# Mass distribution

As mass distribution denote geoscientists, physicists and technicians the spatial distribution of mass within a solid or well -defined fluid. Due to the mathematical or coordinative description of the masses - such as discrete units, as distribution of mass points or as a radially symmetric density function - can be various parameters of the body calculate and set up physical models of its interior.

The mass distribution of the body determines, inter alia, the center of gravity, moment of inertia and influences the dynamic behavior, such as the natural oscillations. Also functionals of the gravitational potential in the inner and outer space are affected by the arrangement of the masses, particularly if their distribution is asymmetric. Therefore, one can infer the internal structure of celestial bodies from perturbations of satellites.

## Density distribution in fluids

In principle, the mass distribution for liquid and gaseous bodies of importance. On Earth, you can indeed for small volumes or incompressible fluids emanating from a homogeneous distribution of the molecules or atoms. The further away but the volume considered extends (especially vertically ), the more accurately the relationship between density and pressure is to model (see gas laws and bulk modulus ). In meteorology and oceanography, the effect of flow is to be considered additionally.

Astronomy investigated the mass and density distribution is also very extensive fluids. Examples include: interstellar gas, dark clouds, gas planets and the interior of stars. Play an important role inhomogeneous mass distributions, inter alia, in the formation and the evolution of stars and the internal structure of planets.

## For the modeling of inhomogeneous and rotating bodies

For the mathematical modeling of celestial bodies and their physical behavior of astronomers and geophysicists know a number of methods in which the body interior is simulated by a large number of mass points and their mutual gravitation. At high-temperature bodies and the thermodynamics must be considered, including magnetic or other forms of interaction, and are as well inside of stars energy radiation and nuclear physics processes.

Cupped built lower body temperature, however, can - mathematically rigorous - are described by methods of potential theory or by hydrostatic equilibrium shapes whose individual shells ( ie constant density ) have a homogeneous mass distribution.

In rotating bodies ( wheels, shafts, parts of machinery, soil, other celestial bodies ), the mass distribution has strong effects on the deformation and stability - see imbalance of a wheel, oblateness and polar motion of the earth - and can at extremely unequal distribution through cracks and uneven centrifugal lead to breakage.

## Distribution of mass in astronomy

From a very different type of mass distribution speaks astronomy at the issue of stellar populations. This is about the frequency distribution of the mass of stars, where they are usually given in units of the solar mass.

Also in the study of galaxy clusters, it is often necessary to break down the mass of the galaxies involved in statistically or physically in classes. Moreover, you can close " to rapid " movement within this heap on the existence of additional, dark masses of that which is called dark matter.

## Others

In medicine, some imaging techniques have the potential to investigate mass distributions in organisms - such as diagnostic radiology and computed tomography.