METEORITICS
Meteorites & Solar System History
ISIS-230 / EOS-230 / Spring 2016
Perkins, Link Classroom #6
Wednesdays, 10:05 - 12:55
Nicholas Gessler

Join us as we explore the origin of our solar system and life itself through the science of meteoritics. 
Every day is punctuated by falling rocks.
Some are seen as fiery meteors and heard as thundering artillerty. Others are unseen, sinking silently to the ocean's depths of falling unheard on unoccupied land. 
Over 50,000 meteorites have been registered worldwide and cataloged in the Meteoritical Bulletin Database. 

(Silvia Seceleanu and Ronen Plesser) An exhibit in the Bryan Center mounted and filmed by Anisha Khemlani, Sarah Garland and Sophia Durand (2013).	Astronomy Days at the North Carolina Museum of Natural Sciences (2014). Emily Morino, Jason Lee and ??? .	Astronomy Days at the North Carolina Museum of Natural Sciences (2014). Yuchen Long.	Astronomy Days at the North Carolina Museum of Natural Sciences (2014). Yuchen Long and Kristin Cole.
Astronomy Days at the North Carolina Museum of Natural Sciences (2014). Charlie Thomson.	Astronomy Days at the North Carolina Museum of Natural Sciences (2014). Kristen Cole and Yuchen Long.	Astronomy Days at the North Carolina Museum of Natural Sciences (2014). Kristen Cole.	Astronomy Days at the North Carolina Museum of Natural Sciences (2014). Emily Morino, Jason Lee and ??? .

Meteorites contain micron-size diamonds and graphite dust dating back 6 billion years, long before our solar system formed 4.57 billion years ago.  These rocks date half-way back to the origin of the Universe some 13.7 billion years ago and of our own Galaxy aged 12.7 billion years.  The vast majority of meteorites (chondrites) date from a time just before the Earth was formed about 4.53 billion years ago.  They contain millimeter-size spherical droplets of once melted minerals (chondrules) fused by lightning flashing through the solar nebula.  Chondrites are "fossils" of the first condensed matter from the hot gaseous solar nebula: millimeter-sized chondrules, flecks of nickel-iron, broken crystals and fine dust. Chondrites retain an "undifferentiated" sample f the particles from which they formed. As chondritic planetary bodies (asteroids, planetoids and meteoroids) grew larger they also grew hotter. These larger planetesimals eventually got hot enough to melt. In a molten state the more dense minerals, like iron, fell to the core.  Lighter minerals floated to the crust.  Fragments of these "differentiated" bodies no longer retained their chondritic structure and are called achondrites. They are considerably more scarce.  We will work, hands-on, with a wide variety of chondrites and achondrites including specimens from Mars, the Moon, Vesta and other asteroids.

Recommended technical text:
(Check for discounted copies on Amazon.com).

Recommended authoratative, concise, well illustrated and well written introductory texts:
(Check for discounted copies on Amazon.com or AbeBooks.com).

Descartes and Lavoisier both championed the theory that meteorites were a phenomenon of weather, meteorology, and formed high above the ordinary atmosphere in a flammable atmospheric layer.  The science of meteoritics began with Ernst Chladni’s publication, “On the Origin of the Pallas Iron and Others Similar to it, and on Some Associated Natural Phenomena”  in 1794.  As he did in his time, we will retrace the cultural and intellectual history of meteoritics from the early accounts in Europe, such as the 1492 fall of a 280-pound stone at Enshsheim, Alsace, to the present hunts, such as the 2012 hunt for a rare carbonaceous chondrite at Sutter’s Mill in California.  Here, in North Carolina, only 29 meteorites are known, the most recent collected in 1934.  None have been reported for nearly 80 years!  We will unearth the historic records to question why.  We may visit collections in the Raleigh Museum of Natural Sciences, known sites of falls and finds, and/or search new localities in order to raise that inventory.*

We will meet in a large computer and multimedia equipped classroom enabling us to actively do research on the Web and to create a resource for North Carolina meteorite information.  We will also experiment with Web-based and PC-based simulations of the origin of the solar system, the ring structures of planets like Saturn, the shepherding influence of moons on smaller particles, the orbits of comets, asteroids and satellites, the odd orbits of Trojan asteroids which lead and follow those of major planets, and the curious wanderings of meteoroids from their ejection from their parent bodies to their arrival on Earth.  These simulations will allow us to run alternative “what if?” scenarios to explain the past and present and to predict the future.

We will investigate different strategies of finding meteorites in the field, in the Antarctic ice, the dry deserts of the Southwest and North Western Africa and in forested regions.  We will learn how to use technologies such as all-sky cameras, Doppler radar and Google Earth to recover falls and ground penetrating radar and metal locators to recover finds.  We will follow the personal narratives of successful international expeditions, meteorite “hunters,” dealers and collectors.

We will actively scrutinize a suite of meteorites as they are found, both fresh and weathered, examining hand specimens by eye and by binocular and petrographic microscope, looking for evidence of their fiery entry through our atmosphere, their fusion crusts and orientation, and their patterns of their arrival on the ground.  We will look closely at 30-micron thin sections, using both inspection and polarizing microscopes.  We may 3D X-Ray some meteorites and characterize others under the microprobe to submit them for publication.* 

* These items are on our active “wish list” and while we will try to make them happen we realize that they may be impractical to implement due to logistical, budgetary and administrative constraints.