[Cosmo-torun] @14:00 @KRA OK? [Re: cosmo workshop Fri 2 March @15.00 @KRA: Jan Ostrowski on Cactus: numerical relativity]

hi everyone,

On Wed, 29 Feb 2012, Tomasz Kazimierczak wrote:

Could we start a little bit ealier, for example @14:00?

Does anyone (especially Jan!) have a problem with starting at 14:00 ?

See everyone this afternoon :)

pozdr boud

I have "dyżur" at control room starting at 16:00.

2012/2/29 Boud Roukema boud@astro.uni.torun.pl hi cosmo-torun

   Cactus: numerical relativity
   cosmo workshop Fri 2 March @15.00 @KRA
   Jan Ostrowski


  Jan is doing very interesting work in finding out how to do numerical
  relativity. One way of saying it is the following:

  "Normal" cosmological N-body simulations consist of *Newtonian*
  gravity simulated on a highly simplified (perfectly homogeneous)
  relativistic "background". In formal scientific language, this is
  called a "heuristic" approach; in informal language, it's called "a
  fudge" - it's a mathematical shortcut that seems like it should work
  and lets us quickly compare some sort of "model" to observations
  instead of waiting 50 years for the mathematics to be solved. In
  principle, every scientist using the heuristic/fudge is aware of
  this. Pure theory is very difficult to apply to the real world.

  Relativistic cosmological simulations should be "directly"
  relativistic, consistent with the Einstein equations, without using
  the heuristic/fudge of adding "perturbations" that obey Newtonian
  gravity to a relativistic "background". So these simulations can be called
  "background-free".

  How can we do background-free cosmology simulations?

  Jan will present a discussion on this.

  pozdr
  boud

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