Multi-Mode Apparatus to Determine Newton's Constant G

The Newtonian gravitational constant, G, is a fundamental constant in nature not linked~by any complete theories to other forces of nature. Compared to all other fundamental constants, G is known with the least precision. Over the last 200 years, its~value~has~been~repeatedly~measured, and even the world's~leading~experiments have produced values which are incompatible with one another. In fact, compared to the most precise experiment,~some measured values differ by~up to~50 times the experimental~uncertainty. Recently, two experiments have measured consistent results at the 12 ppm level. After examination of the methodology used in previous measurements, the research group at IUPUI, in collaboration with Humboldt State University and Syracuse University, will use~multiple~approaches to determine G within a same torsion pendulum apparatus. We expect to obtain a measurement at the 2 ppm level using these new~methods. By continuing the use of a torsion pendulum apparatus, we also hope to better understand the current discrepancies among previous experimental~results. This talk will explore the experimental configurations and give a current update on the multi-mode apparatus.