A lot of galaxies in a very small corner of the sky. Most of the color difference comes from “cosmological redshift”; the redder a galaxy is, the farther away it is. The first galaxies date to when the universe was a bit under an billion years old, with a redshift of a bit u...
theMilky Way. And, the galaxies weren’t standing still. Hubble found that the farther a galaxy is, the faster it appears to be moving away from us. This could be interpreted as the uniform expansion of space. Hubble even said
Beginning in the 1920’s with observations of Lemaitre and Hubble, scientists and astronomers became aware that the Universe is expanding from a point of origin. Hubble also observed that the farther away a galaxy is, the faster it appears to be moving. In what is now referred to as theHub...
which has a redshift of 7.5. Using this, we can determine distance by calculating how long the light has traveled to reach us. With a redshift of 7.5, that comes out to be about 13 billion years. You might think that means it’s 13 billion light years away, but 13 billion years ag...
Ever since, there have beennoserious competitors to the Big Bang, and a plethora of other predictions, such as big-bang nucleosynthesis, the details of structure formation, the presence of pristine gas in the early Universe, and the increase of temperature with redshift have all been observed ...
3.) Arp's alternative cosmology has been discredited by quasar/active galaxy observations over the past 20 years. His predicted quantization of redshifts is no longer consistent with the observations. And finally, 4.) The observation of the CMB dipole -- which dates to 1978 and Smoot, w...