The Cosmic Landscape Read Online Free PDF Page B

astronomical discoveries exactly parallel the theoretical advances. The newest astronomical data about the size and shape of the universe provide confirmation that the universe exponentially “inflated” to a stupendous size much bigger than the standard ten or fifteen billion light-years. There is very little doubt that we are embedded in a vastly bigger megaverse. But the biggest news is that in our pocket of space, the notorious cosmological constant (a mathematical term that Einstein originally introduced into his equations and later rejected in disgust) is not quite zero as it was thought to be. This discovery has rocked the boat more than any other. The cosmological constant represents an extra gravitational repulsion, a kind of antigravity that was believed to be absolutely absent from the real world. The fact that it is not absent is a cataclysm for physicists, and the only way that we know how to make any sense of it is through the reviled and despised Anthropic Principle.
    I don’t know what strange and unimaginable twists our view of the universe will undergo while exploring the vastness of this Landscape. But I would bet that at the turn of the twenty-second century, philosophers and physicists will look back to the present as a time when the twentieth-century concept of the universe gave way to a megaverse, populating a Landscape of mind-boggling proportions.
Nature Has the Jitters
    “Anyone who is not shocked by quantum theory has not understood it.”
    — NIELS BOHR
    The idea that the Laws of Physics can vary throughout the universe is as meaningless as the idea that there can be more than one universe. The universe is all there is; it may be the one noun in the English language that logically should have no plural. The laws governing the universe as a whole cannot change. What laws would govern those changes? Are they not also part of the Laws of Physics?
    But I mean something much more modest by the Laws of Physics than the grand, overarching laws that regulate all aspects of the megaverse. I mean the things that an ordinary twentieth-century physicist, a physicist more interested in the laboratory than the universe, would have meant: the laws governing the building blocks of ordinary matter.
    This book is about these Laws of Physics—not
what
they are but
why
they are. But before we can discuss the why, we need to know the what. Exactly what are these laws? What do they say, and how are they expressed? The task of this first chapter is to bring you up to speed on the Laws of Physics as they were understood circa the year 2000.
    To Isaac Newton and those who came after him, the physical world was a precise deterministic machine whose past determined its future “as sure as night follows day.” The laws of nature were rules (equations) that expressed this determinism in precise mathematical language. For example, one could determine how objects move along precise trajectories given their initial starting points (including their velocities). The great French eighteenth-century physicist and mathematician Pierre-Simon de Laplace expressed it this way:
    We may regard the present state of the universe as the effect of its past and the cause of its future. An intellect which at a certain moment would know all forces that set nature in motion, and all positions of all items of which nature is composed, if this intellect were also vast enough to submit these data to analysis, it would embrace in a single formula the movements of the greatest bodies of the universe and those of the tiniest atom; for such an intellect nothing would be uncertain and the future just like the past would be present before its eyes.
    Just in case the translation from the French is unclear, Laplace was saying that if, at some instant, you (some superintellect) knew the position and velocity of every particle in the universe, you could forever after predict the exact future of the world. This ultra-deterministic view of nature was the