Distance from earth to andromeda. Andromeda is the closest galaxy to the Milky Way. Collision of the Milky Way and Andromeda
Wide angle map of the constellation Andromeda
M31 Photographer Rick Krejci
The daughter of Cassiopeia and Cepheus Andromeda was to become a victim of Poseidon and, chained to a cliff, awaited her fate. Returning after defeating the Gorgon, Perseus found her, freed her and took her as his wife. Andromeda is the 19th largest constellation in the night sky. Together with her mother, father, husband and his winged horse (Pegasus), she participates in the seasonal procession around the pole.
I don't think she looks like a princess at all. I have always seen Andromeda as a cornucopia, appearing just in time for the harvest. But no matter what Andromeda looks like to you, it contains a lot of spectacular deep-sky objects.
The Andromeda Galaxy (also known as M31) became famous for several reasons, but most likely because it was one of the cornerstones in resolving the Great Debate (are there many galaxies in the universe or is it just ours?), and in determining interstellar distances using Cepheid variable stars.
At the turn of the last and the century before last, astronomers wondered whether spiral galaxies like M31 were located in the Milky Way or outside it. In 1923, while working at the Mount Wilson Observatory with a 100-inch telescope, Edwin Hubble photographed the stars in the halo of M31, discovered Cepheids among them, and suggested a distance to the galaxy of 900,000 light years - this was much further than assumed at that time the borders of our galaxy.
In 1944, the German-born astronomer Walter Baade, who was classified as a foreign enemy and not allowed to participate in defense projects, was “stuck” on Mount Wilson. Due to the Los Angeles military blackouts, Baade could take advantage of the blackest Wilsonian skies and may even have been able to see the splitting into individual stars all over M31.
These astronomers studied M31 with the most powerful telescopes of the time, but in all conditions, except for very strong light, it is visible to the naked eye. Andromeda - 31st in the Messier catalog, according to the most accurate data, covers about 5 degrees, is strikingly far from us (from 2.2 to 2.9 million light years) along with its retinue - M32 and M110. A little further, in Cassiopeia, you can find two brighter satellites of the Andromeda galaxy - NGC 185 and NGC 147.
It's fun to experiment on Andromeda with different optics. It's so large that it can be an excellent target for binoculars, but I like the view in a 4" telescope better - the brighter areas look pretty nice, plus you can see M32 and M110. To find M32, look for a brighter dense haze near M31, well, M110 in a small telescope looks much more like a ghostly cigarette smoke. My 8" reflector on a good night easily pulls out one of the dark stripes that are visible in the photographs, and a larger telescope will show both dust lanes in M31.
We are not done with the Andromeda galaxy. We'll be back to visit its brightest globular cluster (as this month's challenge), but we're moving on for now.
Gamma, NGC 752, Beta and Ghost
Gamma Andromedae First, start at the top of the horn - check the wide view finder map to find Andromeda Gamma. This is a nice bright binary that is easy to spot in a small telescope. Even if you manage to separate it at a low magnification, be sure to try switching to a higher magnification. I have found that often as the magnification changes, the colors of the stars change slightly. Gamma illustrates this effect well. At low magnification, I saw an orange tint in both stars, but when I turned up the magnification on my 4 "refractor to 70, I found that the brighter one remained orange, but the dull one appeared whitish. And what do you see? NGC 752 Take your widest eyepiece and scan the sky east of Gamma. Look for a large open star cluster - NGC 752. Because of its large size, it looks best in binoculars or a telescope with large field vision. In my 4" telescope best view comes out at 36x - I counted a few dozen stars. Look fortwo bright golden stars located near this cluster. The size and color of such stars often reminds me of eyes peering at me from the darkness of the night. Beta Andromedae (Mirach) and Ghost of Mirach (NGC 404)
Now again move towards the base of Andromeda until you get to Beta. Take a moment and study Beta closely - you will notice something that looks like a flare on the eyepiece lens. If you hadn't looked for it specifically, you might have missed it altogether. This is the galaxy known as the Mirach Ghost - NGC 404. More advanced observers may say that it is almost impossible to separate NGC 404 from the bright beta light - and, unfortunately, they are somewhat right. And yet, fortunately for us, it is not so difficult to see it in a telescope of any size. To succeed in detecting a galaxy, one only needs to recognize what would otherwise be dismissed as a glare or an optical illusion. Blue Snowball (NGC 7662)
It's a little more difficult to jump up to it. Three starting points are bright stars, on the map above they are lined up practically from north to south. In medium-dark terrain, they are visible to the naked eye. If you can see them, you will successfully reach Snowball. If not, you will have to consult an overview map, more detailed than the map above.
