Galaxies appear to us as completely unchanging and stable objects, but in fact their life is full of movement. The universe is like a giant crossroads where traffic lights have been turned off. True, here numerous collisions of galactic objects do not destroy them, but only contribute to the evolution of galaxies.

The study of galaxies began, as is usually the case, with an attempt to systematize them according to their appearance. This is how the famous Hubble classification arose, which will be discussed later. But when, in the 50s of the last century, astronomers began to closely study galaxies located close to each other, it turned out that many of them have a very unusual, or, as they say, peculiar, appearance. Sometimes, even single ones, they look so “unpresentable” that it is impossible to attach them to any place in the Hubble sequence that is decent in all respects. Often they seem to stretch out their arms to each other - thin stellar jumpers - or throw long twisted tails in opposite directions. Such galaxies are called interacting galaxies. True, at that time no more than 5% of the number of normal objects were observed, and therefore rare freaks did not attract much attention for a long time.

The Whirlpool Spiral Galaxy (M51, NGC 5194/95). Her pronounced spiral structure, appears to be due to the gravitational influence of the smaller galaxy NGC 5195 (right), whose light is partially obscured by dust at the end of M51's spiral arm

One of the first to seriously study them was B.A. Vorontsov-Velyaminov. With his light hand one of the most unusual pairs of NGC 4676 was first called Playing Mice, and then just Mice. Under this nickname, she now appears in serious scientific articles. There are other interesting instances of peculiar objects, better known by their "party nicknames" than by the passport data of the catalogs - Antennas (NGC 4038/39), Atom of the World (NGC 7252), Whirlpool (M 51 or NGC 5194/95).

How does gravity affect appearance galaxies, it is easiest to understand by the example of those objects that have tails and bars. Let us recall how the Moon makes the earth's ocean "swell" from two opposite sides. Due to the rotation of the planet, these tidal waves run across the earth's surface. In the same way, when a disk galaxy approaches another galaxy, tidal humps appear, elongated both in the direction of the troublemaker and in the opposite direction. Later, these humps twist into long tails of stars and gas due to differential rotation: the periods of revolution of stars around the center of the galaxy increase with distance from the center. A similar picture was reproduced in computer experiments, when astronomers began to numerically simulate the gravitational interaction of galaxies.

Mouse Galaxy (NGC 4676). One of the most famous pairs of interacting galaxies.
Tidal forces caused them to form long and thin tails.

The first models were almost toys. In them, the motion of test particles distributed in circular orbits around a massive point was perturbed by another massive point flying by. Using such models in 1972, the brothers Alar and Juri Toomre comprehensively studied how the formation of tidal structures depends on the collision parameters of galaxies. For example, it turned out that stellar bridges connecting galaxies are well reproduced when an object interacts with a low-mass galaxy, and tails - when a disk system collides with a galaxy of comparable mass. Another interesting result was obtained when the perturbing body flew past the disk of a spiral galaxy in the same direction as its rotation. Relative speed The movement turned out to be a small, spiral galaxy effect. The Tumre brothers built models of a number of known interacting systems, including Mice, Antennas and the Whirlpool, and expressed the most important idea that the result of a collision of galaxies could be a complete merger of their star systems - merging.

But toy models couldn't even illustrate this idea, and you can't do an experiment on galaxies. Astronomers can only observe the different stages of their evolution, gradually restoring from disparate links the entire chain of events stretched over hundreds of millions and even billions of years. Once Herschel very accurately formulated this feature of astronomy: “[The sky] now seems to me a wonderful garden in which great amount a wide variety of plants planted on various beds and at different stages of development; we can derive at least one benefit from this state of affairs: our experience can be stretched out over vast stretches of time. After all, does it really matter whether we are successively present at the birth, flowering, leafing, fertilization, wilting and, finally, the final death of plants, or simultaneously we observe many samples taken at different stages of development through which the plant passes during its life? »

Alar Tumre made a whole selection of 11 unusual merger galaxies, which, being lined up in a certain sequence, reflected different stages of interaction - from the first close flyby and tails spreading to the subsequent merger into a single object with whiskers sticking out of it, loops and puffs of smoke.

