C/2014 UN271 (Bernardinelli-Bernstein): The Nearly Spherical Cow of Comets - Bernardinelli, Pedro H.; Bernstein, Gary M.; Montet, Benjamin T.; Weryk, Robert; Wainscoat, Richard; Aguena, M.; Allam, S.; Andrade-Oliveira, F.; Annis, J.; Avila, S.; Bertin, E.; Brooks, D.; et al. (Astrophysical Journal Letters, 2021)