|Aspirin’s Form I has a structure that is more robust all-around, whereas Form II is strongest along one axis and weaker on others, making the second version less stable.|
Speculation began in the early 2000s when calculations were published claiming that, although aspirin has a unique and well-known structure, known as Form I, there is a second possible arrangement which should occur just as often called Form II. This result caused some dismay in the scientific community, since the second form of the drug had never been observed.
In the new research, this preference was found to be attributable to subatomic forces that lose strength quickly with distance, which is why they had been ignored or overlooked by previous investigators; other recent research has shown these same forces to be responsible for the gecko’s miraculous clinging and climbing abilities. Taking into account the behavior of charges within the molecule's constituent atoms, rather than treating them as purely neutral particles on the basis of equal proton and electron numbers, the team found significant differences in the predicted favorability of Forms I and II.
This tale brings to mind the (probably apocryphal) story of the physicist at a dinner party who calculates to everyone’s amazement that, according to the laws of aerodynamics, bumblebees shouldn’t be able to fly. Here, as in that story, the lesson appears to be that when discrepancies arise between mathematical predictions and the observed universe, it’s usually the math that needs revision.