The shapes of atomic nuclei are emergent properties of quantum many-body systems bound by the strong nuclear force. As the nucleon number varies, nuclei can exhibit diverse shapes, including prolate, oblate, triaxial, or pear-like configurations. Traditional low-energy techniques, such as Coulomb excitation, probe nuclear shapes on relatively long timescales (~1000 fm/c). Here, we demonstrate that shapes of nuclei can be imaged on much shorter timescales (~0.1 fm/c) by colliding them at ultra-high energies, as performed at RHIC and LHC. Collisions capture, however, not only the global shapes of nuclei but also quantum fluctuations in the nuclear wavefunction at both nucleonic and subnucleonic levels. But by comparing two collision systems, X+X and Y+Y, with similar masses but different intrinsic shapes, we can disentangle the global nuclear shape from quantum fluctuations. Applying this method to uranium-238, we identify a large prolate deformation, consistent with prior low-energy measurements, while revealing a slight breaking of axial symmetry. This approach provides a fundamentally different perspective for investigating nuclear structure and opens new avenues for integrating nuclear shape information into studies of high-energy quark-gluon plasma dynamics. The potential for leveraging collider facilities to perform experiments with selected isobaric or isobar-like collision pairs is discussed. This talk is based on a recent STAR publication in Nature: https://doi.org/10.1038/s41586-024-08097-2
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Aihong Tang