The Origin of Life Part 1 - Big Bang

The Universe is 13.73 +/- 0.12 Billion Years.

This was calculated like this:

We know that all matter and including galaxies originated from the time of the big bang. We find the oldest star clusters and galaxies that exist and measure their ages.

This is fairly accurate because the first stars formed only a few hundred years after the big bang. So we can pin point the age of the universe to 99% since a millions of years is nothing compared to a few billion years.

Scientists found the age of the star clusters by measuring their distance away from an object. Since we know that light travels at 186,000 miles per second. And that D=RT, thus solving for time would yield the age of the star clusters or the approximate age of the universe. It was found to be 13.3 billion years.




What is the Big Bang and Universe Expansion ?

Well first, many people think the Big Bang was an explosion. Not quite, it is an expansion: this should clarify.




The Big Bang was when all matter/energy was compressed in a space of 0 volume and thus, was really, really, heavy. It was also really hot, as mentioned and thus had infinite density. Since density is mass/volume and it's volume was 0 and mass extreme thus 100000000000000/0 is infinity.

It was so hot, that matter couldn't form. For instance, atoms would just instantly break apart into soup. However, as it expanded it cooled down. This is because the temperature was distributed over a larger volume and since temperatures is defined as when particles bump into each other. And particles don't bump into each other as much if the universe expands.

As the universe expanded and cooled down. Atoms formed, and gravity pulled them together. And over billions of years, stars, planets and asteroids formed as mass started getting attracted to each other by gravity. For instance, Earth was formed from dust and gas that clumped together.

As a result of the big bang. Electromagnetism, Weak and Strong Nuclear Force, and Gravity formed. Before, all these forces were unified. Physicist's are still trying to figure out exactly what this unified force was or how electromagnetism and gravity are related.