JWST uncovers a fully formed galactic bar in the early universe, challenging bar-formation theory
JWST spotted a long, fully formed stellar bar in GN20, a massive galaxy from the early universe, contradicting three predictions that bars shouldn’t exist in young, gas-rich disks. Independent dust maps corroborate the structure, suggesting turbulence-driven gas dynamics can stabilize bars and drive central starbursts and black hole growth. The finding implies early galaxies matured faster than models predicted and will prompt revisions to simulations, with follow-up kinematic studies planned (e.g., ALMA).
