No. The answer is no. But you’d be forgiven for
thinking otherwise, because string theory has had a really rough
couple of years. This is because physicists had two promising opportunities to prove the
accuracy of a simple string theory model, and neither opportunity panned out.
The first serious opportunity came when CERN’s Large
Hadron Collider went live. As Columbia University’s Brian Greene explains in
his 2008 introduction to string theory, the LHC had the potential to prove
string theory correct:
Now it’s six years later, and we know that isn’t going
to happen, at least not the way Greene and others had hoped. The LHC has not detected what we would expect it to detect if a simple
string theory model were accurate, which probably means that either string
theory isn’t accurate, or the particular version of string theory we accept
needs to be more complex. A lot of physicists thought it did anyway; Greene
himself identifies a wide range of string theory models, and most
of them are not affected in any way by the lack of LHC data. What the lack of
proof really does is help refine string theory to exclude some
of the simpler models.
Likewise, the German study that seemed to confirm Lorentz invariance earlier this week—when a small number of string
theory models predicted that Lorentz invariance could be violated—doesn’t
really affect the overall validity of string theory. A number of laypersons are
likely to believe that string theory has been disproven by
this study, and it hasn’t. (The American Physical Society’s statement that “certain quantum gravity theories, such as
string theory, predict [Lorentz invariance] violation at a very small level”
doesn’t help matters; most string theory models do not predict
measurable violation of Lorentz invariance.) As with the LHC data, string
theory has been refined, not disproven.
Here’s a good point of comparison: let’s say you were
somehow able to comprehensively search Yellowstone Park and prove Bigfoot isn’t
there. That doesn’t mean Bigfoot isn’t real; it just means he isn’t in
Yellowstone Park, so you know you can stop looking for him there. That’s fine.
But if you were able to comprehensively search Loch Ness and prove Nessie isn’t
there, that would be a much bigger DEAL
because you’d have categorically proven that the
Loch Ness monster doesn’t exist, period, full stop; if you found Nessie
anywhere else, it wouldn’t be Nessie.
because you’d have categorically proven that the
Loch Ness monster doesn’t exist, period, full stop; if you found Nessie
anywhere else, it wouldn’t be Nessie.
Some string theory skeptics have reacted as if the LHC
and Lorentz invariance data have created a no-Nessie scenario when they’ve
really created more of a no-Bigfoot-in-Yellowstone scenario. A few string
theory models have been discredited by recent studies, but the vast majority of
string theory models are no more or less likely to be accurate than they were
ten years ago. And since it’s impossible for more than one model of string
theory to be accurate anyway, that isn’t really a gamechanger.
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