7662 i.e. Blue Snowball is DEFINITELY worth the effort. I noted that at 37x in a 4" refractor it doesn't look like a star and produces an amazing blue tint in both 8" and 4" telescopes. It's a planetary nebula. Remember they can handle high magnifications? - so now is the time to take advantage of that Plus, you can get a UHC or OIII filter to boost the contrast and see how the image changes - you shouldn't expect much in this case, but it's a good habit anyway.
NGC 891 - The Outer Limits galaxy)
891 can be seen with a four-inch telescope, but to appreciate it, you need an 8" telescope or more. One of the first TV stars (after all, the TV series The Outer Limits is named after her) looks truly exciting.
My 8" telescope usually shows it as a delicate spindle, with a barely visible dust lane (at the most good conditions observations).
In a telescope of about 15 "-20" it already looks like the picture on the left.
The galaxy is edge-on, so it is one of the few galaxies that responds well to Collins I3, an image-enhanced eyepiece. If you consider it in such a device, it looks simply gorgeous.
G1/ Mayall II (Mayall II)
It's not that hard to see this thing - if you have enough aperture - but you have to be really cool to find it.
Basically, this is an exciting goal. Visually - a little short of impressive. On the this moment we've looked at a few globular clusters in our own galaxy, now it's time to take a look at the brightest globular cluster in the local group. What's the catch? It is not located in our galaxy. It is in Andromeda. The picture on the right was taken by the Hubble Space Telescope.
The cluster, called G1 or Mayall II, orbits the Andromeda galaxy at a distance of 130,000 light-years from its center.
What's really surprising is that the G1 can actually be seen through a medium-sized amateur telescope. And not only as a point source. It is, of course, very far from splitting into individual stars, but despite this you can clearly see that there is something here - especially when compared with the two stars in the foreground, on the side of the cluster. At a value of 13.7, the target is quite dim, so the larger the aperture you use, the more likely you are to detect the globule. The task is undoubtedly feasible for a 10" telescope under decent viewing conditions. It is more than plausible to detect a globular in an 8" telescope in a very dark area. I even heard rumors about people who managed to catch it in a 6" telescope.
I always start making a "star trail" from M32 and move straight down to a very recognizable asterism (pictured on the left). Then I make my way to G1. Once I know I'm in the right area, I turn up the zoom and start looking at the multiple stars in that area. G1 is almost halfway between two stars of roughly the same size, which helps a lot when it comes to fishing for the globular.
This search map may help you. I flipped the image on the map to make it easier to navigate through the stars in the eyepiece.
Notice the circled group of stars on the top of the map - in a medium-sized telescope, this group looks a lot like Cassiopeia. As soon as you are in right place, look for three stars in the area marked G1. At high magnification, they resemble Mickey Mouse: the two stars on the side are the ears, and Mickey's head is G1.
The DSS photo (right) should remind you of what you will see. Be sure to pump up the magnification, and you'll find that it's not exactly a stellar point. Visually, it’s not very exciting, but it’s worth considering what exactly you are looking at - and it just blows your mind.
I caught it in my 10" telescope, saw volume at 15", but I got the best view of this object when I observed with Gary Gibbs in his 20" telescope with an image intensifier - a Collins I3 eyepiece. Here it is already obvious that this is not a star - in fact, a star-like core with a fainter halo is visible.In general, the cluster reminded me of the tiny dim globules of the Milky Way, which I caught with a small telescope.
If you manage to capture it, you can be sure that you have very good search skills, because. you managed to see a goal that very few people have achieved.
If you liked this article, check out my other posts in the "
The beautiful spiral galaxy Andromeda or the Andromeda Nebula is the largest in the local group, which consists of the Milky Way, the Triangulum galaxy and, in fact, Andromeda, they are gravitationally connected to each other.
In terms of its size, it is simply huge, over 260 thousand light-years there are trillions of stars, dwarf satellite galaxies, globular clusters, and scientists have also discovered a new cluster of stars, which differs in appearance from the known ones and is located in the halo (invisible component of the galaxy). The scale of the nebula is impressive, it is 2.6 times larger than our Milky Way, approximate weight more than 800 billion of our Sun.
