Zinc
If you developed a cold this winter, someone probably recommended zinc tablets to boost your immune system. And with sunny days ahead, you might stock up on sunscreen, which contains zinc oxide.
Whether you put it on the outside or the inside, though, you're using an element created by the stars. Every atom of zinc on Earth -- and throughout the universe -- was forged inside stars -- heavy stars that were nearing the end of life. When the stars died, they scattered the zinc and other elements into space, where they could be incorporated into new stars and planets.
Today, astronomers learn about a star's history by measuring how much zinc and other metals it contains. The first stars were made only of the elements created in the Big Bang -- mainly hydrogen and helium. But each new generation of stars contains more and more zinc and other heavy elements.
In a recent study, a team of astronomers traced zinc, iron, titanium, and other metals in nearby stars. The team was headed by Texas astronomer Carlos Allende Prieto, and used telescopes at McDonald Observatory and in Chile.
Among other things, the study found that there are a lot more old, metal-rich stars in our region of the galaxy than astronomers had expected. Some of the stars may be more than 10 billion years old, making them some of the oldest in the Milky Way. It's a finding made possible by measuring the heavy elements inside the stars -- including zinc.
Script by Damond Benningfield, Copyright 2003
For more skywatching tips, astronomy news, and much more, read StarDate magazine.
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