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13 - Impacts & Extinctions

13 - Impacts & Extinctions. The Important Rules of Impacts: RULE 1: Impacts Happen RULE 2: There are Consequences to Rule 1. Barringer Crater, near Winslow, Arizona (just east of Flagstaff) - 1 mile wide blemish. (There are also near-misses - 1972 over Tetons).

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13 - Impacts & Extinctions

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  1. 13 - Impacts & Extinctions

  2. The Important Rules of Impacts: RULE 1: Impacts Happen RULE 2: There are Consequences to Rule1 Barringer Crater, near Winslow, Arizona (just east of Flagstaff) - 1 mile wide blemish (There are also near-misses - 1972 over Tetons)

  3. RULE 3: The History of the Solar System is Written on the Face of the Moon

  4. Energy of Impacts Rate of Impacts

  5. The Tunguska Event On the morning of June 30, 1908, a brilliant fireball appeared in the morning skies of Siberia, and exploded at an altitude of about 6 km. At a distance of 60 km from “ground zero” people were knocked to the ground. Those within 30 km were thrown into the air (and one person was killed as a result). No impactor body was ever found. 3-5 Megaton “airburst” a comet or asteroid. No UFOs or black holes required… Aerial photo (above) and close-up (below) of flattened trees

  6. Comet Shoemaker-Levy 9 (SL9) Discovered by Eugene & Carolyn Shoemaker and David Levy on March 24, 1993 using the 18-inch Schmidt telescope at Mt. Palomar, California. Weird appearance due to it being a string of fragments Image by Jim Scotti, Spacewatch Telescope at Kitt Peak, Arizona Hubble WFPC2 image of the SL9 fragments, with labels assigned them

  7. Set for Impact with Jupiter Montage of images of Jupiter & SL9

  8. Great Comet Crash - July 1994 The impacts were particularly impressive in the infrared, as shown in this image from the Calar Alto Observatory “scars” of the impacts as big as the Earth

  9. Impacts & Extinctions

  10. Cretaceous-Tertiary (K-T) Boundary Found world-wide Ir content - in 1980 Luis & Walter Alvarez suggest it was due to an impacting asteroid Also - shocked quartz

  11. Reminder - also affected other forms (example - brachiopods) Though hotly debated in the 1980’s & later, impact hypothesis still favored for much of the K-T extinction event. So where is the “smoking gun”?

  12. Yucatan, Mexico! Gravimetric map & cenotes

  13. Shocked quarts (above) & tectites (below) There are current drilling projects to investigate more

  14. For a nice site on the subject, see the one by Ralph Taggart at MSU

  15. Many Existing Near Earth Object (NEO) Programs in US - discover & track potentially hazardous asteroids & comets Lincoln Near-Earth Asteroid Research (LINEAR) - MIT & Air Force - telescopes near Socorro NM Near Earth Asteroid Tracking (NEAT) - Air Force & JPL - telescopes at Haleakala, Maui, and Mt. Palomar, CA Spacewatch - University of AZ - telescope on Kitt Peak near Tucson AZ Lowell Observatory Near-Earth Object Search (LONEOS) - Flagstaff AZ Catalina Sky Surveys - Catalina Station & Mt. Lemmon Station (near Tucson) & Siding Springs Observatory, Australia C/2002 T7 LINEAR C/2001 Q4 NEAT

  16. Schwassmann-Wachmann 3 Despite claims that crop circles made by aliens were a warning about the destruction of the Earth by SW3, no impact occurred.

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