Where Do the Heavy Elements Come From?

If you were thinking 'One of the gods made them all in a great heavenly forge', you're actually closer than you think.

Science can't say whether divinities were actually involved, but, as it turns out, nothing much besides Hydrogen (element #1) forms on its own. EVERYTHING else gets cooked up in the hearts of the great heavenly furnaces, the stars.

As most people know, stars are powered by nuclear fusion. A huge clump of Hydrogen is compressed under the strain of a terrifically powerful gravitational field, and, at a certain point, something gives. The Hydrogen atoms start getting squished together, and are forced into a new element, Helium.

But where do those elusive 'heavy' elements come from?

When a star starts running low on Hydrogen, it will begin 'burning' the Helium too, forming even heavier elements. Unfortunately for stars, this is a process of diminishing returns - each new elemental fusion yields less energy than the previous. At a certain point, depending on the star's mass, this process grinds to a halt, and the star can go no further.

If this star is small, like our sun, it will eventually burn out, keeping its horde of atomic treasure all to itself.

If it is a bit bigger, though, it will get really, really angry. In a fit of rage, it will tear itself asunder in one of the most dramatic and powerful events in the known universe. It will explode in a Supernova.

Such is the explosive energy unleashed during a Supernova event that even the poorest grade of fuel, the middle-weight elements like Iron, aren't safe from atomic infusion. Brief though the blast is, compared with the life of the star, a Supernova packs enough power to force the creation of Uranium, and even more dense (and more unstable) elements.