In the vast expanses of the Internet, I somehow came across the following picture.
Of course, this small circle in the middle of the Milky Way is breathtaking and makes you think about many things, from the frailty of existence to the limitless size of the universe, but the question still arises: how true is all this?
Unfortunately, the creators of the image did not indicate the radius of the yellow circle, and judging it by eye is a dubious exercise. However, the authors of Twitter @FakeAstropix asked the same question as me, and claim that this picture is correct for about 99% of the stars visible in the night sky.
Another question is how many stars can you see in the sky without using optics? It is believed that up to 6,000 stars can be observed with the naked eye from the surface of the Earth. But in reality, this number will be much less - firstly, in the northern hemisphere we will physically be able to see no more than half of this amount (the same is true for residents of the southern hemisphere), and secondly, we are talking about ideal observation conditions, which in reality are practically impossible to achieve. Just look at the light pollution in the sky. And when it comes to the farthest visible stars, in most cases we need ideal conditions to notice them.
But still, which of the small flickering points in the sky are the farthest from us? Here is the list that I have managed to compile so far (although of course I wouldn’t be at all surprised if I missed a lot of things, so don’t judge too harshly).
Deneb- the brightest star in the constellation Cygnus and the twentieth brightest star in the night sky, with an apparent magnitude of +1.25 (the limit of visibility for the human eye is considered to be +6, maximum +6.5 for people with truly excellent vision). This blue-white supergiant, which is between 1,500 (last estimate) and 2,600 light-years away, means that the Deneb light we see was emitted sometime between the birth of the Roman Republic and the fall of the Western Roman Empire.
Deneb's mass is about 200 times the mass of our star, and its luminosity is 50,000 times greater than the solar minimum. If he were in the place of Sirius, he would sparkle in our sky brighter than the full Moon.
P The swan is painted red
Mu Cephei also known as Herschel's Garnet Star, a red supergiant, possibly the largest star visible to the naked eye. Its luminosity exceeds the solar one from 60,000 to 100,000 times; the radius, according to recent estimates, can be 1500 times greater than the solar one. Mu Cephei is located at a distance of 5500-6000 light years from us. The star is at the end of its life and will soon (by astronomical standards) turn into a supernova. Its apparent magnitude varies from +3.4 to +5. It is believed to be one of the reddest stars in the northern sky.
Plaskett's Star Located 6,600 light-years from Earth in the constellation Monoceros, it is one of the most massive double star systems in the Milky Way. Star A has a mass of 50 solar masses and a luminosity 220,000 times greater than that of our star. Star B has approximately the same mass, but its luminosity is lower - “only” 120,000 solar. The apparent magnitude of star A is +6.05, which means it can theoretically be seen with the naked eye.
System Eta Carina is located at a distance of 7500 - 8000 light years from us. It consists of two stars, the main one - a bright blue variable, is one of the largest and most unstable stars in our galaxy with a mass of about 150 solar, 30 of which the star has already lost. In the 17th century, Eta Carinae had a fourth magnitude; by 1730 it became one of the brightest in the constellation Carinae, but by 1782 it had again become very faint. Then, in 1820, the star’s brightness began to sharply increase and in April 1843 it reached an apparent magnitude of −0.8, temporarily becoming the second brightest in the sky after Sirius. After this, the brightness of Eta Carinae rapidly fell, and by 1870 the star became invisible to the naked eye.
However, in 2007, the star's brightness increased again, it reached magnitude +5 and became visible again. The star's current luminosity is estimated to be at least a million solar and it appears to be a prime candidate for being the next supernova in the Milky Way. Some even believe that it has already exploded.
In conclusion, it is worth mentioning that there have been cases in history when people were able to observe much more distant stars. For example, in 1987, a supernova that could be seen with the naked eye erupted in the Large Magellanic Cloud, located 160,000 light-years away. Another thing is that, unlike all the supergiants listed above, it could be observed over a much shorter period of time.
Events dedicated to the 55th anniversary of the first manned space flight continue in the capital. The exhibition "Russian Space" opens on May 18. Especially for this event, we have collected some interesting facts about the Universe. Even children often ask these seemingly ordinary questions. But they sometimes baffle adults themselves. What is the temperature in space, can you hear the sound of planets and how many stars are there in the Universe - read in our material.
From Earth you can see galaxies with the naked eye
From Earth, we can see as many as four galaxies with the naked eye: our Milky Way and Andromeda (M31) are visible in the Northern Hemisphere, and the Large and Small Magellanic Clouds are visible in the Southern Hemisphere.
The Andromeda Galaxy is the largest closest to us. But if you equip yourself with a large enough telescope, you can see many thousands more galaxies. They will be visible as hazy spots of various shapes.
The solar system is almost 4.5 billion years old
Looking at the night sky, we look into the past
When we look into the night sky and see the stars we are familiar with, we are truly looking into the past.
This is because what we are actually seeing is light sent from a very distant object many years ago. All the stars that we see from Earth are many light years away from us. And the further away the star is, the longer it takes for its light to reach us.
For example, the Andromeda Galaxy is 2.3 million light years away. That is, that is exactly how long its light travels to us. We see the galaxy as it actually was 2.3 million years ago. And we see our Sun eight minutes late.
The sun rotates unevenly around its axis. At the equator - in 25.05 Earth days, at the poles - in 34.3 days
There is not absolute silence in space
Our ears perceive air vibrations, and in space, due to the airless environment, we really cannot hear any sounds.
But that doesn't mean they aren't there. In fact, even a rarefied gas or vacuum can conduct sound of a very long wavelength, inaudible to our ears. Its source can be collisions of gas and dust clouds or supernova explosions.
Of course, we cannot hear such electromagnetic waves. But some spacecraft have instruments that can capture radio emission, and scientists, in turn, can convert it into sound waves. For example, we can listen to the "voice" of the giant Jupiter taken by the Cassini spacecraft in 2001.
