Progress in science is sometimes triggered by surprises. Data collection resembles gathering of new pieces in a jigsaw puzzle and placing them together. Sometimes one of the pieces does not quite fit. It is natural for scientists to instinctively argue that such a piece does not belong; perhaps it is an artifact driven by uncertainties in the data or a misinterpretation of the experiment. This might indeed be the case in most instances. But every now and then, an anomaly of this type signals a real discrepancy from expectations, either a violation of a highly respected but incomplete law of nature—namely an exception to the rule, or an unexpected surprise—signaling the possibility of “new physics.”
