10 fun facts about the Andromeda Galaxy
The nearest neighbor to the Milky Way galaxy is Andromeda. It is much larger in size of our galaxy, and according to various estimates can have a 2, 5-5 times more stars than our Milky Way. It can be easy to see in the night sky from Earth. It is located in the constellation Andromeda, so actually got its name.
The Andromeda Galaxy has attracted the attention of scientists is not one century. The first written mention of this galaxy is contained in the "Catalog of the fixed stars" of the Persian astronomer Al-Sufi (946 years), who described it as a "small cloud." Interest in it is due not only to its close proximity to us, but also some other interesting features, which we now discuss.
also known as Messier 31, M31 or
The name she received from Charles Messier, a French astronomer, who made it in his famous catalog under the definition of M31. Messier cataloged the many facilities of the northern hemisphere, though not all of them have been opened it is messier.
In 1757, the scientist began to search for Halley's Comet, but calculations show that it made a mistake in the coordinates. Nevertheless, in the same place of observation, he discovered the nebula - the first object, which he introduced in his catalog called M1 (also known as the Crab Nebula). What is interesting, first I saw her English astronomer John Bevis back in 1731. Object called M31 in Messier's catalog of hit in 1767. By the end of the same year, a total of 38 sites in the catalog has been added. By 1781 the number was already 103 objects, 40 of which were discovered by Messier himself.
got its name thanks to the constellation Andromeda
See constellation Andromeda the night sky can asterism between large square and star α Cassiopeia (second bottom corner, if the observer sees constellation Cassiopeia the letter W). According to ancient Greek mythology, Princess Andromeda, wife of the Greek hero Perseus, turned into a constellation after death. Constellation was first included in the starry sky catalog of Claudius Ptolemy's "Almagest". Other stars of the constellation (Perseus, Cassiopeia, Cepheus and Keith) also received its name in honor of the characters of this myth.
The constellation Andromeda and is also home to numerous other objects. It is located outside the galactic plane, and does not contain clusters or nebulae of the Milky Way. However, it contains other visible galaxies. One of them is just the Andromeda Galaxy.
It is more than the Milky Way
In astronomy, often used the concept of a light-year, by which determine the distance to various objects, but some astronomers prefer to use the term parsec. When it comes to very large distances, then the term kpc of 1000 parsecs, and Mpc - the equivalent of 1 million parsecs. The Milky Way stretches for about 100 000 light-years, or 30 kiloparsecs. At first glance this may seem like a very long distance, but in fact compared to other galaxies, our looks rather small.
The approximate diameter of the Andromeda galaxy is 220,000 light-years, which is more than twice the size of the Milky Way. It is the largest galaxy in the local group. If the Andromeda galaxy was even brighter, it could in the night sky would look larger than the Moon, even though that is much, much further. By the way, about the distance: the galaxy is located about 9, 5 trillion kilometers from Earth (the Moon, we recall, is only 384,000 kilometers).
contains a trillion stars
According to rough estimates, the Milky Way may contain from 100 to 400 billion stars. But this is nothing compared to the Andromeda, which can contain about one trillion. Due to the space telescope "Hubble" scientists have learned about the presence among trillion this very large and rare population of hot and bright stars.
Hot, young stars tend to appear blue. However, the blue star, discovered in the Andromeda galaxy, look more aging, more like the Sun, stars that burned their internal layers and bared their hot blue core. They are scattered throughout the center of the galaxy in the ultraviolet range are the most striking.
has a dual core
Another interesting fact about the Andromeda Galaxy is its dual core. Observations showed that in the central part of the galaxy has two bright objects (P1 and P2), separated by a distance of just 5 light years. Each of them contains several millions of closely spaced from each other young blue stars.
