Carlo Rovelli's invited talk at the annual Strings-2008 conference

[Martin]

Since we have a thread discussing Rovelli's essay about time in physics, I thought some might enjoy this video of his talk this August at Strings-2008. Gives a good sense of what he's like and how he thinks. Packs a lot into the talk. Also gets half a dozen good questions from audience at end. Check it out.

 

http://cdsweb.cern.ch/record/1121957?ln=en

[npts2020]

I think a better explanation than his essay. At about 45 minutes many will not watch the whole thing, unfortunately. I particularly like the way he ties everything together and kind of sidesteps singularity issues though. If he is correct, and I didn't see anyone telling him he was wrong, it will require a lot of relearning and rewriting. Do you think the LHC will shed any light on this topic?

[Martin]

... Do you think the LHC will shed any light on this topic?

 

I think we need to look at all the new data that will be coming in.

Besides LHC there will be data from, for instance:

 

1. Fermi (space observ.) gammaray astronomy

2. Planck (space observ.) cosmic microwave background

3. Auger (ground) ultrahighenergy cosmic ray

4. Imaging Cherenkov telescopes (ground) TeV photons

5. Neutrino and gravity wave astronomy.

 

I think quantum gravity and its application to cosmology (quantum cosmology) is likely to be impacted by new observations during the next 5 years, and it's hard to anticipate where the new data will be coming from.

 

Learning more about the nature of darks (dark energy dark matter) will affect QG. This could come about by a combination of LHC results and astro observation.

 

Learning something about inflation (did it or didn't it, if it did how might it) would definitely impact QG. An astronomical test of whether inflation actually occurred has recently been proposed by Paul Steinhardt and others. I don't know whether LHC could play a role in understanding inflation but I wouldn't completely rule out the possibility.

 

Learning more about gravitational collapse and the formation of black holes would impact QG. Studying gammaray bursts (Fermi) has a bearing on this. I don't know if gravitational waves will be detected near term. That might also be relevant.

 

LHC might turn out to provide some much needed missing pieces for QG, but I wouldn't offer odds. Observational technology is advancing fast, so I feel pretty sure that some new data will guide QG research in the near-to-medium term. Whether that would include LHC data or not, I can't say.

 

Maybe one way to put it is this: quantum cosmo is to a large extent about understanding the early universe, black holes, and dark energy (quantum cosmo people write papers about these things and some have begun to focus on the job of making testable predictions). To the extent that the LHC says anything relevant to understanding the early universe, black holes, and dark energy, it will provide helpful guidance.

 

There is a conventional saying, which I think is rather shallow, that the LHC cannot provide any information relevant to quantum gravity because the LHC energies are too low. I think that neglects possible synergies with astro observation.

Edited November 10, 2008 by Martin

[npts2020]

I agree. It is the reconciling of large and small that will really tell us the most and not one or the other. Once the data starts coming there will be a mad scramble to describe its implications. I heard that something like 90% of the data from LHC will be lost forever because of lack of data storage. Is that true?