  We review the latest findings on extra-solar planets and their potential to
support Earth-like life. Focusing on planets orbiting Red Dwarf (RD) stars, the
most abundant stellar type, we show that including RDs as potential host stars
could increase the probability of finding biotic planets by a factor of up to a
thousand, and reduce the estimate of the distance to our nearest biotic
neighbor by up to 10. We argue that binary and multiple star systems need to be
taken into account when discussing exoplanet habitability. Early considerations
indicated that conditions on RD planets would be inimical to life, as their
Habitable Zones (where liquid water could exist) would be so close as to make
planets tidally locked to their star. This was thought to cause an erratic
climate and expose life forms to flares of ionizing radiation. Recent
calculations show that these negative factors are less severe than originally
thought. It has been argued that the lesser photon energy of the radiation of
the relatively cool RDs would not suffice for Oxygenic Photosynthesis (OP) and
other related energy expending reactions. Numerous authors suggest that OP on
RD planets may evolve to utilize photons in the infrared. We however argue, by
analogy to the evolution of OP and the environmental physiology and
distribution of land-based vegetation on Earth, that the evolutionary pressure
to utilize infrared radiation would be small. This is because vegetation on RD
planets could enjoy continuous illumination of moderate intensity, containing a
significant component of photosynthetic 400-700 nm radiation. We conclude that
conditions for OP could exist on RD planets and consequently the evolution of
complex life might be possible. Furthermore, the huge number and the long
lifetime of RDs make it more likely to find planets with photosynthesis and
life around RDs than around solar type stars.