Acquaintance
Let's start our acquaintance with the fact that the very first written mention of the Andromeda galaxy, as a small cloud, was found in the astronomical tables of the "Book of Fixed Stars", by the famous Persian astronomer As-Sufi, who lived and worked at the Adud Ad-Daula palace in Isfahan, and the record is dated 964.
Object M31 - Andromeda Nebula. Drawing by C. Messier. Published in 1807
More detailed description The galaxy was made by the German physician and mathematician Simon Mayr, using a telescope to observe the starry sky, in December 1612 he was one of the first European astronomers to notice the Andromeda nebula.
The famous comet hunter, French astronomer Charles Messier, added the nebula to his famous catalog under the designation M 31.
An amateur astronomer from England, William Huggins, contributed, he suggested that M 31 contains a large number of individual stars, he made such a conclusion in 1864, which was confirmed by further observations.
The Andromeda Galaxy delighted astronomers in 1885 when a single orange supernova, called S Andromedae, exploded in one of its brightest regions, the first star of its kind to be found outside the Milky Way. The remnants of the explosion of a star, at a distance of 2,600,000 light-years from us, were able to observe in 1999, with the help of the most powerful Hubble Space Telescope.
The first pictures of the Andromeda nebula were obtained at the observatory founded in 1885 by Isaac Roberts. It was thanks to his experiments using a special telescope for photographing celestial objects that pictures were taken in October 1887, in which it was very possible to see the structure of the nebula in the form of a spiral.
Thanks to Vesto Melvin Slifer, an excellent astronomer from America, science has learned with what radial velocity the Andromeda Galaxy is moving. Back in 1913, it was he who, using spectral analysis, measured the value, which is equal to 300 kilometers per second, it is with this speed that the galaxy moves towards our Sun.
In 1999, the Chandra X-ray observatory was launched, which, while in space, transmits data to Earth. Research has found that the Andromeda galaxy contains a much larger volume of cold gas than previously thought. This allowed us to know more accurately the temperature, what is the density and how the interstellar gas moves in space.
Structure
The magnificent Andromeda galaxy has not yet fully revealed its secrets. In 1998, scientists managed to understand what kind of blue glow comes from a double core and discovered the source, it turned out to be a cluster consisting of blue stars and their number stepped over four hundred, but in fact there are probably more of them. The age of the stars is very impressive, although they are young for space, just over two hundred million years ago they formed and grouped around a candidate for black holes.
The calculations made showed that the mass of a supermassive hole exceeds the solar one by one hundred and forty million times. Young stars, along with old ones, formed a kind of disk, resembling a donut in its shape. At the same time, the old, red stars are located near the center, and the young ones scattered along the edges, and the radial speed of the stars is very high and equal to a thousand kilometers per second. The most interesting thing for scientists was that stars revolve around a black hole, much like planets revolve around our star, so the mysterious disk, one light year in diameter, still has many secrets.
No less questions are raised by another cluster of stars located in the center of the Andromeda nebula. It is double, but for some incomprehensible reason the merger did not happen, although according to all possible calculations made by scientists, it should have happened millions of years ago. According to the theory put forward by Canadian astrophysicist Scott Tremaine, most likely this is a disk surrounding a donut of young stars, and located at a distance of about five light-years from a black hole. But, this is still only an assumption, whether everything is really so - time will tell.
The Andromeda Galaxy boasts the brightest cluster, Mayall II, which was discovered in 1953 by two American astronomers: Nicholas Ulrich Mayall and Olin Jeuk Eggen. Located one hundred and thirty thousand light-years from the center of the nebula, presumably it is itself the center of a small galaxy, which was swallowed up at one time by the Andromeda nebula. This is indicated by more than one generation of stars, which number more than three hundred thousand, and it even has a candidate for black holes, which is twenty thousand times more solar in mass. With its size and brightness, it surpasses the famous Omega Centauri.
Of great interest to astronomers are new clusters, they were discovered in the halo of the galaxy in 2005, their dimensions are very large and reach hundreds of light years. But at the same time, between a huge number of stars, about hundreds of thousands, the distance is much greater than in globular clusters, this suggests that new clusters are in an intermediate state between a globular cluster and galaxies, having a spheroidal shape. The brightness of such clusters is quite low, they have practically no star dust.
Satellite galaxies
To begin with, let's define what satellite galaxies are and how many of them the Andromeda galaxy has. It is clear from the definition that such galaxies are much smaller in mass and, accordingly, under the influence of a larger galaxy, or rather, its gravity, are kept in orbit nearby. The Andromeda Nebula has about 36 such companion galaxies. All of them have a billion stars and many more black holes. Very few satellites can withstand the influence of a larger galaxy, the rest merge with the main one, forming single system, under the influence of gravity, transforming into very interesting structures, because there is an additional influence on the formation.