Galaxies at various stages of merger from the Tumre sequence

But the real breakthrough in research was provided by the Hubble Space Telescope. One of the research programs implemented on it consisted of a long-term - up to 10 days in a row - observation of two small sections of the sky in the Northern and Southern hemispheres of the sky. These images are called the Hubble Deep Fields. They can see a huge number of distant galaxies. Some of them are more than 10 billion light-years away, which means that they are the same number of years younger than the nearest neighbors of our Galaxy. The result of studies of the appearance, or, as they say, the morphology of distant galaxies, was stunning. If Hubble had only the Deep Field images of galaxies at hand, it is unlikely that he would have built his famous "tuning fork". Among galaxies with an age of about half the age of the Universe, almost 40% of objects do not fit into the standard classification. The proportion of galaxies with obvious traces of gravitational interaction turned out to be much larger, which means that normal galaxies had to go through the stage of freaks in their youth. In a denser environment early universe collisions and mergers turned out to be the most important factor in the evolution of galaxies.

But to understand these processes, the first toy models of the interaction of galaxies were no longer enough. First of all, because they did not reproduce the effects of dynamic friction of stellar systems, which ultimately lead to the loss of orbital motion energy and the merger of galaxies. It was necessary to learn how to fully calculate the behavior of systems of billions of stars attracting each other.

Hubble tuning fork

Edwin Hubble (1889–1953) -
discoverer of the expansion of the universe,
author of the first classification of galaxies

The classification of galaxies according to their morphology was proposed by Edwin Hubble in 1936. At the left end of this sequence are elliptical galaxies - spheroidal systems varying degrees flattening. Then it stretches to flat spiral galaxies, lined up in order of decreasing the degree of twist of their spiral arms and the mass of their spherical subsystem - the bulge. Separately, there are irregular galaxies, like the two most noticeable satellites Milky Way visible in the sky of the Southern Hemisphere - the Large and Small Magellanic Clouds. In the transition to spiral galaxies, the Hubble sequence splits into two, giving rise to an independent branch spiral galaxies with jumpers, or bars - giant stellar formations that cross the core of the galaxy, from the ends of which spiral branches extend. It is even believed that this is not just an independent branch of the classification, but almost the main one, since from half to two thirds of spiral galaxies have bars. Due to the bifurcation, this classification is often called the "Hubble tuning fork".

The movement of 10 billion was simulated material points over 13 billion years.
In the top frame, each bright spot corresponds to a galaxy.

With the accumulation of observational material, it became clear that the appearance of galaxies is closely related to their internal properties - mass, luminosity, structure of stellar subsystems, types of stars inhabiting the galaxy, the amount of gas and dust, the rate of birth of stars, etc. It seemed that from here it was only half a step to unraveling origin of galaxies of various types - it's all about the initial conditions. If the original protogalactic gas cloud practically did not rotate, then as a result of spherically symmetric compression under the action of gravitational forces, an elliptical galaxy was formed from it. In the case of rotation, compression in the direction perpendicular to the axis was stopped due to the fact that gravity was balanced by increased centrifugal forces. This led to the formation of flat systems - spiral galaxies. It was believed that the formed galaxies in the future do not experience any global upheavals, alone producing stars and slowly aging and reddening in color due to their evolution. In the 1950s and 1960s, it was believed that in this described scenario of the so-called monolithic collapse, only a few details remained to be clarified. But as soon as the interaction of galaxies was recognized as the engine of their evolution, this simplified picture became irrelevant.

Two in one

Motion prediction problem a large number massive points interacting according to the law gravity, received in physics the name of the N-body problem. It can be solved only by numerical simulation. By setting the masses and positions of bodies at the initial moment, it is possible to calculate the forces acting on them according to the law of gravity. Assuming these forces to be constant for a short period of time, it is easy to calculate the new position of all bodies using the formula uniformly accelerated motion. And by repeating this procedure thousands and millions of times, you can simulate the evolution of the entire system.

The Seyfert Sextet. Four merging galaxies
plus a tidal surge from one of them (lower right)
and a distant spiral galaxy (center)

There are over a hundred billion stars in a galaxy like ours. Even modern supercomputers cannot directly calculate their interaction. We have to resort to all sorts of simplifications and tricks. For example, you can represent a galaxy not by the actual number of stars, but by the number that a computer can handle. In the 1970s, only 200–500 points per galaxy were taken. But the calculation of the evolution of such systems led to unrealistic results. Therefore, all these years there was a struggle to increase the number of bodies. Now they usually take several million stars per galaxy, although in some cases up to ten billion points are used to model the birth of the first structures in the Universe.