What is the temperature in space
In fact, our usual idea of temperature does not quite apply to outer space. Temperature is the state of matter, and as is known, there is practically no such state in outer space.
But still, outer space is not lifeless. It is literally permeated with radiation from a variety of sources - collisions of gas and dust clouds or supernova explosions and much more.
It is believed that the temperature in outer space tends to absolute zero (the minimum limit that a physical body can have in the Universe). Absolute zero temperature is the origin of the Kelvin scale, or minus 273.15 degrees Celsius.
Planets and their satellites, asteroids, meteorites and comets, cosmic dust and much more play an important role in shaping the temperature of space. Because of this, the temperature may fluctuate. In addition, vacuum is an excellent heat insulator, something like a huge thermos. And due to the fact that there is no atmosphere in space, objects in it heat up very quickly.
For example, the temperature of a body placed in space near the Earth and exposed to the rays of the Sun can rise to 473 degrees Kelvin, or almost 200 Celsius. That is, space can be both hot and cold, depending on what point you measure it at.
The moon moves away from our planet by about four centimeters every year
Space is not black
Although we all see a black night sky, and the blue color during the day is due to the atmosphere of our planet. It would seem that everything is simple: space is black because it is dark there. But what about the stars? After all, in fact, there are so many of them that the cosmos must be permeated with their light.
From Earth, we don't see stars everywhere because the light from many of them simply can't reach us. In addition, our solar system is located in a relatively quiet, rather dull and dark part of the galaxy. And the stars here are scattered very far from each other. The closest to our planet, Proxima Centauri, is located 4.22 light years from Earth. This is 270 thousand times further than the Sun.
In fact, if we consider space in the entire range of electromagnetic radiation, it brightly emits mainly radio waves from various astronomical objects. If our eyes could see them, we would live in a much brighter Universe. But now it seems to us that we live in complete darkness.
The Sun makes up 99.86 percent of the total mass of the Solar System
The largest star in the Universe
Of course, we are talking about the largest star known to us. Scientists estimate that the Universe contains more than 100 billion galaxies, each of which, in turn, contains from several million to hundreds of billions of stars. It is not difficult to guess that there may be such giants in them that we do not even suspect.
It turned out that the question of which star is the largest is ambiguous even for scientists themselves. Therefore, we will talk about three currently known giants. For quite a long time, VY was considered the largest star in the constellation Canis Major. Its radius is from 1300 to 1540 solar radii, and its diameter is about two billion kilometers. For comparison, the diameter of the Sun is 1.392 million kilometers. If we imagine our star as a one-centimeter ball, then the diameter of VY will be 21 meters.
The most massive star known is R136a1 in the Large Magellanic Cloud. It's hard to imagine, but the star weighs as much as 256 Suns. She is the brightest of all. This blue hypergiant shines ten million times brighter than our star. But in terms of size, the R136a1 is far from the largest. Despite its impressive brightness, it cannot be seen from Earth with the naked eye because it is located 165 thousand light years away.
Currently, the leader of the list of enormousness is the red hypergiant NML Cygnus. Scientists estimate the radius of this star to be 1650 radii of our star. To better imagine this supergiant, let's place the star at the center of our solar system instead of the Sun. It will occupy all of outer space up to the orbit of Jupiter.
In Earth's orbit there is a "dump" of waste from the development of astronautics. More than 370 thousand objects weighing from a few grams to 15 tons revolve around our planet.
Most of the planets in the solar system can be seen without a telescope
At suitable times, we can observe Mercury, Venus, Mars, Jupiter and Saturn from Earth. These planets were discovered back in ancient times.
Distant Uranus is also sometimes visible to the naked eye from Earth. But before its discovery, the planet was simply mistaken for a dim star. Because of their great distance, scientists learned about the existence of Uranus, Neptune and Pluto only with the help of a telescope. From Earth with the naked eye we will not be able to see only Neptune and Pluto, which, however, is no longer considered a planet.
Life not only on Earth?
There is another celestial body in the Solar System, on which a number of scientists still admit the presence of life. Even in the most primitive forms. This is Saturn's moon Titan.
Titan has a large number of lakes. True, you won’t be able to swim in them: unlike those on earth, they are filled with liquid methane and ethane.
Nevertheless, Titan is considered similar to Earth at the very beginning of its development. Because of this, some scientists believe that the simplest forms of life may exist in the underground reservoirs of Saturn's moon.
- Space debris– failed spacecraft, spent rocket and other devices and their debris that are in near-Earth orbits.
- Weightlessness is a state in which the gravitational forces acting on a body do not cause mutual pressure of its parts on each other.
- Solar wind is a stream of electrons and protons at high speeds constantly emitted by the Sun.
- A black hole is a region of space with such a powerful gravitational field that neither matter nor radiation can leave it. They appear at the final stage of the evolution of some very large stars.
- Exoplanets are planets located outside the solar system.
- A comet is a small object revolving around the Sun in a highly elongated elliptical orbit. When approaching the Sun, it forms a cloud or tail of dust and gas.
- A galaxy is a gravitationally bound system of stars and star clusters, interstellar gas, dust and dark matter.
- A star is a massive ball of gas that emits light and is held together by its own gravity and internal pressure.
- A rocket is an aircraft that moves due to the action of jet thrust arising from the rejection of part of the vehicle’s own mass. Flight does not require air or gas.
- A cosmodrome is an area with a complex of special structures and technical systems intended for launching spacecraft.
- Gravity is the attraction of material objects to each other.
- A planet is a celestial body revolving in orbit around a star. Massive enough to become rounded by its own gravity, but not massive enough to initiate a thermonuclear reaction.
- An asteroid is a relatively small celestial body in the Solar System moving in orbit around the Sun. It is significantly inferior in mass and size to planets, has an irregular shape, and has no atmosphere.
- A light year is the distance that light travels in a vacuum in one year.
- Vacuum is a space free of matter.
- A nebula is a cloud of interstellar gas or dust. It stands out against the general background of the sky due to its emission or absorption of radiation.
