  The search for dark matter, the missing mass of the Universe, is one of the
most active fields of study within particle physics. The XENON1T experiment
recently observed a 3.5$\sigma$ excess potentially consistent with dark matter,
or with solar axions. Here, we will use the Noble Element Simulation Technique
(NEST) software to simulate the XENON1T detector, reproducing the excess. We
utilize different detector efficiency and energy reconstruction models, but
they primarily impact sub-keV energies and cannot explain the XENON1T excess.
However, using NEST, we can reproduce their excess in multiple, unique ways,
most easily via the addition of 31$\pm$11 $^{37}Ar$ decays. Furthermore, this
results in new, modified background models, reducing the significance of the
excess to $\le2.2\sigma$ at least using non-Profile Likelihood Ratio (PLR)
methods. This is independent confirmation that the excess is a real effect, but
potentially explicable by known physics. Many cross-checks of our $^{37}Ar$
hypothesis are presented.
