Measuring the foaminess of space-time with gravity-wave interferometers

By analyzing a gedanken experiment designed to measure the distance l betwe en two spatially separated points, we find that this distance cannot be mea sured with uncertainty less than (ll(P)(2))(1/3), considerably larger than the Planck scale l(P) (or the string scale in string theories), the convent ional-wisdom uncertainty in distance measurements. This limitation to space -time measurements is interpreted as resulting from quantum fluctuations of space-time itself. Thus, at every short distance scales, space-time is "fo amy." This intrinsic foaminess of space-time provides another source of noi se in the interferometers. The LIGO/VIRGO and LISA generations of gravity-w are interferometers, through future refinements, are generations of gravity -wave interferometers, through future refinements, are expected to reach di splacements noise levels low enough to test our proposed degree of foamines s in the structure of space-time.