Despite the gigantic distance to (amounting to 2.54 million light years), it still has a visible magnitude of 3.44 and a linear size of 3.167×1° in the starry sky, which allows it to be observed with the naked eye in the sky as a slightly oblong speck. This is achieved by the fact that Andromeda contains about a trillion stars (thus exceeding its size by at least 2.5 times and being the largest galaxy in the Local Group). However, despite the huge number of stars in it, it is still inferior in brightness to about 150 stars in both hemispheres of the starry sky.
Observation
The Andromeda Galaxy is located in the constellation of the same name, but its search is best to start from the one that is easier to find and move through the constellations or.
Pegasus constellation : in this case, in the continuation of the constellation Pegasus, we will need to find Alferats (the brightest star of the Andromeda constellation) from which we need to move to Mirakh, from which we turn 90° and look for two other bright stars of this constellation. A little further on, the second of these stars will be Andromeda.
Constellation Cassiopeia : another way to find Andromeda also starts from the North Star, but in this case we should find the constellation Cassiopeia, which looks like the letter M or W in the sky, depending on its current position. On the continuation of the Polaris-Shedar line (the 2nd star on the right of this constellation), a little further than half the distance between them will be the Andromeda Galaxy.
Observation history
Since this galaxy is visible to the naked eye, the first mention of it dates back to 946 AD. But before the advent of modern multi-meter telescopes, it was impossible to distinguish individual stars in it, so the true nature of this object was hidden from observers under the guise of a small nebula in our galaxy. The first signs of its extragalactic origin were obtained through spectral analysis made in 1912 (it turned out that it was moving towards us at a speed of 300 km/s) and a supernova explosion recorded in 1917 (which gave the first approximate value of the distance to it - 500 thousand light years). However, only Edwin Hubble managed to put a final point in the dispute between scientists.
Which sounds like this: Here's the question. Everyone has probably seen images of our galaxy. I watched a lot of documentaries on space topics, but nowhere does it explain where these images come from. How did you find out that the galaxy has a spiral shape, and not a disk shape, for example? Are we in the plane of the spiral?
Let's figure out what and how. It is quite difficult to understand the connection between the Milky Way, spread across the night sky, and the concept of “our home”. In an age burning with electric lights, the Milky Way is practically inaccessible to city dwellers. You can only see it away from city lights, and at certain times of the year. It is especially beautiful in our latitudes in August, when it passes through the zenith region and, like a giant celestial arch, rises above the sleeping Earth.
On the banks of the dairy
The mystery of the Milky Way has haunted people for many centuries. In the myths and legends of many peoples of the world, it was called the Road of the Gods, the mysterious Star Bridge leading to heaven, the magical Heavenly River filled with divine milk. It is believed that this was what was meant when ancient Russian fairy tales spoke of a milk river with jelly banks. And the inhabitants of ancient Hellas called him Galaxias kuklos, which means “milk circle”. This is where the word Galaxy, which is familiar today, comes from. But in any case, the Milky Way, like everything that can be seen in the sky, was considered sacred. They worshiped him and built temples in his honor. By the way, few people know that the tree that we decorate for the New Year is nothing more than an echo of those ancient cults when the Milky Way seemed to our ancestors as the axis of the Universe, the World Tree, on the invisible branches of which the fruits of the stars ripen. It is on New Year's Day that the Milky Way “stands” vertically, like a trunk rising from the horizon. That is why, at the beginning of a new annual cycle, in imitation of the tree of heaven, which always bears fruit, the tree of the earth was decorated. They believed that this gave hope for a future harvest and the favor of the gods. What is the Milky Way, why does it glow, and glow non-uniformly, sometimes flowing along a wide channel, sometimes suddenly splitting into two arms? The scientific history of this issue goes back at least 2,000 years.
Thus, Plato called the Milky Way a seam connecting the celestial hemispheres, Democritus and Anaxagoras said that it was illuminated by the stars, and Aristotle explained it by luminous pairs located under the Moon. There was another suggestion, expressed by the Roman poet Marcus Manilius: perhaps the Milky Way is the merging radiance of small stars. How close he was to the truth. But it was impossible to confirm it by observing the stars with the naked eye. The mystery of the Milky Way was revealed only in 1610, when the famous Galileo Galilei pointed his first telescope at it, through which he saw “an immense collection of stars”, for the naked eye merging into a solid white stripe. Galileo was amazed; he realized that the heterogeneity, even the ragged structure of the white stripe was explained by the fact that it consisted of many star clusters and dark clouds. Their combination creates a unique image of the Milky Way. However, why dim stars are concentrated into a narrow strip was impossible to understand at that time. In the movement of stars in the Galaxy, scientists distinguish entire stellar streams. The stars in them are connected to each other. Stellar streams should not be confused with constellations, the outlines of which can often be a simple trick of nature and only appear as a coherent group when observed from the solar system. In fact, it happens that in the same constellation there are stars belonging to different streams. For example, in the well-known Ursa Major bucket (the most prominent figure of this constellation), only five stars from the middle of the bucket belong to one stream, while the first and last in the characteristic figure are from another stream. And at the same time, in the same stream with the five middle stars is the famous Sirius - the brightest star in our sky, belonging to a completely different constellation.
Universe Designer
Another explorer of the Milky Way was William Herschel in the 18th century. As a musician and composer, he was involved in the science of stars and the manufacture of telescopes. The last of them weighed a ton, had a mirror diameter of 147 centimeters and a pipe length of as much as 12 meters. However, Herschel made most of his discoveries, which became a natural reward for diligence, using a telescope half the size of this giant. One of the most important discoveries, as Herschel himself called it, was the Great Plan of the Universe. The method he used turned out to be a simple counting of the stars in the field of view of the telescope. And naturally, different numbers of stars were found in different parts of the sky. (There were more than a thousand areas of the sky where stars were counted.) Based on these observations, Herschel concluded that the Milky Way is shaped like a star island in the Universe, to which the Sun belongs. He even drew a schematic drawing from which it is clear that our star system has an irregular elongated shape and resembles a giant millstone. Well, since this millstone surrounds our world with a ring, then, consequently, the Sun is inside it and located somewhere near the central part.
