Andromeda is the galaxy closest to the Milky Way. Collision of the Milky Way and Andromeda
Andromeda is a galaxy also popular as M31 and NGC224. This is a spiral formation located at a distance of approximately 780 kp (2.5 million light years) from Earth.
Andromeda is the galaxy closest to the Milky Way. It is named after the mythical princess of the same name. Observations in 2006 led to the conclusion that there are about a trillion stars here - at least twice as many as in the Milky Way, where there are about 200 - 400 billion. Scientists believe that the collision of the Milky Way and the Andromeda galaxy will happen in about 3.75 billion years, and eventually a huge elliptical or disk galaxy will be formed. But more on that later. First, let’s find out what a “mythical princess” looks like.
The picture shows Andromeda. The galaxy has white and blue stripes. They form rings around it and cover the hot, red-hot huge stars. The dark blue-gray bands contrast sharply with these bright rings and show areas where star formation is just beginning in dense cloud cocoons. When observed in the visible part of the spectrum, Andromeda's rings look more like spiral arms. In the ultraviolet spectrum, these formations rather resemble ring structures. They were previously discovered by a NASA telescope. Astrologers believe that these rings indicate the formation of a galaxy as a result of a collision with a neighboring one more than 200 million years ago.
Like the Milky Way, Andromeda has a number of miniature satellites, 14 of which have already been discovered. The most famous are M32 and M110. Of course, it is unlikely that the stars of each galaxy will collide together, since the distances between them are very vast. Scientists still have rather vague ideas about what will happen in reality. But a name has already been invented for the future newborn. Mammoth - this is what scientists call the still unborn huge galaxy.
Star collisions
Andromeda is a galaxy with 1 trillion stars (1012), and the Milky Way has 1 billion (3*1011). However, the chance of a collision between celestial bodies is negligible, since there is a huge distance between them. For example, the closest star to the Sun, Proxima Centauri, is located at a distance of 4.2 light years (4*1013 km), or 30 million (3*107) diameters of the Sun. Imagine that our luminary is a table tennis ball. Then Proxima Centauri will look like a pea, located at a distance of 1100 km from it, and the Milky Way itself will extend 30 million km in width. Even the stars in the center of the galaxy (and specifically there their largest cluster) are located at intervals of 160 billion (1.6 * 1011) km. That's like one table tennis ball for every 3.2 km. Therefore, the chance that any two stars will collide during a galaxy merger is extremely small.
Black hole collision
The Andromeda Galaxy and the Milky Way have central supermassive black holes: Sagittarius A (3.6 * 106 solar masses) and an object inside the P2 cluster of the Galactic Core. These black holes will converge on one point near the center of the newly formed galaxy, transferring orbital energy to the stars, which will eventually move to higher trajectories. The above process can take millions of years. When the black holes come within one light year of each other, they will begin to emit gravitational waves. The orbital energy will become even more powerful until the merger is complete. Based on modeling data carried out in 2006, the Earth may first be thrown almost to the very center of the newly formed galaxy, then pass near one of the black holes and be ejected beyond the boundaries of the Milky Way.
Confirmation of the theory
The Andromeda Galaxy is approaching us at a speed of approximately 110 km per second. Right up until 2012, there was no way to know whether a collision would occur or not. The Hubble Space Telescope helped scientists conclude that it was almost inevitable. After tracking the movements of Andromeda from 2002 to 2010, it was concluded that the collision will occur in about 4 billion years.
Similar phenomena are widespread in space. For example, Andromeda is believed to have interacted with at least one galaxy in the past. And some dwarf galaxies, such as SagDEG, continue to collide with the Milky Way, creating a single formation.
Research also shows that M33, or the Triangulum Galaxy, the third largest and brightest member of the Local Group, will also participate in this event. Its most likely fate will be the entry into orbit of the object formed after the merger, and in the distant future - final unification. However, a collision of M33 with the Milky Way before Andromeda approaches, or our Solar System is thrown beyond the boundaries of the Local Group, is excluded.
Fate of the Solar System
Scientists from Harvard claim that the timing of the galaxy merger will depend on the tangential speed of Andromeda. Based on the calculations, it was concluded that there is a 50% chance that during the merger the Solar System will be thrown back to a distance three times greater than the current one to the center of the Milky Way. It is not clear exactly how the Andromeda galaxy will behave. Planet Earth is also under threat. Scientists say there is a 12% chance that, some time after the collision, we will be thrown back beyond the borders of our former “home.” But this event will most likely not have major adverse effects on the Solar System, and celestial bodies will not be destroyed.
