Predicted timescales of stellar bar formation. Theoretical simulations of bar formation in the context of large gas fractions from J. Bland-Hawthorn et al. (2024, 2025), T. Tepper-García et al. (2024) produce galaxies with a striking resemblance to GN20, featuring bars and asymmetric spiral arm structure, driven by baryon sloshing (J. Bland-Hawthorn et al. 2025, snapshot at f_gas = 40% shown). For baryon-dominated disks, the simulations predict that increased gas fractions drive earlier onset of bars, with bar formation in massive disks occurring within a few hundred Myr (f_baryon = 0.7, M_halo = 10¹¹ M_⊙; see Appendix C for more details).