This is exactly what Herschel painted, and this idea survived in the minds of scientists almost until the middle of the last century. Based on the conclusions of Herschel and his followers, it turned out that the Sun has a special central position in the Galaxy called the Milky Way. This structure was somewhat similar to the geocentric system of the world adopted before the era of Copernicus, with the only difference being that previously the Earth was considered the center of the Universe, and now the Sun. And yet, it remained unclear whether there were other stars outside the stellar island, otherwise known as our Galaxy?
The structure of our Galaxy (side view)
Herschel's telescopes made it possible to get closer to solving this mystery. The scientist discovered many faint, foggy luminous spots in the sky and examined the brightest of them. Seeing that some of the spots were breaking up into stars, Herschel made the bold conclusion that these were nothing more than other stellar islands similar to our Milky Way, only very distant. It was then that he proposed, in order to avoid confusion, to write the name of our World with a capital letter, and the rest - with a lowercase letter. The same thing happened with the word Galaxy. When we write it with a capital letter, we mean our Milky Way, when with a lowercase letter we mean all other galaxies. Today, astronomers use the term Milky Way to describe both the “milk river” visible in the night sky and our entire Galaxy, consisting of hundreds of billions of stars. Thus, this term is used in two senses: in one - when talking about the stars in the Earth's sky, in the other - when discussing the structure of the Universe. Scientists explain the presence of spiral branches in the Galaxy by giant waves of compression and rarefaction of interstellar gas traveling along the galactic disk. Due to the fact that the orbital speed of the Sun almost coincided with the speed of the compression waves, it has remained ahead of the wave front for several billion years. This circumstance was of great importance for the emergence of life on Earth. The spiral arms contain many stars of high luminosity and mass. And if the mass of the star is large, about ten times the mass of the Sun, an unenviable fate awaits it, ending in a grandiose cosmic catastrophe - an explosion called a supernova explosion.
In this case, the flare is so strong that this star shines like all the stars in the Galaxy combined. Astronomers often record such catastrophes in other galaxies, but in ours, this has not happened for the last few hundred years. When a supernova explodes, a powerful wave of hard radiation is generated, capable of destroying all life in its path. Perhaps it is precisely because of its unique position in the Galaxy that our civilization has managed to develop to such an extent that its representatives are trying to understand their star island. It turns out that possible brothers in mind can only be looked for in quiet galactic “nooks” like ours.
Spiral galaxy NGC 3982 is located 60 million light-years from the Milky Way, in the constellation Ursa Major. NGC 3982 consists of star clusters, gas and dust clouds and dark nebulae, which, in turn, are twisted into several arms. NGC 3982 can be observed from Earth even with a small telescope. However, upon closer examination galaxies Using the Hubble telescope, scientists discovered 13 variable stars and 26 Cepheid candidates with periods from 10 to 45 days. In addition, when observing the galaxy, a formation was discovered supernova, which received the name SN 1998aq.
Cepheids - beacons of the Universe
In understanding the structure of the “own” Galaxy, studies of the Andromeda nebula played a major role. Foggy spots in the sky have been known for a long time, but they were considered either shreds torn off from the Milky Way, or distant stars merging into a solid mass. But one of these spots, known as the Andromeda Nebula, was the brightest and attracted the most attention. It was compared to both a luminous cloud and a candle flame, and one astronomer even believed that in this place the crystal dome of heaven is thinner than in others, and the light of the Kingdom of God pours onto the Earth through it. The Andromeda nebula is truly a breathtaking sight. If our eyes were more sensitive to light, it would appear to us not as a small elongated foggy speck, about a quarter of the lunar disk (this is its central part), but as a formation seven times larger than the full Moon. But that's not all. Modern telescopes see the Andromeda nebula in such a way that up to 70 full moons fit into its area.
It was possible to understand the structure of the Andromeda nebula only in the 20s of the last century. This was done using a telescope with a mirror diameter of 2.5 m by American astrophysicist Edwin Hubble. He received photographs in which he showed off, now there was no doubt, a giant stellar island consisting of billions of stars was another galaxy. And the observation of individual stars in the Andromeda nebula made it possible to solve another problem - to calculate the distance to it. The fact is that in the Universe there are so-called Cepheids - variable stars that pulsate due to internal physical processes that change their brightness.
These changes occur with a certain period: the longer the period, the higher the luminosity of the Cepheid - the energy released by the star per unit time. And from it you can determine the distance to the star. For example, Cepheids identified in the Andromeda nebula made it possible to determine the distance to it. It turned out to be huge - 2 million light years. However, this is only one of the galaxies closest to us, of which, as it turns out, there are a great many in the Universe. The more powerful the telescopes became, the more clearly the variants of the structure of the galaxies observed by astronomers were outlined, which turned out to be very unusual. Among them there are so-called irregular ones, which do not have a symmetrical structure, some are elliptical, and some are spiral. These are the ones that seem the most interesting and mysterious. Imagine a brightly shining core from which gigantic luminous spiral branches emerge. There are galaxies in which the core is more clearly expressed, while in others the branches dominate. There are also galaxies where the branches come out not from the core, but from a special bridge - a bar. So what type is our Milky Way? After all, being inside the Galaxy, it is much more difficult to understand its structure than observing from the outside. Nature itself helped answer this question: the galaxies are “scattered” in relation to us in a variety of positions. We can see some from the edge, others “flat”, and others from different angles. For a long time it was believed that the closest galaxy to us is the Large Magellanic Cloud. Today we know that this is not so.