So, let's start the Andromeda Nebula, summary, or rather an overview of the largest fellow travelers.
M32
Galaxy
M 32
- is quite small in size, while it is excellently observed from the Earth, as it is quite bright. It was discovered by an astronomer from France, Legentil first met her in October 1749. The distance from Earth to it is about 2.5 million light years, the radius of this elliptical galaxy is 4000 light years. According to the calculations that the scientists received, it became clear that M 32 was most likely spiral, but the tidal forces of Andromeda acted with such
power to completely suppress the formation of sleeves.
M 110
- is larger than the previous galaxy, its radius is 5000 light years, the distance is about three million light years, and can also be observed from Earth.
These two galaxies are compact and fairly large and can easily be seen in any photograph of the Andromeda Galaxy.
NGC 185 - a rather interesting elliptical galaxy in which the process of star formation has recently taken place. Active processes are still taking place in the nucleus with the release of a huge amount of energy. A formation of gas and dust belonging to the supernova remnant has also been discovered. It is removed from the Earth at a distance of a little more than two million light years. It was discovered in November 1787 by the famous English astronomer Herschel.
NGC 147 - Another galaxy that Herschel discovered, though a little earlier, in September 1829. It is located at a distance of 2.2 million light years from us, with a good telescope, you can observe the Earth.
space neighbors
M 34 - a cluster containing about a hundred stars, located to the east of the nebula. The cluster is quite bright and beautiful and can be observed year-round in the constellation Perseus, 1400 sv away from us. years. The size is about fourteen light years, and the age is 180 million years. It was discovered by Giovanni Battista Hodierna, an Italian astronomer, around 1654. During this period, he also discovered the Triangulum galaxy or M 33.
M 33 - is located south of the nebula, in the constellation Triangulum, at a distance of approximately three million years. Spiral galaxy, 50,000 light years across. One of the arms collected two hundred of the brightest hypergiant stars, the rarest type of stars.
M 76 - an interesting nebula in the northeast, which consists of a white dwarf located in the center, and around an ionized shell of gas. The discovery took place in 1780 and belongs to the French astronomer Pierre Méchain. It is observed in the constellation Perseus, located at a distance of 2500 light years.
Searching in the sky
Having read various useful information, and even finding great pictures on the Internet, naturally, there is a desire to go outside and find a beautiful galaxy in the night sky.
I don't know if I'm disappointed or not, but the Andromeda Nebula from Earth looks like an ordinary dim star. Things will be much better, with binoculars, there is a chance to see a small spot, in the form of an ellipse. Through a telescope, you can see a larger spot, bright in the center and fading towards the edges. It will be possible to see M 32 and M 110. And if the diameter of the telescope is 25 cm, galactic dust paths will also become visible.
If you haven’t changed your mind, then we dress warmer, we choose a darker night, and a more cheerful company. And we get out of the city, preferably away, so that the light of the settlements does not interfere with its light. Most best period for observation, as experts say, this is autumn-winter. If you know where the North Star and the asterism of Cassiopeia are located, then you can try to find through them. We draw a segment from the North Star to alpha Cassiopeia, mentally continue the line further and rest just on a blurry oval, this is the Andromeda galaxy.
What's next
Scientists suggest that the collision of the Milky Way galaxies and the Andromeda nebula is possible, but how realistic this is is not clear.
We already know that the galaxy is moving towards the Sun with high speed 300 kilometers per second. Scientists were able to determine how our luminary moves along the Milky Way, in which direction, and having received the data, they calculated that two galaxies are rushing at a speed of 140 kilometers per second towards each other, which should inevitably lead to a collision, according to calculations, this can happen in 4 billion years. It is logical to assume that instead of two small ones, one will turn out, but a large one, while there is a possibility that our system will simply be thrown out in an unknown direction, but the planets will all survive.
According to another scenario, earthlings will be able to observe a gradual absorption or merger, as you like, without any consequences.
But by that time, the inhabitants of the Earth will most likely be occupied with other problems, if we have not yet moved somewhere to another planet, around this time period our luminary will begin to turn into a red giant. Let's wait and see what happens next.
By the way, according to one version, our galactic neighbor Andromeda was formed from two galaxies that went through the same merger process, this event took place about three billion years ago.
