I just thought of a way whereby one could extract some of the rotational
kinetic energy of the rapidly spinning planet of the Rauber/Marlow Chronicles
fame without super-advanced technology. IF this planet was close enough to
a central star so that the central star's gravitational field gradient was
significant at the planet's orbital location and/or if this planet has a
massive moon close enough to the planet to also have a significant
gravitational field gradient in the planet's vicinity, then either or both
of these celestial bodies would be able to raise significant tides on the
planet as it spins (assuming that the planet has a significant ocean surface).
It could be possible to capture some of the energy contained in the tidal
motions by perhaps walling off bays and estuaries from the ocean (assuming the
planet also had significant land area) and outfitting the walls with movable
sluice gates which can let the ocean into the bays when the tide is rising and
can be closed to trap this excess when the tide is falling. During low tide
the head between both sides of the wall can be used to do useful work (e.g.
turn turbines) as the ocean level is allowed to equilibrate across the wall in
a harnessed way. This mechanism would capture some of the planet's rotational
energy that would have been lost anyway to dissipation from friction and
erosional work. Note that this method still needs an extra-planetary agent
to acquire the planet's lost spin angular momentum and to provide the necessary
tidal flexing stresses.
David Bowman
Georgetown College
dbowman@gtc.georgetown.ky.us