The smallest galaxy
In the constellation of Aries, scientists have discovered the smallest galaxy known to humans. Her discovery called into question all theoretical models of understanding the processes and phenomena occurring in the universe.
Being the most massive space objects, galaxies consist of a huge number of stars. The mass and brightness of a single galaxy is billions of times greater than the mass and brightness of the Sun. These are generally accepted norms. But using innovations in science, scientists have managed to discover rare galaxies that go far beyond these limits. An example was the galaxy Segue 2, the smallest of all known today.
This galaxy is separated from the Earth by 114 thousand light-years and is located in the constellation of Aries. The thousand stars that make up it revolve around our Milky Way. The light from it is so weak that in order to detect it, the most powerful astronomical instruments are needed.
But that’s not all. Scientists-astronomers from the Keck observatory in Hawaii, thanks to one of the most powerful telescopes, found that the stars in the Segue 2 galaxy are held not by their gravitational forces, but by a halo of dark matter. Scientists have calculated the masses of the 25 largest stars in this galaxy and concluded that the matter in it has a density 10 times less than the previously accepted density value. This means that this matter clearly does not create enough gravitational forces to hold together all the stars that make up Segue 2. We can only assume that the stars are held by some unknown and invisible factor that has its own gravity. This factor is known as”dark matter”.
Observing the cosmos, scientists were surprised to find that there are far fewer dwarf galaxies on the edge of our galaxy than they expected. This fact shows either the imperfection of astronomical technology, which does not allow making such observations, or the imperfection of the usual theoretical models. Therefore, the Segue 2 dwarf galaxy and its study can confirm the truth of cosmological models describing people’s knowledge about the structure of the Universe, or radically change them.
According to James Bullock, a cosmologist at the University of California, not quite the right understanding of the processes that shape the Universe, developed due to the lack of the ability to observe and measure the characteristics of dim and small space objects. The scientist also hopes that further study of this galaxy will reveal a huge amount of new useful information about dark energy and matter, as well as about their participation in the processes occurring in the Universe.
In an official statement, the researchers said that the discovery of the Segue 2 galaxy is just the beginning and in the near future, scientists plan to discover many dwarf galaxies and small star clusters near the Milky Way.
Well, if the galaxies haven’t been counted yet, how do you know the number of their suns and planets? __ How many galaxies are there in the universe? Across the vast expanses of the universe, clusters of stars – galaxies-are scattered like groups of islands, closely pressed together. A ray of light takes a hundred thousand years to traverse our Galaxy from end to end (light travels at 300,000 kilometers per second, and in a year it travels 9.46 x 1012 kilometers. This distance-9.46 x 1012 kilometers-is called a light-year) . Astronomers with the help of telescopes have established that, in addition to our Galaxy, there are millions of others. Currently, scientists know three main types of galaxies. Galaxies that have a spiral shape, the same as the Milky Way, are called spiral. The nearest of them is located at a distance of about two million light-years, in the constellation Andromeda. Approximately 17% of all galaxies observed from Earth are of the elliptical type (an ellipse is an elongated circle in diameter). These galaxies consist mainly of stars and are almost, if not completely, devoid of cosmic dust and gases. The following types of galaxies are called irregular because their shapes are strictly individual. They are full of stars, dust, and gas. The two galaxies closest to the Milky Way are just wrong. There are also very tiny galaxies – they are called dwarf galaxies. The smallest known star is only a few hundred light-years wide and consists of several thousand stars. Obviously, there are much more dwarf galaxies in the universe than there are large ones. The galaxies are hundreds of thousands of light-years apart. Conventionally, the galaxies can be grouped into groups, each of which consists of a dozen large and several hundred dwarf. The most distant of the observed groups are located at a huge distance from the Milky Way. It is measured in billions of light-years. And some galaxies are located so far from Earth that it is almost impossible to even imagine this distance. So the question is “How many galaxies are there in the universe? “