My sun and stars

Fact: humans are 90% stardust.

Human beings are mostly made up of water, with a few other bits and pieces thrown in for good measure. That means we are largely made of Hydrogen atoms, followed by lots of Oxygen, a fair bit of Carbon, some Nitrogen and a sprinkling of some more interesting stuff.

Immediately after the big bang, the only elements that existed were Hydrogen and Helium: everything else was formed over billions of years as a product of fusion reactions (when two atoms fuse together to make a single heavier atom). These fusion reactions take place in stars, producing heavier elements such as Oxygen, Nitrogen and Carbon, as well as recycling lots of Hydrogen. The really heavy atoms – think Gold and Silver – require something a bit more dramatic, and are made only during the massive energy release of supernovas.

So all those familiar elements – Calcium in your bones and Iron in your blood – are just bits of leftover stardust made in great balls of fire billions of years ago. It’s enough to make you feel just a little bit special.