In 1917, after developing the concept of relativity, einstein described how his findings supported the static universe idea, which was a widespread theory that stated that the size of the universe never changes. however, over the following decades, the theory of a static universe was disproved and replaced by the theory that the universe began with a "big bang” and has been expanding ever since. what most likely led to the change from the static universe theory to the expanding universe theory? scientists’ assumptions that all things, including the universe, must grow and change the use of newly invented telescopes to make more accurate observations of far-off stars new inquiries into the field of quantum physics, which is the study of the smallest possible objects the use of einstein’s ideas about matter and energy to develop nuclear power plants and weapons