikipedia.org/wiki/Hubble_Space_Telescope

http://en.wikipedia.org/wiki/Sirius

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An eclipsing binary star where the smaller, An eclipsing binary star where the smaller, hotter companion alternately eclipses and is hotter companion alternately eclipses and is

eclipsed by the larger companion. eclipsed by the larger companion.

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planets around other starsplanets around other starsastronomers detect planet from

effect of planet’s gravity on motion of star it revolves around

discovered >100 large planets

http://ethel.as.arizona.edu/~collins/astro/navigation.html

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Planets Orbiting Other Stars video clip

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star clustersstar clusters large grouping of many stars 2 types:1. open clusters2. globular clusters

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Open clustersOpen clusters Globular clustersGlobular clustersLoose, disorganized appearance

Round

Made of few thousand stars

Densely packed w/ stars

Have bright supergiants & much gas & dust

Older stars about same age & distance from Earth

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Draw and label a picture of:Draw and label a picture of:

1.1. A binary star systemA binary star system2.2. A triple star systemA triple star system3.3. An eclipsing binary systemAn eclipsing binary system4.4. Open clusterOpen cluster5.5. Globular clusterGlobular cluster

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galaxygalaxyhuge group of single

stars, star systems, star clusters, dust & gas bound together by gravity

billions of galaxies in universe

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3 types3 typesof galaxiesof galaxies

• pinwheel shapepinwheel shape• have arms that have arms that

spiral outspiral out

• look likelook likeflattened ballsflattened balls• contain onlycontain only

old starsold stars

• nonoregular shaperegular shape•young starsyoung stars

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What What galaxy galaxy do we do we live in?live in?

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Milky Way galaxyMilky Way galaxywhere our solar system isbarred-spiral galaxy barred-spiral galaxy = huge bar shaped

region of stars & gas that passes thru ctr.

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The Sun is just one of 200 billion stars in this typical barred-spiral galaxy that is about 90,000 light years in diameter.

Milky Way looking down from above.

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The Milky Way Galaxy The Milky Way Galaxy

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Where is the sun in our galaxy?Where is the sun in our galaxy?

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Galaxies video clip

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universeuniverseall of space & everything in itastronomers use scientific

notation= system that uses powers of 10 to write very large or very small numbers in shorter form

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1,2001,2001.2 X 103

scientific notation

5,400,000,0005,400,000,0005.4 X 109

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100,000,000,000 stars in the Milky Way Galaxyx 50,000,000,000 Galaxies

----------------------------- 5,000,000,000,000,000,000,000

stars in the universe

5 X 1021

in scientific notation ?

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What is a binary star?What is a binary star?a star system with 2 stars

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Name the main types Name the main types of galaxies.of galaxies.

1. spiral2. elliptical3. irregular

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What type of galaxy is What type of galaxy is the Milky Way?the Milky Way?

spiral or barred-spiral

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Suppose astronomers Suppose astronomers discover a galaxy that discover a galaxy that contains only old stars. contains only old stars. What type of galaxy is What type of galaxy is

it likely to be?it likely to be?elliptical

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spiral, elliptical or irregular ?spiral, elliptical or irregular ?

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spiral

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Cigar Galaxy

http://www.seds.org/messier/Jpg/m82.jpg

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elliptical

Cigar Galaxy

http://www.seds.org/messier/Jpg/m82.jpg

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Andromeda Galaxy

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spiral

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Galaxy NGC 4486

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elliptical

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Rainbow Galaxy

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spiral

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Large Magellanic Cloud

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irregular

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spiral, elliptical or irregularspiral, elliptical or irregular

Galaxy NGC 1316

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elliptical

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elliptical

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Glitter GalaxyGlitter Galaxy1. Make a galaxy with glitter2. Name your galaxy and tell what

type of galaxy it is 3. Describe the galaxy (shape, type

of stars found in it, number of stars)

8th Grade-Ch. 4 Sec. 4 Star Systems & Galaxies

Education

Transcript of 8th Grade-Ch. 4 Sec. 4 Star Systems & Galaxies