A galaxy is a large collection of stars held together by its own gravity. The diameter of most galaxies is between 3,000 and 300,000 light-years. The number of stars varies from 108 in dwarf galaxies to 1014 in giant galaxies. In every galaxy there is also gas, dust, largely dark matter and dark energy. The stars, the gas and the dust can be observed. Dark matter has not yet been directly observed, but is probably present because it explains the distribution and movement of the other three.
If you are interested in astronomy, and have looked into the black sky, then you must have seen these galaxies too. Below is the list of Galaxies, visible to the naked eye for a sharp-eyed observer in very dark skies during clear weather. Browse this list and vote for the most beautiful Galaxy. Galaxies that we can see from our naked eyes without the help of a telescope.
Triangulum Galaxy or M33 is a spiral galaxy that is 3 million light-years away. The galaxy is approaching our Milky Way at a speed of 182 km/s and is loosely bound to the Andromeda Nebula by gravity. It is a sister system of our galaxy and is part of the Local Group. A bright H-II region in the galaxy has been given its own designation, NGC 604. Other bright pieces and gas clouds have also been given their own designations in some catalogs. M33 is in the constellation Triangle (Triangulum) and can be seen with the naked eye under exceptionally good conditions. This makes it one of the most distant objects that can be seen with the naked eye. Due to the large expanse and low surface brightness, ordinary binoculars or a telescope with the lowest possible magnification is best suited to observe M33.
The Milky Way system or the galactic system is the galaxy, in which the solar system with the Earth is located. From Earth, the Milky Way is visible from within as a luminous band spanning the sky, provided it is dark enough. Due to light pollution, the Milky Way is difficult or impossible to see in some places. The galaxy contains about 200 billion stars. It has not been easy for astronomers to imagine the structure of the Milky Way, for Earth is part of it. Our view of large parts of it is also obstructed by interstellar dust clouds. After much observation and modeling, it was finally managed to get a fairly accurate picture of this structure. Research into the structure of the Milky Way was done by William Herschel, Jacobus Cornelius Kapteyn and Jan Hendrik Oort, among others. From the side, the Milky Way looks like a saucer (the galactic disk) with a thickened core (the central bulge). The galactic disk is 100,000-120,000 light years in diameter, the thickness outside the central bulge is about 3000 light years. The Milky Way is made up of at least 200 billion stars (more recent estimates speak of around 400 billion stars), the majority of which are in the disk. The galaxy contains old and new stars, dust and molecular gas clouds. It consists of a central bulge, a disk with four large and a few smaller 'spiral arms' and a halo.
The Large Magellanic Cloud (LMC) is an irregular galaxy, initially believed to be a satellite of the Milky Way. The Large Magellanic Cloud is one of the Magellanic Clouds. At a distance of 50 kiloparsecs (about 170,000 light-years), the Large Magellanic Cloud is the third closest galaxy to the Milky Way. The Large Magellanic cloud has a mass equal to about 10 billion times the mass of the Earth's sun, making the galaxy 1/100 the mass of the Milky Way. The diameter of the Large Magellanic Cloud is 14,000 light-years. The Large Magellanic Cloud is the fourth largest galaxy in the Local Group. Although the Large Magellanic Cloud is known as an irregular galaxy (according to the Hubble classification), it still contains some prominent beam-shaped structures in the center. The galaxy may once have been a barred spiral galaxy. The current irregular shape is probably due to interaction with the Milky Way and the Small Magellanic Cloud. Like many irregular galaxies, the Large Magellanic Cloud is rich in gases and dust. Furthermore, there is star formation place.
The Small Magellanic Cloud is a dwarf galaxy that is part of the Magellanic Clouds. The galaxy is about 7000 light years in diameter and contains hundreds of millions of stars. The total mass is estimated at around 7 billion times the mass of the sun. It is theorized that the Small Magellanic Cloud was once a barred spiral galaxy, which was disturbed by the Milky Way and thus obtained its present form. The Small Magellanic Cloud is one of the closest galaxies to the Milky Way and one of the few objects near the Milky Way galaxy to be seen with the naked eye. The Small Magellanic Cloud is only visible from the southern hemisphere and from the lower latitude of the northern hemisphere. Viewed from Earth, the Small Magellanic Cloud is located in the constellation Toucan. Visible to the naked eye, the Small Magellanic Cloud was observed centuries ago by the indigenous people of Australia and some islands in the Pacific. European skippers may have first seen the cloud in the Middle Ages, and then used it for navigation. Portuguese and Dutch sailors also called the Small Magellanic Cloud one of the cape clouds.
