Essay by Lee Carkner, Professor of Physics and Astronomy, Director of the John Deere Planetarium

To a casual observer, the universe seems static and unchanging. The stars we see in the sky appear to be immortal, always showing the same color and brightness night after night. This however is an illusion, the universe is dynamic and constantly changing, but the dynamic nature of the universe can only be detected by careful observation. Horsehead Nebula, an astrophotograph by Mel Peterson and his wife Betty Peterson, helps us to see the complexities of the universe. Discovered in 1888 by Williamina Fleming at Harvard Observatory, the Horsehead nebula is located fifteen hundred light years away in the constellation of Orion. For most of astronomical history, the nature of these diffuse objects was not clear, but using the new tools of photography and spectroscopy available in the late 19th century, scientists were able to determine that nebulae are clouds of dust particles and hydrogen gas. The galaxy is composed not just of stars, but enormous amounts of diffuse material between the stars. Inside the Horsehead nebula (and other interstellar clouds) new stars are constantly being formed. These stars will slowly evolve over billions of years and eventual die, returning their material back to the interstellar medium from which new clouds and eventually new stars will be made. The Horsehead nebula gives us a glimpse into the great cycle of stellar birth, life and death in our galaxy.

Dr. Mel Peterson (who graduated from Augustana in 1953 and was a member of the chemistry department from 1958 to 1995) was deeply involved in the work of Augustana's John Deere Planetarium from the day it was dedicated in 1969. He served as its second director from 1988 to 1999 and remained highly active in its operations until his death in July 2011. In that time, he gave planetarium shows, observing sessions and open houses to the thousands of school children and members of the general public that visit the facility every year. Mel had a passion for teaching astronomy, for sharing beautiful images of the heavens and for helping people to understand the beauty and complexity of the physical properties that govern the universe. Thanks to Mel Peterson, thousands of people got a chance to see the universe in a whole new way.