Gravitational acceleration

About: Gravitational acceleration is a research topic. Over the lifetime, 3245 publications have been published within this topic receiving 51702 citations.

Is Cosmic Speed-Up Due to New Gravitational Physics?

Abstract: We show that cosmic acceleration can arise due to very tiny corrections to the usual gravitational action of general relativity, of the form ${R}^{\ensuremath{-}n}$ with $ng0.$ This model eliminates the need for a nonzero cosmological constant or any other form of dark energy, attributing a purely gravitational origin to the acceleration of the universe.

Gravitational Radiation and the Motion of Two Point Masses

Abstract: The expansion of the field equations of general relativity in powers of the gravitational coupling constant yield conservation laws of energy, momentum, and angular momentum. From these laws, the loss of energy, momentum and angular momentum of a system due to the radiation of gravitational waves is found. Two techniques, radiation reaction and flux across a large sphere, are used in this calculation and are shown to be in agreement over a time average. These results are then applied to the system of two point masses moving in elliptical orbits around each other. The secular decays of the semi-major axis and eccentricity are found as functions of time and are integrated to specify the decay by gravitational radiation of such systems as functions of their initial conditions. For completeness, the secular change in the perihelion of the orbit for two arbitrary masses is found by a method which is in the spirit of the above calculations. The case of gravitational radiation when the bodies are relativistic is then considered, and an equation for the radiation similar to that of electromagnetic radiation is found. Also a proof is given that, regardless of coordinate systems or conditions, the energy of a system must decrease as a result of the radiation of gravitational waves, providing the potentials are inversely proportional to the distance from the source for large distances.

Gravitational radiation from point masses in a Keplerian orbit

Abstract: The gravitational radiation from two point masses going around each other under their mutual gravitational influence is calculated. Two different methods are outlined; one involves a multipole expansion of the radiation field, while the other uses the inertia tensor of the source. The calculations apply for arbitrary eccentricity of the relative orbit, but assume orbital velocities are small. The total rate, angular distribution, and polarization of the radiated energy are discussed.

Determining the Hubble constant from gravitational wave observations

Abstract: I report here how gravitational wave observations can be used to determine the Hubble constant, H0. The nearly monochromatic gravitational waves emitted by the decaying orbit of an ultra–compact, two–neutron–star binary system just before the stars coalesce are very likely to be detected by the kilometre–sized interferometric gravitational wave antennas now being designed1–4. The signal is easily identified and contains enough information to determine the absolute distance to the binary, independently of any assumptions about the masses of the stars. Ten events out to 100 Mpc may suffice to measure the Hubble constant to 3% accuracy.