In 1994, cosmic distances were measured more accurately, and the dwarf galaxy in the constellation Sagittarius took precedence. However, more recently, this statement also had to be reconsidered. An even closer neighbor to our Galaxy has been discovered in the constellation Canis Major. From it to the center of the Milky Way is only 42 thousand light years. In total, 25 galaxies are known that make up the so-called Local System, that is, a community of galaxies directly connected to each other by gravitational forces. The diameter of the Local System of galaxies is approximately three million light years. In addition to our Milky Way and its satellites, the Local System also includes the Andromeda nebula, the giant galaxy closest to us with its satellites, as well as another spiral galaxy of the Triangulum constellation. She is turned “flat” towards us. The Andromeda nebula dominates the Local System, of course. It is one and a half times more massive than the Milky Way.
Beautiful spiral galaxy NGC 5584 in the constellation Virgo. This Hubble image shows some of the brightest stars in the galaxy, including variable stars called Cepheids, which periodically change their brightness. By studying Cepheids in different galaxies, astronomers are able to measure the expansion rate of the Universe. Photo: NASA, ESA.
Outskirts of the Star Province
If the Cepheids of the Andromeda nebula made it possible to understand that it is located far beyond the boundaries of our Galaxy, then the study of closer Cepheids made it possible to determine the position of the Sun inside the Galaxy. The pioneer here was the American astrophysicist Harlow Shapley. One of the objects of his interest was globular star clusters, so dense that their cores merge into a continuous glow. The region richest in globular clusters is located in the direction of the zodiacal constellation Sagittarius. They are also known in other galaxies, and these clusters are always concentrated near galactic nuclei. If we assume that the laws for the Universe are the same, we can conclude that our Galaxy should be structured in a similar way. Shapley found Cepheids in its globular clusters and measured the distance to them. It turned out that the Sun is not located in the center of the Milky Way, but on its outskirts, one might say, in a stellar province, at a distance of 25 thousand light years from the center. Thus, for the second time after Copernicus, the idea of our special privileged position in the Universe was debunked.
Where is the core?
Realizing that we are on the periphery of the Galaxy, scientists became interested in its center. It was expected that, like other stellar islands, it had a core from which spiral branches emerged. We see them exactly as a bright stripe of the Milky Way, but we see them from the inside, from the edge. These spiral branches, projected onto each other, do not allow us to understand how many there are and how they are arranged. Moreover, the cores of other galaxies shine brightly. But why is this radiance not visible in our Galaxy? Is it possible that it does not have a core? The solution came again through observations of others. Scientists have noticed that in spiral nebulae, the type of which our Galaxy was classified as, a dark layer can be clearly visible. This is nothing more than a collection of interstellar gas and dust. They made it possible to answer the question - why we do not see our own core: our Solar system is located precisely at such a point in the Galaxy that giant dark clouds block the core for an earthly observer. Now we can answer the question: why does the Milky Way bifurcate into two arms? As it turned out, its central part is obscured by powerful dust clouds. In reality, there are billions of stars behind the dust, including the center of our Galaxy. Research has also shown that if the dust cloud had not interfered with us, earthlings would have seen a grandiose spectacle: a giant shining ellipsoid of the core with countless stars would have occupied an area of more than a hundred moons in the sky.
Milky Way and Andromeda Nebula
Superobject Sagittarius A*
Telescopes operating in such ranges of the spectrum of electromagnetic radiation, to which the dust shield is not an obstacle, helped us to see the core of the Galaxy behind this dust cloud. But most of these radiations are delayed by the Earth’s atmosphere, therefore, at the present stage, cosmonautics and radio astronomy play a significant role in understanding the Galaxy. It turned out that the center of the Milky Way glows well in the radio range.
Scientists were especially interested in the so-called radio source Sagittarius A* - a certain object in the Galaxy that actively emits radio waves and X-rays. Today it can be considered virtually proven that a mysterious cosmic object is located in the constellation Sagittarius - a supermassive black hole. It is estimated that its mass could be equal to the mass of 3 million suns. This object of monstrous density has such a powerful gravitational field that even light cannot escape from it. Naturally, the black hole itself does not glow in any range, but the matter falling onto it emits X-rays and makes it possible to detect the location of the cosmic “monster”.
True, the radiation from Sagittarius A* is weaker than what is found in the nuclei of other galaxies. This may be due to the fact that the fall of matter is not intense, but when it occurs, a flash of X-ray radiation is recorded. Once, the brightness of the object Sagittarius A* increased literally in minutes - this is impossible for a large object. This means that this object is compact and can only be a black hole. By the way, to turn the Earth into a black hole, it needs to be compressed to the size of a matchbox. In general, many variable X-ray sources have been discovered in the center of our Galaxy, which may be smaller black holes grouped around the central supermassive one. It is they that are being monitored today by the American space X-ray observatory Chandra. Further confirmation of the presence of a supermassive black hole at the center of the core of our Galaxy was provided by a study of the motion of stars located in close proximity to the core. Thus, in the infrared range, astronomers were able to observe the movement of a star that slipped from the center of the nucleus at a distance that was insignificant on a galactic scale: only three times the radius of Pluto’s orbit. The orbital parameters of this star indicate that it is located near a compact invisible object with a monstrous gravitational field. This can only be a black hole, and a supermassive one at that. Her research continues.