Another simplification consists in an approximate calculation of the mutual attraction of bodies. Since the force of gravity decreases rapidly with distance, the attraction of each distant star need not be calculated too accurately. Distant objects can be grouped by replacing them with a single point of total mass. This technique is called TREE CODE (from the English tree - a tree, since groups of stars are assembled into a complex hierarchical structure). Now this is the most popular approach, greatly speeding up calculations.

Collision of galaxies NGC 2207 and IC 2163
has been going on for 40 million years. In the future, they are waiting for a complete merger

But the astronomers did not rest on this either. They even developed a special GRAPE processor, which can do nothing but calculate the mutual gravitational attraction of N bodies, but it copes with this task extremely quickly!

The numerical solution of the N-body problem confirmed Tumre's idea that two spiral galaxies could merge into a single object in a collision, which is very similar to an elliptical galaxy. Interestingly, not long before this result was obtained, the famous astronomer Gerard de Vaucouleurs skeptically stated at the symposium of the International Astronomical Union: “After the collision, you will get a mangled car, not a new type of car.” But in the world of interacting galaxies, two colliding cars, oddly enough, turn into a limousine.

The consequences of the merger of galaxies are even more striking if we take into account the presence of a gas component in them. Unlike the stellar component, gas can lose kinetic energy: it goes into heat, and then into radiation. When two spiral galaxies merge, this leads to the fact that the gas "flows" to the center of the merger product - the merger. Some of this gas turns into young stars very quickly, resulting in the phenomenon of ultra-bright infrared sources.

The Cartwheel Galaxy (left) experienced a blow millions of years ago,
perpendicular to the plane of the disk. Its trail is an expanding ring of active star formation.
Infrared observations have revealed a similar ring in the famous Andromeda Nebula (M31, bottom)

The effect of the collision of a small "satellite" with a large spiral galaxy is also interesting. The latter eventually increases the thickness of its stellar disk. Observational data statistics confirm the results of numerical experiments: spiral galaxies that are part of interacting systems are, on average, 1.5–2 times thicker than single ones. If a small galaxy manages to “drive” literally into the forehead of a large spiral, perpendicular to its plane, then diverging annular density waves are excited in the disk, like from a stone thrown into a pond. Together with scraps of spiral branches between the crests of waves, the galaxy becomes like a cart wheel. That's what one of the freaks of the world of galaxies is called. Head-on collisions are very rare, all the more surprising that two such waves have been found in the quiet galaxy of the Andromeda Nebula. This was announced in October 2006 by a team of astronomers processing observations from the Spitzer Space Telescope. The rings are clearly visible in the infrared in the area where the dust associated with the gaseous disk emits. Computer simulations have shown that the reason for the unusual morphology of our nearest neighbor is its collision with the satellite galaxy M32, which pierced through it about 200 million years ago.

The fate of the satellites of the galaxies themselves is more sad. Tidal forces eventually literally smear them into orbit. In 1994, an unusual-looking dwarf satellite of the Milky Way was discovered in the constellation Sagittarius. Partially destroyed by the tidal forces of our Galaxy, it stretched out into a long ribbon of moving groups of stars stretching in the sky for about 70 degrees, or 100,000 light years! By the way, the dwarf galaxy in Sagittarius is now listed as the closest satellite of our Galaxy, having taken this title from the Magellanic Clouds. It is only about 50,000 light years away. Another giant stellar loop was discovered in 1998 around the spiral galaxy NGC 5907. Numerical experiments reproduce such structures very well.

Collision model of spiral galaxies.
The third frame is very reminiscent of the Mouse galaxy (T - time in millions of years)

Hunting for dark matter

Back in the early 1970s, there were serious arguments in favor of the fact that galaxies, in addition to stars and gas, contain so-called dark halos. Theoretical arguments followed from considerations of the stability of the stellar disks of spiral galaxies, the observational ones - from large, non-decreasing gas rotation rates on the far periphery of galactic disks (there are almost no stars there, and therefore the rotation speed is determined from gas observations). If the entire mass of the galaxy were contained predominantly in stars, then the orbital velocities of gas clouds located outside the stellar disk would become smaller and smaller with distance. This is exactly what is observed in the planets in the solar system, where the mass is mainly concentrated in the Sun. In galaxies, this is often not the case, which indicates the presence of some additional, massive, and most importantly, extended component, in whose gravitational field gas clouds acquire high speeds.

