# Collaborative Research: Measuring G with a Levitated Test Mass

> **NSF 01002526DB NSF RESEARCH & RELATED ACTIVIT** · Regents of the University of Idaho (ID) · $150,010

## Abstract

Gravity was the first force mathematically described by scientists as an explanation of the motion of the moon, planets, and stars. Hundreds of years later, gravity is still considered to be the most poorly understood force. It cannot be consistently described across different theories in physics, and even its strength is poorly known. The Newtonian constant of gravitation, which quantifies the strength of gravity, is perhaps the most poorly measured fundamental property of the universe. This project seeks to greatly improve our knowledge of this constant with the most significant change in technique since the experiments of Henry Cavendish in 1798, who used a torsion balance for his measurements. The measurement funded by this award may be of value across many areas of physics and astronomy, and the new experimental tools being developed may lead to new instruments for measuring extremely small forces and accelerations for use in studying the Earth and for inertial navigation. In addition, the attention to detail required in these experiments makes them an exceptional training ground for tomorrow's STEM workers.

This project aims to resolve discrepancies in measurements of the Newtonian constant of gravitation, G, advancing our understanding of fundamental forces and potentially uncovering new physics. The approach is to levitate a graphite composite test mass in ultra-high vacuum. Changes in the oscillation frequency of the test mass, induced by carefully positioned fie

## Key facts

- **NSF award ID:** 2513014
- **Awardee organization:** Regents of the University of Idaho (ID)
- **SAM.gov UEI:** QWYKRJH5NNJ3
- **PI:** Zachariah B Etienne
- **Primary program:** 01002526DB NSF RESEARCH & RELATED ACTIVIT
- **All programs:** EXP PROG TO STIM COMP RES
- **Estimated total:** $150,010
- **Funds obligated:** $150,010
- **Transaction type:** Standard Grant
- **Period:** 09/01/2025 → 08/31/2028

## Primary source

NSF Award Search: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2513014

## Citation

> US National Science Foundation, Award 2513014, Collaborative Research: Measuring G with a Levitated Test Mass. Retrieved via AI Analytics 2026-06-06 from https://api.ai-analytics.org/grant/nsf/2513014. Licensed CC0.

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