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Out of This World Clearly, I get a thrill out of collecting elements. It’s also exciting to think about where they all came from in the first place. To find my answer, I look to space. T at’s where elements are born. It all started with the Big Bang. According


to this theory, the universe is expanding matter. As the cloud of cosmic dust and gases from the Big Bang cooled, stars formed. T ese then grouped together to form galaxies. Hydrogen and helium gases are the most


Like Glue I like to think about how elements are part of everyday objects. So I collect more than pure elements. I collect objects that represent, or stand for, each element. For instance, a tube of toothpaste contains


fluorine, an element that helps build strong teeth. T e tip of a match contains phosphorus, an element that starts fire. I even have a set of colorful dishes from the 1940s. I don’t eat off them, though. T e color on the dishes contains the element uranium, a radioactive poison! We need all these elements. One element


may be more important to us than all the others, though. T at’s carbon. Carbon is the sixth most abundant element in the universe. In its purest form, carbon is diamond, one of the hardest known substances. Sparkly diamonds are considered very valuable. But there’s something even more valuable about carbon. Life on Earth as we know it couldn’t exist without it. You see, all living things are made up of


the same elements. T ese include oxygen, hydrogen, nitrogen, phosphorus, and sulfur. Carbon combines with all of them. It’s


like the glue that holds everything together. Carbon builds everything from a speck of bacteria to a tree to you. Without it, living things would just be a pile of loose atoms.


14 NATIONAL GEOGRAPHIC EXPLORER


common elements in the universe. Other elements found in nature were created in nuclear reactions within stars. Most elements come from dying stars.


Take our sun, for example. Right now, it’s mostly made up of hydrogen. Massive reactions in its core turn the hydrogen into helium. It’s not dying yet, but in a few billion


years, our sun will start to die. It will cool and expand and become a red giant. When that happens, it will start turning helium into carbon, the building block of life.


Making Elements Other stars are dying right now. Some are more massive than our sun. When they die, reactions inside them make carbon, oxygen, iron, and other elements. Many elements come from the most


massive stars. When they die, they explode. T ese supernovas create brilliant flashes. T ey release large amounts of energy, which allows elements heavier than iron, such as uranium and gold, to be produced. In the supernova explosion, all of these elements are expelled out into space. T ese elements driſt slowly through


space. Over billions of years, some pull together. T ey form new stars and planets, like Earth. So look around. Everything you see is


made of elements that once were part of an exploding star. Even you.


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