According to one theory, the Magellanic Clouds will merge with milky way, approximately before the collision with the fog occurs. Andromeda.
Science does not stand still, new equipment is being invented, new research methods are being developed, stations are moving further and further into space and what was scientifically proven and substantiated yesterday will prove to be wrong tomorrow. Theories and hypotheses put forward today, a year later are no longer considered in the light of constant discoveries, losing their relevance.
New data is constantly being discovered, space throws up interesting riddles that humanity will have to deal with. So, astronomers, astrophysicists, astronauts and everyone who is involved can only be envied in a good way, their life definitely does not stand still.
And you do not lag behind, raise your heads more often, bowed to the ground with problems and thoughts upwards - to where, behind every foggy speck or dot, billions and trillions of the most beautiful galaxies can be hidden, and maybe at this moment somewhere there, someone is looking into our side, just admiring the magnificent starry veil.
The Andromeda Galaxy or the Andromeda Nebula (M31, NGC 224) is an Sb-type spiral galaxy. This large galaxy closest to the Milky Way is located in the constellation Andromeda and is removed from us, according to the latest data, at a distance of 772 kiloparsecs (2.52 million light years). The plane of the galaxy is inclined to us at an angle of 15°, its apparent size is 3.2°, the apparent magnitude is +3.4m.
Observation history
The first written mention of the Andromeda galaxy is contained in the "Catalogue of fixed stars" by the Persian astronomer As-Sufi (946), who described it as a "small cloud". The first description of an object based on telescope observations was made by the German astronomer Simon Marius in 1612. When creating his famous catalog, Charles Messier entered an object under the definition of M31, mistakenly attributing the discovery to Marius. In 1785, William Herschel noted a faint red speck in the center of M31. He believed that the galaxy is the closest of all nebulae, and calculated the distance to it (completely untrue), equivalent to 2000 distances between and Sirius.
In 1864, William Huggins, observing the spectrum of M31, found that it differed from the spectra of gas and dust nebulae. The data indicated that M31 consisted of many individual stars. Based on this, Huggins suggested the stellar nature of the object, which was confirmed in subsequent years.
In 1885, the supernova SN 1885A, known in astronomical literature as S Andromedae, exploded in the galaxy. For the entire history of observations, this is so far only one such event recorded in M31.
The first photographs of the galaxy were taken by Welsh astronomer Isaac Roberts in 1887. Using his own small observatory in Sussex, he photographed M31 and determined the object's spiral structure for the first time. However, at the time, M31 was still considered to belong to our galaxy, and Roberts mistakenly believed it to be another solar system with planets forming.
The radial velocity of the galaxy was determined by the American astronomer Westo Slifer in 1912. Using spectral analysis, he calculated that M31 was moving towards the Sun at a speed unheard of for known astronomical objects of that time: about 300 km/s.
Experts at the Harvard-Smithsonian Center for Astrophysics, after analyzing the results of a 10-year observation of M31 using the Chandra orbital observatory, discovered that the glow of matter falling on the core of the Andromeda galaxy was dim until January 6, 2006, when a flash occurred that increased the brightness of M31 in the X-ray range by 100 times. Further, the brightness decreased, but still remained 10 times more powerful than before 2006.
General characteristics
The Andromeda Galaxy, like the Milky Way, belongs to the Local Group, and is moving towards k at a speed of 300 km/s, so it belongs to the violet-shifted objects. Having determined the direction of the Sun's movement along the Milky Way, astronomers found out that the Andromeda Galaxy and our Galaxy are approaching each other at a speed of 100-140 km/s. Accordingly, the collision of two galactic systems will occur approximately in 3-4 billion years. If this happens, they both will most likely merge into one large galaxy. It is possible that in this case our solar system will be ejected into intergalactic space by powerful gravitational perturbations. The destruction of the Sun and planets, most likely, will not occur during this catastrophic process.
Structure
The Andromeda Galaxy has a mass 1.5 times that Milky Way and is the largest in the Local Group: based on data obtained using the Spitzer space telescope, astronomers have found that it includes about a trillion stars. It has several dwarf satellites: M32, M110, NGC 185, NGC 147 and possibly others. Its length is 260,000 light years, which is 2.6 times greater than that of the Milky Way.
However, some results suggest that the Milky Way contains more Dark Matter and therefore our galaxy may be the most massive in the Local Group.
