The Milky Way Galaxy – Our Galaxy The Universe  A galaxy is a group of stars, dust, and gases held together by gravity.  Our solar system is a part of the Milky Way Galaxy  The universe is made of billions of galaxies.

Structure of the Milky Way #1.

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THE BIG BANG  The big bang theory states that at one time, the entire universe was confined to a dense, hot, supermassive ball. Then, about 13.7 billion years ago, a violent explosion occurred, hurling this material in all directions. Click on this link:

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The Big Bang #6. #7.

The Expanding Universe Red shift, or a Doppler shift toward the red end of the spectrum, occurs because the light waves are “stretched,” (longer wavelengths) which shows that Earth and the source are moving away from each other.  Red Shift #8.

Doppler Effect – apparent shift in the wavelength of energy (sound or light) when emitted by a source moving away from or toward an observer. Stationary Moving Away Moving Toward

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Wavelength – the distance between wavecrests (the top of each wave). Frequency – the number of wavelengths in a given distance.

Spectrum – band of various colors of light.

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Characteristics of Stars The temperature of a star is determined by it’s color. BLUE=HOT ; RED=COOL The composition of stars is determined by looking at their spectrum.

H-R Diagram A chart that shows the relationship between the luminosity and temperature of stars.

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STARS Luminosity – the brightness of a star compared to the brightness of the Sun as seen from the same distance.

Apparent Magnitude Apparent – a star’s brightness as it appears from Earth. The sun APPEARS brighter than the other stars because it is closer to us!

USE YOUR STAR GRAPH (pg.15 in ESRT) #18. #19. #20.

USE YOUR STAR GRAPH (pg.15 in ESRT) #21. #22.

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#24. Which shows the correct order for the age of stars from YOUNGEST to OLDEST. a) Polaris, Alpha Centauri, Procyon B b) Procyon B, Alpha Centauri, Polaris c) Alpha Centauri, Polaris, Procyon B d) Polaris, Procyon B, Alpha Centauri

The Sun Process that generates the sun’s energy: Nuclear Fusion occurs in the Core of the sun. Fusion is the nuclei of hydrogen atoms fusing into helium. This process converts mass into energy.

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Sunspots- cool, dark areas of gas within the photosphere that are caused by powerful magnetic fields.

#26. The observations of sunspots show that the sun: a. Revolves b. Rotatesc. does not moved. is made of fire

Terrestrial Planets – “Earth-like” land/rock planets; 4 planets closest to the sun they are solid, smaller in size and more dense NO LONGER CONSIDERED A PLANET

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Jovian Planets - like “Jupiter”, 4 outer planets, made of mostly gases, large, and low density

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Oblate Spheroid- a slightly flattened sphere Roundness Ratio- Comparing the polar diameter of a sphere to the equatorial diameter to determine if the object is perfectly round.

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