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Comets, Asteroids, and Meteors, Oh My!. Comets. Loose collections of ice, dust, and small rocky particles Orbits are usually very long, narrow eclipses When orbit come close to Sun, it heats up, ice turns into gas, releasing dust. Structure of a Comet.
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Comets • Loose collections of ice, dust, and small rocky particles • Orbits are usually very long, narrow eclipses • When orbit come close to Sun, it heats up, ice turns into gas, releasing dust
Structure of a Comet • Coma – gas and dust that form an outer layer • Nucleus – inner layer of comet • Tail – can stretch for millions of kilometers
Where are comets found? • Kuiperbelt – disc-shaped region of icy objects • beyond the orbit of Neptune (billions of kilometers from our sun) • OortCloud – spherical cloud of comets • Spans 30 trillion kilometers from the sun
Oort Cloud • Jan Oort • Hypothesized cloud in 1950
Bayeux Tapestry • Commemorates the Norman Conquest of England in 1066, depicts an apparition of Comet Halley.
Halley’s Comet • 76 years
Comet Shoe-Maker Levy 9 • Short periodic comet • 1993 collided with Jupiter
Meteoroid • Come from comets or asteroids • Chunk of rock or dust in space Fun Fact: On average a meteor streaks overhead every 10 minutes!
The Life of a Meteoroid • Comets or asteroids break to create a meteroid • Meteroid enters Earth’s atmosphere meteor (burns up in the sky) • Meteroid passes through Earth’s atmosphere and hits Earth’s surface meteorite
Meteor Showers • October 20, 2011 – pieces of Halley’s comet
Asteroids • Rocky objects revolving around the sun • Too small and numerous to be planets • Asteroid belt found between Mars and Jupiter Asteroid Ida
Asteroid Belt • Where the majority of asteroids are found
Big Bang Theory • 65 million years ago • Yucatan Pennisula, Mexico • Crater 200 kilometers in diameter
Why are there so many craters on the moon compared to the Earth? • Moon has no atmosphere • Earth’s atmosphere • wipes away evidence of craters (wind and water erosion, earthquakes) • Burns up meteors
Impact Craters • Eye of QuibecBarringer Crater (AZ) • 200 million years old 50,000 years old