The Binary Pulsar Is Not the Ultimate Test for the Theory of Gravity

TL;DR

This paper introduces the NDL theory of gravity, which matches general relativity in key predictions like gravitational radiation from binary pulsars, but differs in the predicted velocity of gravitational waves, offering a new ultimate test for gravity theories.

Contribution

The paper demonstrates that the NDL gravity theory can accurately predict binary pulsar radiation emission, matching GR, and highlights gravitational wave velocity as the critical test distinguishing gravity theories.

Findings

NDL theory matches GR in binary pulsar radiation predictions.

The quadrupole formula in NDL is equivalent to that in GR.

Gravitational wave velocity is the key observable to differentiate gravity theories.

Abstract

General relativity can be formulated either as in its original geometrical version (Einstein, 1915) or as a field theory (Feynman, 1962). In the Feynman presentation of Einstein theory an hypothesis concerning the interaction of gravity to gravity, which was hidden in the original version, becomes explicit. This is nothing but the assumed extension of the validity of the equivalence principle not only for matter-gravity interaction, but also for gravity-gravity. Recently we have presented a field theory of gravity (from here on called the NDL theory) which does not contain such a hypothesis. We have shown that, for this theory, both the cosmological structure and the PPN approximation for the solar tests are satisfied. The proposal of this paper is to go one step further and to show that NDL theory is able to solve the problem of radiation emission by a binary pulsar in the same degree of accuracy as it was done in the GR theory. In the post-Newtonian order of approximation we show that the quadrupole formula of this theory is equal to the corresponding one in general relativity. Thus, the unique actual observable distinction of these theories concerns the velocity of gravitational waves, which becomes then the true ultimate test for gravity theory.