This may look like one of Saturn’s moons, but it’s actually a tiny sphere of metal rubidium -- an unexpected byproduct in a new process that enables Magnetic Resonance Imaging (MRI) of air-filled organs like the lungs. For imaging lungs, patients inhale “hyperpolarized” xenon gas, which is in a special state that allows it to “light up” lung functionality. Hyperpolarization requires contact with laser-illuminated rubidium vapor. However, in a recent study, physics major Chris Flower, ’16, showed via electron microscopy that illuminated rubidium vapor sometimes forms these spherical clusters that disrupt hyperpolarization. Flower’s insights provide a basis for improving the efficiency and cost-effectiveness of hyperpolarized gas MRI.