2013 Arthur O. Williams Lecture: From Mars to the Multiverse

Sir Martin J. Rees (University of Cambridge & Trinity College)

“From Mars to the Multiverse”

Hosted by Prof. Richard Gaitskell

April 22, 2013

Astronomers have made astonishing progress in probing our cosmic environment. We can trace cosmic history from some mysterious 'beginning' nearly 14 billion years ago, and understand in outline the emergence of atoms, galaxies, stars and planets.

Unmanned spacecraft have visited the other planets of our Solar System (and some of their moons), beaming back pictures of varied and distinctive worlds. An exciting development in the last decade has been the realization that many other stars are orbited by retinues of planets -- some resembling our Earth.

Looking further afield, we are understanding galaxies and their nuclei in fuller detail, and can check models of their evolution by detecting objects all the way back to an epoch only a billion years after the 'big bang'.  Indeed we can trace pre-galactic history with some confidence back to a nanosecond after the 'big bang'.

But the key parameters of our expanding universe -- the expansion rate, the geometry and the content -- were established far earlier still, when the physics is still conjectural but can be pinned down by future observations. These advances pose new questions: What does the long-range future hold? Should we be surprised that the physical laws permitted the emergence of complexity? and Is physical reality even more extensive than the domain that our telescopes can probe? This illustrated lecture will attempt to address such issues.