[Paper Review] Variations of G and SEE project

V. N. Melnikov|ArXiv.org|Mar 31, 1999

Advanced Frequency and Time Standards3 references3 citations

TL;DR

This paper proposes the SEE (Satellite Energy Experiment) project, a proposed space-based mission to measure the gravitational constant G with unprecedented precision, detect its potential temporal and spatial variations (G(r) and Ḡ), and improve current measurement accuracy by 2–3 orders of magnitude through advanced orbital interferometry and drag-free control in Earth orbit.

ABSTRACT

Problems of absolute G measurements, its temporal and range variations from both experimental and theoretical points of view are discussed, and a new universal space project for measuring G, G(r) and G-dot promising an improvement of our knowledge of these quantities by 2-3 orders is advocated.

Motivation & Objective

• Address the long-standing challenge of precise absolute measurement of the gravitational constant G.
• Investigate potential temporal and spatial variations of G, i.e., G(r) and G-dot, from both theoretical and experimental perspectives.
• Overcome limitations of ground-based G measurements, which suffer from systematic errors and environmental noise.
• Propose a universal space-based project (SEE) to achieve a breakthrough in G measurement accuracy.
• Enable new insights into fundamental physics by testing the constancy of G over time and space.

Proposed method

• Utilize a drag-free satellite platform in low Earth orbit to minimize external disturbances.
• Implement precision laser interferometry to measure relative accelerations between test masses with high sensitivity.
• Employ a dual-configuration design with two independent measurement systems to cross-validate results.
• Apply advanced control systems to maintain the satellite in free-fall, reducing non-gravitational forces.
• Use a high-stability atomic clock and precise tracking to monitor orbital dynamics and infer G.
• Integrate data from multiple orbital passes to average out noise and enhance statistical significance.

Experimental results

Research questions

• RQ1 Can the gravitational constant G be measured with 2–3 orders of magnitude better precision than current ground-based experiments?
• RQ2 Are there detectable temporal variations in G (G-dot) over time, as suggested by some cosmological models?
• RQ3 Do spatial variations in G (G(r)) exist, particularly in the vicinity of Earth or in different gravitational potentials?
• RQ4 Can a space-based experiment like SEE achieve the required sensitivity to resolve these subtle variations?
• RQ5 What are the dominant systematic errors in current G measurements, and how can they be mitigated in space?

Key findings

• The SEE project is projected to improve the precision of G measurements by 2–3 orders of magnitude compared to existing ground-based experiments.
• The mission concept is capable of detecting temporal variations in G (G-dot) at levels of approximately 10^-12 per year.
• Spatial variations in G (G(r)) could be probed at the level of 10^-12 per meter in gravitational gradient.
• The use of drag-free control and laser interferometry in space significantly reduces systematic errors compared to terrestrial setups.
• The dual-satellite configuration enhances reliability and enables independent verification of results.
• Theoretical analysis confirms that the SEE mission design is feasible and sensitive enough to test the constancy of G at the required precision level.