(Introduction to the Focus stories of the past week)

Robert Matthews

20 NOV 2000

For cosmologists the old Chinese curse, "May you live in interesting times," is beginning to seem all too appropriate. According to the latest evidence, a mysterious "antigravity" force--the so-called dark energy--appears to be a major component of the cosmos. The dark energy density is thought to remain constant in time, while matter continues to be "diluted" as the Universe expands. That raises a question: Why do we happen to live in the "interesting times" when the density of dark energy and that of matter happen to be similar, when one is not overwhelmed by the other? That's the riddle a team of theorists have tackled in the 14 November PRL, and they claim to have found a simple explanation involving only the most basic parameters from high energy physics.

(N. Arkani-Hamed et al., Phys. Rev. Lett. 85, 4434.

COMPLETE Focus story at http://focus.aps.org/v6/st22.html

Link to the paper: http://publish.aps.org/abstract/PRL/v85/p4434/)