Also highly recommend Terry Tao's talk on the cosmic distance ladder: https://terrytao.wordpress.com/2010/10/10/the-cosmic-distance-ladder-ver-4-1/ https://ter

Also highly recommend Terry Tao's talk on the cosmic distance ladder: https://terrytao.wordpress.com/2010/10/10/the-cosmic-distance-ladder-ver-4-1/ https://terrytao.wordpress.com/2010/10/10/the-cosmic-distanc...