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Warm Up April 10, 2013. Draw a circle the size of a quarter and label it “the sun”. Then draw the relative sizes of the other planets compared to your sun. Agenda. Warm Up Correct HW 14.1 Notes “Bill Nye: The Sun“ Video Cool Down. 14.1 Our Solar System.
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Warm Up April 10, 2013 • Draw a circle the size of a quarter and label it “the sun”. Then draw the relative sizes of the other planets compared to your sun.
Agenda • Warm Up • Correct HW • 14.1 Notes • “Bill Nye: The Sun“ Video • Cool Down
14.1 Our Solar System • Ancient Greeks believed in a geocentric model with the earth at the center.
Ptolemy’s Model • Claudius Ptolemy realized that the geocentric model did not match observations of the motion of the planets. • He proposed the idea of epicycles, or circles around circles to explain planetary motion.
Heliocentrism • In a heliocentric system, the earth and planets orbit around the sun. • Nicolaus Copernicus was the first to propose the heliocentric solar system.
Tycho Brahe • Brahe collected volumes of quantitaive data on the planets – all without a telescope! (Telescopes had not been invented yet).
Johannes Kepler • Kepler was a student of Brahe and after Brahe’s death, analyzing all that quantitiative data.
Kepler’s Laws of Planetary Motion • Planets move in elipses, not circles. • Planets move faster when closer to the sun and slower when farther away from the sun. • The time it takes to orbit the sun and the distance from the sun are related.
Galileo Galilei • Galileo improved upon the recently invented telescope and found evidence supporting the (unpopular but correct) heliocentric model.
Modern View of Our Solar System • Since Galileo’s time we have discovered 2 more planets, Uranus and Neptune, as well as Pluto, which was classified as a planet for about 75 years before being re-classified as a dwarf planet.
Planets • Planets orbit the sun, may have moons, and clear out their orbital paths. • The planets are: • Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, and Neptune • OR….. • My Very Educated Mother Just Served Us Nachos.
Pluto • Pluto is in the Kupier Belt, a ring of many icy objects that orbit the sun. • Also, Ceres, and asteroid in the Asteroid belt, is larger than Pluto, as is Earth’s Moon and a few other moons. • Finally, Pluto’s orbit is highly eliptical and crosses Neptune’s. No other planets have orbits that cross. • It was actually the discovery of Eris, another dwarf planet that got people thinking that perhaps Pluto needed to be reclassified.
Moons • Moons are natural satellites that orbit planets. • There are also artificial satellites that orbit earth. We use these to communicate with our cell phones, receive Sirius-XM radio, and learn about the solar system.
Asteroids • Asteroids are smaller rocky bodies that orbit the sun, but do not clear their orbital paths. • Most are found in the asteroid belt between Mars and Jupiter. • Ceres is an example of a large asteroid.
Measuring Distance • Because objects in the solar system are so far apart, it is impractical to measure distance in meters or kilometers. • One unit we do use is the Astronomical Unit (AU) • 1 AU = the distance from the sun to the earth = 150,000,000 km
Cool Down • Title: Objects in our Solar System Tree Map Solar System Planets Moons Asteroids Examples Examples Examples