Date: February 17, 2010
Title: 80th Anniversary of the Paragould Meteorite of 1930
Podcaster: Ken Renshaw
Links: Solar System Ambassadors: http://www2.jpl.nasa.gov/ambassador/index.html
Saturn Observation Campaign: http://soc.jpl.nasa.gov/index.cfm
Description: On February 17, 1930, an 820 lb. meteorite hit Paragould, in northeast Arkansas. At that time, it was the largest stony meteorite in the world to be seen fall and recovered. Kenneth Renshaw, a native of Paragould, will take you back 80 years ago this morning to that historic event, and describe what is being done to prevent any future mass extinction, like what is believed to have happened when far larger asteroids or comets have hit our planet in the distant past.
Bio: Kenneth Renshaw is a volunteer Solar System Ambassador and Saturn Observation Campaign member for NASA/Jet Propulsion Laboratory. A resident of Piggott, Arkansas, Renshaw teaches piano, tunes pianos, is a photographer and videographer, a church choir director, and an adjunct instructor of music for Three Rivers Community College, as well as a NASA volunteer doing presentations on space at schools and organizations. He has a masters degree in music education, attending Southern Baptist College and Arkansas State University. He is married to the former Rachel Burden, and has 2 step-daughters, Melody, 17, and Liberty, 16, as well as 5 cats, 1 dog, 1 hamster, a robin, and a blue jay!
Today’s sponsor: This episode of “365 Days of Astronomy” is sponsored by Cheap Astronomy. Get more Big Bang for your buck at www.cheapastro.com.
021710 IYA Podcast: 80th Anniversary-The Paragould Meteorite
Hello, and welcome to the “365 Days of Astronomy” podcast for February 17, 2010. I am Kenneth Renshaw of Piggott, Arkansas, a Solar System Ambassador and Saturn Observation Campaign member for NASA. I am also a native of Paragould, Arkansas. Speaking of Paragould, a city of 25,000 people in Northeast Arkansas–80 years ago this morning, what was to be one of the world’s largest meteorites, struck a few miles southwest of Paragould, waking the town and causing a cattle stampede at 4:08 A.M.
Near Bethany Methodist Church, an 820 pound meteorite hit a field, creating a 10 foot hole. About 2 miles away, near Finch Baptist Church, a 73 pound piece hit another farmer’s field. The 820 lb. piece was, at that time, the largest stony meteorite in the world to be seen fall and recovered. Numerous people in several states saw the incoming rock, and some thought it was a plane coming down in flames. There were 3 sonic booms reported and 3 fireballs seen that morning, although only 2 fragments have been recovered. There may be another piece somewhere in Northeast Arkansas, although all leads I have run into have turned out to be terrestrial rocks.
The record-breaking 820 lb. meteorite is now on permanent loan at the University of Arkansas, although it has been owned by the Field Museum in Chicago since shortly after the 1930 fall, when famed meteorite collector, Harvey Ninnenger sold it to Stanley Field. Small pieces are in other institutions around the world and private collections, including my own. The 73 lb. piece is in the U. S. National Museum in Washington, D.C.
By sheer coincidence, Clyde Tombaugh discovered Pluto the day after the Paragould meteorite, so tomorrow is the 80th anniversary of that event.
For more information on the Paragould meteorite, go to my 365 Days of Astronomy podcast on February 8 of last year, or go to my article in the Encyclopedia of Arkansas online at http://www.encyclopediaofarkansas.net/encyclopedia/entry-detail.aspx?search=1&entryID=3716 .
Although this meteorite strike is one of the largest recovered, many much larger boulders or chunks of ice have hit the earth in the past, including a possible comet hitting a remote area of Siberia in 1908, near the Tunguska River. It, being a possible comet, broke up upon striking the atmosphere, and very little has been recovered, although it leveled forests for tens of miles around. It was a very isolated area, with very few people in the immediate area. What it actually was is still a matter of debate.
