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Chapter 28.4 Asteroids, Comets & Meteoroids

Chapter 28.4 Asteroids, Comets & Meteoroids . Std 1f: Know the evidence for the dramatic effects that asteroid impacts have had in shaping the surface of planets and their moons and in mass extinctions of life on Earth

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Chapter 28.4 Asteroids, Comets & Meteoroids

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  1. Chapter 28.4 Asteroids, Comets & Meteoroids Std 1f: Know the evidence for the dramatic effects that asteroid impacts have had in shaping the surface of planets and their moons and in mass extinctions of life on Earth Objective 1: Describe the physical characteristics of asteroids and comets Objective 2: Describe the Kuiper Belt and the Oort Cloud Objective 3: Compare meteoroids, meteorites and meteors

  2. Asteroids • Asteroids - a small, rocky object that orbits the sun • The largest of the small bodies in the solar system • More than 50,000 have been discovered • The larger asteroids are known as “minor planets”

  3. Asteroid Belt • Most asteroids are located in a region between Mars and Jupiter known as the Asteroid Belt

  4. Composition of Asteroids • Composition (made out of) is similar to inner planets • 3 categories of asteroids composition: • 1) Silicate materials • 2) Iron & Nickel • 3) Carbon material (rarest)

  5. Near-Earth Asteroids • More than 1,000 asteroids have orbits that bring them very close to Earth • Asteroids could strike Earth causing significant damage • Asteroid detection programs track these near-Earth asteroids to help predict possible collisions

  6. Comets • Comets-small bodies of ice, rock and cosmic dust with an elliptical orbit around the sun • It gives off gas and dust in the form of a tail as it passes close to the sun • Most famous is Halley’s Comet which passes by Earth every 76 years (last time 1986) • Hale-Bopp passed by in 1997

  7. Composition of comets • Comets have several parts: • Core (nucleus)- made of rock, metals, and ice • Coma- a spherical cloud of gas and dust surrounds the core (core & coma form the head of the comet) • Tail- form when sunlight changes the comet’s ices to gases. Solar wind pushes the gas away from the sun

  8. Objective 1: Describe the physical characteristics of asteroids and comets • Where are most asteroids found? • Between Mars and Jupiter (Asteroid belt) • What are the 3 different compositions of asteroids? • Silicate materials, nickel and iron, and Carbon • What is a small, icy, rocky object that orbits the sun? • comet • What are the 3 parts that make up a comet? • Core, coma, tail

  9. Comets

  10. The Oortcloud • Most comets originate in the Oort cloud • Oortcloud -a spherical cloud of dust and ice that surrounds the solar system and extends from the Kuiper belt to almost halfway to the nearest star • Long-period comets – comets that take more than 200 years to complete one orbit of the sun

  11. The Kuiperbelt • Pluto may be the largest body in this belt • Kuiper belt - A region of the solar system just beyond the orbit of Neptune that contains small bodies of mainly ice

  12. Objective 2: Describe the Kuiper Belt and the Oort Cloud • Where is the Kuiper belt located? • Beyond Neptune • Where is the Oort cloud located? • Surround the solar system almost to the next star • Where do most comet originate? • Oort cloud • What is the largest body in the Kuiper belt? • Pluto

  13. Short period comets • They take less than 200 years to complete one orbit around the sun • Halley’s comet is a short period comet

  14. Meteoroids (in space) • Meteoroids -A relatively small, rocky body that travels through space • Diameter is less than 1mm • They are probably pieces of matter that come from passing comets • Produce meteor showers • Lyrid meteor shower (caused by dust from Thatcher comet) • Peaks April 22 (best viewing 3:30 – 4:40am)

  15. Meteors (in the atmosphere) • Meteors -A bright streak of light that results when a meteoroid burns up in Earth’s atmosphere • Meteors are commonly called shooting stars • Meteoroids sometimes vaporize very quickly in a brilliant flash of light called a fire ball • Meteor shower - A large number of small meteoroids entering Earth’s atmosphere in a short period of time • D New report • Amazing video

  16. Meteorites (hits Earth) • Large meteors may not burn up completely in the atmosphere • If it hits the Earth’s surface it is known as a meteorite 3 types of meteors: 1) Stony 2) Iron 3) Stony iron

  17. Objective 3: Compare meteoroids, meteorites and meteors • What is a small rocky body that travels through space? • meteoroid • What is the bright streak of light caused by meteoroid burning up? • meteor • What is a meteor that hits the Earth? • meteorite • What are 3 types of meteors? • Stoney, iron, stoney iron

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