  Under the spirit of J. Polchinsky's introduction of D-brane in the string
target spacetime (or 'bulk', for short), we consider the presence of both
closed and open superstrings and coupling of their low-lying modes in the bulk.
As a probe to explore the astrophysical and cosmological implications of the
superstring theory at larger length scale or in low-energy dynamics, we
construct the Yang-Mills monopole black hole solution and investigate its
features. Our results exhibit that as a result of intimate interactions among
low-lying modes, some cherished features of classical gravitation and cosmology
break down. They are the violation of black hole no-hair theorem and the break
down of cosmic censorship hypothesis. We learn from this lesson that these
implications of fully developed superstring theory in classical gravitation and
cosmology largely depart from our conventional wisdom signaling that the most
current version of superstring theory is indeed the best candidate for quantum
theory of gravitation.
