Tritium as an Anthropic Probe
  I show that if tritium were just 20 keV lighter relative to helium-3, then
the current deuterium burning phase of pre-main-sequence stellar evolution
would be replaced by deuterium+tritium burning. This phase would take place at
the same temperature but would last a minimum of 4 times longer and a maximum
of 8 times longer than deuterium burning and so would yield total energies
comparable to the binding energy of solar-type pre-main-sequence stars. Hence,
it could in principle radically affect the proto-planetary disk, which forms at
the same epoch. I suggest that this may be one of the most "finely-tuned"
parameters required for intelligent life, with the mass range only a few
percent of the neutron-proton mass difference, and 10^{-5} of their masses. I
suggest that the lower limit of this range is set by the physics of disk
formation and the upper limit by the statistical properties of fundamental
physics. However, if this latter suggestion is correct, the statistical
distribution of physical "constants" must be a power-law rather than an
exponential. I also suggest a deep connection between fundamental physics and
the search for extrasolar life/intelligence.
