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(meteorobs) Yukon Meteorite May Provide 'New Window Into The Universe'



Donald Savage
Headquarters, Washington, DC                      March 16, 2000
(Phone:  202/358-1547)

Ann Hutchison
Johnson Space Center, Houston, TX
(Phone:  281/483-5111)

Jean-Claude Paradis
Natural Resources Canada, Ottawa, ON 
(Phone:  613/992-9426)   

RELEASE:  00-41

YUKON METEORITE MAY PROVIDE "NEW WINDOW INTO THE UNIVERSE"

     A meteorite that exploded over a remote area of northwest 
Canada in January may offer "a new window into the universe before 
the solar system was created," said a NASA scientist who has begun 
analyzing some of the meteorite fragments.

     The very primitive composition and pristine condition of the 
4.5-billion-year-old meteorite "offers us a snapshot of the 
original composition of the entire solar system before the planets 
formed," said Dr. Michael Zolensky, a cosmic mineralogist at 
NASA's Johnson Space Center (JSC) in Houston.  "It tells us what 
the initial materials were like that went into making up the 
Earth, the Moon and the Sun."  The age of the solar system is 
about 4.5 billion years.
  
     "These meteorite fragments are of immense scientific value 
and interest," said Dr. Richard Herd, Curator of National 
Collections for the Geological Survey of Canada.  "This rare find 
potentially will contribute to a better understanding of the 
nature of the universe."  He added that finding previously 
undetected compounds in the fragments will have implications for 
both planetary and biological sciences worldwide.

     The scientists described the fragments -- lumps of crumbly 
rock with scorched, pitted surfaces -- as resembling partly used 
charcoal briquettes:  black, porous, fairly light and still 
smelling of sulfur. 

     Several factors combined to make this meteorite a cosmic 
bonanza for scientists.  First, it is a carbonaceous chondrite, a 
rare type of meteorite that contains many forms of carbon and 
organics, basic building blocks of life.  Carbonaceous chondrites, 
which comprise only about 2 percent of meteorites known to have 
fallen to Earth, are typically difficult to recover because they 
easily break down during entry into Earth's atmosphere and during 
weathering on the ground.   

     Zolensky said the last time a carbonaceous chondrite like 
this fell to Earth and was recovered was 31 years ago.   "This is 
probably the only time in my career this will happen," he said. 

     The location and timing of the fireball also contributed to 
the scientific value of the samples.  The fragments are part of a 
meteor that blew apart over a remote area of the Yukon Territory 
the morning of Jan. 18, 2000.  The resulting sonic booms startled 
residents as far away as British Columbia and Alaska.  The frozen, 
snow-covered ground of the remote Yukon provided near-ideal 
conditions for preservation, Herd said.  

     The finder, a local resident who has requested anonymity, 
collected the fragments in clean plastic bags and kept them 
continuously frozen.  These are the only freshly fallen meteorite 
fragments recovered and transferred to a laboratory without 
thawing.  Keeping the fragments continuously frozen minimized the 
potential loss of organics and other volatile compounds in the 
fragments.

     About 2 pounds of meteorite fragments have been recovered so 
far.  Of those, Zolensky has about a pound of fragments provided 
by the Canadian government and the University of Calgary.  The 
finder loaned them to the university and to the National Meteorite 
Collection of the Geological Survey of Canada, Natural Resources 
Canada (NRCan) in Ottawa, which provided the still-frozen samples 
to JSC for study and analysis.  NASA is working closely with NRCan 
scientists and is providing results of the analysis to them.  "We 
are very sensitive to the fact that these are Canadian 
meteorites," Zolensky said.  Any future studies will be done in 
cooperation with scientists worldwide.
  
     Scientific analysis of the fragments has just begun.  Tests 
have been limited to two non-destructive activities: making a thin 
section to analyze the mineralogy of the fragments, and measuring 
induced radioactivity.  Tests for induced radioactivity, which are 
being carried out by Dr. David Lindstrom of JSC, measure the 
object's exposure to space radiation.  This can be used to 
determine the size of the original meteoroid in space, estimates 
of which range up to 50 feet in diameter, with a mass of more than 
55 tons. 

     The next step in the study of the fragments will be baseline 
analyses of the organics in the meteorite.  This would require the 
destruction of some samples, and negotiations are under way with 
the finder for permission to do such tests. 

     "The nice thing about having a sample like this is that you 
don't really know what you're going to find or where it's going to 
lead," Zolensky said.  "You can tuck samples away for the future 
when new questions come along that people can't even think up 
now."  

                              - end -


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