Origins of the Universe: The Big Bang and Expanding & Contracting Universes

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  • 0:06 The Big Bang
  • 1:19 Universe Time Line
  • 2:52 The Future
  • 3:18 Lesson Summary
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Lesson Transcript
Instructor: Amy Meyers

Amy holds a Master of Science. She has taught science at the high school and college levels.

Students will learn the origins of the universe, the Big Bang theory, the timeline of the universe, how the universe is still expanding to this day, and what astronomers expect the universe to look like in the future.

Big Bang

A timeline of universe development
Universe Development Timeline

Have you ever wondered how the universe started? How all of this came into being? Ever hear of the Big Bang theory? No, not the TV show. The Big Bang is the theory astronomers use to explain how our universe came into being, and it's too bad we couldn't be there to witness it because the Big Bang was quite a show! The Big Bang theory is the current model that describes the early development of the universe.

The universe started as a little speck of a hot, super-massive, and super-dense ball. Everything that is currently in the universe came from that speck. Every single proton, neutron, atom, and so forth came from that ball. About 13.7 billion years ago, BANG! A violent explosion hurled the material within that ball into all directions of space.

The universe expanded quickly after the Big Bang and continues to expand today. As the universe expanded and cooled, things started to form, including neutrons, protons, atoms, stars, and galaxies. All the different elements in the universe that exist today developed from that initial ball 13.7 billion years ago.

Universe Time Line

Early galaxies formed from groups of stars a billion years after the Big Bang
Early Galaxies

You can visualize the development of the universe by imagining a time line. The time line starts with the birth of the universe. Here you see the initial speck. Then the Big Bang happened. BANG! In this instant, all energy and matter is created.

One second later, the universe expands and all the particles form, such as neutrons, protons, electrons.

Three minutes later, the universe takes shape. The protons, neutrons come together to form elements. At this time, the universe is largely made up of helium and hydrogen, which are two of the simplest elements in existence.

Five hundred thousand years after the Big Bang, the universe is a huge, hot cloud of gas that is starting to cool.

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