Inside Orion's arm
There is surprisingly little information about the structure of the spiral arms of our Galaxy. From the appearance of the Milky Way, one can only judge that the Galaxy has the shape of a disk. And only with the help of observations of the radiation of interstellar hydrogen - the most common element in the Universe - was it possible to reconstruct to some extent the picture of the arms of the Milky Way. This became possible again thanks to an analogy: in other galaxies, hydrogen is concentrated precisely along the spiral arms. Star formation regions are also located there - many young stars, accumulations of dust and gas - gas-dust nebulae. In the 50s of the last century, scientists managed to create a picture of the distribution of clouds of ionized hydrogen located in the galactic neighborhood of the Sun. It turned out that there are at least three areas that could be identified with the spiral arms of the Milky Way. Scientists called one of them, the closest to us, the Orion-Cygnus arm. The one more distant from us and, accordingly, closer to the center of the Galaxy is called the Sagittarius-Carinae arm, and the peripheral one is called the Perseus arm. But the explored galactic neighborhood is limited: interstellar dust absorbs the light of distant stars and hydrogen, so it becomes impossible to understand the further pattern of spiral arms. However, where optical astronomy cannot help, radio telescopes come to the rescue. It is known that hydrogen atoms emit at a wavelength of 21 cm. It was this radiation that the Dutch astrophysicist Jan Oort began to catch. The picture he received in 1954 was impressive. The spiral arms of the Milky Way could now be traced over vast distances. There was no longer any doubt: the Milky Way is a spiral star system, similar to the Andromeda nebula. But we don’t yet have a detailed picture of the spiral pattern of the Milky Way: its branches merge with one another and it is very difficult to determine the distance to them.
Clickable 1800 px
Credits: Serge Brunier, Translation: Kolpakova A.V.
Explanation: Climb 5,000 meters above sea level near Cerro Chainantor in the northern Andes of Chile and you'll see a night sky like the one pictured. This photo was taken in that dry, high mountain area using a fisheye lens. The photograph captures the myriad stars and extensive dust clouds of our Galaxy. The direction towards the center of the Galaxy is near the zenith, i.e. in the center of the image, but the galactic center itself is hidden from us because it is located behind light-absorbing dust. Jupiter shines above the central bulge of the Milky Way. To the right of Jupiter the less bright yellow giant Antares is visible. A small faint spot can be seen at the right edge of the image - this is one of the many satellite galaxies of the Milky Way, the Small Magellanic Cloud.
Stellar results
Today it is known that our Galaxy is a gigantic star system, including hundreds of billions of stars. All the stars that we see above our heads on a clear night belong to our Galaxy. If we could move in space and look at the Milky Way from the side, a star city would appear to our eyes in the form of a huge flying saucer 100 thousand light years across. In its center we would see a noticeable thickening - a bar - with a diameter of 20 thousand light years, from which gigantic spiral branches extend into space. Despite the fact that the appearance of the Galaxy suggests a flat system, this is not entirely true.
Around it extends the so-called halo, a cloud of rarefied matter. Its radius reaches 150 thousand light years. Around the central bulge and core are many globular star clusters made up of old, cool, red stars. Harlow Shapley called them the “skeletal body” of our Galaxy. Cool stars make up the so-called spherical subsystem of the Milky Way, and its flat subsystem, otherwise known as the spiral arms, is made up of “stellar youth”. There are many bright, prominent stars of high luminosity here. Young stars in the galactic plane appear due to the presence of a huge amount of dust and gas there. It is known that stars are born due to the compression of matter in gas and dust clouds. Then, over millions of years, newborn stars “inflate” these clouds and become visible. The Earth and the Sun are not the geometric center of the World - they are located in one of the quiet corners of our Galaxy.
And, apparently, this special location is ideal for the emergence and development of life. For ten years now, scientists have been able to detect large planets - no smaller than Jupiter - around other stars. Today about one and a half hundred of them are known. This means that such planetary systems are widespread in the Galaxy. Armed with more powerful telescopes, it is possible to find such small planets as the Earth, and on them, perhaps, brothers in mind. All the stars in the Galaxy move in their orbits around its core. A star called the Sun also has its own orbit. To complete a full revolution, the Sun requires no less than 250 million years, which constitute a galactic year (the speed of the Sun is 220 km/s). The Earth has already flown around the center of the Galaxy 25-30 times. This means that she is exactly that many galactic years old. Tracing the Sun's path through the Milky Way is very difficult. But modern telescopes can detect this movement too. In particular, to determine how the appearance of the starry sky changes when the Sun moves relative to the nearest stars. The point towards which the solar system moves is called the apex and is located in the constellation Hercules, on the border with the constellation Lyra.
So, what can be a brief conclusion on the essence of the issue? Sometimes it is unsuccessfully said that the Milky Way is our Galaxy. The Milky Way is a bright ring visible to us in the sky, and our Galaxy is a spatial star system. We see most of its stars in the band of the Milky Way, but it is not limited to them. The Galaxy includes stars of all constellations. We are so small compared to the Milky Way. that we can shoot in all directions. The Sun is not at the center of the galactic disk, but at a distance of two-thirds from its center to the edge. And most importantly, do not forget that most of these beautiful pictures are just a collage, graphics, model and drawings. Or it’s simply a snapshot of some other spiral galaxy. Well, here are real photographs, albeit heavily processed.
How to photograph the Milky Way? This is what he writes renat:
Many people think that in order to take beautiful photographs of space, you simply need to have super-expensive equipment, and even study for five years at a specialized university. However, in fact, photographing the starry sky is not at all difficult and is quite accessible to everyone.
To demonstrate the validity of this statement in practice, I plan to write a short series of notes, each of which will contain one or more photographs, as well as a short story about how they were obtained. I will try to present it as clearly as possible, and the photographs will be selected in such a way that their creation does not require particularly complex equipment. So…
One of the easiest celestial objects to photograph is the Milky Way. However, many have never even seen him! Paradox? Not at all! The thing is that the visibility of celestial objects, except for the Moon and planets, dramatically depends on the degree of illumination of the sky. Most people live in cities where the night light is so bright that only a few of the brightest stars can be seen in the sky. And therefore, for many, many people, the sight of the real, black Night Sky is simply mesmerizing...
So, to see – and photograph – the Milky Way, you need to get out of the city, and preferably further away. Here you can enjoy the starry sky in all its glory! It will be absolutely wonderful to make observations somewhere in the south, at least at the latitude of the Crimea or the Caucasus. Israel, Egypt, Morocco, and the Canary Islands are even better suited. The fact is that in Central Russia the most beautiful, bright areas of the Milky Way are simply not visible, hidden by the horizon. That is why the southern sky is so attractive.
