The Universe, probably

Imperial College

December 11

Lecture Theatre 1, Blackett Building

Join us for Professor Daniel Mortlock’s Imperial Inaugural online or in person.

There is no need to register to attend so please be sure to use the add to calendar button.

We look forward to seeing you on Wednesday 11 December!

Summary

Astrophysics and statistics might not seem like a natural pairing, but they are in fact intimately linked, having developed together over several centuries. While all science relies on probabilistic reasoning – no theory can ever be proved with absolute certainty – astronomers face the additional restriction that they cannot freely design experiments; it is only possible to observe whatever happens to be in our sky. With no option for repeated or independent trials, making sense of the Universe from astronomical data not only requires careful statistical techniques but also provides insights into such basic concepts as probability, arguing strongly for a logic-based Bayesian approach.

Daniel Mortlock is a Professor of Astrophysics and Statistics at Imperial College London and has been applying Bayesian statistical methods to a range of problems in astronomy including the measurement of the Hubble constant, the origin of the highest energy cosmic rays, galaxy evolution and the search for the most distant quasars.

This last topic will be the focus of Daniel’s inaugural lecture. Quasars are remarkable objects in their own right: a quasar is the glow from the super-heated disc of material falling into a super-massive black hole which can outshine an entire galaxy of stars. Quasars are so bright that they can be detected even if billions of light years away; the most distant quasars are, due to the finite speed of light, seen as they were when the Universe was just 5% of its current age (of 13.8 billion years). How such super-massive black holes formed so quickly after the Big Bang is one of the biggest mysteries in astrophysics – one of the motivations for the recently launched Euclid satellite was to find quasars at even earlier times to better understand how these black holes formed. The “big data” problem of searching the huge Euclid catalogues for just a handful of possibly record-breaking quasars is currently Daniel’s main research focus. This talk will describe how Bayesian methods enable such “needle in a haystack” searches to reveal the Universe’s hidden secrets

Biography

Daniel Mortlock grew up in Melbourne, Australia, where he did first an undergraduate degree and then a PhD, both in physics, at the University of Melbourne. He then moved to the UK to work on the Planck cosmic microwave background mission at the University of Cambridge, where he subsequently held a PPARC (now STFC) research fellowship. Daniel moved to Imperial in 2005, becoming a permanent member of staff in 2011. In his research he develops and uses Bayesian statistical methods to analyse large astronomical data-sets, working on a broad range of problems including the measurement of the Hubble constant, the origin of the highest energy cosmic rays, galaxy evolution and the search for the most distant quasars and super-massive black holes. He also plays cricket, tennis and the guitar.