The periodic table classifies all the known elements in the universe. Of the 118 elements that exist in our universe, only 94 are created naturally. In this article, we will discover where all the elements of the periodic table come from, starting with the lightest of them to the heavier ones.
The creation of the first elements
The Big Bang, which took place 14 billion years ago, represented the creation of our universe, and with this event appeared the particles that exist nowadays, such as photons, electrons or protons. The first atoms didn’t start forming until 380,000 years after the Big Bang, when the temperature of the universe was cold enough to maintain them stable.
The stars come into play
As we have explained, the Big Bang only created two elements in great quantities. Most of the atoms in the periodic table have formed inside the stars.
During most of their lives, stars fuse hydrogen atoms to form helium atoms. Once they run out of hydrogen, they start fusing helium atoms, which creates even heavier elements, such as carbon, oxygen, calcium,… This process is known as nuclear fusion, and it emits a vast amount of energy, in the form of light and heat.
So, the atoms that form our bodies were created billions of years ago in the nucleus of a star.
Supernovae and neutron stars
Even if stars form many of the known elements of the universe, when they arrive at iron they don’t have the capacity to fuse more elements. The fusion of iron doesn’t create energy any more, but it rather consumes it. Not being able to counteract the force of gravity, the star collapses under its own weight, in an explosion called supernova. In this phenomenon, which can shine brighter than entire galaxies, the right conditions are matched to create heavier elements, such as nickel or zinc.
However, supernovae explosions haven’t got the energy necessary to create the universe’s heaviest elements, such as platinum, gold or uranium. The formation of these elements comes from the bodies that are left behind the supernova explosion: neutron stars.
Neutron stars are extremely dense objects. They contain the mass of 1.5 Suns in a sphere of only 20 kilometres in diameter. According to Einstein’s equations, when this type of stars are in pairs, that to say, they orbit one around the other, they will end up colliding. It is in these collisions that exist the right conditions for the creation of the heaviest elements of the universe.
For example, on the 17th of April 2017 a collision between two neutron stars was observed, 130 million light years away from the Earth, which produced 10 times the mass of the Earth worth of gold.
As we have explained at the beginning of the article, only 94 elements are naturally created in the universe. The other 24 elements have been synthesised by humans.
One way to create new elements is by bombarding uranium atoms with neutrons travelling at high speeds. This was made possible by cyclotrons. However, fermium (with atomic number 100) is the last element that can be formed with this technique.
The heavier elements could be only synthesised with the development of particle accelerators, much more powerful than cyclotrons. The next elements were created by bombarding entire atoms to other elements. For example, nobelium (102) was synthesised by fusing neon (10) and uranium (92), and the heaviest element, oganesson (118), was created by fusing californium (98) with calcium (20).