## Conventional gravitational massEdit

Kepler

Galileo found that for an object in free fall, the distance that the object has fallen is always proportional to the square of the elapsed time:

### Newtonian Gravitational mass Edit

The Newtonian concept of gravitational mass rests on Newton's law of gravitation. Let us suppose we have two objects A and B, separated by a distance *r*_{AB}. The law of gravitation states that if A and B have gravitational masses *M*_{A} and *M*_{B} respectively, then each object exerts a gravitational force on the other, of magnitude

where *G* is the universal gravitational constant. The above statement may be reformulated in the following way: if *g* is the acceleration of a reference mass at a given location in a gravitational field, then the gravitational force on an object with gravitational mass *M* is

This is the basis by which masses are determined by weighing. In simple spring scales, for example, the force *F* is proportional to the displacement of the spring beneath the weighing pan, as per Hooke's law, and the scales are calibrated to take *g* into account, allowing the mass *M* to be read off. A balance measures gravitational mass; only the spring scale measures weight.

## Photo-gravitational mass of central bodyEdit

To find the total absolute Momentum of light radiated for an object from mass m, we have to take into account the surface area, A(in m^{2}) of the astronomic object:

where *j* is known variously as the black-body **irradiance**, **energy flux density**, **radiant flux**, or the **emissive power**
and k is proportional constant.
The constant of proportionality σ, called the Stefan–Boltzmann constant or **Stefan's constant**, is non-fundamental in the sense that it derives from other known constants of nature. The value of the constant is

where k is the Boltzmann constant, h is Planck's constant, and c is the speed of light in a vacuum. Thus at 100 K the energy flux density is 5.67 W/m^{2}, at 1000 K 56,700 W/m^{2}, etc.

Define Photogavitational mass as follows,

Where is inertial mass and is photogravitational constant. However without bulk, the surface temperature couldn't be maintained. With T cube inertial mass assumption,

and can be written as follows.

Thus Momentum from unit area

The difference between surface temperature and core temperature is also important for near field gravity. with lattitude, it increases resulting in value between 9.78 and 9.82 m/s2

## Physical quantityEdit

It is important to check physical meaning of . The value is proportional to the pressure for ideal gas.

The Physical quantity is proportional to the radiational pressure for solid.

## See alsoEdit

- Stefan–Boltzmann law
- AME
- Mass
- Esther -electra
- Photogravity