In rural Wisconsin, there are barns everywhere--or nearly everywhere, it seems. Most of them are red. This is no coincidence.
The changing of seasons causes the paint on the barns weather. This means farm owners must re-paint their barns frequently. Red is often the go-to color because it’s the cheapest option. Its ingredients, iron and oxygen, are plentiful. And it is iron that is the key to red barns.
Stars create iron, and they also get their power from fusing matter. Protons and neutrons, the building blocks of matter, are the key to understanding stellar energy. A star begins by fusing three hydrogen atoms, each which has one proton, to make a helium atom, which in turn made up of one proton. Eventually, the star starts fusing helium atoms together, thus creating heavier elements with more protons and neutrons. At the end of this cycle, the star begins producing elements with 56 protons and neutrons. When this happens, the star can’t get any more energy by fusing elements. And when a star can’t produce any more energy, it explodes--spewing matter all over the cosmos.
Fifty-six protons and neutrons make various elements, but most are unstable because they break down into other smaller elements. Iron is the only stable element and has 26 protons and 30 neutrons, totaling 56. Iron sticks together while all the other elements break apart, so a great amount of it exists in the universe.
And there’s the connection. Because so much iron is found in the universe, and it comprises red paint, red paint is especially cheap. This is why most barns are red. So, in short, barns are red because stars explode.
[Source: The Smithsonian]