Space rock collection lands at Homecoming
Meteorites, solid bodies from outer space that have fallen to the Earth’s surface, represent the building blocks of the terrestrial planets, including Earth. Although they are a rare find, meteorites do land all over the planet. Dry hot deserts or cold barren landscapes are the best locations for finding and preserving meteorites. The dry desert climate slows rusting of the metal within many meteorites and the lack of vegetation makes meteorites easier to find.
It only seems logical then that the world’s largest university-based meteorite collection is based in Arizona. The Center for Meteorite Studies in the School of Earth and Space Exploration at ASU houses around 10,000 specimens representing more than 1,600 separate meteorite falls, making it not only the largest university-based collection but also placing it in the top 10 in the world. This collection is actively used for geological and space-oriented research by scientists at ASU and throughout the world.
The age of most of the specimens in the collection is about 4.57 billion years old, and some come from as far away as the moon and Mars. But when it comes to agreeing on a favorite, everyone has a different opinion. “Some of our most precious and interesting meteorites are theMartian andLunar ones,” says professor Meenakshi Wadhwa, director of the center and a professor in the College of Liberal Arts and Sciences.
The center’s collection has eight Martian meteorites and three lunar specimens.
Meteorites from Mars and the moon are distinguished from Earth rocks and other meteorites by their chemical compositions, mineralogy, and age. Meteorites vary in size from a few centimeters across to several feet in diameter. In general, meteorites are heavier than Earth rocks of the same size due to their increased abundance of nickel-iron metal. The heaviest individual specimen in the collection is a piece of Hugoton currently on loan to ASU’s Robert S. Dietz Geology Museum, weighing in at 313.4 kg.
There are three types of meteorites: stony, iron, and stony-iron. The surface of a freshly fallen meteorite, regardless of its type, will appear black and shiny. As it falls through the atmosphere, friction heats and smoothes the meteoroid’s outer surface. Over time, however, this once ebony surface will weather and fade to a rusty brown color.
L’Aigle, which fell in France in 1803 in a shower of thousands of stones – is of significant historical importance because its fall finally convinced people that meteorites actually fall from space. Also of historical importance is the piece of Ensisheim, an ordinary stony meteorite that fell in 1492, in the village of Ensisheim (Alsace, France). This meteorite is the second oldest ever recovered from a witnessed and recorded fall.
This year, the center at ASU was awarded an ASU Women and Philanthropy grant that will aid in extending its educational and outreach activities. This grant will allow the center to develop hands-on modules that will include actual meteorites and that will be on loan to teachers in the greater Phoenix area.
Homecoming visitors will have the chance to stop by the center’s booth and touch meteorites and test their knowledge. This display contains representative specimens of all three main meteorite types, including a piece of Allende that contains microscopic grains that predate the formation of our solar system. Visitors are encouraged to touch the specimens, especially Canyon Diablo, a piece of the iron meteorite responsible for the formation of Meteor Crater.
Visitors can also engage in a game of “meteorwrong”. Using the information learned while handling the display meteorites, visitors are asked to find the meteorite hidden within a group of common “meteorwrongs” such as magnetite, slag, and hematite. A magnet and a streak plate are provided as tools to help distinguish the meteorite from the “meteorwrongs.”
Nikki Staab, firstname.lastname@example.org
School of Earth and Space Exploration