Note to users. If you're seeing this message, it means that your browser cannot find this page's style/presentation instructions -- or possibly that you are using a browser that does not support current Web standards. Find out more about why this message is appearing, and what you can do to make your experience of our site the best it can be.

Science 21 August 2009:
Vol. 325. no. 5943, pp. 951 - 952
DOI: 10.1126/science.1176730
Prev | Table of Contents | Next

Perspectives

Astronomy:

Early Solar System Chronology

Andrew M. Davis

The short-lived radioisotope 26Al (1) has long been used as a relative chronometer of events in the early solar system. However, although much is known about its initial abundance in the early solar system, there remain doubts on applicability of 26Al chronometry, because it is not known whether it was uniformly distributed. On page 985 of this issue, Villeneuve et al. (2) report the development of new techniques that allow magnesium isotopic measurements to be made with unprecedented precision. They confirm that 26Al/27Al was indeed uniform in the early solar system to about the 10% level and find that chondrules formed in discrete events over a time period of more than 1 million years. These data are a major step forward in developing a precise and accurate chronometer, but also raise new questions about early solar system processes.

Department of the Geophysical Sciences, Enrico Fermi Institute and Chicago Center for Cosmochemistry, University of Chicago, Chicago, IL 60637, USA.

E-mail: a-davis{at}uchicago.edu

Read the Full Text

To Advertise     Find Products

Science. ISSN 0036-8075 (print), 1095-9203 (online)