If we exclude planetary engineering, then by the time the galaxies collide, the surface of the Earth will become very hot and there will be no water left on it in a watery state, and therefore no life.
Possible side effects
When two spiral galaxies merge, the hydrogen present in their disks is compressed. The intensive formation of new stars begins. For example, this can be observed in the interacting galaxy NGC 4039, otherwise known as the Antennae Galaxy. If Andromeda and the Milky Way merge, it is believed that there will be little gas left on their disks. Star formation will not be as intense, although the birth of a quasar is entirely possible.
Merger result
Scientists tentatively call the galaxy formed during the merger Milcomeda. The simulation result shows that the resulting object will have an elliptical shape. Its center will have a lower density of stars than modern elliptical galaxies. But a disk form is also possible. Much will depend on how much gas remains within the Milky Way and Andromeda. In the near future, the remaining galaxies of the Local Group will merge into one object, and this will mark the beginning of a new evolutionary stage.
Facts about Andromeda
Andromeda is the largest Galaxy in the Local Group. But perhaps not the most massive. Scientists suggest that there is more dark matter concentrated in the Milky Way, and this is what makes our galaxy more massive. Scientists will study Andromeda in order to understand the origin and evolution of formations similar to it, because it is the closest spiral galaxy to us. Andromeda looks amazing from Earth. Many even manage to photograph her. Andromeda has a very dense galactic core. Not only are huge stars located at its center, but there is also at least one supermassive black hole hidden at its core. Its spiral arms were bent as a result of gravitational interaction with two neighboring galaxies: M32 and M110. There are at least 450 globular star clusters orbiting inside Andromeda. Among them are some of the densest that have been discovered. The Andromeda Galaxy is the most distant object that can be seen with the naked eye. You'll need a good vantage point and minimal bright light.
In conclusion, I would like to advise readers to raise their gaze to the starry sky more often. It stores a lot of new and unknown things. Find some free time to observe space on the weekend. The Andromeda Galaxy in the sky is a sight to behold.
The science
Scientists were able to measure the exact distance for the first time to our nearest galaxy. This dwarf galaxy is known as Large Magellanic Cloud. She is located at a distance from us 163 thousand light years or 49.97 kiloparsecs to be exact.
The Large Magellanic Cloud galaxy slowly floats through space, bypassing our galaxy Milky Way around like The moon revolves around the earth.
Huge clouds of gas in the region of the galaxy slowly dissipate, resulting in the formation of new stars, which illuminate interstellar space with their light, creating bright colorful cosmic landscapes. A space telescope was able to capture these landscapes in photographs. "Hubble".
The shallow galaxy Large Magellanic Cloud includes Tarantula Nebula- the brightest stellar cradle in space in our neighborhood - they were seen in it signs of new star formation.
Scientists were able to make the calculations by observing rare close pairs of stars known as eclipsing double stars. These pairs of stars are gravitationally connected to each other, and when one star eclipses the other, as seen by an observer on Earth, the overall brightness of the system decreases.
If you compare the brightness of stars, you can calculate the exact distance to them with incredible accuracy.
Determining the exact distance to space objects is very important for understanding the size and age of our Universe. For now the question remains open: what is the size of our Universe None of the scientists can say for sure yet.
After astronomers managed to achieve such accuracy in determining distances in space, they will be able to deal with more distant objects and eventually be able to calculate the size of the Universe.
Also, new capabilities will make it possible to more accurately determine the expansion rate of our Universe, as well as more accurately calculate Hubble constant. This coefficient was named after Edwin P. Hubble, an American astronomer who in 1929 proved that our The universe has been constantly expanding since the beginning of its existence..
Distance between galaxies
Galaxy Large Magellanic Cloud - closest to us dwarf galaxy, but a large galaxy - our neighbor is considered Andromeda spiral galaxy, which is located at a distance of approximately 2.52 million light years.
Distance between our galaxy and the Andromeda galaxy gradually decreasing. They approach each other at a speed of approximately 100-140 kilometers per second, although they will not meet very soon, or rather, after 3-4 billion years.
Perhaps this is what the night sky will look like to an observer on Earth in a few billion years.
The distances between galaxies are thus can be very different at different stages of time, since they are constantly in dynamics.
The scale of the Universe
The visible universe has incredible diameter, which is billions or maybe tens of billions of light years. Many objects that we can see with telescopes no longer exist or look completely different because the light took an incredibly long time to reach them.
The proposed series of illustrations will help you imagine at least in general terms the scale of our Universe.
