Big Bang

Episode #1 of the course “Scientific laws and theories everyone should know”

If there is any theory that you need to know, learn about one that begins with the history of the universe and extends to its form in present day. The Big Bang theory was taken from the work of Edwin Hubble, Albert Einstein, and Georges Lemaitre. It states that the universe started 14 billion years ago from an enormous explosion. Shortly thereafter, the entire universe was brought to one point, pulling all of the matter in the universe together. From that time, the universe kept expanding outward to give us the world that we see today.

The theory gained monumental scientific support in 1965 when Arno Penzias and Robert Wilson found cosmic microwave background radiation. With radio telescopes, the astronomers found cosmic static that failed to dissipate. The pair confirmed earlier hypotheses regarding low-level radiation left by the Big Bang in the universe.

In the universe’s first three minutes, Big Bang nucleosynthesis created light elements. The temperature got somewhat cooler, and protons and neutrons impacted, making deuterium that then combined and created helium. However, for the universe’s first 380,000 years, there was too much heat to shine light. The hotness from the explosion crushed atoms into a dense plasma that made light scatter.

Afterwards, matter cooled down so that atoms formed during the recombination era, making a transparent, inactive gas. The gas fostered initial flashes of light now known as cosmic microwave background radiation. But the universe still lacked good sources of light.

After 400 million years, the universe came out of darkness. After lasting more than 500 million years in their single state, globs of gas fell apart during this time to form the initial stars and galaxies. Universal expansion started slowly, but about 6 billion years after the Big Bang, dark energy sped up universal expansion. About 9 billion years after Big Bang, our solar system developed.

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