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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.

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Presentation on theme: "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."— Presentation transcript:

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 Oort cloud Most comets originate in the Oort cloud Oort cloud - 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 Kuiper belt 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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