Core
In the core of M31, as in many other galaxies (including the Milky Way), there is a candidate for supermassive black holes (SMBHs). Calculations have shown that its mass exceeds 140 million solar masses. In 2005, the Hubble Space Telescope discovered a mysterious disk of young blue stars, surrounding the SCHD. They revolve around a relativistic object, just like the planets around the Sun. Astronomers have been puzzled by how such a donut-shaped disk could form so close to such a massive object. According to calculations, the monstrous tidal forces of the NBH should not allow gas and dust clouds to thicken and form new stars. Further observations may provide a clue.
The discovery of this disk put one more argument in the treasury of the theory of the existence of black holes. For the first time, blue light in the core of M31 was discovered by astronomers back in 1995 using the Hubble telescope. Three years later, the light was identified with a cluster of blue stars. And only in 2005, using a spectrograph mounted on a telescope, observers determined that the cluster consists of more than 400 stars that formed approximately 200 million years ago. The stars are grouped into a disk only 1 light year in diameter. In the center of the disk, older and cooler red stars, previously discovered by Hubble, nest. The radial velocities of the disk stars were calculated. Thanks to the gravitational influence of the NBH, it turned out to be a record high: 1000 km / s (3.6 million kilometers per hour). At this speed, you can circle the globe in 40 seconds or get from to the moon in six minutes.
In addition to the SMBH and the disk of blue stars, there are other objects in the core of the galaxy. In 1993, a double star cluster was discovered in the center of M31, which came as a surprise to astronomers, since the two clusters merge into one in a fairly short period of time: about 100 thousand years. According to calculations, the merger should have occurred many millions of years ago, but for strange reasons this did not happen. Scott Tremaine of Princeton University suggested explaining this by saying that the center of the galaxy is not a double cluster, but a ring of old red stars. This ring may look like two clusters, since we only see stars on opposite sides of the ring. Thus, this ring should be located at a distance of 5 light years from the SMBH and surround a disk of young blue stars. The ring and the disk are turned to us on the same side, which may indicate their interdependence. Studying the center of M31 using the XMM-Newton space telescope, a group of European researchers discovered 63 discrete sources x-ray radiation. Most of them (46 objects) have been identified as low-mass binary X-ray stars, while the rest are either neutron stars or black hole candidates in binary systems.
Other objects
About 460 globular clusters have been registered in the galaxy. The most massive of them - Mayall II, also called G1 - has a luminosity greater than that of any cluster in the Local Group, it is even brighter than Omega Centauri (the brightest cluster in the Milky Way). It is located at a distance of about 130,000 light-years from the center of the Andromeda galaxy and contains at least 300,000 old stars. Its structure as well as the stars belonging to different populations, indicate that this is most likely the core of an ancient dwarf galaxy that was once swallowed up by M31. According to research, at the center of this cluster is a candidate black hole with a mass of 20,000 suns. Similar objects also exist in other clusters:
In 2005, astronomers discovered a completely the new kind star clusters. The three newly discovered clusters contain hundreds of thousands of bright stars, almost as many as globular clusters. But what distinguishes them from globular clusters is that they are much larger—several hundred light-years across—and also less massive. The distances between the stars in them are also much greater. Perhaps they represent a transitional class of systems between globular clusters and dwarf spheroids.
The galaxy hosts the star PA-99-N2, which is orbited by an exoplanet - the first to be discovered outside the Milky Way.
Observations
The best time to observe the Andromeda Nebula is autumn-winter. In a dark rural sky, the luminous diffuse oval M31 can be seen with the naked eye next to ν And even by not very experienced observers. It is the most distant object visible from Earth to the naked eye. Moreover, because of the finite speed of light, we see it as it was 2 and a half million years ago. Say, on Earth 2.5 million years ago there were no representatives of the modern human species! But at the same time, we must not forget that according to the Special Theory of Relativity, there is no way to know how this galaxy looks in " this moment", because what we see is for us the" present moment ".
With binoculars, the galaxy is visible even in the illuminated sky of large cities. But her observations in amateur telescopes of medium aperture (150-200 mm) are usually disappointing. Even in the best skies and on a moonless night, the galaxy appears as just a huge luminous ellipsoid with blurry and increasingly dimmer edges and a bright core. An attentive observer notices a hint of one or two encircling dust lanes on the northwestern (closest to us) edge of the galaxy and a small local increase in brightness in the southwest (a huge star-forming region near our neighbor). No other details, except for two satellites - small elliptical galaxies M32 and M110, nothing like colorful photographs and illustrations of popular publications!
