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Meteors and Meteorites

Meteors and Meteorites. Voorhees High School Astronomy Club Nick Meligari Mrs. Bellows. 2010. Terms about Meteors. Meteoroid – any particle in space from the size of a sand grain to boulder Meteor – Flash of light from a meteoroid that burns in the Earth’s atmosphere. Terms Cont.

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Meteors and Meteorites

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  1. Meteors and Meteorites Voorhees High School Astronomy Club Nick Meligari Mrs. Bellows 2010

  2. Terms about Meteors • Meteoroid – any particle in space from the size of a sand grain to boulder • Meteor – Flash of light from a meteoroid that burns in the Earth’s atmosphere.

  3. Terms Cont. • Meteorite – A meteoroid that lands on Earth. • Bolide – Large meteor; seen in broad daylight, sometimes explodes (can knock down entire forests)

  4. Why Meteors Glow? • Front side begins to melt and release chemicals • These substance glow when they are heated • Friction with atmosphere due to speed: 160,000 mph or 20-40 km / s (a rifle bullet travels .7km/s)

  5. Zenith Hourly Rate • ZHR is a count of how many meteors you can see in an hour under the best conditions for a meteor shower: • Zenith (darkest part of sky, 6.5 limiting mag) • After midnight (when Earth turns into the meteoroids) • Maximum shower debris period

  6. Classifying Meteorites • They’re classified according to distinguishing features and of what they are made (elements). • Example: iron meteorites, have a main make up of iron (Fe) and nickel (Ni)

  7. Composition of Iron Meteorite • Iron 91%Nickel 8.5%Cobalt 0.6%

  8. Widmanstatten Lines • Crystals of iron and nickel show up when meteorite is cut and acid-polished. • Form under extreme pressure and long cooling in space

  9. Composition of Stony Meteorite • Oxygen 36%Iron 26%Silicon 18%Magnesium 14%Aluminum 1.5%Nickel 1.4%Calcium 1.3% • Like Earth’s mantle

  10. Composition of Stoney Chondrite Meteorites (80%) • Mainly carbon; contain chondrules (spheres) • Most primitive objects in the solar system • Can supply us with materials from beyond our solar system • Weather very easily

  11. Achrondite • Has gone through melting • Magma of parent body • Stony meteorite without chondrules • The cube is 1 cm • The meteorite sells for $5,000

  12. Tektites • Blobs of molten iron & silica that cooled rapidly • Fragments from a major impact recaptured by Earth • Origin can be Earth, Moon or Io • Four major tektite fields

  13. Iridium • Most corrosive resistant metal known • A heavier element, rare on the Earth’s crust (.03 ppb), but common in meteorites (500 ppb). • A thin layer (3 ppb) of Iridium lies at the K-T boundary, dating back 65 million years. • Best hypothesis is an ash cloud containing iridium dust covered the planet. This is believed to have been from an impact that caused the dinosaur extinction.

  14. Impact Craters (so far!)

  15. Coesite • Coesite is a form of shocked quartz (SiO2) • The pressure and temperature required are by meteorite impact or atomic bomb explosion. • It helps identify a crater’s origin. • In the image, coesite is the entire dark blue area

  16. Barringer Meteor Crater • Winslow, Arizona • Hit by a 70,000 ton object • 60 meters in diameter • Traveling at 40,000mph

  17. Barringer Crater Statistics • The crater is 1,219 meters wide • The force of the impact was 750 times more powerful than that of the Hiroshima atomic bomb

  18. AMNH’s Largest Displayed Meteorite • Named “Ahnighito” by the Eskimos • Discovered in Greenland, and brought to the U.S. by explorer Robert Peary • Mainly composed of Iron

  19. “Ahnighito” • Ahnighito was used by the Inuits to create tools, knives, etc • Ahnighito weighs a WHOPPING 34 – tons

  20. The largest meteorite 65-ton Hoba Meteorite Still in ground, Namibia, Africa Fell 80,000 years ago

  21. Gibeon Meteorite • An estimated 12,000 years ago an Iron Nickel meteorite hit Africa. • It left a trail of shrapnel and debris 70 miles wide and 230 miles long

  22. Gibeon Cont. • The meteorite was created in an atmosphere with temperatures excess of 2,500 degrees and 0 gravity, and cooled extremely slowly over millions of years, forming crystals of Fe and Ni.

  23. Zagami Fall • Largest meteor fall: 40 lbs, 1962 • All 14 Meteors found came from Mars, total 175 lbs. • The gas trapped in the pockets matched the composition of the Mars atmosphere as determined by Viking missions in the 1970’s.

  24. Chicxulub Meteor Crater • Located on the Yucatan Peninsula • The meteorite or asteroid was the size of a small city, approx. 15 – 20 miles in diameter

  25. Chicxulub: the KT Event • The impact sent tsunamis, and earthquakes around the globe • Global dust storm; ash obscured Sun for centuries, global cooling • Thin layer of iridium all over the world

  26. Chicxulub • Believed to be the cause of the dinosaur extinction, through either a global firestorm or major global environmental changes (global dust blocking Sun)

  27. Sylacauga Meteorite • 1954 – A meteorite crashed through the roof of Mrs. E. Hewlett Hodges in Sylacauga, Alabama. It bounced throughout her home and hit her in the leg

  28. Wethersfield Meteorite • 1982 – Wethersfield, CT The Donahues were home when a 6lb meteorite crashed into their home and destroyed furniture in a near room. They donated the rock to The New Haven Museum

  29. Peekskill Meteorite • 1992 – Peekskill, NY an 8lb meteorite hit a Chevy Malibu owned by Michelle Knapp. She sold the car and meteorite for $69,000. The car now tours the country.

  30. Asteroid 2008 TC3 had diamond dust! This December 2008 photo, released by NASA, shows a black chunk of rock found in the Sudan desert, the first time astronomers have tracked an asteroid from space, toward Earth, into the atmosphere and down on the ground as a meteorite; the fireball fell 10/2008.

  31. Perseid Meteor Shower • Source of the shower is from the Comet Swift-Tuttle • Come every year, late July through August • Swift-Tuttle is nowhere near Earth, we pass through its tail

  32. Perseid Cont. • The meteors from Swift-Tuttle hit Earth traveling at 132,000 mph • Perseid meteors appear to fly out from the direction of the constellation Perseus

  33. Leonid Meteor Storm • Greatest Meteor Storm, occurred 166 years ago on Nov. 13, 1833 • Shower went on for over 4 hours with thousands of meteors falling every minute

  34. Leonids Cont. • In 1998 the Leonids, (appear to be coming from the constellation Leo) fell as a storm. • There were approx. 1 meteor per second, for some locations on Nov. 18, 2001, another year for a storm.

  35. Find a meteorite? • Send a brief letter describing your sample to: Director of the Center for Meteorite Studies Arizona State University Main Campus PO Box 872504 Tempe, AZ 85287-2504 This is a free service; if you send in your sample for evaluation, and it is a meteorite you will have an offer for purchase before it is returned.

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