When it comes to theories about the sun’s composition, most astrophysicists are full of gas.

At least that’s the opinion of Oliver Manuel, a professor of chemistry who has spent the better part of his career attempting to disprove conventional thinking about the sun.

For years, scientists have assumed that the sun is an enormous mass of hydrogen. But in a paper presented in January at the American Astronomical Society’s 199th annual meeting in Washington, D.C., Manuel says iron, not hydrogen, is the sun’s most abundant element. He agrees that hydrogen fusion creates some of the sun’s heat, as hydrogen – the lightest of all elements – moves to the sun’s surface. But most of the heat, he contends, comes from the core of an exploded supernova that continues to generate energy within the sun’s iron-rich interior. “We think that the solar system came from a single star, and the sun formed on a collapsed supernova core,” Manuel says. “The inner planets are made mostly of matter produced in the inner part of that star, and the outer planets of material form the outer layers of that star.”

Manuel’s assertion – that the solar system was born catastrophically out of a supernova – goes against astrophysicists’ widely held belief that the sun and planets were formed 4.5 billion years ago in a relatively ambiguous cloud of interstellar dust. Iron and the heavy element known as xenon are at the center of Manuel’s efforts to change the way people think about the solar system’s origins. Analyses of meteorites reveal that all primordial helium is accompanied by “strange xenon,” he says, adding that both helium and strange xenon came from the outer layer of the supernova that created the solar system. Data from NASA’s Galileo probe of Jupiter’s helium-rich atmosphere in 1996 reveals traces of strange xenon gases – solid evidence against the conventional model of the solar system’s creation, Manuel says.