The solar system with its largest objects (planets and dwarf planets)
The Sun (in the center) and the stars closest to it
The Milky Way Galaxy, showing the group of star systems closest to the Solar System
A group of nearby galaxies, including more than 50 galaxies, the number of which is constantly increasing as new ones are discovered.
Local supercluster of galaxies (Virgo Supercluster). Size: about 200 million light years
Group of superclusters of galaxies
Visible Universe
Of the large star systems nearby, the Andromeda nebula (M31) is located - a spiral galaxy 2.6 times larger in size than our home - the Milky Way galaxy: its diameter is 260 thousand light years. The Andromeda nebula is located at a distance of 2.5 million light years (772 kiloparsecs) from us, and its mass is 300 billion solar masses. It consists of about a trillion stars (for comparison: the Milky Way contains about 100 billion stars).
The Andromeda nebula is the most distant cosmic object from us that can be observed in the starry sky (northern hemisphere) with the naked eye, even in urban light conditions - it looks like a luminous blurry oval. It should be remembered that due to the fact that the light from the Andromeda galaxy travels to us for 2.5 million years, we see it as it was 2.5 million years ago, and we do not know what it looks like now moment.
B - Andromeda Galaxy in ultraviolet rays
Astronomers have found that the Andromeda Galaxy and our Galaxy are approaching each other at a speed of 100-140 km/s. In about 3-4 billion years, perhaps they will collide and then they will merge into one giant galaxy. We hasten to reassure those who are concerned about the fate of the Solar System as a result of this collision: most likely there will be no impact on the Sun and planets. Galactic merger processes are not accompanied by catastrophic stellar collisions, since the distances between stars are very large compared to the size of the stars themselves.
However, one should not think that the process of merging galaxies, stretched over millions of years, occurs without dramatic effects. When two galaxies approach each other, clouds of interstellar gas come into contact first. Due to the rapid interpenetration, their density increases sharply, they heat up, and the growing pressure turns these gas and dust clouds into centers for the formation of new stars. A violent, explosive process of star formation begins, accompanied by flares, explosions and the ejection of monstrously extended jets of dust and gas.
However, let's return to our neighbors. The second closest spiral galaxy to us is M33. It is located in the constellation Triangulum and is 2.4 million light years away from us. Its diameter is 2 times smaller than the Milky Way and 4 times smaller than the Andromeda Galaxy. It can also be seen with the naked eye, but only on a moonless night and outside the city. It looks like a dim, foggy speck between α Triangulum and τ Pisces.
A - the position of the galaxy in the starry sky
B - Triangulum Galaxy (NASA photo in ultraviolet and visible range)
All other galaxies in our immediate environment are dwarf elliptical and irregular galaxies. Of the irregular galaxies closest to us, two are of greatest interest: Large and Small Magellanic Clouds.
The Magellanic Clouds are satellites of our Milky Way Galaxy. They are also visible to the naked eye, although only in the southern hemisphere. The Large Magellanic Cloud is located in the constellation Doradus. It is 170 thousand light years away from us (50 kiloparsecs), its diameter is 20 thousand light years, and it contains about 30 billion stars. Despite being an irregular galaxy, the Large Magellanic Cloud has a structure similar to that of crossed spiral galaxies. It contains all the types of stars that are known in the Milky Way. Another interesting object was discovered in the Large Magellanic Cloud - one of the brightest known gas and dust complexes with a length of 700 light years - Tarantula Nebula, a hotbed of rapid star formation.
Survey with the TRAPPIST telescope (La Silla Observatory, Chile)
The Small Magellanic Cloud is 3 times smaller than the Large Magellanic Cloud and also resembles a crossed spiral galaxy. It is located in the constellation Tucana, next to Dorado. The distance from us to this galaxy is 210 thousand light years (60 kiloparsecs).
The Magellanic Clouds are surrounded by a common shell of neutral hydrogen, which is called the Magellanic System.
Both Magellanic clouds are victims galactic cannibalism from the Milky Way: the gravitational influence of our Galaxy gradually destroys them and attracts the matter of these galaxies. Hence the irregular shape of the Magellanic Clouds. Experts believe that these are the remains of two small galaxies in the process of gradual disappearance. According to astronomers, in the next 10 billion years the Milky Way will completely absorb all the material of the Magellanic Clouds. Similar processes occur between the Magellanic clouds themselves: due to their gravity, the Large Magellanic Cloud “steals” millions of stars from the Small Magellanic Cloud. Perhaps this fact explains the high star-forming activity in the Tarantula Nebula: this region is exactly in the path of the gas flow that the gravity of the Large Magellanic Cloud pulls from the Small Magellanic Cloud.
