answersLogoWhite

0

Nuclear fusion can be either exothermic or endothermic. We're most familiar with the exothermic kind. Fusion in stars releases immense quantities of energy. A fusion nuclear weapon releases enormous energy. But there are situations where fusion is endothermic. We don't usually think of them because of the subtle way they occur. You're wondering what's up, and the answer is in the stars. When a star burns all its energy fusing atoms together, it "hits the wall" at iron. Iron making is the last of the exothermic nuclear fusion reactions. But in stars that have sufficent mass and makeup, those that go supernova, endothermic nuclear fusion is the mechanism by which all the elements heavier than iron are created. It's the only way that they can be created in nature. When the star collapses and that tipping point where the exothermic fusion reactions can't hold it up against its own massive gravity, then it's "go time" and endothermic fusion can occur. The "big squeeze" put on all the matter creates gigantic amounts of heat - enough to drive endothermic fusion. Then the blast distributes all that material across the universe. Including the trans-iron elements created in endothermic fusion reactions during collapse and the nova event.

User Avatar

Wiki User

16y ago

What else can I help you with?