Cosmic Chemistry

            In 1572, the Danish astronomer Tycho Brahe was witness to one of the most exciting cosmic phenomena known to exist -- a supernova, or gigantic stellar explosion. Little did he know that this same supernova - which now bears his name - would be so well-studied in later years that astronomers would know such intricate details as its chemical composition. Today the still-brilliant remnants of the Tycho supernova, which is located in the constellation Cassiopeia, has two major observers - the European XMM-Newton telescope and the NASA Chandra X-ray Observatory. These telescopes have, in a matter of months, already uncovered a wealth of data about the exploded star. Most recently, the European telescope has detailed the composition of Tycho, identifying in the supernova remnant many of the same chemical building blocks used to make the planets and life on Earth. Supernovae are some of the most violent events in the universe. They occur at the end of a giant star's life, when the star has used up all of its nuclear fuel. When that happens, the stellar core collapses in on itself, releasing huge amounts of energy into the local interstellar space around it in a giant explosion.
             Tycho Brahe was witness to one of the only three or four supernovae known to explode during human history. Though today the Tycho supernova is visible only through a telescope, at the time of its initial blast it was visible to the naked eye for about 18 months. In fact, the initial explosion probably appeared as one of the brightest stars in the sky. Today, astronomers are not studying visible light from the supernova, as Tycho would have seen it, but rather its X-ray light, which can be detected by both XMM-Newton and Chandra. .
             Scientists are interested in supernovae because they are thought to be great cosmological chefs. Most of the chemicals in the universe are created as a direct result of supernova explosions.