Galileo's Belated Gravity Experiment: The Small Low-Energy Non-Collider
Galileo proposed a simple gravity experiment that has yet to be per- formed. Suppose we drop a test mass into a hole through the center of a larger source mass. What happens? Using a modified Cavendish balance or an orbiting satellite, modern technology could have revealed the answer decades ago. General Relativity is widely regarded as being supported by empirical evidence throughout its acces- sible range. Not commonly realized is that, with regard to gravity-induced motion, this evidence excludes the interior regions of material bodies over this whole range. If only to fill this huge gap in our empirical knowledge of gravity, Galileo's experiment ought to be performed without further delay. PACS 04.80.Cc - Experimental tests of gravitational theories.