Dr. Rex Hanger, UWW Dept. of Geography & Geology, will talk about Death from Above: Asteroid collisions and mass extinctions on Earth on Fri., Nov. 12, at 8 p.m. (Upham Hall 140), followed by a public viewing session at the Whitewater Observatory at 9:15 p.m. (weather permitting). This is the third of four fall 2010 Observatory Lecture Series, all of which are free and open to the public! An abstract of the lecture is at the bottom of this blog entry.
The remaining lecture in the series is (Mark your calendars!):
- Dec. 3: Collisions on the Extragalactic Superhighway: What happens to their stars, gas, and dust when galaxies collide
Harold Andersen Library has relevant resources if you’d like to learn more. Search the HALCat catalog to find books or videos, e.g,. Rogue asteroids and doomsday comets: The search for the million megaton menace that threatens life on Earth (3rd-Floor Main Collection, QB651 .S74 1995), Rain of iron and ice: The very real threat of comet and asteroid bombardment (3rd-floor Main Collection, QB721 .L42 1997), and Fire on Earth: Doomsday, dinosaurs, and humankind (3rd-floor Main Collection, QB377 .G83 1996). Search article databases for articles such as “Hypervelocity impact of asteroid/comet on the oceanic crust of the earth” (International journal of impact engineering, 2008, vol.35:no.12, pp.1770-1777), “Impact lethality and risks in today’s world: Lessons for interpreting Earth history” (Special paper – Geological Society of America, 2002, vol.356), “Mass extinctions caused by large bolide impacts” (by Luis W. Alvarez, in Physics Today, July 1987, vol.40:no.7, pp.24-33, and “Grain size of Cretaceous-Paleogene boundary sediments from Chicxulub to the open ocean: Implications for interpretation of the mass extinction event” (Geology, March 2010, vol.38:no.3, pp.199-202).
Please ask a librarian for assistance with finding materials.
“Mass extinctions of life are defined as relatively short periods of time during which greater than normal numbers of species disappear. Hypotheses for the causes of mass extinctions traditionally revolved around slow, Earth-bound, “uniformitarian” processes, such as climate/oceanic change, or competition among organisms. In 1980, a team of distinguished scientists from the University of California at Berkeley, led by Nobel-prize winning physicist Dr. Luis Alvarez and his geologist son Dr. Walter Alvarez, put forth the bold hypothesis that the Earth had been hit by large asteroid at approximately 65 million years ago, forcing the mass extinctions of the dinosaurs and thousands of other species on land and even in the oceans. Their principal evidence was the presence of high concentrations of cosmically abundant (but rare on Earth) iridium. The decades that followed brought forth unprecedented cooperation between scientists of all disciplines as corroborative evidence continued to support asteroid collision, including the “smoking gun” crater buried in the subsurface of eastern Mexico. Asteroid collisions have now been hypothesized for other mass extinction events, though none are as well-supported as the one from Mexico. I will summarize the current understanding of asteroid collisions as the cause of mass extinction and critically evaluate their role in other mass extinction events.”
UWW’s Andersen Library is a federal depository with many federal, state, local, and international documents on a variety of current and relevant issues available to you in print, microfiche, CD-ROM, and online. Come check out your government at Andersen Library!