Cosmic Ladder
How this connects (Unit 7, The Universe): No single ruler reaches the far galaxies. Parallax, Cepheids and Type Ia supernovae each reach farther, each calibrated by the one before, and redshift reaches the farthest.
How this connects (Unit 7, The Universe): No single ruler reaches the far galaxies. Parallax, Cepheids and Type Ia supernovae each reach farther, each calibrated by the one before, and redshift reaches the farthest.