Why is it essential for us that big stars explode?
What do you mean by essential? We don’t need them to explode. We do know that stars do explode and we can find good reasons to think that a big star would end its life in a gi-mongous explosion known as supernova. But that is not a “need” we have. This is simply an observation. Presently, we have no way to explain any elements heavier than Carbon without resorting to fusion inside stars as a production mechanism. As far as we know, all elements from Carbon upwards can only have been produced inside stars. In smaller stars, they would be sent back into space through the stellar wind. And this method cannot produce anything heavier than iron (element number 26). You cannot fuse iron and produce energy. In bigger stars, convection is insufficient to bring the core fusion products up to the surface. So they cannot be sent out into space (where they can later be used to form planets and humans). Also, since energy must be added to form heavier elements than iron, you need events with lots o
The “exploding big stars” are supernovas that help synthesise elements heavier than Iron. Stars produce all elements up to Iron during their life, but only in a supernova the pressure and the temperature are high enough for heavier elements to form. Without those elements, there wouldn’t be the Earth.
