SIGHTINGS


 
Greenland Meteorite
May Be From Inter-Stellar Space
By Gene Emery
8-21-98

 
COPENHAGEN (Reuters)- A meteorite which crashed into Greenland last December may have come from outside our solar system, the first time such a thing has happened, a Danish astronomer said on Thursday.
 
 
A four-week expedition to the southwestern part of the Greenland ice cap failed to find fragments of the meteorite but returned home on Wednesday with about 200 samples of dust.
 
 
Astronomer Lars Lindberg Christensen from Denmark's Tycho Brahe Planetarium astronomy centre, a member of the seven-man expedition, said analysis of the dust samples could yield clues to the origin of the meteorite.
 
 
``It may have come with enough speed that it actually originated outside our solar system. That would make it a world first,'' he told Reuters by telephone.
 
 
The centre has collected more than 100 witness reports, three seconds of videotape and data from a U.S. defence satellite of the meteorite's plunge through the Earth's atmosphere.
 
 
Calculations based on the video frames of the meteorite's descent, which lit up the night sky over Greenland on December 9, put its velocity at 56 km (35 miles) per second, or 1.5 times the maximum speed of any known meteorite in our solar system, Christensen said.
 
 
At such a speed, the object would have disintegrated and the only traces would be dust, he said.
 
 
``It also means that it is most likely that the snow samples contain dust from the meteorite,'' he said.
 
 
The expedition collected enough dust to allow the particles to be examined thoroughly, revealing their molecular and atomic composition.
 
 
If analysis shows the dust particles are more than 4.5 billion years old that would confirm the meteorite originated in inter-stellar space, he said.
 
 
Our solar system is estimated to have been formed 4.5 billion years ago.
 
 
Preliminary findings from the Niels Bohr astro- and geophysics institute and the geological institute of the University of Copenhagen could be ready in a matter of months, Christensen said.
 
 
Traces of more than 10,000 meteorites have been found on Earth but the Greenland find is special because it is one of the few that have been seen plunging from space.





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