IMPORTANT NOTICE: Due to a major conference at QUB at this time –

1) There will be no parking in front of the physics building or around Whitla Hall. Parking will be available via the Botanic Avenue entrance, or on-street if you can find a spot.

2) The normal entrance to the Larmor Lecture Theatre will be closed. Entry and exit will be via the original entrance for the Bell Lecture Theatre at the other end of the building to the main physics building, and through it to the Larmor via the ground floor. This entrance requires QUB card access, so QUB staff will let people in and show them the way to the Larmor in batches. It also applies to exiting after the meeting, so your co-operation is requested. This will be inconvenient, but it can’t be avoided.

3) There will be no tea/coffee after the meeting this time.

4) As parking spaces will be at a premium, consider using public transport or car-sharing.

 “Cosmology on the Brink: What exploding stars tell us about the history of the Universe”

Abstract: Our Universe is expanding. The theory of the Big Bang and cosmic expansion is backed up by countless evidence, but what it is made of and how that content controls the expansion rate is still a mystery: 70% is some `dark energy’ which appears to be countering gravity to accelerate the expansion rate, and what dark energy is and how it works are some of the largest open questions in modern physics.

Measuring the expansion rate at different points in cosmic history is key to understanding how dark energy works and eventually what it is made of. The most simple models suggest that dark energy should be the same at all places and times, while myriad more exotic theories exist that predict an evolving dark energy. Modern day experiments are able to make expansion-rate measurements to extraordinary precision. This year, two major astronomical surveys combined to provide the most accurate measurements of dark energy’s effects and left tantalising clues that it is indeed evolving, a result which if proven would require a full re-write of one of the fundamental theories of the Universe. One of these, the Dark Energy Survey, makes use of a particular type of exploding star (supernova) to make its distance measurements. DES has re-defined how cosmology is performed with supernovae, with stunning success. In this talk I will introduce the background of dark energy and supernova-cosmology, describe how DES managed to make such precise measurements, and discuss the implications of a non-constant dark energy for our cosmological understanding.

Bio:

Phil Wiseman is a Senior Research Fellow at the University of Southampton. He received an undergraduate Masters in Physics from Durham University in 2014 before moving to Munich for a PhD at the Max-Planck-Institute for Extraterrestrial Physics. There, he worked on gamma-ray bursts and the interstellar medium of very distant galaxies. In 2017 he moved to Southampton to begin work on the Dark Energy Survey. He has since worked on numerous aspects of supernovae with a particular interest in how they relate to the galaxies in which they explode. Recently, he led a team that discovered and analysed the most energetic cosmic event ever observed, believed to be caused by a supermassive black hole. He will continue research to understand that new phenomenon for which he was awarded an Ernest Rutherford Fellowship.

Admission free, all are welcome.