Glossary term: Big Bang Theory

Description: The Big Bang theory is the basic explanation for the evolutionary stages of the Universe. In its simplest form, this theory gives us an idea of the origin of the Universe from its hot, dense early phase, to its expansion over the next 13.8 billion years, to become the Universe we know today. We see evidence of this expansion today in the Hubble Diagram.

Because our current tools do not allow astronomers to look back directly to the beginning of the Universe, much of what we understand about the Big Bang theory comes to us from mathematical models and theories. However, astronomers can study the chemical elements produced during the hot few minutes after the Big Bang (known as Big Bang Nucleosynthesis). They can also study the afterglow left from the Big Bang, a phenomenon known as the cosmic microwave background.

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Term and definition status: This term and its definition have been approved by a research astronomer and a teacher

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