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Post by Chicago Astronomer Joe on Jul 1, 2005 12:19:00 GMT -6
Scientist Refines Cosmic Clock To Determine Age Of Milky Way
The University of Chicago's Nicolas Dauphas has developed a new way to calculate the age of the Milky Way that is free of the unvalidated assumptions that have plagued previous methods. Dauphas' method, which he reports in the June 29 issue of the journal Nature, can now be used to tackle other mysteries of the cosmos that have remained unsolved for decades.
Dauphas, an Assistant Professor in Geophysical Sciences, operates the Origins Laboratory at the University of Chicago. In his latest work, Dauphas has honed the accuracy of the cosmic clock by comparing the decay of two long-lived radioactive elements, uranium-238 and thorium-232. According to Dauphas' new method, the age of the Milky Way is approximately 14.5 billion years, plus or minus more than 2 billion years.
The 14.5 +/- 2BY age of the galaxy is in good agreement with the best estimate of the age of the universe, 13.7 BY. The method is still plagued with the assumption of the initial uranium and thorium production ratio. Still, it's a step in the right direction because we'll get a better handle on the ratio as time goes on.
If the universe is a ball the size of America, then the solar system is almost as large as the smallest cell in the human body.