Monday, March 25, 2013

'The Existence of Nothing' - Issac Asimov discussion March 2013

 h/t Dean Robertson. Facebook discussions at Dorset Humanists.

Eve Silverstein (ES), professor of theoretical physics, Stanford University, and co-editor of Strings, Branes and Gravity
J. Richard Gott (RG), professor of astrophysical sciences, Princeton University, and author of Sizing Up the Universe: The Cosmos in Perspective
Jim Holt (JH), science journalist and author of Why Does the World Exist? An Existential Detective Story
Charles Seife (CS), professor of journalism, New York University, and author of Zero: The Biography of a Dangerous Idea
Lawrence M Krauss (LK), professor of physics, Arizona State University and author of A Universe from Nothing: Why There is Something Rather Than Nothing

Neil deGrasse Tyson (NdGT) moderator and Hayden Planetarium Director - leads a spirited discussion The event, which was streamed live to the web, took place at the American Museum of Natural History on March 20, 2013.

my notes
ES 7 mins 50s (7:05-9.20). The structure in the universe started with Quantum fields which were in their ground or vacuum state. This, combined with the inflationary expansion of the early universe in quantum mechanics leads to the origin of the structure of the early universe that we see today. Sensitivity to high energy physics questions that bring in problems of quantum gravity which are accessible to experiments and observations of the Cosmic Microwave Background (CMB) radiation. The most interesting version of nothing.
Chris: What an opening 1 minute statement by ES! Full of technical technical terms like 'quantum fields', 'groundstate', 'vacuum state', 'inflationary expansion', 'quantum mechanics', 'quantum gravity', Cosmic Microwave Background (CMB) radiation. This is a kinda tough opening statement which assumes the audience has a lotta knowledge about her subject!
LK  9 mins 16s - 10 55s: Universe does not supernatural deity for explanations.
RG ~11 mins - General Relativity, Quantum vacuum state relevant for creation of universe, time travel, cosmic string, Goedel. Nuts.
JH ~ maths guy.
CS 15m - Romans didn't have concept of zero. Humans have a diminished revulsion of nothing.
JH: ex nihilo creation; Leibniz
RG: 23m space - photons - atoms ---> empty space = quantum vacuum space = close your eyes (its alive with virtual particles and fields;
LK: 26m - Biblical definition of nothing: Infinite empty void - space without particles, radiation, fields but it still has energy - there is  no stuff there but it still weighs something. 29m 2nd type of nothing: No space, no time
RG: greater density than a neutron star, Hawking radiation
JH: 36m: Alex Valenkin?? definition of nothingness: ball of radius zero, closed spacetime, false vaccuum by inflation will evolve into galaxies. Problem: physical laws, consciousness.
EV: in string theory zero radius does not mean nothing, how many dimensions do you have?
RG: 46m; Really Nothing: no quantum state, quantum tunnelling, can the laws of physics create the universe rather than creating the universe out of nothing? Leibniz asked 'why is there something rather than nothing' His answer was God.
LK: 49m: best physical definition of nothing is the absence of something. You have to understand what 'something' is and also what is 'the absence of something'. All these are physical not philosophical questions. When you apply quantum mechanics to gravity, if you make space and time quantum variables, then universes and space and time can pop into existence where there was no space and time. Multiverse
ES: 55m: string theory model, dimensionality, masses grow exponentially but no of dimensions decreases to zero.
RG 1hr.07m: different laws of physics invoke different Multiverses. Some friendly to humans = anthropic principle.
JH: 1hr.15m: Theory of Plenitude, Heidegger
NdGT: when you die your awareness is what you knew of the world before you were born, like what was behind your head.
JH: dreamless sleep
LK: Nothing has 3 physical definitions 1) empty space 2) No space 3) no space, no time, no particles, no laws. Don't assume intentionality - that's for theologians
ES: 1hr 23m Nothing: absence of degrees of freedom in quantum field theories. Ground state of a gapped quantum system is her best theory of nothing.
NdGT: 1hr 25m - Nothing used to be described as ....  summary

Question Time
1hr 26m: xxx
1hr 39: NdGT - are there multiple multiverses? Don't assume it's religious just because it's not what your first set of theories are. God of the Gaps!
1hr 46: Is fascination of views coming down to the Why? question. LK: Why no has no meaning. Why assumes a purpose. Why always means how! Unless you assume some intentionality. Then you are assuming the answer before you ask the question! Why may not be a good question!! There may be no intentionality. There may be no reason why the universe exists. There is a process of how it exists. If time does not exist before the big bang what do you mean by cause? What do you mean by before?
1hr 48m: JH disagrees with LK:  why do the laws of physics pick the form they do? Use the Principle of Sufficient Reason - some why questions are valid!!

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