Alas, these are the features of human night vision. Our eyes, for all their phenomenal light sensitivity, are not capable, like modern photodetectors, of accumulating light during a long (sometimes hours!) exposure. In addition, the nighttime sensitivity of our eyes is achieved, among other things, by the sacrifice of color recognition - “at night all cats are gray!” - and a sharp decrease in visual acuity. So it turns out that when observing diffuse objects in deep space, only obscure light gray images are visible on a dark gray background. Added to this is the huge size of the M31, which additionally hides its contrasts and detail.
Astronomy is an amazingly fascinating science that reveals to inquisitive minds all the diversity of the Universe. There are hardly any people who, in childhood, would never have watched the scattering of stars in the night sky. This picture looks especially beautiful in the summer, when the stars seem so close and incredibly bright. AT last years Astronomers around the world are particularly interested in Andromeda, the galaxy closest to our own Milky Way. We decided to find out what exactly attracts scientists in it and whether it can be seen with the naked eye.
Andromeda: a brief description
The Andromeda Nebula, or simply Andromeda, is one of the largest galaxy in the galaxy. It is larger than our Milky Way, where the solar system is located, approximately three to four times. In it, according to preliminary estimates, about one trillion stars.
Andromeda is a spiral galaxy, it can be seen in the night sky even without special optical devices. But keep in mind that the light from this star cluster travels to our Earth for more than two and a half million years! Astronomers say that we now see the Andromeda Nebula as it was two million years ago. Isn't that a miracle?
Andromeda Nebula: from the history of observations
Andromeda was first seen by an astronomer from Persia. He cataloged it in 1946 and described it as a hazy glow. Seven centuries later, the galaxy was described by a German astronomer who observed it for a long time with a telescope.
In the middle of the nineteenth century, astronomers determined that the spectrum of Andromeda differed significantly from previously known galaxies, and suggested that it was composed of many stars. This theory is fully justified.
The Andromeda Galaxy, which was photographed only at the end of the nineteenth century, has a spiral structure. Although in those days it was considered only a large part Milky Way.
The structure of the galaxy
With the help of modern telescopes, astronomers have managed to analyze the structure of the Andromeda Nebula. The Hubble telescope made it possible to see about four hundred young stars revolving around the black hole. This star cluster is approximately 200 million years old. This structure of the galaxy was very surprising to scientists, because until now they had not even imagined that stars could form around a black hole. According to all previously known laws, the process of condensing gas to form a star out of it is simply impossible under the conditions of a black hole.
The Andromeda Nebula has several satellite dwarf galaxies, they are located on its outskirts and could be there as a result of absorption. This is doubly interesting given that astronomers are predicting a collision between the Milky Way and the Andromeda Galaxy. True, this phenomenal event will happen very soon.
The Andromeda Galaxy and the Milky Way: moving towards each other
Scientists have long been making certain predictions by observing the movement of both star systems. The fact is that Andromeda is a galaxy that is constantly moving towards the Sun. At the beginning of the twentieth century, an American astronomer was able to calculate the speed at which this movement occurs. This figure, which is three hundred kilometers per second, is still used by all astronomers in the world in their observations and calculations.
However, their calculations differ significantly. Some scientists claim that the galaxies will collide only after seven billion years, while others are sure that the speed of Andromeda is constantly growing, and the meeting can be expected in four billion years. Scientists do not exclude such a scenario in which in a few decades this predicted figure will again significantly decrease. At the moment, however, it is generally accepted that collisions should not be expected earlier than in four billion years. What threatens us Andromeda (galaxy)?
Collision: what will happen?
Since the absorption of the Milky Way by Andromeda is inevitable, astronomers are trying to simulate the situation in order to have at least some information about this process. According to computer data, as a result of absorption, the solar system will be on the outskirts of the galaxy, it will fly over a distance of one hundred and sixty thousand light years. Compared to the current state of our solar system to the center of the galaxy, it will be twenty-six thousand light-years away from it.
The new future galaxy has already received the name - Milky Honey, and astronomers say that due to the merger, it will be rejuvenated by at least one and a half billion years. In this process, new stars will be formed, which will make our galaxy much brighter and more beautiful. She will also change shape. Now the Andromeda Nebula is at some angle to the Milky Way, but in the process of merging the resulting system will take on the shape of an ellipse and become more voluminous, so to speak.
The fate of mankind: will we survive the collision?
And what will happen to people? How will the meeting of galaxies affect our Earth? Surprisingly, scientists say that absolutely nothing! All changes will be expressed in the appearance of new stars and constellations. The sky map will change completely, because we will find ourselves in a completely new and unexplored corner of the galaxy.
