The prototype of a Taub string is formed by successive junctions of copies of Taub's space { \cal T}, joined at their null boundaries \Sigma to create the axially-symmetric Bianchi-type-XI (with compact SL sections of scale { \rm L_o}) vacuum { \cal B}^4_{ \rm T}= ...\vee { \cal T}\vee { \cal T}\vee { \cal T}\vee..., which is a { \em proper} one, namely a stable non-singular geodesically complete and globally fit solution of Einstein's vacuum equations without torsion and without a cosmological constant. Each { \cal T} contributes to { \cal B}^4_{ \rm T} with its entire life-span as a quantum of time \delta t\sim{ \rm L_ o} between two consecutive \Sigma. The latter propagate as shock-wave fronts under string tension of Planck-scale strength \kappa_{ \rm o}. The incurring dynamics entails stability and the foundation of hierarchy in { \cal B}^4_{ \rm T}. Appropriate averaging of this dynamics generates { \em effective} stress-energy content and torsion in a static \bar{ \cal B}^4_{ \rm T} vacuum. With the latter as ground state, excitations thereof must involve two new independent scales, \kappa and { \rm L_1}\gg{ \rm L_o}, in addition to \kappa_{ \rm o}, { \rm L_o}. Elemental finite Taub strings and variant vacua, including the { \rm L_o}\gg\kappa_{ \rm o} cosmological case, are also discussed.
Categories: gr-qc hep-th