The ability and tendency of certain systems to maintain a relatively constant internal state in spite of changes in external conditions; this ability is achieved by the presence of feedback mechanisms which can adjust the state of the system to compensate for changes in the state caused by the external environment. It is exemplified in homeothermal biological systems, such as animals which maintain relatively constant blood temperature and composition in spite of variations in external temperature or the composition of the food ingested.
The galactic disk is a component of the spiral galaxies and consists of stellar and gaseous components as it forms a random motion with the circular objects that orbit around the galactic center.
The rotational curve in a milky way is similar to that of the rotation of the universal rotating disk and is evident by the dark matter in the galaxies.