The Andromeda Galaxy or Andromeda Nebula is a spiral galaxy in the constellation Andromeda. The system has the same shape as our own galaxy, the Milky Way, but is much larger. The distance is estimated to be approximately 2.54 million light-years, the diameter approximately 250,000 light-years. The mass is estimated at 300 to 400 billion solar masses, the total mass including the haloon 1.2 trillion solar masses. Thus, compared to the latest estimates of the Milky Way's total mass, which is 1.9 trillion solar masses, M31 would be somewhat lighter, and much less dense. Together with the Milky Way and a number of smaller galaxies, the Andromeda Nebula forms the Local Group. In 1925, Edwin Hubble showed through measurements of Cepheid variables that the Andromeda Nebula is not a cloud of dust or other object within the Milky Way, but a separate galaxy far beyond the Milky Way. Before that, there was doubt about the true nature of the "spiral nebulae" and it was believed that the Milky Way was the only galaxy in the universe and that the spiral nebulae were objects within it.
Centaurus A or NGC 5128 is a lenticular galaxy in the constellation Centaur. The celestial object was discovered on April 29, 1826 by the astronomer James Dunlop. Centaurus A is located about 12 million light-years from Earth and has a mass of about 1 trillion solar masses. Rather, the shape is elliptical, and its dimensions are 300,000 × 450,000 light-years (90 kpc × 140 kpc). On October 22, 2012, it was announced that the galaxy contains a hidden spiral. It probably comes from a spiral galaxy that collided with Centaurus A. The galaxy is girded by an unusual band of cosmic dust. Centaurus A is a strong source of radio waves (it is the closest radio galaxy) and is part of the M83 group. It is the fifth brightest system in the sky. The galaxy NGC 5128 was discovered on April 29, 1826 by the Scottish astronomer James Dunlop, who conducted extensive studies of the southern celestial hemisphere at the Australian observatory located in Parramatta, near Sydney. In 1949, the Australian scientist John Bolton, together with Gordon Stanley and Bruce Sli, proved that within the galaxy NGC 5128 there is a source of strong radio emission, and that this galaxy thus relates to a new class of space objects discovered by it.
Messier 81 or Bode's Galaxy (Messier 81, M81, NGC 3031) is a spiral galaxy in the constellation Ursa Major and is the brightest member of the M81 group. M81 has an absolute magnitude of -20.8 and is located 12 million light-years away. With the nearby galaxy M82 it can be observed with small telescopes. M81 was discovered in 1774 by Johann Elert Bode, who described it as a "nebula-like blotch". In 1993, a supernova was observed in M81 that had a maximum brightness of magnitude 10.5. The Bode's galaxy is presumed to contain approximately 250 billion stars, being slightly smaller than the Milky Way. The galaxy is one of the best examples of spiral design in a galaxy, with nearly perfect arms spiraling toward its center. Bode's galaxy and its satellite (or binary galaxy), the Cigar galaxy, or M82, are among the most prominent members of the M81 Group. Both are visible in the same field of view for most telescopes. Bode's galaxy has an apparent magnitude of 6.93, making it one of the brightest galaxies. Under exceptional conditions and truly dark skies in remote locations, away from light pollution, it can be seen with the naked eye.
Sculptor Galaxy NGC 253 - also known as the Silver Coin Galaxy - is a barred spiral galaxy discovered in 1783 by Caroline Herschel located in the constellation Sculptor, 12.9 million light years (3.94 mega parsecs) from the Milky Way, which places it among the closest galaxies to the Local Group. It is also one of the apparently largest and apparently brightest galaxies (with an apparent magnitude of 7.1 and apparent dimensions of 27.5' * 6.8'). In absolute terms, it is considered by some authors as the third intrinsically brightest galaxy within a radius of 10 megaparsecs around ours, second only to Andromeda and the Sombrero Galaxy (and could even be the second brightest). Visually it is somewhat reminiscent of the aforementioned Andromeda, looking almost on edge, and also its spiral arms are loaded with interstellar dust, which makes it difficult to study at least as long as wavelengths other than visible light are not used. Thanks to studies carried out at such wavelengths, it is known that after galaxy IC 10 it is the closest galaxy with a stellar outbreak to the Milky Way, and also the brightest (apparently) of this type.
The Sagittarius Dwarf Spheroidal Galaxy or SagDEG is a galaxy satellite of the Milky Way. With a diameter of about 10,000 light years, it is currently 70,000 light years from Earth and moving in a polar orbit about 50,000 light years from the center of our galaxy. Discovered in 1994 by Rodrigo Ibata, Mike Irwin and Gerry Gilmore, it was at the time of his discovery of the closest known galaxy to ours - a title it lost in 2003 to the benefit of the Dwarf galaxy. It is located in a location opposite to the solar system in relation to the galactic center, which makes it a very difficult object to observe, although it covers a wide region of the sky. SagDEG must traverse the galactic disk of the Milky Way in the next 100 million years and will finally be absorbed by our galaxy. It seems that it was originally a spheroidal dwarf galaxy, but it has been stretched considerably by the tidal forces of the Milky Way. A large number of its stars and a gas stream appear scattered throughout its orbit. Four globular clusters belonging to the Milky Way galaxy visibly originate from SagDEG: M54, Arp2, Terzan 7 and Terzan 8. In fact, M54 is thought to be part of this galaxy and not the Milky Way, and it has even been suggested that it may be its nucleus.