[Baps] Monday, April 4th, Jay Melosh colloquium

[Michael Person]

Please  join us on Monday, April 4th, 4pm for the EPS colloquium series with: 

Jay Melosh

From: Purdue University

Title: “Tiny Worlds of the Ice and Grit: NASA’s Latest Encounters with Comets Hartley 2 and Tempel 1”

Abstract:
NASA’s most recent successes in exploring new worlds took place on November 4, 2010  and February 14, 2011 when two spacecraft made close passes by comets Hartley 2 and Tempel 1. Although small, Hartley 2 turned out to be a feisty customer, burping CN gas six weeks before encounter and blasting huge quantities of CO2 gas and water vapor into space, along with dust and tarlike organic material.  Images sent back from the spacecraft show an elongated nucleus about 2.0 km long, shaped like a peanut.  It is divided into two major lobes separated by a smooth collar. The lobes are sources of powerful jets of gas and dust that loft chunks of material into space.  Its surface is pitted, ridged and littered with blocks of ice and dust tens of meters in diameter.  Tempel 1, which was the target of the Deep Impact collision in 2005, is much larger, seems to lack clumps of material and appears to be composed of a fine, weak powder.  It nevertheless possesses a complex geologic history, with layers, crater-like depressions and what appear to be several pyroclastic flow deposits.   In this presentation I will show images of these comet's surfaces and discuss what these observations mean, so far as we currently understand them. 

At: Haller Hall (Geo-Museum 102)  24 Oxford St.

Please also join us for a reception following the talk in the Student Lounge, Hoffman Lab 4th Floor.