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Discover the origins and significance of asteroids, comets, and meteoroids - remnants of our solar system's formation, with comets containing valuable materials essential for life. Learn about their orbits, structures, and how meteor showers occur on Earth.
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Section 28.4 Asteroids, Comets and Meteoroids • Left over from nebula from when the solar system was formed. • Travel in some type of orbit. .
Comets • mixture of ice, frozen gases and dust
nucleus (solid – rock, metal and ice) • coma (cloud of gas and dust surrounds nucleus) • tails (dust and ionized gases). Always points away from the sun
Orbits of Comets • Highly elliptical • Velocity increases greatly when they are near the Sun • Visible only when near the sun • Dark and virtually invisible throughout most of orbit
Why are comets important? • Contain leftover materials that formed the planets and the Sun more than 4.5 billion years ago. • Contain many of the organic materials thought to be essential for life
Origin of Comets 1. Kuiper Belt – short period comets – up to 200 years
Origin of Comets 2. Oort Cloud long period comets – up to 30 million years.
NASA's Hubble Space Telescope took this photo of Comet ISON on Oct. 9, 2013, when the comet was inside Mars’ orbit and about 177 million miles from Earth. The nucleus of ISON appears to be intact.
Comet Hale-Bopp 1997
Meteor Showers • Earth passes through the orbit of some comets • comet debris burns up in Earth’s atmosphere. • predictable time each year. • named after the constellation they seem to originate from
Asteroids • Rocky or metallic objects • Most orbit the Sun in the asteroid belt between Mars and Jupiter.
40,000 known asteroids that are over 0.5 miles in diameter in the asteroid belt • range in size from tiny pebbles to about 578 miles in diameter
small asteroid. Usually less than 1 mm Meteoroids
Meteor • METEOR - meteoroid that enters earth’s atmosphere. Most burn up as a shooting star.
Meteorite • Meteor or part of a meteor that does not burn up entirely and falls to the ground.