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I've never heard of "gravity's rainbow". It seems that it's what happens when one derives general relativity using "doubly special relativity" instead of normal

by nilkn 12y ago

I've never heard of "gravity's rainbow". It seems that it's what happens when one derives general relativity using "doubly special relativity" instead of normal special relativity. I hadn't heard of "doubly special relativity" either. http://en.wikipedia.org/wiki/Doubly_special_relativity http://en.wikipedia.org/wiki/Doubly_special_relativity It seems to have been around for at least ten years but perhaps never gained much traction. In short, this seems like it may be an interesting result that only applies in a fringe variation of accepted modern theory. Perhaps someone with actual training in physics can comment in more detail.

tjradcliffe 12y ago
This isn't a "fringe" variation in any but the sociological sense. I hadn't heard of either of these ideas until today, but my first thought was, "Yeah, that makes sense" (I'm a physicist, but not a gravity person.) If you believe in the Planck scale (and almost everyone does) then incorporating it into SR as an "observer independent maximum energy" that is comparable to the usual "observer independent maximum velocity" is a very natural thing to do. The theory might not have got much play, but this result will definitely increase interest because the black hole information paradox is a pain. However: the amount of interest a theory gets does not reflect the likelihood that it is correct. Caloric was once a very popular idea. Currently string theory is. Tomorrow maybe "extra special relativity" will be.
- otakucode 12y ago
  >If you believe in the Planck scale (and almost everyone does) What? The idea that spacetime is quantized is most definitely not widely accepted. Spacetime is presumed to be continuous by basically every mainstream physicist (though most will admit that we don't have conclusive evidence either way, we only know that spacetime is not quantized down to a certain scale (which is short of the planck length by a good deal)). I personally think spacetime is quantized, but the only physicists pursuing the consequences of such an idea tend to be the fringe ones...
  - tjradcliffe 12y ago
    I should have said "take seriously" rather than "believe in". Most people take the notion seriously, for some value of "seriously". It's not a binary state.
    - deleted 12y ago
      [deleted]
swamp40 12y ago
Perhaps people don't take it seriously because it sounds a lot like "double secret probation"?

by nilkn 12y ago

tjradcliffe 12y ago

This isn't a "fringe" variation in any but the sociological sense. I hadn't heard of either of these ideas until today, but my first thought was, "Yeah, that makes sense" (I'm a physicist, but not a gravity person.) If you believe in the Planck scale (and almost everyone does) then incorporating it into SR as an "observer independent maximum energy" that is comparable to the usual "observer independent maximum velocity" is a very natural thing to do. The theory might not have got much play, but this result will definitely increase interest because the black hole information paradox is a pain. However: the amount of interest a theory gets does not reflect the likelihood that it is correct. Caloric was once a very popular idea. Currently string theory is. Tomorrow maybe "extra special relativity" will be.

otakucode 12y ago
>If you believe in the Planck scale (and almost everyone does) What? The idea that spacetime is quantized is most definitely not widely accepted. Spacetime is presumed to be continuous by basically every mainstream physicist (though most will admit that we don't have conclusive evidence either way, we only know that spacetime is not quantized down to a certain scale (which is short of the planck length by a good deal)). I personally think spacetime is quantized, but the only physicists pursuing the consequences of such an idea tend to be the fringe ones...
- tjradcliffe 12y ago
  I should have said "take seriously" rather than "believe in". Most people take the notion seriously, for some value of "seriously". It's not a binary state.
  - deleted 12y ago
    [deleted]

swamp40 12y ago

Perhaps people don't take it seriously because it sounds a lot like "double secret probation"?