University of California, Berkeley, USA
In 1984, the charismatic scientist Carl Sagan remarked that determining whether or not other stars have planetary systems is “one of the great unsolved problems in astronomy”. He was hopeful that the answer was on the horizon, given that astronomers had just discovered several nearby stars – Vega, Beta Pictoris and Fomalhaut – are surrounded by disks of dust and sand. Progress was indeed rapid, with new data revealing that hundreds of mature stars have disks of solid material related to the erosion of exosolar asteroids and comets, followed by the landmark discovery of the first exosolar planet in 1995. Today we have detected over 200 planets outside of our own solar system, and we even have estimates for their mean density, composition and, in a few cases, their weather.
Nevertheless, observing that other stars have comets, asteroids and planets does not directly answer the questions of how they formed, and why do the majority of stars lack a comparable inventory of solid material? The additional clues that we need come from new knowledge of the universe on vastly different scales of time and space. Matthias Steinmetz will discuss how elements in the universe evolved over 14 billion years of time, and introduce us to the frontier science of dark energy. Gerhard Wurm will then zoom in to the primitive grains from meteors and comets that provide a priceless record of physical conditions around the young Sun 4.6 billion years ago. Innovative laboratory experiments combined with theoretical analysis reveal how these primordial materials may have joined together to form macroscopic objects. Ultimately the study of extraterrestrial materials seeks to connect the physical pathways that start from the cosmic soup of the Big Bang, and end with the success, or failure, of creating habitable planets around stars.