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COMETS AND IMPACT CRATORS

COMETS AND IMPACT CRATORS. Mullard Space Science Laboratory University College London http://www.mssl.ucl.ac.uk. What is a Comet ?. Comets are small, fragile, irregularly shaped bodies composed mostly of a mixture of water ice, dust and carbon- and silicon-based compounds.

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COMETS AND IMPACT CRATORS

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  1. COMETS ANDIMPACT CRATORS Mullard Space Science Laboratory University College London http://www.mssl.ucl.ac.uk

  2. What is a Comet ? Comets are small, fragile, irregularly shaped bodies composed mostly of a mixture of water ice, dust and carbon- and silicon-based compounds. Comets have highly elliptical orbits that repeatedly bring them close to the Sun and then swing them into Space.

  3. Parts of a Comet Hydrogen Cloud Ion Tail Nucleus Dust Tail Coma

  4. Water Ammonia Sand or Fine-grained Dirt Salt Methane Crushed Charcoal briquettes Organic compounds Alcohol Dry Ice Ingredients for the Nucleus of a Comet

  5. Shoemaker-Levy 9Collision with Jupiter Date: July 16th – July 22nd 1994 Diameter: 20 fragments up to 2 km The large dark “scars” seen on the above image were the result of the impact of fragment G

  6. Tunguska Comet Impact Area : Earth, Siberia, Tunguska Date : 7.17AM, June 30th, 1908 A mysterious explosion occurred in the skies over Siberia. This explosion was caused by the impact and breakup of a large meteorite, at an Altitude of roughly 6km in the atmosphere.

  7. Chicxulub Impact Crater Area : Earth, Mexico, Yucatan Peninsula Age : 65 million years Diameter : 170 km Thought to be the cause of the extinction of the dinosaurs !

  8. How is an Impact Crater Formed ?

  9. Two Types of Impact Crater • Simple Crater – Bowl-shaped, smooth-walled craters • of a small size. 2) Complex Crater – Larger craters that can collapse, form terraces, central peaks, central pits, multiple rings and peak ring basins.

  10. Fill a pan with surface material (flour) to a depth of about 2.5cm. Smooth the surface, then tap the pan to make the material settle evenly. Sprinkle a fine layer of coloured material (dry paint, or powdered drink mix), evenly and completely over the surface. (Use a sieve or sifter for more uniform layering). Then sprinkle a fine layer of sand or flour over the top. Use different side balls and drop from different heights, and observe the impact craters produced. Making an Impact Crater

  11. Barringer Meter Crater Area : Earth, Arizona Age : 49,000 years Diameter : 1.186 km Simple meteorite impact crater

  12. Wolfe Creek Crater Area : Earth, Australia Age : 300,000 years Diameter : 0.875 km Simple impact crater

  13. Aorounga Crater Area : Earth, Chad Age: 200 million years Diameter : 17 km A buried complex crater with dark streams

  14. Bessel Crater Area : Moon Diameter : 16 km In between a simple and complex crater

  15. Copernicus Crater Area : Moon Age: > 1 billion years Diameter : 93 km Complex crater with central peak and rays

  16. Yuty Crater Area : Mars, North Hemisphere Diameter : 10 km Complex crater with central peak and fluid flow

  17. Meitner Crater Area : Venus Diameter : 150 km 3rd Largest impact feature on Venus with 2 circular rings

  18. Meteor - aflash of light in the night sky due to the friction of a meteoroid passing through the atmosphere. Meteoroid - an interplanetary chunk of matter smaller than 1km and frequently millimeters in size. Meteorite – an partof a Meteoroid that survives the fall through the atmosphere and lands on the Earth. Asteroid – a larger chunk of rock that comes from the asteroid belt located between the orbits of Mars and Jupiter. What is a Meteor, a Meteoroid, a meteorite, and an Asteroid.

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