Lisa Randall - Knocking on Heavens Door: How Physics and Scientific Thinking Illuminate the Universe and the Modern World

Warped Passages

Knocking

on Heavens

Door

HOW PHYSICS AND SCIENTIFIC

THINKING ILLUMINATE THE UNIVERSE

AND THE MODERN WORLD

Lisa Randall

KNOCKING ON HEAVENS DOOR. Copyright 2011 by Lisa Randall.

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FIRST EDITION

Library of Congress Cataloging-in-Publication Data
Randall, Lisa.

Knocking on heavens door : how physics and scientific thinking illuminate the universe and the modern world / Lisa Randall.1st ed.

p. cm.

Summary: From the one of Time magazines 100 Most Influential People in the Worldand bestselling author of Warped Passagesan exhilarating and readable overview of the latest ideas in physics and a rousing defense of the role of science in our livesProvided by publisher.

ISBN 978-0-06-172372-8

1. ScienceSocial aspects. 2. PhysicsSocial aspects. I. Title.

Q175.5.R365 2011

500dc22

2011010521

EPub Edition SEPTEMBER 2011 ISBN: 9780062096890

11 12 13 14 15 OV/RRD 10 9 8 7 6 5 4 3 2 1

We are poised on the edge of discovery. The biggest and most exciting experiments in particle physics and cosmology are under way and many of the worlds most talented physicists and astronomers are focused on their implications. What scientists find within the next decade could provide clues that will ultimately change our view of the fundamental makeup of matter or even of space itselfand just might provide a more comprehensive picture of the nature of reality. Those of us who are focused on these developments dont anticipate that they will be mere post-modern additions. We look forward to discoveries that might introduce a dramatically different twenty-first-century paradigm for the universes underlying constructionaltering our picture of its basic architecture based on the insights that lie in store.

September 10, 2008, marked the historic first trial run of the Large Hadron Collider (LHC). Although the nameLarge Hadron Collideris literal but uninspired, the same is not true for the science we expect it to achieve, which should prove spectacular. The large refers to the collidernot to hadrons. The LHC contains an enormous 26.6 kilometer circular tunnel deep underground that stretches between the Jura Mountains and Lake Geneva and crosses the French-Swiss border. Electric fields inside this tunnel accelerate two beams, each consisting of billions of protons (which belong to a class of particles called hadronshence the colliders name), as they go aroundabout 11,000 times each second.

The collider houses what are in many respects the biggest and most impressive experiments ever built. The goal is to perform detailed studies of the structure of matter at distances never before measured and at energies higher than have ever been explored before. These energies should generate an array of exotic fundamental particles and reveal interactions that occurred early in the universes evolutionroughly a trillionth of a second after the time of the Big Bang.

The design of the LHC stretched ingenuity and technology to their limits and its construction introduced even further hurdles. To the great frustration of physicists and everyone else interested in a better understanding of nature, a bad solder connection triggered an explosion a mere nine days after the LHCs auspicious initial run. But when the LHC came back on line in the fall of 2009working better than anyone had dared anticipatea quarter-century promise emerged as a reality.

In the spring of that same year, the Planck and Herschel satellites were launched in French Guiana. I learned about the timing from an excited group of Caltech astronomers who met May 13 at 5:30 A.M. in Pasadena, where I was visiting, to witness remotely this landmark event. The Herschel satellite will give insights into star formation, and the Planck satellite will provide details about the residual radiation from the Big Bangyielding fresh information about the early history of our universe. Launches such as this are usually thrilling but very tensesince two to five percent fail, destroying years of work on customized scientific instruments in those satellites that fall back to Earth. Happily this particular launch went very well and sent information back throughout the day, attesting to just how successful it had been. Even so, we will have to wait several years before these satellites give us their most valuable data about stars and the universe.

Physics now provides a solid core of knowledge about how the universe works over an extremely large range of distances and energies. Theoretical and experimental studies have provided scientists with a deep understanding of elements and structures, ranging from the extremely tiny to the very large. Over time, we have deduced a detailed and comprehensive story about how the pieces fit together. Theories successfully describe how the cosmos evolved from tiny constituents that formed atoms, which in turn coalesced into stars that sit in galaxies and in larger structures spread throughout our universe, and how some stars then exploded and created heavy elements that entered our galaxy and solar system and which are ultimately essential to the formation of life. Using the results from the LHC and from such satellite explorations as those mentioned above, todays physicists hope to build on this solid and extensive base to expand our understanding to smaller distances and higher energies, and to achieve greater precision than has ever been reached before. Its an adventure. We have ambitious goals.

You have probably heard very clear, apparently precise definitions of science, particularly when it is being contrasted with belief systems such as religion. However, the real story of the evolution of science is complex. Although we like to think of itat least I did when first starting outas a reliable reflection of external reality and the rules by which the physical world works, active research almost inevitably takes place in a state of indeterminacy where we hope we are making progress, but where we really cant yet be sure. The challenge scientists face is to persevere with promising ideas while all the time questioning them to ascertain their veracity and their implications. scientific research inevitably involves balancing delicately on the edge of difficult and sometimes conflicting and competingbut often excitingideas. The goal is to expand the boundaries of knowledge. But when first juggling data, concepts, and equations, the correct interpretation can be uncertain to everyoneincluding those most actively involved.