James Webb Didn't Just Find Unexpected Galaxies. It Found a Timeline Problem.

The James Webb Space Telescope launched on Christmas Day 2021 and began returning the deepest images of the early universe ever obtained. Within months, it was finding galaxies at redshifts above 10, 12, and eventually 14, objects so early and so massive that the standard model of cosmology, Lambda Cold Dark Matter, did not predict they should exist. Tonight, we spend the entire night following this story: what the standard model predicted, what Webb actually found, and what the leading explanations are. We cover JADES-GS-z14-0, the most distant confirmed galaxy at redshift 14.32, 290 million years after the Big Bang, showing oxygen emission that requires at least one prior stellar generation. We explore the Hubble tension, the 5-sigma discrepancy between the Planck early-universe measurement of the expansion rate and the local distance ladder measurement. Sources: Robertson, B.E. et al. (2023). Identification and Properties of Intense Star-forming Galaxies at Redshifts z 10. Nature Astronomy, 7, 611-621. Carniani, S. et al. (2024). Spectroscopic confirmation of two luminous galaxies at redshift 14. Nature, 633, 318-322. [JADES-GS-z14-0/1] Finkelstein, S.L. et al. (2023). A Long Time Ago in a Galaxy Far, Far Away: A Candidate z~14 Galaxy in Early JWST CEERS Imaging. Astrophysical Journal Letters, 940, L55. [Maisie's Galaxy] Bunker, A.J. et al. (2023). JADES NIRSpec Spectroscopy of GN-z11. Astronomy & Astrophysics, 677, A88. Maiolino, R. et al. (2023). JADES. New Galaxy Candidates at z 11.5 Up to z ~ 14. Astronomy & Astrophysics, 677, A184. Riess, A.G. et al. (2022). A Comprehensive Measurement of the Local Value of the Hubble Constant. Astrophysical Journal Letters, 934, L7. Planck Collaboration (2020). Planck 2018 Results. VI. Cosmological Parameters. Astronomy & Astrophysics, 641, A6. Freedman, W.L. et al. (2024). JWST, the LMC Tip of the Red Giant Branch, and the Hubble Tension. Astrophysical Journal, 970, 87. Labbe, I. et al. (2023). A Population of Red Candidate Massive Galaxies 600 Myr After the Big Bang. Nature, 616, 266-269. Pillepich, A. et al. (2018). Simulating Galaxy Formation with the IllustrisTNG Model. MNRAS, 473, 4077.