Technics

New research reveals a large asteroid breakup to be the likely source of the impactor that caused a mass extinction event on Earth 65 million years ago

The impactor believed to have wiped out the dinosaurs and other life forms on Earth some 65 million years ago has been traced back to a breakup event in the main asteroid belt. A joint U.S.-Czech team from Southwest Research Institute (SwRI) and Charles University in Prague suggests that the parent object of asteroid (298) Baptistina disrupted when it was hit by another large asteroid, creating numerous large fragments that would later create the Chicxulub crater on the Yucatan Peninsula as well as the prominent Tycho crater found on the Moon.

The team of researchers, including Dr. William Bottke (SwRI), Dr. David Vokrouhlicky (Charles University, Prague) and Dr. David Nesvorny (SwRI), combined observations with several different numerical simulations to investigate the Baptistina disruption event and its aftermath. A particular focus of their work was how Baptistina fragments affected the Earth and Moon.

At approximately 170 kilometers in diameter and having characteristics similar to carbonaceous chondrite meteorites, the Baptistina parent body resided in the innermost region of the asteroid belt when it was hit by another asteroid estimated to be 60 kilometers in diameter. This catastrophic impact produced what is now known as the Baptistina asteroid family, a cluster of asteroid fragments with similar orbits. According to the team's modeling work, this family originally included approximately 300 bodies larger than 10 kilometers and 140,000 bodies larger than 1 kilometer.

Once created, the newly formed fragments’ orbits began to slowly evolve due to thermal forces produced when they absorbed sunlight and re-radiated the energy away as heat. According to Bottke, “By carefully modeling these effects and the distance traveled by different-sized fragments from the location of the original collision, we determined that the Baptistina breakup took place 160 million years ago, give or take 20 million years.”

The gradual spreading of the family caused many fragments to drift into a nearby “dynamical superhighway” where they could escape the main asteroid belt and be delivered to orbits that cross Earth’s path. The team’s computations suggest that about 20 percent of the surviving multi-kilometer-sized fragments in the Baptistina family were lost in this fashion, with about 2 percent of those objects going on to strike the Earth, a pronounced increase in the number of large asteroids striking Earth.

The team then investigated the origins of the 180-kilometer diameter Chicxulub crater, which has been strongly linked to the extinction of the dinosaurs 65 million years ago. Studies of sediment samples and a meteorite from this time period indicate that the Chicxulub impactor had a carbonaceous chondrite composition much like the well-known primitive meteorite Murchison. This composition is enough to rule out many potential impactors, but not those from the Baptistina family.

The article, “An asteroid breakup 160 Myr ago as the probable source of the K/T impactor,” was published in the Sept. 6 issue of Nature.

Contact Bottke at (303) 546-6066 or william.bottke@swri.org.
 

SwRI signs international autonomous vehicle collaborative agreement

Southwest Research Institute (SwRI) is joining forces with The Institut National de Recherche en Informatique et en Automatique (INRIA) of France to advance autonomous vehicle technologies, focusing on the areas of perception, intelligence, command and control, communications, platforms and safety.

SwRI signed an international collaboration agreement in September 2007 with INRIA, a French national institute that conducts fundamental and applied research in information and communication science and technology. The partnership will conduct joint research and exchange intellectual property to foster rapid technology and system advancements in vehicle autonomy.

“We believe that the vehicle autonomy field is entering a rapid growth phase, as evidenced by recent advances associated with defense science programs such as the DARPA Grand Challenge and the European Commission PReVENT programs, as well as automotive industry advances in active safety devices,” said Dr. Steven W. Dellenback, director of the Intelligent Transportation Systems Department at SwRI.

In 2006, SwRI established a $5 million internal research and development program, called the Southwest Safe Transport Initiative (SSTI), to improve safety in urban traffic environments. SSTI is charged with developing new sensor, computing and mobile technologies to augment vehicle platforms and provide autonomous vehicle capabilities.

Operated under the dual authority of the French Ministry of Research and the Ministry of Industry, INRIA plays a major role in technology transfer, training, research and development, and scientific and technical information dissemination. Within INRIA, the IMARA team specializes in applying information and communication technologies in the intelligent transportation systems field.

Contact Dellenback at (210) 522-3914 or steven.dellenback@swri.org.
 

Army fuels and lubricants laboratory at SwRI marks 50th anniversary

The U.S. Army TARDEC Fuels and Lubricants Research Facility (TFLRF) at Southwest Research Institute (SwRI) celebrated its 50th anniversary with a ceremony in October.

