The Foundation of the Universe: Hydrogen and Helium

We are all stardust (Carl Sagan), but our elemental structure is neither similar to stars, nor the Earth, nor the atmosphere. Life on our planet is carbon-based, but this element is quite rare on our planet and in the universe, so life on other planets does not have to be carbon-based, especially silicon can be a source of life. So which elements are dominant in the universe?

During the Big Bang, the universe was 75% Hydrogen, 25% Helium and a small amount of Lithium, but in the 13.8 billion years that have passed, the amount of other elements has increased to about 2%. Today, Hydrogen is now accepted as 74.5% and Helium as about 23.8%. Other elements are accepted as approximately Oxygen 1%, Carbon 0.5%, Neon 0.1%, Iron 0.1%, Nitrogen 0.1%, Silicon 0.06% etc.

In other words, the Big Bang and the star transformations and supernova explosions that took place in the billions of years following it transformed Hydrogen and Helium into other elements, and this change continues, albeit at speeds too small for us to notice.

Our planet was also formed by the big bang and the subsequent stellar explosions, in fact the Sun can be considered a third generation star. 78.5% of the Sun's mass is Hydrogen, 19.7% Helium, 0.86% Oxygen and 1% other elements. Although it is close to the known element ratio in the universe, it is not the same. In the Earth's crust, the ratio is much different, for example the Hydrogen ratio is only 0.14%. The most abundant element on Earth is Oxygen approximately 46%, Silicon 27%, Aluminum 8%, Iron 5%, Calcium 4%, Sodium 3%. Of course, these ratios are much different in the atmosphere, Nitrogen in the atmosphere is 78%, Oxygen 21%, Argon 1%, Helium 0.0005%, Hydrogen 0.00006%. In other words, Hydrogen and Helium, which are the basis of the universe, are not even 1% on our planet.

Our body consists of 65% Oxygen, 18.5% Carbon, 9.5% Hydrogen, 3.2% Nitrogen, 1.5% Calcium, 1.0% Phosphorus, 0.4% Potassium and the remaining 1% consists of 50 elements such as Potassium, Sulfur, Sodium, Chlorine, Magnesium and trace amounts of Boron and Chromium.