Free 13 Things That Don't Make Sense by Michael Brooks Page B

have to change in the near future.
    It’s an exciting thought, but it doesn’t allow us to say anything concrete about the future of science. All we can do is press
     on and add a new finding to the pile of evidence.

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    VARYING CONSTANTS
    Destabilizing our view of the universe
    F lap your arms and see if you fly. Chances are, you won’t. The downward pressure of your arms on the air, and the equal and
     opposite reaction upward, are not enough to lift your body weight against gravity. The exact figures involved come from Newton’s
     universal law of gravitation. (Whatever its accuracy over cosmological distances, it works just fine here.) The lift you would
     need to generate for takeoff involves the mass of the Earth, your mass, your distance from the center of the Earth, and a
     number known as Big G.
    Newton’s equation arose from the simple observation that two masses pull on each other, and Big G is a measure of how strong
     that pull is. The interesting thing is, there is no rationale for that number, no explanation for why Big G has the value
     it does. Scientists have worked out its value from experiments that balance the gravitational pull against another known force,
     such as the centrifugal force that wants to throw Earth out of its orbit, but just as scientists don’t know where gravity
     comes from, they also don’t know why it should have the strength that it does.
    Big G has another, more scientific name: the gravitational constant. It is probably the most familiar of the fundamental constants of physics, the collection of numbers that describe just how
     strong the forces of nature are. Though every one of their values is derived from experiments, not from some fundamental understanding,
     they are integral to what we call the laws of physics: the constants make the laws work when we use them to describe the processes
     of nature. And because we assume that flying by flapping our arms will be as difficult tomorrow as it is today—that is, we
     assume that the laws of physics are immutable, eternal—we have to assume the constants don’t change either. Which is why John
     Webb has got himself into such trouble.
    The laws and constants have helped us define and tame the natural world. But what if there are no immutable laws? What if
     the constants aren’t constant? Or, as Webb puts it, a wry smile playing across his lips, “Who decided they were constant,
     anyway?”
    WEBB is a professor of physics at the University of New South Wales in Sydney, Australia, but his first encounter with this question
     came while he was a graduate student in England. One of his professors, the cosmologist and mathematician John Barrow, suggested
     they resurrect a question first raised in the 1930s by the British physicist Paul Dirac: Have the laws of physics remained
     the same for all time?
    What is known as the standard model of physics inserts something like twenty-six numbers in its equations in order to accurately describe the strengths of the
     various forces in nature. The values we have for those numbers come from experiments done on Earth, and mostly in the twentieth
     century. Who’s to say whether the same experiments done on Alpha Centauri, or 10 billion years ago, would give the same result?
    If you want to check whether something has been the same for a long time, you need a sample that’s as old as possible. Webb
     and Barrow quickly realized they had access to a perfect sample: the light emitted, 12 billion years ago, by quasars, the
     hearts of young galaxies. The emission of light from a star involves a constant that is officially known as the fine structure constant , but is more often referred to as alpha . The quasar light would depend on alpha as it was 12 billion years ago, so analyzing that light would provide the best possible
     chance of answering Paul Dirac’s question. By 1999 John Webb had what looked like an answer.
    The photons of light that carried his answer had traveled 12