‘The cosmic origin of the elements: From the Big Bang and exploding stars to planets and life’

The history of the cosmos is encrypted in star-light. How stars are born and die, how galaxies form and evolve over eons of time and indeed how the Universe was created in the Big Bang 13.7 billion years ago are all imprinted in the stars we see today. In fact we here on Earth are all star-dust: the carbon in our bodies was produced in the fiery interiors of stars like the Sun, the oxygen we breathe originated in the cataclysmic deaths of massive stars while the iron in our blood stems from the explosive mergers of small stellar embers. In this talk, Prof. Asplund – director of the Max Planck Institute for Astrophysics in Munich – describes how astronomers extract the chemical fingerprints of stars and how this information can be used to unravel the cosmic evolution from the Big Bang to the present day. Among other topics, he will discuss how the tiny amount of lithium observed in the oldest stars may challenge our understanding of the Big Bang, how new large stellar surveys enable the history of the Milky Way to be inferred and cosmological models to be tested, the still unknown cosmic origin of heavy elements like gold and finally how unseen planets may surprisingly reveal themselves in the chemical signatures of the stars they orbit.