\section{Big Bang to Heavy Elements}

\lettrine[lraise=0.15]{A}{fter} the Big Bang, the universe was extraordinarily uniform --- almost featureless hot gas. Gravity nudged tiny quantum fluctuations into galaxies and stars. Order and structure emerged from near-uniformity.

But it doesn't stop there. Every element is defined by the number of protons 
in its nucleus --- the more protons, the heavier and more complex the atom. 
The two simplest elements --- Hydrogen (1 proton) and Helium (2) --- 
are almost everything the Big Bang produced.

The heavier elements were forged inside stars. The larger the star, the hotter the star's core furnace, and the heavier the elements it can forge. Our Sun, of modest size, can forge up to Carbon (6) and Oxygen (8).
Even this process has its limits. 
The heaviest element that can be produced in the largest star's core is 
Iron (26). 

Elements heavier than these can only be produced in a supernova, 
when a large enough star at the end of its life collapses into a cataclysmic explosion. Zinc (30), Selenium (34) and Iodine (53) are a few elements created in supernovae. These are elements without which life on Earth would not be possible.

In other words, we have life on Earth today because a star died in a supernova before the Earth was born, 
seeding the four corners of the Cosmos with heavier elements. Some found their way to our tiny planet in the making.

Every living thing on Earth embodies shards of supernovae. 
Every bacterium, every fungus, every plant and animal requires elements 
that could only have been forged in the death throes of a star.
