visions of the universe

visions of the universe - Visions of the universe 1) How...

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Visions of the universe 1) How big is the universe? a) The milky way is one of about 100 billion (10^11) galazies b) 10^11 stars/galaxy is 10^11 galazies = 10^22 stars c) stars = grains of sand 2) suppose you counted the stars in the milky way galaxy, at a rate of 1 per second. How long would it take to count all of them…? Answer: a few thousand years 3) how fast does sound travel? a) it takes some time for sound to travel from lightning bolt to your ear b) speed of sound is about 0.3 km/s i) in 5 seconds, sound goes 0.3x5 = 1.5 km about one mile 4) how fast does light travel? a) Light travels at 300,000 km/s and no signal goes faster b) Light transit times i) Destination light travel time ii) Moon 1 second iii) Sun 8 minutes iv) Sirius 8 years v) Andromeda galaxy—2.5 million years (1) The farther away we look in distance, the further back we look in time c) A light year i) The DISTANCE that light can travel in one year (1) l l-y= (2) (300,000km/s) x (3.600s/hr) x (24 hr/day) x 365 day/yr
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visions of the universe - Visions of the universe 1) How...

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