Big Bang Theory: Origins and Expansion of the Universe

Big Bang Theory

Origin of the Universe

The Big Bang Theory is a concept used to describe the creation of the universe about 13.8 billion years ago. Initially, everything was contained within an extremely dense and hot point, known as a singularity. With the passage of time, this point expanded rapidly in every direction. This expansion caused the entirety of the matter and energy that make up the universe to spread across space.

Expansion of the Universe

The expansion of the universe refers to the ongoing increase in distance between galaxies and other celestial objects. This expansion is evident through the observation of redshifts in light from distant galaxies, indicating that they are moving away from us, and Hubble's Law, which demonstrates a correlation between the velocity of galaxies and their distance from the observer. These phenomena suggest that the universe is still expanding and has been doing so since the Big Bang event.

Early Universe

Immediately following the Big Bang, the universe underwent a series of significant changes. Within a mere fraction of a second, the universe increased dramatically in size due to a phenomenon known as cosmic inflation. During this phase, the universe grew more than 60 orders of magnitude larger, becoming the seed for the formation of galaxies and other large-scale structures observed today.

The universe then passed through various stages, including a period of recombination lasting about 378,000 years, where electric charges began to combine, allowing for the formation of neutral atoms. After this stage, photons no longer interacted with electrons, enabling the cosmic microwave background to form, which remains as the earliest known object that researchers can study directly. This radiation is evidence for the Big Bang theory, providing a snapshot of the conditions of the early universe.