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the solar system song. Sec. 7.4 The Planets. Name the planets in our Solar system. In order of increasing distance from the sun Your task: research, model planet assigned to your group. Some things to know.
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the solar system song Sec. 7.4 The Planets
Name the planets in our Solar system • In order of increasing distance from the sun • Your task: research, model planet assigned to your group
Some things to know... Planet = an object that orbits one or more stars, is spherical and does not share it’s orbit. • Classification of planets: Inner planets (terrestrial) • Relatively small, rocky crust • Eg. Outer Planets (gas giants) • Large clumps of gas, ice and dust • Eg.
Our Solar system Solar syst. = the planets, or sun and other smaller objects that circle it. Early thoughts: • The first model of the solar system stated that Earth was the centre of our solar system; Geocentric model. • In 1500s Copernicus argued the heliocentric model.
Observing planets • Planet vs. Star How do you know which is which? • Venus, Mercury visible early evening or morning why? • Mars, Jupiter, Saturn seen along with other stars moving westward in sky. When Earth “catches up to them” they exhibit retrograde motion. • retro motion of mars
Comparing the planets, terms to know Astronomical Unit: AU is equal to the average distance between Earth and the Sun (150 million kilometers) Earth’s orbital radius= 1AU Mercury orbital radius = 0.39 Neptune orbital radius = 30.06AU (in other words, Neptune is 4500 million km. away)
Light year • 1 light year = the DISTANCE light can travel in 1 year OR 10 X 1015 km So what? -it takes light from Sun 8.32min to reach the Earth -Oort Cloud is about 2 light years in Diameter -Milky way (center of our Galaxy) is 26kilolightyears away Sirius is 8 ly away