All the matter around you is made up of microscopic units called molecules. Molecules are made up of individual atoms, often broken down and forming new molecules. On the other hand, most of the atoms that make up the ground, the air, the food, and every living thing, including you, have existed for billions of years.
The formation of the molecule began 14 billion years ago with an event called the Big Bang , creating a universe composed entirely of gas, without any stars or planets. Gas is made from atoms the simplest elements. About 75 percent is hydrogen and the rest is almost helium. There are no elements such as carbon, oxygen or nitrogen, nor iron, silver or gold.
In some places that have slightly higher gas densities, due to gravity, these places are getting more and more gas, which in turn makes gravity stronger, so there's more and more gas and it's like so. Finally, create a giant balloon, cowering under its own gravity and warming up from the inside.
Molecular formation began 14 billion years ago with an event called the Big Bang.
The core of the balloon is so hot that it forms a fusion reaction. Hydrogen atoms act together to form helium, accompanied by the release of energy, strong enough to disrupt gravity. When the released energy is in equilibrium with gravity, the gas cloud is compressed and a star is born.
From here, the fusion in its core will produce not only helium but also carbon, oxygen, nitrogen and other elements in the periodic table until iron. When the core runs out of fuel, the star collapses, causing a huge explosion called a supernova. There are two things to note about how supernovae make up the elements.
Stars are born and fall and so on and so forth. The gas cloud, now contains not only hydrogen and helium but also many other elements. Our Sun was born in this way five billion years ago, meaning it has evolved from a cloud of gas containing many elements from the supernova explosion since the beginning of the universe. Unlike the first stars made only of hydrogen and helium, the Sun is made up of 71% hydrogen, 27% helium and 2% of the remaining elements in the periodic table that make up the Sun.
Small planets like Earth do not have enough gravity to retain much hydrogen or helium because both are very light. So even though carbon, nitrogen, oxygen, . only make up 2% of the gas cloud, they are what makes up most of our planet.
When science first started to study this problem, in the first half of the 20th century Harlow Shapley, the famous astronomer remarked, "We are brothers of the rocks, relatives of the clouds . " We are made up of stars.