is a physical theory that describes how the universe expanded from initial state of high density and temperature.
What is the physical theory that describes the expansion of the universe from an initial state of high density and temperature?
Answer:
The physical theory that describes the expansion of the universe from an initial state of high density and temperature is called the Big Bang theory. This theory suggests that the universe began as an extremely hot and dense singularity, and has been expanding ever since. The Big Bang theory explains the observed redshift of distant galaxies, the abundance of light elements in the universe, and the cosmic microwave background radiation.
According to the Big Bang theory, the universe started expanding rapidly and underwent a period of exponential growth known as cosmic inflation. During this inflationary period, the universe expanded faster than the speed of light, stretching out the fabric of space-time. This expansion caused the universe to cool down and become less dense.
As the universe continued to expand and cool, particles began to form, and eventually, the first atoms formed. These atoms, primarily hydrogen and helium, clumped together under the influence of gravity to form the first stars and galaxies.
The Big Bang theory is supported by a variety of observational evidence, including the observed redshift of galaxies, the distribution of cosmic microwave background radiation, and the abundance of light elements such as helium and deuterium.
It is important to note that while the Big Bang theory describes the expansion of the universe from an initial state of high density and temperature, it does not explain what caused the Big Bang or what existed before it. These remain open questions in cosmology.