Sunday space: How are humans similar in make-up to stars and planets?

Take for instance, the simple action of having a shower. Have you ever considered the water you're bathing in?

Water, or H20, is made up of hydrogen and oxygen. Consider the hydrogen in both the water and in you.

That hydrogen has been around since the beginning of time as we know it. At 13.8 billion years old, all hydrogen in the universe was created mere moments after the Big Bang. Everything has an origin.

Inside the core of every star, hydrogen drives nuclear reactions that power the stars and provide our Universe with light. Those nuclear reactions are responsible for almost every other element save helium, lithium, boron and beryllium.

Boring old boron for instance, a primary ingredient in Borax soap, is created in the empty vacuum of space when a high energy proton collides with a carbon or oxygen atom. Surprisingly exciting origins for a typical household cleaner.

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In the reaction that ignites a star for the first time, hydrogen is fused to create helium, releasing energy in the process in the form of light.

The light that heats your skin came from the core of the Sun roughly 100,000 years ago before making its way to the surface, and eventually to you. But what about the iron in your blood? Or the carbon in your DNA?

Powered by the intense heat and pressure inside stars, heavier elements are fused in chain reactions.

What reactions occur and what elements are produced as stars evolve is largely dependent on the mass of the star. More massive stars can continue fusing elements until their cores consistent mostly of iron.

At this point, fusion reactions are energetically costly as fusing iron requires more energy than it generates. An iron core therefore signifies the beginning of the end for a star. Elements beyond iron are not produced through this, but instead for example, through the death of massive stars as supernovae.

In medium-sized stars like our Sun, one important element fused is carbon-12, a type of carbon that forms the backbone of our DNA. Carbon-12 is created by fusing two helium atoms to form a short-lived beryllium atom. The beryllium atom exists just long enough to fuse with another helium atom to form carbon-12.

All fusion reactions obey Einstein's famous equation, in the case of carbon-12 the energy contained in the helium-beryllium combination is almost exactly that of an excited carbon-12 atom. This greatly increases the odds of it happening.

If this wasn't the case, carbon-12 would not be made inside stars, and the very element fundamental to life would not exist. The creation of carbon-12 is wonder-filled for me and now I hope it is for you as well. In summary, we're not so different, us and stars. We are all the same stuff, just arranged differently.

I hope that when you look out into the universe tonight it feels a little less alien, a little less abstract and a lot more wonder-filled.