The study of galaxy formation and growth is primarily concerned with the development of galaxies from a rapidly homogenous seed to the present massive, clustered, faint images of galaxies. Inflation, galaxy formation, super wind, gravitational collapse, and red pulsar wind are some of the most prevalent theories about how the evolution of a galaxy happens. A recent theory on how galaxies formed the X-ray map was also developed.
It has been proven that black holes are produced in very cold and dense centers.
A research conducted at the Institute of Space Sciences and Astronomy, University of Toronto claimed that there are four such giant galaxies. One of them has a mass almost the same as the sun while the others are extremely compact.
Galaxy formation is dependent upon many factors and none of them are constant.
The only constant factor is the presence of gas in a system. Gas is necessary for the process of galaxy formation. If there is no gas, no stars will form and no galaxies will form. Hence, it is concluded that without the presence of some kind of gas, no stars can form.
There are many theories formulated by astronomers that suggest a relation between galaxy formation and the presence of dark matter halos. They are either produced or evolved from a primordial cloud of gas. The gas Cloud has no escape route and so astronomers think that it forms large dark holes at the centers of merging massive galaxies. These holes may be responsible for creating large concentrations of neutral but neutral gas which eventually makes the clouds opaque and forming stars.
Stellar formation, galaxy formation and structure formation all depend on gravity.
Gravity alone does not account for all the matter in the universe. The core regions of the universe are much less dense than the rest. This means that something other than gravity must be responsible for the creation of large-scale structure. Gravity plus the strong pull of other large-scale structures like superclusters must have caused the emergence of what we call stars in the early universe. Star formation also seems to have a hand in ensuring that the universe is in a state of expansion.
One theory is the idea of cluster formation.
Basically, clusters are groups of very small stars which, due to their mutual rotation, cause the light from these stars to spread out and reach us at a very long distance. Many studies show that most of the clusters have a huge mass, a good estimate being over 10 solar masses, with numerous small stars within them. Some models of cluster formation suggest the presence of small planet-like objects at the centers of the clusters, with a mass not much greater than the mass of the star alone.
Another hypothesis regarding the formation of galaxy-sized objects involves the idea of halo formation.
What do astronomers mean by this? Basically, a halo is a ring or “hump” around a large galaxy. In spiral galaxies like the Milky Way, many of the halo regions are filled with extremely cold dust. While astronomers have detected the presence of this cold dust around many of our elliptical galaxies, they do not have a complete idea of what the nature of this dark matter is. Scientists speculate that a filament of material, which contains molecules of ice and metal, might be forming around many of these spiral arms.
A more complex model of galaxy formation involves a combination of multiple theories.
One of these theories concerns the idea of a so-called “solar halo” around very hot regions of a galaxy. According to this model, a halo will not only give off infrared radiation, but also emit X-rays and gamma rays, moving faster than the solar system. Evidence has already been found to support this halo formation process, including the discovery of a huge galaxy cluster which contains nearly a hundred thousand stars.
Other galaxy formation theories involve a more massive concentration of dark matter halos around extremely compact and fast-moving gas clouds. It is important to note that most of the most massive halos are very faint and are usually found very close to the centers of galaxy clusters, making them difficult to spot through telescopes. While astronomers have found a number of dark matter halos in clusters, they have been unable to determine their exact sizes, which makes them nearly impossible to study directly.
Astronomers have theories about the evolution of these halos, which suggest that they are made up of several hundred millions of low-density gas clouds that are rotating very quickly. They may also form a halo around a very dense galaxy like the Milky Way, which is composed primarily of cool gas.