January 12, 2000
You were cooked in a star – UW faculty lecture will explain how
To paraphrase an old car ad, “This is not your father’s universe.” Well, actually it is – he just didn’t know it.
Scientists today understand the universe in a very different way than they did 50 years ago. They understand the origin of every atom, something that Bruce Margon, a University of Washington astronomy professor, regards as “a fundamental intellectual triumph.”
“It’s neat because it makes people realize we’re living in a special time. A generation ago, no one knew how all the atoms were made, but now we do.”
What’s more, those atoms all have been recycled several times over. The bottom line, Margon said, is that we are made of stars. And that will be his topic as he delivers the 24th annual UW Faculty Lecture on Jan. 25. The free public lecture, which also is the first of three UW Science Forum lectures, is at 7:30 p.m. in room 130 of Kane Hall on the UW campus, followed by a reception in the Walker-Ames Room of Kane Hall.
There are only three ways the universe cooked the atoms that make up everything, and two of those processes continue to this day, Margon said.
The first is the big bang, the explosion that started the universe and created all of its hydrogen and most of its helium and lithium.
“That happened once and never again,” Margon said. “Every hydrogen atom that you drink in a glass of water was manufactured in the big bang 15 billion years ago.”
The second process – cooking atoms in the multi-million-degree furnaces inside stars – is the most important for humans because it creates another dozen chemical elements, including carbon, nitrogen and oxygen. Carbon is the basis for all life forms on Earth, and nitrogen and oxygen make up the air that we breathe.
The stars that produced these atoms were themselves formed from large gas clouds floating in the cosmos. As these older stars burned out, they produced a new vapor containing carbon, nitrogen and oxygen, a vapor that ultimately formed new stars and planets.
“The function of the stars is to cook the atoms that we need for life,” Margon said. “The carbon in your skin and the oxygen and nitrogen in the air that we breathe were once in the center of a star that’s long gone.”
The third process is the occasional cataclysmic explosion that destroys a star entirely, known as a supernova, which, at the instant of explosion, produces the most complex atoms. There are very few supernovas, but they are the only way to make the atoms to form materials that humans regard as commonplace – nickel, tin, copper, lead and zinc, to name a few. The atoms in the coins jingling in your pocket were created many eons ago when a supernova spewed the elements in a gas that then settled into forming the Earth and sun.
In time, the supernova provided jobs for a fair number of ore miners.
“How many of us realize,” Margon said, “that astronomy is so directly related to everything we see, everything we touch and everything we are?”
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For more information, contact Margon at margon@astro.washington.edu
