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eclipse--to hide or to block

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Early Tools to understand the sky

astrolabe--measures angles to predict patterns in the sky

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Sextant--also measures angles between the horizon and the stars

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Galileo--the first astronomer to use a telescope (did not invent the telescope)

discoveries:*moon has mountains*Sun spins/rotates*Venus has phases like the moon*Jupiter has four moons that orbit around it

*Earth and all the planets revolve around the Sun!*

Isaac Newton--developed the reflecting telescope

used a curved mirror to allow people to see things far away

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Stars*stars are made up of hydrogen and helium*these two gases react to give off thermal and kinetic energy (light and heat)*

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Types of Stars/Life Cycle of a Star

*nebula--cloud of dust and gas*protostar--gets smaller and warmer*main sequence star--gets smaller and warmer*red giant--gets bigger and cooler*variable stage--stars do different things here*supernova--giant explosion

*neutron star--cluster of neutrons about 12 miles across*black hole--a point in space that has gravity that pulls in everything, even light

black dwarf

white dwarf

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Characteristics of a Star

Color: tells us the temperaturered--cooler in temperature

blue-white--hottest

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Our Star, the Sun--big ball of hot gasses (hydrogen and helium)--prominences--loops and fountains of blazing gas--sun spots--darker in color; cooler than other areas of the sun

3 layersphotosphere--innermost layerchromosphere--layer in betweencorona--outermost layer