Do you know you are made of star's stuff ? Do you know that the calcium in your bones was produced by powerful nuclear reactions in a big star interior, several billion years ago ? The iron which colors the Red Rocks of Arizona, and of the Mars planet, comes from ancient supenovae, exploded long before our Sun was born. Here is how the story goes. In the Big Bang, at the dawn of our Universe, all the matter was created basically at once. But, it mostly consisted of hydrogen and helium atoms. So, where did the variety of chemical elements that populate the periodic table come from ? To discover the answer, we must go back to when the first stars were born.

A star is a powerful nuclear energy furnace, which is turned on when a huge cloud of gas and dust in the interstellar space condenses under its own weight. Then the star shines bright. But the inner combustion (nuclear fusion) not only releases light and energy, it transforms the primordial "fuel" (hydrogen and helium) into other chemical elements, such as Oxygen, Silicon, Nitrogen, Carbon. Well, not always. Which elements are produced? How much of them? How long does it take? It all depends on the mass of the star. (CLICK here for more explanations)

At the end of its life, when the fuel is all burned and no more reactions can take place, different things can happen to our star. Again, depending on how massive it was. In some cases part of the processed elements gets dispersed into the vast space, to form new clouds of gas and dust, which then will form new stars (which in turn will produce different elements yet...) and their planets, including life-supporting planets like our own Earth.
Here you can watch what happens throughout a star's life. Chose the mass of your star: smaller than our Sun ? or, perhaps, five times larger? or fifty times larger? Click below to "make your own star", watch it evolve, and learn which chemical elements are produced.

Need sunshine ? just click! Make a small star

Some greens? Wood? Paper? just click! Make a medium star

Need a hammer? A golden ring? just click! make a massive star

Interesting? Want to learn a bit more about stellar evolution? read here Also, if you want to read some of the new facts that astronomers found out about massive stars with the FUSE satellite, and with Hubble, click here For some recent discoveries about supernova remnants, massive stars, or planetary nebulae, search here

CREDITS: This activity is partly based on an hands-on exhibitry developed by the Maryland Science Center, in collaboration with the Office of Public Outreach of the Far Ultraviolet Spectroscopic Explorer (FUSE).