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

examination. The
     software has all been checked, too; there are no faults that would result in a false reading of the trajectory or a slight
     shove off course. A fuel leak could do the trick, but it would have to be one that happened on both craft, in exactly the
     same way, and was not picked up by the internal instruments on either craft.
    After three decades of trying to find an answer, the researchers investigating the Pioneer anomaly have nothing. If it’s frustrating,
     it’s also intriguing—so intriguing, in fact, that even NASA’s head honcho, Michael Griffin, has become interested. Turyshev
     has had a number of conversations with Griffin about Pioneer. Maybe that’s why, after years of studying Pioneer in their spare
     time, NASA researchers now have money for the project.
    And rightly so. From the start, the Pioneer investigators have been almost exemplary when dealing with things that don’t make
     sense. They won’t embrace the extraordinary until they rule out the ordinary. Turyshev is almost pathologically opposed to
     talking about the exotic physics ideas, even the tamer ones, like a modified version of Newton’s law. Nieto is the same. He
     is proud of all the Pioneer investigators have achieved so far, all the possible explanations they have ruled out. And his
     gut feeling is that the explanation for the Pioneer anomaly will turn out to be something like forgetting to turn off the
     lights. Or whatever is the NASA equivalent.
    EVERY month, one or two new papers appear that espouse some exotic explanation for the Pioneer anomaly. The arguments often appear
     slightly unhinged; perhaps, for instance, the expansion of the universe caused the clocks involved in the measurements of
     the Pioneer probes’ position to accelerate relative to each other? If that were true, Einstein’s special relativity would
     require the analysis to be redone. The trouble is, this kind of outlandish phenomenon (and more than one has been offered)
     would also affect the motions of the outer planets, and these planets are not doing anything odd.
    Or maybe the signal photons, the particles of radiation that carried information from the craft, had their wavelengths altered
     by the expansion of the universe? The researchers offering this suggestion admit that it fails a crucial test: it would push
     the apparent position of the Pioneer probes the wrong way. Perhaps the anomaly has to do with the signal photons having their
     quantum states shifted, or their being accelerated according to the laws of nonlinear electrodynamics , a theory developed in 2001 by a pair of Brazilian physicists? Or maybe the answer lies with John Moffat’s extra universal
     force, the force that would also explain dark matter? The proponents of MOND think their theory also explains the Pioneer
     anomaly. Or, depending on which way you want to see things, is backed up by it.
    Nieto disagrees. The MOND hypothesis doesn’t tie in with the Pioneer data, he says; it doesn’t produce the right kind of drift.
     He is OK—more OK than Turyshev, at least—with all the speculation. He wants to push the boundaries; he wants to know more
     than we know at present. But not at any cost; he understands the dangers of scientists wanting something extraordinary to
     be true. “If you go into it believing you’re going to find something—oh God, you are in for trouble,” he says.
    In the end, Nieto believes they will find a straightforward explanation for the Pioneer anomaly. He is not deflated by this
     prospect, he says—not at all. We will have gained innumerable analysis techniques, and experience of handling data with exquisite
     precision, he points out. We will know the anatomy of a spacecraft—and of the space and time it travels in—with an intimacy
     that we never would have gained without Pioneer.
    And if he’s wrong—if all that effort reveals a force that is new to physics—so much the better. “For science it’s a win-win,”