E-Book Content
FUSION POWER PLANTS Why We’re Still Waiting
grand experiments Testing Climate Change
Fierce Storms, Methane Seas:
TITAN REVEALED page 36
March 2010
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The Brain’s
D Dark Energy Mysterious brain activity holds clues to disorders and maybe even to
consciousness
The Toxic Gas That
Saves Lives
How Life Shaped
Mineral “Evolution”
© 2010 Scientific American
CONTENTS features ■ Scientific American March 2010 Volume 302 Number 3 ■
PL ANETARY SCIENCE
36 T he Moon That Would Be a Planet
36
By Ralph Lorenz and Christophe Sotin Titan, Saturn’s largest natural satellite, has an atmosphere thicker than Earth’s and a surface that is almost as varied. NEUROSCIENCE
44 The Brain’s Dark Energy By Marcus E. Raichle
Brain regions active when we allow our minds to wander may hold a key to understanding neurological disorders and even consciousness itself. ENERGY
50 Fusion’s False Dawn By Michael Moyer
As a historic milestone nears, skeptics question whether it will ever be possible to build a working fusion reactor that could supply virtually unlimited clean energy.
44
50
geoLOGY
58 Evolution of Minerals By Robert M. Hazen
Looking at the mineral kingdom through the lens of deep time leads to a startling conclusion: most mineral species owe their existence to life.
78
medicine
66 Toxic Gas, Lifesaver By Rui Wang
Though lethal, hydrogen sulfide turns out to play key roles in the body— a finding that could lead to new treatments for heart attack victims and others. animal behavior
72 Worm Charmers By Kenneth Catania
Follow an intrepid scientist as he learns why earthworms rush to the surface when bait hunters rub a piece of metal across a stick poked into the ground. ENVIRONMENT
78 Climate Change: A Controlled Experiment
On The Cover
By Stan D. Wullschleger and Maya Strahl Scientists have manipulated grasslands and forests to see how precipitation, carbon dioxide and temper ature changes will affect the future of the biosphere.
2 S C I E N T I F I C A M E R I C A N
58 Remarkably, the brain carries out a great deal of meaningful activity all the time, even when a person is sitting back and doing nothing at all. Image by Aaron Goodman.
© 2010 Scientific American
M a r c h 2 0 10
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