Colloquia
Talks given by high profile astronomers and scientists.
Abstract
According to Quantum Chromodynamics, which is the well established theory of strong interactions, quark and gluons are forced to live inside hadrons because of the property of confinement. However, under extreme conditions of temperature and pressure, a new phase called quark-gluon plasma is possible, where quarks and gluons became basically free. In the last years it has been possible to study this phase experimentally by using new facilities called Heavy Ion Colliders like the RHIC (Brookhaven) or the LHC (CERN).
Abstract
This lecture will address recent progress in modeling the emergence of cosmic structure at high redshifts. Also new insights gained from numerical simulations into the processes relevant for star formation are presented. Rapid magnetic field growth in galaxies and the important role of proto-stellar outflows regulating star formation up to pc scales are particularly highlighted.
Abstract
In this talk I will summarise the events that led to the discovery of the first four pulsars, recount several instances where pulsars were almost discovered and reflect on what lessons we might draw from these stories.
Abstract
Rutherford discovered the atomic nucleus in 1912 in an experiment on a table top. The LHC will be producing its first major results by 2012, involving teams of thousands and apparatus that is bigger than Rutherford's entire laboratory. How did science come to this, and what are the questions the LHC hopes to answer? What is Higgs' boson, and is it really Higgs that invented it? I will explore the role of symmetry and asymmetry in physics, and illustrate how the ideas that have been associated with Higgs' name have a long history.
Abstract
Since 2003 there has been a new period of excavation and research on Stonehenge. With two excavations inside Stonehenge and many more around it, archaeologists now have a new chronology for this famous monument as well as the prehistoric monuments with which it is associated. While theories of its use as an astronomical observatory were proposed in the late 20th century, current approaches re-interpret Stonehenge’s astronomical alignments as calendrical indicators for the timing of social gatherings, in which Stonehenge was part of a larger complex of monuments in wood and stone, centered on a short stretch of the River Avon. Many of these other monuments were also designed to mark astronomical events but these have received less attention than their more famous stone counterpart. In 2009 the Stonehenge Riverside Project, which has been conducting most of the new research, discovered a new stone circle, named as Blue stonehenge, next to the River Avon at the end of Stonehenge’s avenue.
Abstract
Contrary to popular belief, on very large distance scales visible matter stubbornly refuses to "fall" according to the laws of gravity of both Newton and Einstein. The paradox has led to the introduction of dark matter, purporting to explain the observed surplus of gravitational pull. The logical possibility remains that there is no dark matter, what you see is all there is, and that the paradox simply signals the break down of the Einstein-Newton theory of gravity. I will review alternative theories of gravity that do away with the need for dark matter. Surprisingly Solar system gravitational experiments, such as those associated with the LISA Pathfinder mission, might settle the score between the two approaches.
Abstract
A new method of imaging in the visible has given the highest resolution images ever taken anywhere. It needs a natural guide star of only 18.5 mag (I band). This talk will show how it can be done on the WHT, the VLT and even on the GTC.
Abstract
Teams from industry, universities and institutes across Europe are contributing to the design and development phase of the European Southern Observatory's project to build the world's biggest optical/infrared telescope. I will outline some of exciting scientific prospects for a fully-adaptive 42m telescope, from studying exoplanets to the furthest galaxies, and then show how some of the technical challenges are being addressed. I will place special emphasis on the work UK teams are doing on instrumentation, detectors and adaptive optics.
Abstract
The Sun presents us with many unsolved mysteries. In this talk I discuss three of them that have intrigued me for the last 50 years. Solar flares are the most powerful explosions in space between here and the nearby stars. The only viable power source is stored magnetic energy. Yet definitive observations of changes in the magnetic field associated with flares have been lacking until recently. Measurements with the GONG network have helped to address this mystery and the results are surprising. Efforts to observe the weak magnetic fields in the solar photosphere date nearly to the discovery of magnetism on the Sun. Improvements in observational capabilities have made this area a 'hot' topic with many important contributions from people at the IAC. High resolution observations are clarifying many features. I will focus on the role played by lower resolution work in defining the uniformity of the still mysterious weak magnetic fields over large spatial and temporal scales. Physics changes from hydrodynamic to magnetic dominance as one moves upward from the photosphere to the chromosphere. This leads to significant and complicated changes in the magnetic field in both the active and quiet Sun. Observations of the chromospheric magnetic field show several unexpected and mysterious features. Solving these mysteries will be an exciting area as observational and spectral inversion capabilities develop.
Abstract
Nature is one of the world's leading scientific journals, publishing many papers that receive wide attention by the general public. But, Nature is very selective —> < 7% of submitted papers are published. In order to maximize your chances of getting published, papers should present fundamental new physical insights, or startling observations/results. Theory papers pose additional problems, as we want only those papers that are likely to be the correct explanation, and not simply exploring parameter space. The writing should be clear, concise and directed at the level of a graduate course in the subject. I encourage authors to contact me in advance of submission of a paper, both to ascertain the appropriateness of the result for Nature, and to ensure that the writing is close to our standards. Posting to ArXiv is and always has been allowed, but authors should discuss the specifics with their institutional public affairs officers before doing so. Lapses in professional ethics seem to be on the rise? I will discuss some examples, and what we should be doing to keep astronomy clean.
Upcoming talks
- Properties and origin of thick disks in external galaxiesDr. Francesca PinnaThursday January 16, 2025 - 10:30 GMT (Aula)
- Seminar by Luigi TibaldoLuigi TibaldoTuesday January 21, 2025 - 12:30 GMT (Aula)
Recent Colloquia
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