How elements were made by cosmos !

 So, to begin with we can understand that all elements are a gift of fusion of fundamental sub atomic particles under high energy and pressure.

Like sun combines protons and forms hydrogen isotopes and helium isotopes. Some other massive stars produces heavier elements like beryllium ,boron ,carbon ,etc. This combination is based on the simple theory of binding energy and mass defect. When an atom is combined the net mass of the atom is slightly less than the mass of individual corresponding particles in native state.   Thus this change in mass is known as mass defect, which according to Einstein's mass energy equivalence can be used to calculate the energy(Binding energy of nucleus). 

Now lets get back to the topic and understand why the formation of higher elements after a certain level intrigues me. The binding energy curve has a peak at z(nucleons=protons + neutrons)=56 (Fe: nuclei). But we see so many elements occurring naturally and the last stable nuclei is of Bismuth(Atomic no. 83). And the binding energy curve shows decrease in value further, but still we see more and more unstable nucleus  formed in cosmos. Thus this compels me to think of a massive fusion reactor(cosmos) which would be able to perform this herculean task of combing nuclei for the formation of unstable nuclei. 

Here at this point I would recommend to read the wonderful article for more better knowledge if this topic amazed you !

Link:

https://lweb.cfa.harvard.edu/~ejchaisson/cosmic_evolution/docs/fr_1/fr_1_stel6.html