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Discover the vastness of our Solar System and the measurements used to comprehend cosmic distances. Learn about the Astronomical Unit (AU), which equals about 149.6 million kilometers—the average distance from Earth to the Sun. Understand the difference between terrestrial and Jovian planets, their compositions, and sizes. Explore the roles of asteroids, comets, and dwarf planets like Pluto. Dive into the scale of our Solar System, with a radius over 5,900 million kilometers, and gain a fresh perspective through engaging comparisons.
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The Solar System A Review
Measuring Distance in Space • What does the Astronomical Unit (AU) measure? • The Astronomical Unit (au) is a measure of distance that makes it easier to comprehend such large distances. • The au covers planetary distances. • The au is based off of the average distance between the Earth and the sun: • 1 au = 149598000 km (92955887.6 mi.), or approximately 150 million km (93 million miles) • Galactic distances are measured by even larger units • The light year (ly), which is the distance light can travel in one year at the speed of light (which is about 299,792,458 m/s) • One light year is about 9.5 trillion km
A Quick Review of the Parts of our Solar System • One star (the sun) at the center • Eight planets • Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, Neptune • Asteroid belt (between Mars and Jupiter);Kuiper belt • Pluto • Meteoroids, Comets, Asteroids • Moons
Terrestrial vs. Jovian Planets • Earth-Like Planets • Include Mercury, Venus, Earth, Mars • Called “terrestrial” or inner • Similar in composition (rocks and metals, not a lot of hydrogen and helium) • Similar in size (smallish) • Similar in density (denser than outer planets) • Jupiter-like planets • Include Jupiter, Saturn, Uranus, Neptune • Called “Jovian” • Similar in composition (high percentage of hydrogen and helium) • Similar in size (big) • Similar in density (not very dense!)
Density=amount of mass per volume Tennis ball vs. baseball vs. lax ball Density Pattern
Does Pluto fit the pattern? • NO – why? (Handout: 2006 National Geographic article) • http://www.pbslearningmedia.org/resource/hew06.sci.ess.eiu.planetdefine/what-is-a-planet/ • Pluto is NOT considered a planet because… • It has not cleared the neighborhood around its orbit • Has different orbital habits…very eccentric orbit, orbit very tilted • Other dwarf planets: Ceres (asteroid), Eris • All dwarf planets are rocky/icy
Minor Members of Solar System • Dwarf Planets • Spherical and orbits the Sun but has not cleared orbital path • Rocky/icy composition • Asteroids • Small rocky bodies that orbit the Sun but need not be spherical • Located between Mars and Jupiter although path may cross other planets • Bigger than 10 meters in diameter and orbit in period of 3-6 years • Comets • Rocky metallic ice balls, tail of ionized gasses and dust • Travel in long elliptical orbits from beyond Pluto • Meteoroids • Asteroids, leftover debris/parts of a comet
A Quick Review of the Parts of our Solar System: Asteroid vs. Kuiper Belt http://science.nationalgeographic.com/science/space/solar-system?2d#close-modal
The SIZE of the Solar System • Radius: over 5900 million km!! • Diameter? VOLUME? • How can we put this into perspective? • We modeled the solar system after the size of something we are familiar with…..like the WHS practice football field!