What is the universal constant of gravity

Gravitational constant

Gravitational constant, 1) Newtonian constant of gravity G, Proportionality factor im Newton's law of gravitation

that the force F. between two masses m1 and m2 at a distance r each other describes with G = (6,672 59 ± 0,000 85) · 10-11N · m2 / kg2. In order to determine it, a laboratory experiment is necessary, in which the masses and spacing of the specimens are precisely known. The first experiment of this kind was carried out by Cavendish in 1798 with a rotary balance.

In some cosmological hypotheses, G not viewed as a fundamental constant, but as changing over time.

2) Einstein's constant of gravity κ, in the General Relativity used constant κ = 8π G / c4 = 2,076 12 · 10-43 s2 / (m kg).

3) Gaussian constant of gravity k, in the third Kepler's law (the square of the period of revolution of a body around a central star of mass m2 is proportional to the cube of its mean distance um m2) Part of the constant 4π2 / k2m2. The name used in astronomy comes from the fact that in the relationship

the numerical values ​​of

, ω and k are the same if the mass of the sun, the astronomical unit AE and the day are used as a unit. (astronomical constants)