But we, however, are not only going to admire - no, we also need to adequately capture what we see. What technology do we need for this? It all depends on what we want to get. So, the above frame was taken using a Canon 350D 18-55mm/3.5-5.6@18mm/3.5 camera. That is, the widest possible angle was used for shooting. The point is, firstly, to include as large a fragment of the Milky Way as possible in the frame, as well as sufficient areas of the sky and surrounding landscape not occupied by it. Our galaxy is best seen against the background of other objects, and that is why it is highly desirable to capture them. If you use a normal rather than a wide-angle lens, the Milky Road will somewhat blend into the background.
In addition, we should not forget that the celestial sphere tends to rotate - and the shorter the lens we use, the longer the shutter speed we can set without blur being noticeable in the final frame. And for such a dim object as the one we chose, this is very, very important. In my case, the shutter was open for thirty seconds. Of course, there is no question of holding the camera motionless in your hands for half a minute. As you know, tremor is characteristic of humans, and therefore blurring during such exposures is inevitable. Unless, of course, you mount the camera on something stable - for example, a standard photographic tripod will do.
However, in order for the Milky Way to be studied in more detail, the shutter speed must be increased even more - but this is no longer so easy if we do not want to get blurry. There is a way out - the camera must rotate after the celestial object being photographed. Of course, a regular tripod will no longer work for us; we need a special mount.
When shooting this shot, we used just such a thing, alt-azimuth. A platform with a camera attached to it is capable of automatically moving left and right and up and down, following the rotation of the celestial sphere. However, the latter, as is known, rotates in an arc - and therefore, when using a mount of this type, we will get field rotation. And in fact, take a closer look: at the edges of the frame the stars are no longer quite dots. Therefore, I had to limit the shutter speed to one minute - but the detail still increased quite significantly when compared with a thirty-second exposure.
To neutralize the effect of field rotation, you can use an equatorial mount. She will rotate the camera around the Celestial Pole, and the specified problem will not arise.
Here are the professional staff:
Milky Way over Monument Valley (USA). Below we see huge rocks - outcrops. Outcrops are rocks of hard rock left after water has washed away all the soft material surrounding them. The two mountains - the closest mountain on the left and the mountain to the right of it - are called Mittens. The Milky Way stretches out like a giant arch above. Above the left Mitten is the constellation Cygnus, along with the reddish North America Nebula. Next, the Milky Way follows through the constellations Chanterelle, Sagittarius, Serpens, Eagle and Scutum until it enters the constellations Sagittarius and Scorpio. Here it becomes the brightest and most noticeable. This image became the winner of the Astronomical Picture of the Day competition on August 1, 2012. Photo: Wally Pacholka
sources
http://www.vokrugsveta.ru - Dmitry Gulyutin
http://renat.livejournal.com/15030.html
http://www.astrogalaxy.ru/151.html
Let's remember , and also the answer to the question The original article is on the website InfoGlaz.rf Link to the article from which this copy was made -Doctor of Pedagogical Sciences E. LEVITAN, full member of the Russian Academy of Natural Sciences
Science and life // Illustrations
One of the best modern astrophysical observatories is the European Southern Observatory (Chile). In the photo: a unique instrument of this observatory - the New Technologies Telescope (NTT).
Photo of the reverse side of the 3.6-meter main mirror of the New Technologies Telescope.
Spiral galaxy NGC 1232 in the constellation Eridanus (distance to it is about 100 million light years). Size - 200 light years.
Before you is a huge gas disk, perhaps heated to hundreds of millions of degrees Kelvin (its diameter is about 300 light years).
It would seem a strange question. Of course, we see the Milky Way and other stars of the Universe that are closer to us. But the question posed in the title of the article is actually not so simple, and therefore we will try to figure it out.
The bright Sun during the day, the Moon and the scattering of stars in the night sky have always attracted human attention. Judging by the rock paintings, in which the most ancient painters depicted the figures of the most noticeable constellations, even then people, at least the most inquisitive of them, peered into the mysterious beauty of the starry sky. And of course they showed interest in the rising and setting of the Sun, in the mysterious changes in the appearance of the Moon... This is probably how “primitive contemplative” astronomy was born. This happened many thousands of years earlier than writing arose, the monuments of which have already become for us documents testifying to the origin and development of astronomy.
At first, the heavenly bodies, perhaps, were only a subject of curiosity, then - deification, and, finally, began to help people, acting as a compass, calendar, clock. A serious reason for philosophizing about the possible structure of the Universe could be the discovery of “wandering stars” (planets). Attempts to unravel the incomprehensible loops that describe the planets against the background of supposedly fixed stars led to the construction of the first astronomical pictures or models of the world. The geocentric system of the world of Claudius Ptolemy (2nd century AD) is rightfully considered their apotheosis. Ancient astronomers tried (mostly unsuccessfully) to determine (but not yet prove!) what place the Earth occupied in relation to the seven then known planets (these were considered the Sun, Moon, Mercury, Venus, Mars, Jupiter and Saturn). And only Nicolaus Copernicus (1473-1543) finally succeeded.
Ptolemy is called the creator of the geocentric, and Copernicus - the heliocentric system of the world. But fundamentally, these systems differed only in the ideas they contained about the location of the Sun and Earth in relation to the true planets (Mercury, Venus, Mars, Jupiter, Saturn) and to the Moon.
Copernicus essentially discovered the Earth as a planet, the Moon took its rightful place as a satellite of the Earth, and the Sun turned out to be the center of revolution of all planets. The sun and six planets moving around it (including the Earth) - this was the solar system as it was imagined in the 16th century.
