Abstract
General relativity is founded on the experimental fact that in a gravitational field all bodies fall with the same acceleration regardless of their mass and composition. This is the weak equivalence principle, or universality of free fall. Experimental evidence of a violation would require either that general relativity is to be amended or that another force of nature is at play. In 1916 Einstein brought as evidence the torsion balance experiments by Eötvös, to 10-8–10-9. In the 1960s and early 70s, by exploiting the "passive" daily rotation of the Earth, torsion balance tests improved to 10-11 and 10-12. More recently, active rotation of the balance at higher frequencies has reached 10-13. No other experimental tests of general relativity are both so crucial for the theory and so precise and accurate. If a similar differential experiment is performed inside a spacecraft passively stabilized by 1 Hz rotation while orbiting the Earth at ≃ 600 km altitude the test would improve by 4 orders of magnitude, to 10-17, thus probing a totally unexplored field of physics. This is unique to weakly coupled concentric macroscopic test cylinders inside a rapidly rotating spacecraft.
Highlights
In 1687, in the opening paragraph of the Principia Newton stated the equivalence of inertial and gravitational mass on the basis of “. . . experiments on pendulums, very accurately made. . . ”
General relativity is founded on the experimental fact that in a gravitational field all bodies fall with the same acceleration regardless of their mass and composition
If mi = mg the equations require that all bodies in the field of the Earth acquire the same acceleration regardless of their mass and composition
Summary
In 1687, in the opening paragraph of the Principia Newton stated the equivalence of inertial and gravitational mass on the basis of “. . . experiments on pendulums, very accurately made. . . ”. General relativity is founded on the experimental fact that in a gravitational field all bodies fall with the same acceleration regardless of their mass and composition.
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have