I was sitting with my wife and daughter watching the movie “Stardust”. And it turned out to be a much more interesting movie than I was expecting. The movie is a modern fairytale about a young man finding his true love, and his true identity as the heir to the throne in a fantastical enchanted land.

Myself, my wife and my daughter really loved the movie, and would recommend it to children of all ages, including children as old as myself.

However, there was one particular hook in the plot that I had a strong empathy for being a physicist. The hero was on a quest to find a falling star, and was amazed to find, in the middle of a crater, that the star that had fallen to earth had taken the form of a sparkling young woman. A ludicrous idea you might think? But I would say that there is a great deal of truth behind this transformation.

And, although, the instantaneous transformation, from stardust to human form, is not possible, the transformation from stardust to human form is exactly what has happened over billions of years, since the beginnings of the universe in the Big Bang to the abundance of life that walks the Earth today. This is probably understood by most people on a subconscious level, and it this hook in the fairytale that adds to the enchantment and wonderment of the story.

So let me see if I can explain my statement “We are Stardust” on a more solid footing. And don’t worry, I won’t be delving into the depths of particle physics, or complicated chemical formulae, the science will be kept to some very simple explanations, with some basic ideas, and understanding of how the universe has evolved. I don’t want to turn you off.

Firstly, let’s consider what we know about the make up of human beings. Body chemistry and physical processes are very complicated. However, to keep things simple, we do know that humans are carbon based life forms. The actress who plays the role of the fallen star, like all other humans, is composed mainly of water, which makes up approximately 80% of our body mass. And we can think of all the tissues within our bodies as either organic or inorganic substances.

All the substances within the human body are made up from basic elements. Some of the more common elements in the human body are hydrogen, carbon, oxygen, calcium, sodium, potassium, magnesium, and iron. For example a water molecule is made up from two hydrogen atoms and one oxygen atom. But where do these atoms come from.