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Recent conjectures that there are mesoscopically "large" extra dimensions, through which gravity propagates have interesting implications for much of physics. The scenario implies gross departures from Newton's law of gravity at small length scales. Testing departures from Coulomb's law on sub-millimetre scales is hard. It is now possible to routinely create Bose-Einstein condensates with de Broglie wavelengths of order a µm and total size of order 10 µm. BEC condensates move coherently under gravitational acceleration, and I propose that the transverse fringe shift due to the acceleration of a pair of interfering BECs passing a dense linear mass may be measurable, and provide direct evidence for anomalous gravitational acceleration. Ideally such experiments are best carried out in free fall to maximise the time spent by a BEC in the non-Newtonian regime. [ABSTRACT FROM AUTHOR]

Recent conjectures suggest the universe may have large extra dimensions, through which gravity propagates. This implies gross departures from Newton's law of gravity at small length scales. Here I consider some implications for particle dynamics on scales comparable to the compactification radius, R[sub c] ... 1 mm. During planet formation, coalescence of micron sized dust grains to planetesimals is a rate critical step. Blum et al. (2000) found dust grain aggregates form low fractal dimension structures in microgravity, consistent with high angular momentum coalescence. I consider the effects of non-Newtonian gravity on dust aggregation on scales less than R[sub c] and show they naturally coalesce into low-dimensional structures with high specific angular momentum. We infer R[sub c] ≈ 80 microns. [ABSTRACT FROM AUTHOR]