Distance measures are used in physical cosmology to give a natural notion of the distance between two objects or events in the universe.They are often used to tie some observable quantity (such as the luminosity of a distant quasar, the redshift of a distant galaxy, or the angular size of the acoustic peaks in the cosmic microwave background (CMB) power spectrum) to …

The cosmic distance ladder (also known as the extragalactic distance scale) is the succession of methods by which astronomers determine the distances to celestial objects. A real direct distance measurement of an astronomical object is possible only for those objects that are "close enough" (within about a thousand parsecs) to Earth.The techniques for determining distances …

Sep 26, 2017 · Cosmology (the study of the physical universe) is a science that, due to both theoretical and observational developments, has made enormous strides in the past 100 years. It began as a branch of theoretical physics through Einstein’s 1917 static model of the universe (Einstein 1917) and was developed in its early days particularly through the ...