Have you ever wondered where the elements of the periodic table come from? At the time our own Milky Way was forming, there was plenty of hydrogen and helium around, and only a splattering of other chemical elements.
The elements that make up Earth, for example, were not available about 12 billion years ago. They were around, however, about 7.5 billion years later when the Sun and Earth formed.
Without elements greater than hydrogen and helium there would be no Earth, so where did these elements come from that make up the ground and the materials used to build our houses? Where did the carbon come from that is used to build ourselves? To find out the answer, we need to look to the stars.
Stars like the Sun shine for one simple reason: they produce helium from hydrogen in vast amounts each second of their lives.
Stars that are even bigger and more massive than the Sun produce energy at the start of their lives also by the process of nuclear fusion of hydrogen. Once these more massive version of the Sun run out of hydrogen, they can then produce all the different naturally-occurring elements of the periodic table, ranging from beryllium with an atomic number (number of protons) of only 4 up to iron with an atomic number of 26.
Stars more massive than the Sun end their lives by destroying themselves in giant explosions called supernovae. In doing so they literally spread their ‘shrapnel’ over vast regions space. These recently created metals then get incorporated into the next generation of stars.
Thus, over time, and thanks to contributions from neighboring massive stars, the region of space which later was to become the Sun and Earth is given all the necessary chemical elements.
In fact, these previous generations of massive stars even formed the carbon and other elements that we are make of. As Carl Sagan first said, ‘We are starstuff!’