Final answer:
The Big Bang Theory explains the origin and evolution of the universe. Here is a middle school timeline of key events, from the Big Bang to the appearance of humans on Earth.
Step-by-step explanation:
The Big Bang Theory is a scientific explanation for the origin and evolution of the universe. It states that the universe began as a singularity, a point of infinite density and temperature, approximately 13.8 billion years ago. Here is a middle school timeline of the Big Bang Theory with key events:
13.8 billion years ago: The universe begins with the Big Bang.
380,000 years after the Big Bang: The universe cools down enough for protons and electrons to combine, forming neutral hydrogen and helium atoms.
600 million years after the Big Bang: First galaxies and stars begin to form.
9 billion years after the Big Bang: Our Sun and Solar System form from a collapsing molecular cloud.
4.5 billion years ago: Earth forms as part of the Solar System.
3.5 billion years ago: Life appears on Earth in the form of simple single-celled organisms.
200,000 years ago: Homo sapiens, modern humans, evolve and begin to populate the Earth.