Thanks to the Heising Simons Foundation (https://www.hsfoundation.org/) for their support of this video, and of short range gravity research. This video is about how little we know about the behavior of gravity at short length and distance scales, what the constraints are on the inverse square law/Newton's law of universal gravitation, at the human and microscopic and atomic scales. Only on solar system scales or larger do we have good constraints on Newton's law of gravitation. REFERENCES Review of short-range gravity experiments in the LHC era https://arxiv.org/abs/1408.3588v2 Zeptonewton force sensing with nanospheres in an optical lattice https://arxiv.org/abs/1603.02122 Large extra dimensions https://en.wikipedia.org/wiki/Large_extra_dimension Search for Screened Interactions Associated with Dark Energy Below the 100 μm Length Scale https://arxiv.org/abs/1604.04908 Tests of the Gravitational Inverse-Square Law below the Dark-Energy Length Scale https://arxiv.org/abs/hep-ph/0611184v1 Photon Mass Experiment http://dx.doi.org/10.1119/1.13149 Torsion balance experiments: A low-energy frontier of particle physics E.G. Adelberger, J.H. Gundlach, B.R. Heckel, S. Hoedl, S. Schlamminger doi:10.1016/j.ppnp.2008.08.002 TESTS OF THE GRAVITATIONAL INVERSE-SQUARE LAW E.G. Adelberger, B.R. Heckel, and A.E. Nelson Annu. Rev. Nucl. Part. Sci. 2003. 53:77–121 doi: 10.1146/annurev.nucl.53.041002.110503 Physical Review A, Vol 33, No 1: Improved result for the accuracy of Coulomb's law: A review of the Williams, Faller, and Hill experiment. Lewis P. Fulcher. Support MinutePhysics on Patreon! http://www.patreon.com/minutephysics Link to Patreon Supporters: http://www.minutephysics.com/supporters/ MinutePhysics is on twitter - @minutephysics And facebook - http://facebook.com/minutephysics And Google+ (does anyone use this any more?) - http://bit.ly/qzEwc6 Minute Physics provides an energetic and entertaining view of old and new problems in physics -- all in a minute! Created by Henry Reich