Later astronomers found that the two cores are not two separate clusters of stars, but rather one cluster in a donut shape and supermassive black hole whose mass is greater than 140 millions of the sun. The stars in the cluster P1 treated very closely around the black hole, like the planets around the sun, thereby creating the effect of the availability of dual-core.
collide with our galaxy
We expect intergalactic collapse. At the moment, the Andromeda galaxy is moving toward the Milky Way at a speed of 400,000 kilometers per hour. At this speed can fly around the globe in only 6 minutes. Astronomers predict that in about 3, 75 billion years to happen collision of the Milky Way and Andromeda. What will happen to the Earth then? Experts believe that, despite such a large-scale event, the Earth still survive. Together with the rest of the solar system. Scientists suggest that our planet is practically not be affected by this intergalactic collapse, as both galaxies have a lot of free space. Nevertheless, from the Earth to observe the event will be very interesting (unless, of course, lives by the time her still remain). Both galaxies are attracted to each other for as long as the black holes at their centers, eventually merge into one. Once this happens, our solar system will be part of a completely different galaxies - elliptical. If the sun does not engulf the Earth in about 5 billion years, every night it will be very bright, thanks to the presence of many new stars. Instead of a strip of light of the Milky Way, we see a spheroidal light source.
has an absolute value of 3, 4
In astronomy, absolute magnitude is characterized by the luminosity of a celestial object. It allows us to determine the brightness of an object, regardless of its distance from us.
Andromeda has an absolute value of 3, 4, which allows it to be the brightest object Messier. In the moonless night galaxy visible to the naked eye. True it is worth noting that the naked eye will be visible only the central part of the galaxy. It will look like a faint star. If you look at it through the binoculars, then it will look like a small elliptical cloud. If lead her observation in a large telescope, it can look up to six times larger than the Moon.
It is full of black holes
Once upon a time in a galaxy Andromeda has 9 known black holes, but the actual number grew to 35 in 2013. Astronomers have observed for the 26 new candidates for a black hole, making it one of the galaxy's most populous similar objects. Most of these new black holes have a mass of 5-10 times greater than the mass of our sun. Seven black holes are located at a distance of about 1000 light-years from the galactic center.
Astronomers believe that in the future they will be able to find out in this galaxy more such facilities. For example, two new black hole was discovered in 2017. At the same time it was noted that both objects are in the most dangerous ever documented proximity. They are separated by a distance of only 0, 01 light-years, equal to about a couple of hundred of distances from the Earth to the sun. According to experts, these black holes may collide with each other in less than 350 years, merged into a single supermassive black hole.
450 globular clusters
Globular clusters are densely packed clusters of old stars tightly bound by gravity. They may be hundreds of thousands or even millions of stars. Globular clusters help determine the age of the universe, and often help to determine where the center of the galaxy. In the Milky Way, astronomers have found at least 200 globular clusters in the Andromeda - about 450.
The number of globular clusters in the Andromeda could be much higher, but the outer reaches of the galaxy are still poorly understood. If the globular clusters of the Andromeda galaxy have similar dimensions of the Milky Way clusters, then the real number could be that somewhere between 700 and 2800.
Once the Andromeda Galaxy was considered Nebula
Nebulae are huge concentrations of gas, dust, hydrogen, helium, and plasma, in which new stars are born. Very remote from us galaxies are often mistaken for these massive clusters. In 1924, astronomer Edwin Hubble announced that the spiral Andromeda Galaxy is actually a galaxy and the Milky Way is not the only galaxy in the universe.
Hubble discovered a number of stars belonging to the Andromeda Galaxy, including several Cepheids. The latter are a class of pulsating variable stars with a fairly accurate the period-luminosity. He determined how far away are the stars that helped him to calculate the distance, which was the Andromeda galaxy from us. It amounted to 860 000 light-years, which is more than 8 times greater than the distance to the most distant from us the stars of the Milky Way. This helped prove that the Andromeda galaxy is just, and not the nebula, as it was originally proposed. Later Hubble confirmed the existence of several dozen other galaxies.