Magnesium is an element that's close to our hearts -- as well as our bones and muscles. It's an essential nutrient that plays a broad role in the healthy functioning of our bodies.

Although it's found in foods such as milk, whole grains, and peanut butter, magnesium's true origin lies far beyond the farm -- in the hearts of massive stars.

These stars were born with at least eight times the mass of the Sun. A couple of examples are Betelgeuse and Rigel, the two brightest stars of Orion. Both are well up in the east-southeast at nightfall -- orange Betelgeuse to the left of Orion's Belt, and blue-white Rigel to the right of the Belt.

Stars produce energy by combining lighter-weight chemical elements to make heavier ones -- a process known as nuclear fusion. The first such element is hydrogen, which is also the lightest and most abundant element, and generates the most energy for the star. The star transforms the hydrogen into helium. Eventually, the helium also is fused, making carbon and oxygen.

Magnesium is created near the end of a massive star's life, when it begins to fuse together the carbon. It's also created when the star fuses neon.

Soon after that, the star explodes as a supernova, casting much of its material into space. The residue includes lots of magnesium -- an element that plays a role not only in the lives of some of the brightest stars, but also in our own lives and bodies.

We'll talk about another element tomorrow.

Script by Ken Croswell, Copyright 2009