Below is the provisional termcard for Michaelmas Term 2009. The actual details of each event will be sent out a few days before each event in an email to the mailing list. To join the mailing list, look at the ‘Contact us’ page.
The talks should take place from 8.15pm in the Lindemann Lecture theatre of the Clarendon Laboratory in the Physics department (click here to a see map). We will meet members in the foyer of the Physics department from 8.00pm onwards. The talks usually last about an hour, and there is an opportunity to ask the speaker questions about their talk. There are refreshments afterwards, giving you the opportunity to meet other members of the society and people interested in Physics.
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1st Week (Tue 13th October) - Freshers’ Social
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2nd Week (Tue 20th October)- Brian Foster, title TBC
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3rd Week (Tue 27th October)- Frank Arntzenius, title “Physics and the existence of
mathematical objects”
Abstract: Physics as standardly formulated makes use of mathematical objects all
over the place. Functions, sets, numbers, etc. are mathematical objects whose
nature is quite different from physical objects such as tables, electrons and
fields. If one denies, or even doubts, the existence of mathematical objects,
one has reason to investigate whether one can formulate physics without the use
of mathematical objects. But even if one does not doubt the existence of
mathematical objects, one could still be interested in attempting to formulate
physical theories while not making use of objects which appear not to be
intrinsic to the enterprise of physics. I will discuss how one might go about
formulating physics without the use of mathematical objects.
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4th Week (Tue 3rd November) -Julian Barbour, title “Does time exist?”
Abstract: Leibniz long ago argued, against Newton, that time is not a
thing but merely the order of coexisting things. I shall first show
how Leibniz is correct by recovering Newton’s dynamics from the
difference of things without the prior assumption that they change in
time. This result changes our notion of time in classical physics
relatively little, but has potentially profound implications for the
long sought theory that will unify quantum mechanics with general
relativity. It may well lead to a completely timeless, indeed static,
description of the universe. I shall say something about this and how
our experience of a vibrant dynamic world may nevertheless emerge from
it. For those interested in prior reading, I suggest my essay The
Nature of Time at fqxi.org/community/essay and my book The End of
Time.
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5th Week (Tue 10th November) - Bob Cywinski, title “Towards an Alternative Nuclear Future”
Abstract: There is little doubt that both nationally and globally we
are rapidly approaching an energy crisis arising from diminishing
resources and over-production of CO2. Controversially, the UK and
other governments are suggesting that maintaining or even increasing
production of electricity by nuclear power must be an essential
component of the solution to this problem. In this seminar I will
briefly review the “energy crisis” and the potential role that
conventional nuclear power is expected to play. I will then focus on a
hitherto untapped energy resource – thorium – and show how, using some
rather unconventional but achievable technologies thorium could
provide the key to safe, low waste and proliferation-resistant nuclear
energy.
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7th Week (Tue 24th November) – Dr Chris Davis. Living with a Star
Violent eruptions from the surface of the Sun known as Coronal Mass Ejections (CMEs) eject vast clouds from the Sun’s atmosphere into space. When one of these clouds reaches Earth it can have a significant impact on satellites, ground-based power grids and radio communication as well as representing a major radiation hazard for astronauts. The occurrence of these storms has become known as ‘space weather’ and missions like the NASA STEREO spacecraft are providing vital clues in understanding the processes that lead to these eruptions and have demonstrated our ability to track them out to Earth. As we become increasingly reliant on spacecraft in many aspects of our daily lives, predicting the occurrence and direction of these solar storms is of great importance and will be vital if mankind is every to set up colonies on other planets such as the Moon or Mars where there is little or no atmosphere to protect the colonists from direct exposure to the space environment.
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8th Week (Tue 1st December) – Myles Allen. Climate Change: Beware of what you wish for in Copenhagen
The risk of dangerous climate change is predominantly determined by cumulative emissions of carbon dioxide, not emissions in any given year. This calls for a fresh approach to climate change mitigation. It is not enough to reduce the rate of emissions by 50% or 80%: they have to net to zero before we exhaust the atmospheric capacity, which is estimated at around one trillion tonnes of carbon, half of which has been emitted already.
That much is relatively uncontroversial climate physics (although still largely ignored in the Copenhagen negotiations), but the limit on cumulative carbon dioxide emissions has more controversial implications. While tradable permits and carbon taxes may begin the process of reducing the flow of emissions, they do not provide a complete strategy for avoiding dangerous climate change, because no conceivable permit or tax regime would reduce global carbon dioxide emissions to zero before we exhaust the overall stock. One alternative approach would be a mandatory link between fossil fuel extraction and carbon sequestration. I will introduce the notion of Sequestered Adequate Fraction of Extracted carbon (SAFEcarbon), which needs to converge to 100% before we exhaust the atmospheric capacity, as a way of breaking the apparent conflict between short-term consumption and long-term climate protection.
My personal view (and feel free to come along and disagree) is that the best possible outcome in Copenhagen would be a strong endorsement of the objective of limiting global warming to two degrees above pre-industrial and an agreement to defer agreement on how this is to be achieved. The wrong “deal”, with excessive focus on short-term targets, risks diverting attention from what really matters and another wasted decade in combating dangerous climate change.