Of course, some astronomers leave an extremely small percentage of negative developments. In this scenario, the Earth could collide with the Sun or another stellar body from the Andromeda galaxy.
Are there planets in the Andromeda Nebula?
Scientists regularly search for planets in galaxies. They do not leave attempts to find in the expanses of the Milky Way a planet that is close in characteristics to our Earth. At the moment, more than three hundred objects have already been discovered and described, but they are all located in our star system. In recent years, astronomers have begun to look more and more closely at Andromeda. Are there any planets out there?
Thirteen years ago, a group of astronomers using latest method hypothesized that one of the stars of the Andromeda Nebula has a planet. Its estimated mass is six percent of the major planet our solar system - Jupiter. Its mass is three hundred times the mass of the Earth.
At the moment, this assumption is being tested, but it has every chance of becoming a sensation. After all, until now, astronomers have not discovered planets in other galaxies.
Preparing to search for a galaxy in the sky
As we have said, even with the naked eye you can see the neighboring galaxy in the night sky. Of course, for this you need to have some knowledge in the field of astronomy (at least know what the constellations look like and be able to find them).
In addition, it is almost impossible to see certain clusters of stars in the night sky of the city - light pollution will prevent observers from seeing at least something. Therefore, if you still want to see the Andromeda Nebula with your own eyes, then go to the village at the end of summer, or at least to the city park, where there is no a large number lanterns. The best time for observation is October, but from August to September it is quite clearly visible above the horizon.
Andromeda Nebula: search scheme
Many young amateur astronomers dream of knowing what Andromeda really looks like. The galaxy in the sky resembles a small bright spot, but you can find it thanks to bright stars that are located nearby.
The easiest way is to find Cassiopeia in the autumn sky - it looks like the letter W, only more stretched than it is customary to designate it in writing. Usually the constellation is clearly visible in the Northern Hemisphere and is located in the eastern part of the sky. The Andromeda Galaxy lies below. To see it, you need to find a few more landmarks.
They are three bright stars below Cassiopeia, they are elongated in a line and have a red-orange hue. The middle one, Miraak, is the most accurate guide for beginner astronomers. If you draw a straight line upwards from it, you will notice a small luminous spot resembling a cloud. It is this light that will be the Andromeda galaxy. Moreover, the glow that you can observe was sent to the Earth even when there was not a single person on the planet. Amazing Fact, is not it?
M31 Andromeda Nebula.
11/28/2010, Deepsky 80\560ED telescope, WO 0.8x II corrector, Canon 1000D, ISO 1600, exposure 1 minute, 10-15 frames. Mount - EQ5
How to find the famous Andromeda Nebula (M31)? The best time for its observation - autumn, however, at other times of the year you can try to find it (for example, in the summer in the morning). To search, you must first face the northern part of the sky, find the constellation Ursa Major, draw a line from the "ladle" handle through the North Star, and on the continuation of this imaginary line you will see an inverted letter M or W - this is the constellation Cassiopeia. Cassiopeia is a fairly bright constellation, so you can easily find it. 
Then we turn to the right, to the southeast side of the sky - we see that under Cassiopeia there are two large constellations - Andromeda and Pegasus. Feature- the so-called "Pegasus Square" - four stars that form a kind of "square". 
We will orient ourselves from it - we draw an imaginary line along the stars, first to the left, and then up. If you did everything right and look at the desired place with binoculars, a spyglass or a good optical finder, you will see a small bright oval cloud. Congratulations, this is the Andromeda Nebula - a huge galaxy with which our Galaxy is approaching (the collision will occur in 3-4 billion years). 
In small telescopes, it is visible in the same way as in binoculars / spyglasses, but larger - a large oval spot. Several of its satellites, small galaxies (M32 and M110), also become visible. With 20x60 binoculars, it is visible throughout the entire field of view. The visual size of the Andromeda Nebula is about 3 ... 3.5 degrees - 7 times the apparent size of the Moon! In telescopes of larger diameters (from 250 mm or more), dust lanes near the center of the galaxy become available for observation.
The main guarantee of success in observations is the dark sky and the absence of flare.
In pictures, the Andromeda Nebula looks much more beautiful than visually, primarily due to the visibility of dust clouds along the center of the galaxy. The simplest images of the galaxy can be obtained with even the simplest motorized equatorial mount and a kit lens reflex camera.