What is Earth Made of

One aspect of astronomy that I have grown to love and appreciate is the tie in to the other areas of science. For example, planetary geology which, in turn, ties into our study of our own Earth’s geology. Of course this also ties into chemistry. And biology. And on on and.

This morning as I browsed Apple News1 I came across this very nice introduction to the geology of our planet. A quick read that might lead you to a much deeper exploration.

So, for example, this little bit about the Earth’s crust:

Earth’s crust is made up of several elements: oxygen, 46.6 percent by weight; silicon, 27.7 percent; aluminum, 8.1 percent; iron, 5 percent; calcium, 3.6 percent; sodium, 2.8 percent, potassium, 2.6 percent, and magnesium, 2.1 percent.

I always enjoy sharing with folks that particular tidbit about the crust being almost half oxygen. I think we generally think of oxygen as an important part of the air we breath and forget that it’s not just a gas. It’s fun to remind people that it also exists as a primary element in the oxide compounds of the ground we walk on!


  1. The app included on every iOS device and a great way to enjoy a variety of subjects with your morning coffee! ↩︎