Numerical models of stellar disks also presented surprises. The disks turned out to be very "fragile" formations - they quickly and sometimes catastrophically changed their structure, spontaneously folding from a flat and round cake into a loaf, scientifically - a bar. The situation became somewhat clearer when mathematical model galaxies introduced a massive dark halo, which does not contribute to its overall luminosity and manifests itself only through the gravitational effect on the stellar subsystem. We can judge the structure, mass, and other parameters of dark halos only by indirect evidence.

One way to obtain information about the structure of dark halos is to study the extended structures that form in galaxies during their interaction. For example, sometimes during a close flyby, one galaxy “steals” part of the gas from another, “winding” it around itself in the form of an extended ring. If you are lucky and the ring turns out to be perpendicular to the plane of rotation of the galaxy, then such a structure - the polar ring - can exist for quite a long time without being destroyed. But the very process of formation of such details strongly depends on the distribution of mass at large distances from the center of the galaxy, where there are almost no stars. For example, the existence of extended polar rings can be explained only if the mass of dark halos is approximately twice the mass of the luminous matter of the galaxy.

Tidal tails also serve as reliable indicators of the presence of dark matter in the peripheral regions of galaxies. They can be called “reverse” thermometers: the greater the mass of dark matter, the shorter the “mercury column”, which acts as a tidal tail.

Results of the Millennium Simulation project.
The movement of 10 billion material points was simulated
over 13 billion years. On the top frame, each
bright spot corresponds to the galaxy

Two remarkable discoveries of extragalactic astronomy - the existence of dark matter and the merging of galaxies - were immediately adopted by cosmologists, especially since a number of cosmological observational tests also indicated that there is about an order of magnitude more dark matter in nature than usual. Perhaps the first evidence of the existence of a hidden mass was obtained back in 1933, when F. Zwicky noticed that the galaxies in the Coma of Veronica cluster are moving faster than expected, which means that there must be some kind of invisible mass that keeps them from scattering. The nature of dark matter remains unknown, so they usually talk about some abstract cold dark matter (CDM), which interacts with ordinary matter only gravitationally. But due to its large mass, it is precisely this active background against which all scenarios of the origin and growth of structures in the Universe are played out. Ordinary matter only passively follows the proposed scenario.

These ideas formed the basis of the so-called hierarchical crowding scenario. According to it, the primary perturbations of the density of dark matter arise due to gravitational instability even in the young Universe, and then multiply, merging with each other. As a result, many gravitationally bound dark halos are formed, differing in mass and angular (rotational) moment. Gas rolls into the gravitational pits of dark halos (a process called accretion), which leads to the formation of galaxies. The history of mergers and accretion of each dark matter clot largely determines the type of galaxy that is born in it.

The attractiveness of the hierarchical crowding scenario is that it describes the large-scale distribution of galaxies very well. The most impressive numerical experiment carried out in this scenario is called Millennium Simulation. Astronomers reported its results in 2005. The experiment solved the N-body problem for 10 billion (!) particles in a cube with an edge of 1.5 billion parsecs. As a result, it was possible to trace the evolution of dark matter density fluctuations from the moment when the Universe was only 120 million years old to the present day. During this time, almost half of the dark matter managed to gather into dark halos of various sizes, of which there were about 18 million pieces. And although it was not possible to obtain full and unconditional agreement with the results of observations of a large-scale structure, everything is still ahead.

In search of the missing dwarfs

The hierarchical clustering scenario predicts that in the halo of large spiral galaxies like ours, there should be hundreds of "mini-holes" that serve as the embryos of dwarf satellite galaxies. The absence of so many small satellites creates some difficulties for standard cosmology. However, it is possible that the whole point is simply an underestimation of the real number of dwarf galaxies. That is why their targeted search is so important. With the advent of large digital surveys of the sky, stored in special electronic archives and available to everyone, astronomers are increasingly conducting such searches not in the sky, but on the monitor screen.

