he saw that galaxies were moving away from each other at a rate constant to the distance between them (Hubble's Law). The further away they were, the faster they receded. This led to the ...

This phenomenon, known as Hubble’s Law, was based on his studies of the redshift of galaxies and provided the first observational evidence of the universe's expansion—a critical element of the ...

In recent years, trouble has been brewing in attempts to measure the universe's expansion, which is governed by the ...

The Hubble constant is one of the most important numbers in cosmology because it tells us how fast the universe is expanding, which can be used to determine the age of the universe and its history. It ...