Torsion-balance experiments report no deviation from the gravitational inverse-square law down to separations of about 52 micrometres.

Torsion-balance experiments report no deviation from the gravitational inverse-square law down to separations of about 52 micrometres.

Why it is stated this way

This is a direct laboratory measurement, published in Physical Review Letters, and one of the few genuinely settled empirical inputs on this map. It constrains any scenario predicting a mesoscopic extra dimension.

Scope and limitations

A null result bounds the parameter space; it does not exclude the Dark Dimension scenario, whose predicted scale sits near the current experimental frontier. Systematics modeling, not the raw sensitivity, is the practical limit.

Sources

• New Test of the Gravitational 1/r² Law at Separations down to 52 μm ↗ · Lee, Adelberger, Cook, Fleischer, Heckel · arXiv:2002.11761 · PRL 124, 101101 (2020)
• Tests of the Gravitational Inverse-Square Law below the Dark-Energy Length Scale ↗ · Kapner, Cook, Adelberger, Gundlach, Heckel, Hoyle, Swanson · hep-ph/0611184 · PRL 98, 021101 (2007)

Related atlas concepts

Extra dimensionsObservational cosmology