In 2002, a team of researchers led by Beth Wilman began searching for unknown satellites of the Milky Way in the Sloan Digital Sky Survey. Since their surface brightness was expected to be very low - hundreds of times weaker than the nighttime glow of the atmosphere - they decided to look for areas of the sky with a statistically significant excess of distant red giants - bright stars that are at the final stage of their evolution. The first success came in March 2005. in the constellation Ursa Major At a distance of 300 thousand light years from us, a dwarf spheroidal galaxy was discovered. It became the thirteenth satellite of the Milky Way, and with a record low luminosity - together all its stars radiate as one supergiant, for example Deneb - the brightest star in the constellation Cygnus. It was possible to detect this galaxy at the limit of the method's capabilities. The year 2006 turned out to be extremely fruitful for the satellites of our Galaxy, when two other teams of researchers discovered seven dwarf spheroidal galaxies around the Milky Way at once. And this, apparently, is not the limit.

So, galaxies grow from small systems, which, through multiple mergers, form large ones. Simultaneously with the merger process, there is a “precipitation” (accretion) of gas and small satellite galaxies on large galaxies. It is still unclear to what extent both of these processes determine the modern adult form of galaxies - Hubble types.

But even after growing up, galaxies continue to change. On the one hand, changes are caused by gravitational interactions between them, which can even lead to a change in the type of galaxy, and on the other hand, by slow processes of dynamic evolution of already fully formed objects. For example, the stellar disks of spiral galaxies are subject to various kinds of instabilities. Bars of "bridge" can spontaneously form in them, through which the gas is effectively "driven" to the central regions of galaxies, which leads to a redistribution of matter in the system. The bars themselves are also slowly evolving - they grow both in length and in width. And the spiral structure of the galaxy itself is the result of the instability.

Once upon a time, Hubble divided the galaxies in the following way. The ellipticals were relegated to the early types, and the spiral line to more and more recent ones. Perhaps because of this, the "Hubble tuning fork" was given evolutionary meaning. However, the dynamic evolution of galaxies goes, rather, in the opposite direction - from late types to early ones towards the slow growth of the central spheroidal subsystem - the bulge. But one way or another, all three processes - mergers, accretion and slow secular evolution - are responsible for the appearance of galaxies. We already understand much in this picture, but there is much more we have to learn and understand.

Screenshot from the application

Space, boundless and majestic space... How many mysteries lurk in its depths? Probably, a person will never solve even half of them. Our solar system is just a part of an infinite number of star clusters - galaxies, cradles of stars and planetary systems. They slowly float through the boundless expanses of the Universe. Sometimes it happens that the paths of the Galaxies intersect. Then there are clashes of truly grandiose proportions.

During the collision of the Galaxies, energy emissions of such force occur that it is difficult to comprehend. As a result of such events, the galaxies that have merged into one begin to glow with even greater force.

The collision of galaxies is an incredibly long process, given the size of these space objects. It can take millions and even billions of years. Naturally, scientists will never be able to observe the process from beginning to end. Therefore, to the aid of astronomers comes Computer Engineering. Modern computers allow you to recreate the process, accelerated thousands and thousands of times.

Galactic collisions on the monitor screen

An interactive 3D collision of two galaxies allows each of us to look at the process of collision.

You can watch two galaxies collide. At the same time, gravity attracts their nuclei, which are most often black holes, and they begin their cosmic dance. At the same time, part of the stellar systems is thrown out of the region and they begin their lonely journey through the expanses of space. In the program, star systems are represented by colored dots.

How to use

The mouse is used to navigate the program. By moving it in the application window, the angle changes, and the rotation of the wheel allows you to change the scale. Clicking the mouse button resets the simulation. The process starts over.

This small program makes you wonder what will happen to our world when the Milky Way and the Andromeda Nebula cross in three billion years, hurrying towards each other? Will we end up on the outskirts of the universe as a lonely wandering solar system? Or will our skies light up with new stars? And will there be people on our Earth by that time who will catch it?

Find out, Who will the Milky Way collide with?: distance from neighboring galaxies, approach and merger with Andromeda, observations Hubble telescope what will happen to us.

