The Chaotic Birth of Planets (Scientific American Magazine 05.2008)

50 The Genesis of Planets - Douglas N. C. LinTheorists long imagined that the formation of young solar systems was a serene process with a stately progression, in which the eventual appearance of planets was a foregone conclusion. The latest evidence, however—including observations of worlds circling other stars—argues that planet formation is startlingly chaotic.60 Regulating Evolution - Sean B. Carroll, Benjamin Prud’homme and Nicolas GompelMost animals share similar genes. The staggering diversity in their physical forms springs from switches in the DNA that govern where and when those genes are active.68 Science 2.0 - M. Mitchell WaldropIs posting raw experimental data online, for all to see, a great tool or a great risk?74 How Cells Clean House - Vojo Deretic and Daniel J. KlionskyAutophagy, a process that normally keeps cells in good working order, seems to be linked to aging and diseases such as Alzheimer’s.82 Hooked from the First Cigarette - Joseph R. DiFranzaCigarette addiction can arise astonishingly fast. New research could help make quitting easier.88 Rethinking Nuclear Fuel Recycling - Frank N. von HippelPlans are afoot to reuse spent reactor fuel in the U.S. But the advantages of the scheme pale in comparison with its dangers.94 Fighting Killer Worms - Patrick SkellyBloodsucking worms called schistosomes are among the world’s most worrisome human parasites. A new genome sequence and powerful genetic tools promise to help crack their secrets. Cover 1 Table of Contents 2 From the Editor 5 Letters 6 50, 100 & 150 Years Ago 8 Updates 10 News Scan 12 SciAm Perspectives: Taking Heed 32 Sustainable Developments: The African Green Revolution 34 Forum: The Mad Scientist Myth 36 Skeptic: A New Phrenology 38 Antigravity: Are You Buying This? 41 The Genesis of Planets 42 Regulating Evolution 52 Science 2.0 60 How Cells Clean House 66 Hooked from the First Cigarette 74 Rethinking Nuclear Fuel Recycling 80 Fighting Killer Worms 86 Insights: Dark Forces at Work 92 Working Knowledge: Living Cover 94 Reviews 96 Ask the Experts 98