I think it would be great if w turned out to be less than -1, because then we’d all know for sure what we currently only suspect, ie that we don’t understand anything!

]]>Peter: I think the “phantom” term for w < -1 originates from Rob Caldwell's paper in 1999, http://arxiv.org/abs/9908168/ , and the phrase comes from the Star Wars prequel of 1999… this theme re the "dark side" has continued, e.g. pic of Darth Vader on the cover of the Kolb 2006 dark energy task force.

Ian : I'm not quite sure what your point is re "knowing the answer". Most cosmologists probably would "prefer" to prove w not equal to -1 (or GR wrong) which gets a strong chance of a Nobel Prize, while just getting closer and closer to -1 probably does not. There was considerable discussion at the Durham Ripples meeting about the need for "blinding" in future cosmological analyses to avoid "confirmation bias".

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