Meteorite, comet, and asteroid strikes have been of some concern to astronomers in the recent past, although this type of research and detection has, in the past, been placed on the back burner of research more than I think safety would recommend. However, more attention is now being placed on finding earth-crossing rocks. It is now recognized that much larger impacts have occurred in prehistoric times, and it may be just a matter of time until a devastating blow will threaten life on earth. Rocks on the order of miles across have hit the earth in the past, including a 6-mile rock that struck the Yucatan Peninsula in Mexico about 65 million years ago, that some scientists believe wiped out the dinosaurs and other species. The biggest threat of such a strike is not so much the strike area that, of course, would be literally pulverized, but the debris that would go into the atmosphere (or steam in the 75% chance of an ocean strike). This potential climate disaster would be a threat to most species throughout the Earth for an extended period of time, particularly larger land animals. Small animals and water life would be threatened less. For example, the modern cockroach survived whatever killed off the much larger dinosaurs, as they date back much further back than the time of this extinction event.
Current work detecting space hazards include finding the earth-crossing objects that may strike the planet in the future. Fortunately, space is an enormous area, and, although thousands of objects cross our orbit, it takes a long time for the earth and the object to be at the same place at the same time. As of January 2, 2010, the date I wrote this podcast, there are 1091 space rocks larger than about 100 meters across that are a potential hazard (within .05 of an astronomical unit from the earth’s orbit). However, of these, none is on a known collision course in the near future. The WISE spacecraft, recently launched, should detect many more rocks, as well as smaller rocks. WISE, the Wide-angle Infrared Space Explorer is designed to survey the entire sky of infrared sources rather than focus on individual targets like the Spitzer Space Telescope or the upcoming James Webb Telescope. Since space rocks are relatively dark, an infrared telescope will show many more targets than an optical survey. Normally, an earth or space telescope will compare 2 or more photographs to see what moved, in order to detect an orbiting asteroid, as opposed to an apparently stationary star.
Research is also being done on the constituency of these objects. If an asteroid is weakly bound together, moving it would be a different process than if the rock is solidly held together. It is pretty well established that moving an asteroid would be preferable to blowing it up with a missile, since flying debris would be as bad, or worse than a single impact. The sooner a potential strike is discovered, the smaller amount an object would have to be moved to cause it to miss the earth. If discovered soon enough, an ion engine or smaller conventional rocket engine could be placed on the asteroid, or perhaps shooting a laser beam at it, to make a small change in its orbit, to miss the earth. A discovery right before the strike might spell disaster, however. Astronomers have the goal of discovering the larger rocks in the next few years, and plotting their orbit, to see what potential strikes need to be averted. The sky is large, and objects coming from a sunward direction make this a difficult task. A few years ago, it was stated that there are more employees in a McDonald’s restaurant than astronomers working on saving the planet, but that is likely not true now, and WISE will open a huge door of discovering these hazards.
A number of spacecraft are on the way to asteroids or comets, to study the structure of these objects, as well as their chemistry. Dawn is on its way to orbit 2 contrasting asteroids, Vesta and Ceres. By the way, Ceres was promoted to a dwarf planet when Pluto was demoted to one. A few years ago, Deep Impact struck comet Tempel I with a copper impactor. Another probe, Stardust, returned a capsule with particles from the tail of another comet, Wild II. Now Stardust is on its way to Tempel I to study the impact crater, therefore the structure, on Tempel I.
Some astronomers have noticed a pattern of heavy bombardment of comets to the earth every several million years. Some have theorized a, yet to be discovered, star (likely a dim brown dwarf) orbiting our Sun, disrupting the Oort Cloud of icy comet nuclei, far from the Sun, and sending comets Sunward to strike the planets with a higher frequency, with a regular pattern of mass extinctions. This nemesis star theory is still controversial.
In the meanwhile, astronomers are working on detecting all earth-crossing asteroids over around 100 meters in size, to avert future disasters. These strikes are so rare, however, that we need to be aware and prepared, but not paranoid. As of 2010, no humans have been killed by a meteorite, although one unfortunate dog fatality has been reported. To a safe future, clear skies, and happy New Year 2010, this has been the 365 Days of Astronomy podcast.
End of podcast:
365 Days of Astronomy
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