H. Manishankar (KV Pattom) Asked
Question: Iron is the heaviest element that can be formed by nuclear reactions in a star.So how the heavier elements after iron were formed?And could there be further heavier elements out there in the cosmos?
Nuclear fusion inside a star is not the only process my which new elements are created. There are many others too.
During a supernova explosion many unpredictable nuclear transmutations occur, fusing elements and forming heavier elements.
But however, the amount of elements heavier than iron is less.
It’s a good idea to think back (say from the time of BigBang)
Every explosion has a consequent implosion resulting in creation of heavier elements
Remember that birth and death of stars are taking place everyday in some part or other of the universe. The earlier stars had relatively lighter elements in their core. As they die, the remains form part of other stars and other celestial bodies thereby forming heavier elements in the universe.
(I don’t claim that this is a complete answer. Visitors are requested to suggest amendments to this Answer via comments)