Thus, using the example of what is happening in the vicinity of our Galaxy, you can again be convinced that the merger of galaxies and the absorption of small galaxies by larger ones is a completely ordinary phenomenon in galactic life.
Our Galaxy, the Andromeda Galaxy and the Triangulum Galaxy form a group of galaxies connected by gravitational interaction. They call her Local group of galaxies. The size of the Local Group is 1.5 megaparsecs across. In addition to three large spiral galaxies, the Local Group includes more than 50 dwarf and irregular (shaped) galaxies. Thus, the Andromeda Galaxy has at least 19 satellite galaxies, and our Galaxy has 14 known satellites (as of 2005). In addition to them, the Local Group includes other dwarf galaxies that are not satellites of large galaxies.
Divided into social groups, our Milky Way galaxy will belong to a strong “middle class”. Thus, it belongs to the most common type of galaxy, but at the same time it is not average in size or mass. Galaxies that are smaller than the Milky Way are larger than those that are larger than it. Our “star island” also has at least 14 satellites - other dwarf galaxies. They are doomed to circle around the Milky Way until they are absorbed by it, or fly away from an intergalactic collision. Well, for now this is the only place where life probably exists - that is, you and me.
But the Milky Way remains the most mysterious galaxy in the Universe: being on the very edge of the “star island”, we see only a part of its billions of stars. And the galaxy is completely invisible - it is covered with dense arms of stars, gas and dust. Today we will talk about the facts and secrets of the Milky Way.
The Milky Way, a very typical example of its type of galaxy, is so huge that it takes light more than 100 thousand years to cross the Galaxy from edge to edge at a speed of 300,000 kilometers per second. The Earth and the Sun are located at a distance of about 30 thousand light years from the center of the Milky Way. If we tried to send a message to a hypothetical creature living near the center of our Galaxy, we would receive a response no sooner than 60 thousand years later. A message sent at the speed of an airplane (600 miles or 1000 kilometers per hour) at the moment of the birth of the Universe would by now have traveled only half of the way to the center of the Galaxy, and the waiting time for a response would have been 70 billion years.
Some galaxies are much larger than ours. The largest of these—vast galaxies that emit enormous amounts of energy in the form of radio waves, such as the famous southern sky object Centaurus A—are a hundred times larger in diameter than the Milky Way. On the other hand, there are many relatively small galaxies in the Universe. The dimensions of dwarf elliptical galaxies (a typical representative is located in the constellation Draco) are only about 10 thousand light years. Of course, even these inconspicuous objects are almost unimaginably huge: although the galaxy in the constellation Draco can be called a dwarf, its diameter exceeds 160,000,000,000,000,000 kilometers.
Although space is inhabited by billions of galaxies, they are not at all cramped: the Universe is huge enough for galaxies to fit comfortably into it, and there is still a lot of free space left. The typical distance between bright galaxies is about 5-10 million light years; the remaining volume is occupied by dwarf galaxies. However, if we take into account their sizes, it turns out that the galaxies are relatively much closer to each other than, for example, the stars in the vicinity of the Sun. The diameter of the star is negligible compared to the distance to the nearest neighboring star. The diameter of the Sun is only about 1.5 million kilometers, while the distance to our nearest star is 50 million times greater.
In order to imagine the enormous distances between galaxies, let’s mentally reduce their size to the height of an average person. Then, in a typical region of the Universe, “adult” (bright) galaxies will be located on average at a distance of 100 meters from each other, and a small number of children will be located between them. The universe would resemble a vast baseball field with a lot of open space between the players. Only in some places where galaxies gather in close clusters. our scale model of the Universe is like a city sidewalk, and nowhere would be anything like a party or a subway car at rush hour. If the stars of a typical galaxy were reduced to the scale of human growth, the area would be extremely sparsely populated: the nearest neighbor would live at a distance of 100 thousand kilometers - about a quarter of the distance from the Earth to the Moon.
From these examples it should be clear that galaxies are quite sparsely scattered throughout the Universe and consist mainly of empty space. Even if we take into account the rarefied gas filling the space between the stars, the average density of matter still turns out to be extremely low. The world of galaxies is huge and almost empty.
Galaxies in the Universe are not alike. Some of them are smooth and round, others have the shape of flattened, scattered spirals, and some have almost no structure at all. Astronomers, following the pioneering work of Edwin Hubble published in the 1920s, classify galaxies based on their shape into three main types: elliptical, spiral and irregular, designated respectively E, S and Irr.