아인슈타인의 상대성 이론은 양자 도전 이후에도 여전히 강력합니다.

Leibniz University Hannover와 University of Bremen의 연구팀은 또 다른 등가 원칙을 확인했습니다.

과학자들은 모든 질량 특성이 동일하다는 것을 100배 더 정확하게 확인하기 위해 반세기 동안의 달 레이저 거리 측정 데이터를 사용했습니다. 이 발견은 상대성 이론의 초석인 아인슈타인의 등가 원리를 크게 뒷받침합니다.

기본 물리학의 가장 기본적인 가정 중 하나는 무게, 관성 및 중력과 같은 질량의 서로 다른 특성이 서로에 대해 항상 동일하게 유지된다는 것입니다. 이러한 동등성이 없다면 아인슈타인의 상대성 이론은 모순이 될 것이며 현재의 물리학 교과서는 다시 쓰여져야 할 것입니다. 지금까지의 모든 측정이 등가 원리를 확인했지만 양자 이론은 위반이 있어야 한다고 가정합니다. 아인슈타인의 중력 이론과 현대 양자 이론 사이의 이러한 불일치는 등가 원리에 대한 보다 엄격한 테스트가 특히 중요한 이유입니다.

독일 하노버 라이프니츠 대학의 측지학 연구소(IfE)와 협력하여 브레멘 대학의 응용 우주 기술 및 미세중력 센터(ZARM) 팀이 100배 더 크다는 것을 성공적으로 시연했습니다.[{” attribute=””>accuracy that passive gravitational mass and active gravitational mass are always equivalent – regardless of the particular composition of the respective masses. The research was conducted within the framework of the Cluster of Excellence “QuantumFrontiers.” On July 13, the team published their findings as a highlights article in the scientific journal Physical Review Letters.

Binary system Earth-Moon. Credit: AEOS Medialab, ESA 2002

Physical context

Inertial mass resists acceleration. For example, it causes you to be pushed backward into your seat when the car starts. Passive gravitational mass reacts on gravity and results in our weight on Earth. Active gravitational mass refers to the force of gravitation exerted by an object, or more precisely, the size of its gravitational field. The equivalence of these properties is fundamental to general relativity. Therefore, both the equivalence of inertial and passive gravitational mass and the equivalence of passive and active gravitational mass are being tested with increasing precision.

First Author of the Publication, Vishwa Vijay Singh. Credit: Singh

What was the study about?

If we assume that passive and active gravitational mass are not equal – that their ratio depends on the material – then objects made of different materials with a different center of mass would accelerate themselves. Since the Moon consists of an aluminum shell and an iron core, with centers of mass offset against each other, the Moon should accelerate. This hypothetical change in speed could be measured with high precision, via “Lunar Laser Ranging.” This involves pointing lasers from Earth at reflectors on the Moon placed there by the Apollo missions and the Soviet Luna program. Since then, round trip travel times of laser beams are recorded. The research team analyzed “Lunar Laser Ranging” data collected over a period of 50 years, from 1970 to 2022, and investigated such mass difference effects. Since no effect was found, this means that the passive and active gravitational masses are equal to approximately 14 decimal places. This estimate is a hundred times more accurate than the best previous study, dating back to 1986.

Unique expertise

LUH’s Institute of Geodesy – one of only four centers worldwide analyzing laser distance measurements to the Moon – has unique expertise in assessing the data, particularly for testing general relativity. In the current study, the institute analyzed the Lunar Laser Ranging measurements, including error analysis and interpretation of the results.

Vishwa Vijay Singh, Jürgen Müller and Liliane Biskupek from the Institute of Geodesy at Leibniz University Hannover, as well as Eva Hackmann and Claus Lämmerzahl from the Center of Applied Space Technology and Microgravity (ZARM) at the University of Bremen published their findings in the journal Physical Review Letters, where the paper was highlighted in the category “editors’ suggestion.”

Reference: “Equivalence of Active and Passive Gravitational Mass Tested with Lunar Laser Ranging” by Vishwa Vijay Singh, Jürgen Müller, Liliane Biskupek, Eva Hackmann and Claus Lämmerzahl, 13 July 2023, Physical Review Letters.
DOI: 10.1103/PhysRevLett.131.021401