The Grip of Gravity: The quest to understand the laws of motion and
gravitation by Prabhakar Gondhalekar, Cambridge University Press, 拢18.95,
ISBN 0521803160
NOBODY understands gravity. It鈥檚 more than a bit ironic. After all, Isaac
Newton discovered the universal law of gravitation more than 300 years ago. With
it, he predicted the motion of planets and cannon balls, a feat that hammered
home the stupendous potential of science like no other. But all Newton really
did was describe the behaviour of gravity, as did Einstein, though admittedly in
a much more sophisticated way. To this day, nobody has figured out what gravity,
at the nuts and bolts level, actually is.
Given this, it鈥檚 remarkable how much we have learned. We鈥檝e learned that
gravity is synonymous with deformed space-time; that through accretion on
鈥渟upermassive鈥� black holes, it powers the most energetic galaxies in the
Universe; that despite it being the feeblest of all nature鈥檚 forces, it
orchestrates the evolution and ultimate fate of our Universe.
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Astrophysicist Prabhakar Gondhalekar guides us through gravity鈥檚 maze. He
begins with Aristotle, dwells on the insights of Galileo, Newton and Einstein,
and finishes with 10-dimensional 鈥渟uperstring鈥� theory, the great hope for a
theory that unifies gravity with quantum theory. The Grip of Gravity is
replete with entertaining digressions and biographical sketches. If just
thinking about the geometry of curved space gives you a migraine, you might be
reassured to learn that it gave its inventor, Bernhard Riemann, a nervous
breakdown.