PHYSICAL MATHEMATICS SEMINAR


TITLE:	LIFE ON THE EDGE: MELTING, SURFACES, 
	AND THE PERSISTENCE OF LIFE IN ICE



SPEAKER:	JOHN S. WETTLAUFER
		Yale University


ABSTRACT:

The survival of life in extreme environments relies on the presence of liquid water.  
Therefore, the question "Is there water in subfrozen environments?" is central to a 
core issue in astrobiology.  The answer to the question derives from recent advances 
in the theory of phase transitions. The stable existence of unfrozen interfacial water at 
temperatures below the bulk freezing point has been associated with large scale terrestrial 
phenomena for decades, but a major impediment to the development of macroscale 
understanding is a first-principles treatment of the local mechanisms that allow the unfrozen 
water to persist. The basic causes are only just now being understood in the context of 
"interfacial premelting".  Supercooled liquid of any material is metastable in bulk but may find 
a stable existence at interfaces between a solid and a foreign substrate, a solid and its vapor or 
other background gas, and between solid grains of the same material.  In the case of water, the 
mobility and concomitant pressure of this liquid can have dramatic effects in terrestrial polar and 
subpolar regions by controlling impurity redistribution within sea and glacier ice, weathering rocks, 
soils, and permafrost.  In both a terrestrial and astronomical context, this water can serve as a 
biological habitat.


TUESDAY, NOVEMBER 4, 2003, 2:30 pm, Building 2, Room 338

Refreshments will be served at 3:30 PM in Room 2-349

             
Massachusetts Institute of Technology, Department of Mathematics, Cambridge, MA  02139