Galaxies

Inner galaxies are (outside the Milky Way) extragalactic nebulae.
Galaxies are defined as huge star systems outside of our own galaxy (the Milky Way system). Their composition includes many stars, their number can reach 10 trillion pieces; their clusters and the end results of their evolution (see Stars, evolution); clouds of gas and dust, which are the result of the interaction of magnetic and gravitational fields, as well as electromagnetic radiation, which is the source of energy for charged particles.
Many, many billions of galaxies have been discovered through the use of the largest telescopes in the world. They are located here.
The largest of the galaxies are 30-40 thousand parsecs in diameter, and the smallest are 1,000 times smaller. The masses of these objects can vary within a million times, whereas for stars the ratio is about a thousand times.
90% of the total number of galaxies are organized into clusters. In general, the space around us is filled with stellar galaxies with a much higher relative density than galaxies on average. The average distance between stars and galaxies is 20 million times their diameter, while the interstellar distance is 10-20 times smaller than their size. Because of this, gravitationally interacting galaxies can often be observed.
Many galaxies have different shapes and sizes, but several basic morphological types can be distinguished: elliptical (see here), spiral (see here), lens-shaped (see here), and irregular (see here).
It should be remembered that when we observe distant galaxies and quasars, sources of gamma-ray and X-ray bursts that are billions of light-years away (see Light-year), we find ourselves in the past tense. We are presented with a picture of the stage of development of the Universe that took place billions of years ago, when the electromagnetic radiation that was created by these objects began its journey through space. It is worth noting that in those distant Worlds, people are also observing the place in the Universe where we are now, and can visualize it as it was billions of years ago.
Despite the possibility of seeing the past, modern technical means do not allow us to fully understand the mechanisms of the origin of galaxies. We can now say with certainty that the conditions for the birth of galaxies were conditioned by a variety of conditions for their formation.
Galaxies, which later became spiral galaxies, arose from gas-dust clouds that possessed significant moments of the quantity of motion – rotation reserves and compression centers. The initial stages of their evolution are probably similar to those through which our Galaxy passed (see Galaxy (Milky Way system, structure).
Clouds of gas that lacked rotation gave rise to elliptical galaxies. The lack of rotation slowed their development, as all the gases in them were channeled to form the first generation of stars. The gas which was ejected by them in the absence of rotation of galaxies, in the absence of rotation of planets descends to the centers of such star systems and is used without remainder for the formation of stars of the second generation. As a consequence, elliptical galaxies, unlike spiral galaxies, do not have a flat component, but possess only a spherical system.
Similarly, irregular galaxies have arisen from clouds of gas with spin reserve and without the presence of condensations at their center.
We can assume that the mass of the protogalactic gas cloud also had a great influence on the appearance of the nascent galaxy. Most likely, there is some genetic connection between quasars and young galaxies. In many centers of several dozen galaxies found giant black holes. They have an array of more than a million solar masses. It has also been observed that these objects are present only in those galactic systems that have a “bulge” (see Galaxy (Milky Way system, balloon) at the center). At the same time, as a rule of thumb, the mass of a black hole is about 0.2% of the mass of the galactic “bloat”. Nevertheless, there are still too many uncertainties and questions that need answers about the evolution of galaxies.
There are three galaxies within sight: the Andromeda Nebula, the Large and Small Magellanic Clouds, which are visible to the naked eye. Nearly forty galaxies can be observed with a small telescope. Their main part is concentrated in the northern hemisphere of the starry sky.”