Scientists are convinced that in 4 billion years the Milky Way will lose its usual shape, as it will collide with the Andromeda galaxy. As a result, we will get a new giant hybrid galaxy. Most likely, it will form in the form of an ellipse.

On the one hand, this is not something special. Even now, in the vast expanses of space, such galactic mergers can be observed. But let's not forget that this event concerns our home (the solar system and the Earth).

The future collision of the Milky Way and Andromeda is not considered shocking news, as scientists have known about this for a long time. The galaxies are approaching at a speed of 400,000 km/h. But before that it was just an assumption, because no one was able to measure the lateral movement. Now everything has changed.

For 7 years, researchers have been using the Hubble Space Telescope to observe specific areas of a neighboring galaxy. They found out that Andromeda would not pass by, but was aimed at a head-on collision. The first impact will occur in 4 billion years, and the merger process will be completed in 6 billion years.

Space Collision of the Milky Way

Our galaxy has never experienced anything like this in the entire period of its existence (13.5 billion years). Of course, it has previously swallowed dwarf galaxies, but this is the first contact with such a large object.

There is no point in worrying about your safety, since nothing threatens either our planet or ours. We are talking about the passage of two massive spaces, whose objects are scattered over large distances. That is, the probability of a collision of stars is minimal. But we are destined to change our place of residence, as the new galaxy will look different. Most likely, the system will be much further from the core.

What would the night sky look like after such a collision?

The collision of the Milky Way and Andromeda galaxies will change what we are used to seeing in the night sky. If after 3.75 billion years humanity continues to exist, then people are destined to observe bright areas of star formation in the new galaxy. After 7 billion years, the brightest core of the elliptical giant will become dominant. But let's not forget that at that moment it should go into the stage of a red giant and we may simply not catch this sight.

The use of Hubble made it possible to learn not only to look into the past, but also to model the future for which the Universe is preparing us. Therefore, we now know not only where we came from, but also where we are going.

Milky Way and Andromeda's nebula- the largest of the 40-plus galaxies that form our local group.
The local group of galaxies is united by gravitational forces, and therefore they are expected not by expansion, but by a gradual merger.

Merger of the Milky Way and Andromeda galaxies (figuratively)

As astronomers have established, 4.7 billion years ago, when our Sun was just formed, Andromeda and the Milky Way were separated by a distance of 4.2 million light years, and by now it has decreased to 2.5-2.6 million light years , and the rate of convergence is constantly increasing.

Back in 1912, the American astronomer Westo Slifer, based on an analysis of the Doppler shift of the spectral lines of stars, found that Andromeda was moving towards the Sun at a speed of about 300 km / s.

By the middle of the 20th century, it became clear that the high speed of Andromeda's approach to the Solar System is mainly associated with the orbital movement of the Solar System itself around the center of the Galaxy at a speed of about 225 km / s, directed approximately towards Andromeda.

According to updated estimates, the speed of convergence of the actual galaxies - the Milky Way and Andromeda is 110-120 km / s. Moreover, conducted in the period 2002-2010. With the help of the Hubble Space Telescope, measurements showed that Andromeda is approaching us almost in a straight line and a "collision" of galaxies is almost inevitable.

Speaking of "collision", one must understand that a physical collision of objects like stars is unlikely due to the low concentration of matter in galaxies and the extreme distance of objects from each other.

For example, the closest star to the Sun, Proxima Centauri, is about 4.22 light year from the Earth, which is 270,000 times more distance from the earth to the sun. For comparison: if the Sun were the size of a coin with a diameter of 2.5 centimeters, then the nearest coin / star would be at a distance of 718 kilometers.

Scientists predict that in 4 billion years the halos of galaxies will first intersect, which will increase their mutual gravitational attraction, and after another 2-3 billion years, these two star systems will finally merge into a single conglomerate, which has already come up with the name "Milkomeda" (Milkomeda), compiled from the everyday name of our Galaxy - the Milky Way (Milky Way) and "Andromeda".

Based on calculations, the stars and gas of the Andromeda galaxy will become visible to the naked eye from Earth in about three billion years.
"Today, the Andromeda galaxy from Earth looks like a small fuzzy object. Astronomers first looked at it over a thousand years ago," says Roland van der Marel of the Space Telescope Science Institute in Baltimore. “There are few things that interest people more than issues related to space. And we can predict that this small, fuzzy object could one day swallow our Sun and the entire solar system,” the astronomer adds.

