The explosion that created our Universe

In this video, Dr Morten Andersen explains the importance of the formation of elements through the Big Bang.

Elements are the building blocks of everything in the universe and without them we would not exist.

Following the formation of the very first elements, a series of extreme events eventually led to the formation of the Earth, planets and solar system.

Formation of light elements

The first simple and light elements, hydrogen and helium were formed within minutes of the Big Bang as the universe expanded and began to cool down from extreme temperatures.

Formation of the first stars and galaxies

A further cooling and the continued expansion of the universe then led to the formation of the first galaxies, and the very first stars within them.

These first-generation stars mainly consisted of the light elements hydrogen and helium and were formed because of gravitational forces and attraction due to mass.

We can observe those forces today, because as the moon orbits our planet it exerts a gravitational force that attracts Earth towards it due to its mass. This influences tidal forces on Earth, making water levels or the tide higher or lower.

Stars clustered into galaxies, which can contain anywhere between a few hundred million stars up to trillions of stars. We are part of the galaxy called the Milky Way, it contains an estimated 250 billion stars.

The spiral galaxy NGC 4414 by NASA, Public Domain

Each year about 7 new stars are created in the Milky Way and so it appears that the creation of stars is a regular event. But, if we think about the tremendous size of the Milky Way, the creation of stars can certainly qualify as another extreme event.

Formation of the heavy elements

The first generation stars held intense energy within them and this made them burn. A process that we see today if we look at our nearest star, the Sun.

It was this process that led to new elements with larger mass (and proton numbers) to be formed. So we can think of these first generation stars as factories of heavier elements, such as calcium and iron.

The formation of even heavier elements (heavier than iron) required an even larger amount of energy than can be generated within stars.

They were formed by the massive energy release and fusion processes following the gravitational collapse and death of large stars in supernovae explosions. These explosions expelled the elements into the universe.

Roughly, two such supernovae events occur within our Milky Way every century. Another extreme event.

Summary

In this step we’ve moved quickly through a series of extreme events that led to the formation of light elements and then heavier elements. If we were to look at these events in more depth it would take up many weeks of study.

The most important thing to understand here is that elements are the building blocks of everything in the universe. The number and diversity of these building blocks grew through extreme events until all the ingredients that were needed for the universe, our planet and life came into being.