The TFLRF is a Government-Owned Contractor-Operated (GOCO) facility that provides state-of-the-art research, development and engineering services for the Army's fuels and lubricants needs, said Ed Owens, director. The facility, which opened May 9, 1957, reports to the U.S. Army Tank Automotive Research, Development and Engineering Center (TARDEC) in Warren, Mich., and is operated by SwRI's Fuels and Lubricants Research Division.

The facility is a unique resource where a highly trained and experienced staff perform integrated fuels-lubricants-engine systems research and development programs. These programs involve combustion, performance characterization, engine cleanliness, vulnerability assessments and tribology.
TARDEC's capabilities range from fundamental investigations to field validation testing and rapid response problem-solving.

Early results from the partnership included identifying the causes and chemistry of engine sludge and deposit formation, developing a fundamental understanding of low-temperature wax formation in diesel fuels, analyzing engine exhaust emissions, understanding diesel ignition and combustion, and evaluating fuel alternatives for spark ignition and diesel engines. These efforts led to changes and developments of new procedures and requirements subsequently adopted by commercial industry.

Today, while still predominantly supporting the Army, staff members are involved in a variety of projects to support all U.S. military services as well as other government agencies such as the Department of Energy.

A significant project under way is the development and fielding of a fire-resistant JP-8 fuel for Army ground equipment, both combat and tactical. This JP-8 fuel will self-extinguish, thereby saving lives, reducing severe burns and reducing equipment loss caused by fire.

Other activities include supporting a project for the Defense Advanced Research Projects Agency to qualify jet fuels made from non-petroleum sources, evaluating a variety of oil lifetime extension approaches for Army ground vehicles, and conducting a study to assess the feasibility of a single-specification, single-viscosity-grade lubricant for military ground vehicles.

Contact Steve Marty, (210) 522-5929 or steve.marty@swri.org.
 

SwRI's Dinwiddie receives Rossiter W. Raymond Award, Alfred Noble Prize

Cynthia L. Dinwiddie, Ph.D., a senior research engineer in the Geosciences and Engineering Division at Southwest Research Institute, has received the 2007 Rossiter W. Raymond Memorial Award from the American Institute of Mining, Metallurgical and Petroleum Engineers (AIME) and the 2007 Alfred Noble Prize from the American Society of Civil Engineers (ASCE).

These awards are in recognition for her paper "The Small-Drillhole Minipermeameter Probe for In-Situ Permeability Measurement," published in December 2005 in Reservoir Evaluation & Engineering, a Society of Petroleum Engineers' (SPE) journal. The work documented in this paper led to an understanding of the effect of the measurement instrument on the natural system; size and shape of and weighting within its averaging volume; and general guidelines for its use. Dinwiddie and colleagues at Clemson University have a statutory invention registration for the device.

The awards were presented during the 2007 SPE Annual Technical Conference and Exhibition last November in Anaheim, Calif. The Rossiter W. Raymond Memorial Award, established in 1945 to honor one of AIME's founders, recognizes the best paper by an author under age 35 published by an AIME member society. The Alfred Noble Prize was established in 1929 honoring Noble, a past president of the American Society of Civil Engineers and the Western Society of Engineers.

Dinwiddie, who joined the SwRI staff in 2001, is a hydrogeologist with broad expertise in mechanical engineering, environmental engineering and science, and the mathematical sciences including application of numerical analysis and applied mathematics to model hydraulic and pneumatic flow behavior near measurement instruments. Her work at SwRI includes in situ field measurement and analysis of heterogeneities within volcanic rocks, geomorphologic and hydrologic studies of Martian outflow channels and geophysical characterization of terrestrial analogs to Mars using multiple near-surface techniques.

Dinwiddie holds a doctorate in environmental engineering and science and a master of science degree in environmental systems engineering from Clemson University. She holds a bachelor of science in engineering degree from Walla Walla College. She is the author or co-author of 12 peer-reviewed publications. She has also served as a panel reviewer for the National Science Foundation, a technical reviewer for NASA grant proposals and a peer reviewer for several technical journals including Transport in Porous Media, Journal of Hydrology, Journal of Hydrologic Engineering, and Environmental Science and Technology, and for the Proceedings on the Scientific Basis for Nuclear Waste Management.

Dinwiddie is past president of the Alamo Chapter of Sigma Xi. She is also a member of the Association of Environmental Engineering and Science Professors, American Geophysical Union, Geological Society of America - Divisions of Hydrogeology and Planetary Geology, Houston Geological Society and the National Ground Water Association.

Contact Dinwiddie at (210 522-6085 or cynthia.dinwiddie@swri.org.
 

Published in the Winter 2007 issue of Technology Today®, published by Southwest Research Institute. For more information, contact Joe Fohn.

Winter 2007 Technology Today
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