Final answer:
The Big Bang Theory posits that the universe began from a singularity that expanded 13.8 billion years ago, with evidence from the universe's expansion and the Cosmic Microwave Background Radiation supporting this model.
Step-by-step explanation:
Formation of the Universe and the Big Bang Theory The Big Bang Theory describes the formation of the universe as originating from a singularity, which was an incredibly dense and hot point. Approximately 13.8 billion years ago, this singularity expanded rapidly in a massive explosion, leading to the formation of the universe that we observe today. Evidence of the Big Bang of evidence for this model include: The expansion of the universe as witnessed by the observed galactic redshifts. The redshift indicates that galaxies are moving away from us, which can be explained by the notion that the universe itself is expanding. The discovery of the Cosmic Microwave Background Radiation (CMBR), which is the relic radiation from the Big Bang. This radiation is the most perfect blackbody spectrum ever detected, with a temperature of about 2.725 K. Tools such as telescopes and specialized detectors are used to collect this evidence, allowing us to measure galactic redshifts and the Cosmic Microwave Background Radiation from any direction in space.