As a result of the merger of galaxies, a giant cluster of stars will be formed, randomly swarming around a common center. In the center, a system of two supermassive black holes will appear, into which former centers two galaxies. They will more and more actively absorb matter, which, accelerating near black holes, will emit powerful gamma rays. In addition, powerful jets will form near black holes - relativistic jets of matter ejected from their poles. In places where jets and gas and dust clouds collide, bright clusters of young massive stars will appear.

What fate awaits the solar system during the merger of galaxies?

Scientists estimate that there is a 12 percent chance that our Sun will be ejected into interstellar space during this merger. But it is also possible that the solar system will be completely captured by the Andromeda Nebula - the probability of this is equal to three percent.

However, the following scenario is most probable: the solar system will be ejected to the periphery of the new galaxy, to the region of the diffuse gas cloud surrounding it - the halo. At the same time, it will be at a fairly safe distance - at least 100 thousand light years - from the galactic center.

However, it should be borne in mind that by the time the merger of galaxies is completed

much more important for life on Earth than all the scenarios mentioned above will be the evolution of our Sun and its subsequent transformation into a red giant in 5-6 billion years.

Scientists, based on observations, suggest that a small satellite of Andromeda - the Triangulum Galaxy (M33) - will also be involved in the merger process. In 3-4 billion years after the merger of Andromeda and the Milky Way, the M33 galaxy will collide with a neoplasm ("Milkomeda") and will probably merge with it according to the same scenario.

Whether everything will happen this way or not quite like that, or maybe not at all, it is difficult to judge this reliably today, trying to look into the future billions of years ... . For.

Collision of galaxies- an event of truly grandiose proportions. Nothing in the entire universe can compare with this phenomenon in magnitude, except perhaps the Big Bang.

The alleged collision of two "nearby" galaxies - Milky Way and andromeda nebulae(M31) - will happen in about 5 - 5.5 billion years. The collision of galaxies is not quite normal. Unlike collisions, for example, in asteroids, in which there is direct contact and destruction of the objects themselves, in the collision of dust-star clusters, it is extremely unlikely that objects like stars and planets contained in each galaxy will actually collide with each other due to the low concentration substance and high remoteness of individual objects. For example, Proxima Centauri from the constellation Lyra - the closest star after the Sun, 4.22 light years away from us, this distance is 270,000 times greater than the distance between the Earth and the Sun. For comparison, if you imagine the Sun as a golf ball, then Proxima will be at a distance of 700 km.

The fact that galaxies merged earlier is not news for a long time, evidence of this has already been found abound. But whether our galaxy will collide with the Andromeda Nebula is still not exactly clear: firstly, too little data has yet been collected regarding the characteristics of both galaxies, in particular, the main snag is the measurement of Andromeda's transverse rotation speed; secondly, the power of even the most advanced supercomputers is still not enough to simulate such large-scale processes, and even more so to take into account all possible and impossible conditions and factors. As scientists note, a slight shift from the dead center will occur later this year thanks to the launch of the new Gaia space telescope, which will have to measure the transverse velocity of the neighboring galaxy by determining the exact luminosity of Andromeda stars.

pictures of merging galaxies taken by the Hubble telescope

Even if the collision does not occur in about 3 billion years, the above galaxies will approach so much that the Andromeda nebula and its brightest stars will be clearly visible from the Earth with the naked eye, in size and brightness it will approach the Moon.

this is what Andromeda will look like in the night sky in 3 billion years

Such collisions are quite common - under the influence of gravity, galaxies are attracted to each other from time to time and merge. The same Andromeda, for example, in the past swallowed up at least one dwarf galaxy like the Milky Way. It is also not excluded, and the fact that the solar system can be ejected to the very edge of the new galaxy or even beyond it. However, no matter how strange it may sound, such an event will not bring any negative impacts for our planetary system.

These videos are the result of collision simulations on the most powerful supercomputers in the world. The first two were created by Frank Summers of the Science Institute for Cosmological Research based on the work of professors Chris Migos and Lars Hernquist. It is not worth trusting computer visualization 100 percent, since it has already been noted above that the computing power of the computer is still insufficient.

The formed galaxy is proposed to be called Mlekomed.