starship-design: ANOTHER UNIVERSE

["L. Parker" <lparker@cacaphony.net>]

ANOTHER UNIVERSE MIGHT LURK ONLY MILLIMETERS
away from our universe, but we wouldn't know it because it exists
on its own membrane separated from our membrane in some extra
spatial dimension.  Matter on the other membrane would be
invisible but could exert a gravitational effect and would, in fact,
constitute the "dark matter" for which astrophysicists have sought
for some years.  In a recent paper Paul Steinhardt (Princeton) and
Neil Turok (Cambridge) propose that the structure in our universe
may well have come about in the collision of two such membrane
universes.  All the historical events in the life of our
cosmos initial big bang, subsequent expansion of galaxies, even
the currently observed accelerated expansion phase, and finally a
contraction into a "big crunch" would be played out in a recurring
drama.  This cyclic cosmology (an extension of Steinhardt's
"ekpyrosis" theory; see Update 535) uses all the latest tools of
string theory, accounts for the "dark energy" supposedly firing
cosmic acceleration, and would have no need for an ad-hoc
"inflationary" phase appended to the standard big bang model to
explain such cosmological features such as the horizon problem
(why the extreme edges of the visible universe seem to be at the
same temperature).  (Sciencexpress, 25 April, soon to be in
Science.)