The expansion of the universe from a state of high density and temperature, known as the Big Bang, can be explained without invoking the need for a creator or designer. The current understanding of the universe's expansion is based on scientific theories and evidence, particularly the field of cosmology.
The physics behind the expansion of the universe is described by the theory of general relativity, which was formulated by Albert Einstein. According to general relativity, the universe can expand or contract based on the distribution of matter and energy within it. It provides a mathematical framework to explain how space and time are affected by the presence of matter and energy.
The evidence for the Big Bang and the subsequent expansion of the universe comes from various observations, such as the cosmic microwave background radiation and the redshift of distant galaxies. These observations support the idea that the universe was once in a highly compressed and hot state and has been expanding ever since.
While our understanding of the exact details of the early universe and the physics at extremely high temperatures is still an active area of research, scientists have developed theories, such as inflationary cosmology, that provide possible explanations for the initial expansion and subsequent evolution of the universe. These theories do not require the intervention of a creator or designer but instead rely on natural processes and fundamental physical laws.
It's important to note that science seeks to explain natural phenomena through empirical evidence, observation, and the formulation of testable theories. The question of whether a creator or designer is necessary to explain the origins of the universe is a philosophical or religious one that lies outside the realm of scientific inquiry.