The system, as we now know, is far from complete. Indeed, in addition to the six planets known to Copernicus, it also includes Uranus, Neptune, and Pluto. The latter was discovered in 1930 and turned out to be not only the most distant, but also the smallest planet. In addition, the Solar System includes about a hundred satellites of planets, two asteroid belts (one between the orbits of Mars and Jupiter, the other, recently discovered, the Kuiper Belt, in the region of the orbits of Neptune and Pluto) and many comets with different orbital periods. The hypothetical “Cloud of comets” (something like their sphere of habitation) is located, according to various estimates, at a distance of about 100-150 thousand astronomical units from the Sun. The boundaries of the solar system have accordingly expanded many times over.
At the beginning of 2002, American scientists “talked” with their automatic interplanetary station Pioneer 10, which was launched 30 years ago and managed to fly away from the Sun to a distance of 12 billion kilometers. The response to the radio signal sent from Earth arrived in 22 hours 06 minutes (at a speed of radio waves of about 300,000 km/sec). Taking into account what has been said, Pioneer 10 will have to fly for a long time to the “borders” of the Solar system (of course, quite conditional!). And then he will fly to the closest star on his path, Aldebaran (the brightest star in the constellation Taurus). "Pioneer 10" may arrive there and deliver the messages of earthlings embedded in it only in 2 million years...
We are separated from Aldebaran by at least 70 light years. And the distance to the closest star to us (in the a Centauri system) is only 4.75 light years. Today, even schoolchildren should know what a “light year”, “parsec” or “megaparsec” is. These are already questions and terms of stellar astronomy, which simply did not exist not only in the time of Copernicus, but also much later.
It was assumed that the stars were distant bodies, but their nature was unknown. True, Giordano Bruno, developing the ideas of Copernicus, brilliantly suggested that the stars are distant suns, and, perhaps, with their own planetary systems. The correctness of the first part of this hypothesis became completely obvious only in the 19th century. And the first dozens of planets around other stars were discovered only in the very last years of the recently ended 20th century. Before the birth of astrophysics and before the application of spectral analysis in astronomy, it was simply impossible to get closer to the scientific solution to the nature of stars. So it turned out that the stars played almost no role in the previous systems of the world. The starry sky was a kind of stage on which the planets “performed,” and they did not think much about the nature of the stars themselves (sometimes they were referred to as ... “silver nails” stuck in the firmament of heaven). The “sphere of stars” was a kind of boundary of the Universe in both the geocentric and heliocentric systems of the world. The entire Universe, naturally, was considered visible, and what was beyond it was the “kingdom of heaven”...
Today we know that only a tiny fraction of stars are visible to the naked eye. The whitish stripe stretching across the entire sky (Milky Way) turned out, as some ancient Greek philosophers guessed, to be a multitude of stars. Galileo (at the beginning of the 17th century) discerned the brightest of them even with the help of his very imperfect telescope. As the size of telescopes increased and they improved, astronomers were able to gradually penetrate into the depths of the Universe, as if probing it. But it did not immediately become clear that the stars observed in different directions of the sky had some relation to the stars of the Milky Way. One of the first who managed to prove this was the English astronomer and optician W. Herschel. Therefore, the discovery of our Galaxy (it is sometimes called the Milky Way) is associated with his name. However, it is apparently not possible for a mere mortal to see our entire Galaxy. Of course, it is enough to look into an astronomy textbook to find clear diagrams there: a view of the Galaxy “from above” (with a distinct spiral structure, with arms consisting of stars and gas-dust matter) and a view “from the side” (in this perspective, our stellar island resembles biconvex lens, if you do not go into some details of the structure of the central part of this lens). Schemes, diagrams... Where is at least one photograph of our Galaxy?
Gagarin was the first earthling to see our planet from outer space. Now, probably, everyone has seen photographs of the Earth from space, transmitted from artificial Earth satellites, from automatic interplanetary stations. Forty-one years have passed since Gagarin's flight, and 45 years have passed since the launch of the first satellite - the beginning of the space age. But to this day, no one knows whether a person will ever be able to see the Galaxy by going beyond its borders... For us, this is a question from the realm of science fiction. So let's get back to reality. But just at the same time, please think about the fact that just a hundred years ago, current reality could seem like the most incredible fantasy.
So, the Solar System and our Galaxy have been discovered, in which the Sun is one of trillions of stars (about 6,000 stars are visible to the naked eye in the entire celestial sphere), and the Milky Way is a projection of part of the Galaxy onto the celestial sphere. But just as in the 16th century earthlings realized that our Sun is the most ordinary star, we now know that our Galaxy is one of many other galaxies now discovered. Among them, as in the world of stars, there are giants and dwarfs, “ordinary” and “extraordinary” galaxies, relatively quiet and extremely active. They are located at enormous distances from us. The light from the closest of them rushes towards us for almost two million three hundred thousand years. But we can see this galaxy even with the naked eye; it is in the constellation Andromeda. This is a very large spiral galaxy, similar to ours, and therefore its photographs to some extent “compensate” for the lack of photographs of our Galaxy.
Almost all discovered galaxies can only be seen in photographs taken using modern giant ground-based telescopes or space telescopes. The use of radio telescopes and radio interferometers has helped to significantly supplement optical data. Radio astronomy and extra-atmospheric X-ray astronomy have lifted the curtain on the mystery of the processes occurring in the nuclei of galaxies and in quasars (the most distant currently known objects in our Universe, almost indistinguishable from stars in photographs taken using optical telescopes).
In an extremely huge and practically hidden from view megaworld (or in the Metagalaxy), it was possible to discover its important patterns and properties: expansion, large-scale structure. All this is somewhat reminiscent of another, already discovered and largely unraveled microworld. There they study the very close to us, but also invisible building blocks of the universe (atoms, hadrons, protons, neutrons, mesons, quarks). Having learned the structure of atoms and the patterns of interaction of their electron shells, scientists literally “revitalized” D. I. Mendeleev’s Periodic Table of Elements.
The most important thing is that man turned out to be able to discover and cognize worlds of various scales that were not directly perceived by him (megaworld and microworld).
In this context, astrophysics and cosmology seem to be not original. But here we come to the most interesting part.
The “curtain” of the long-known constellations opened, taking with it the last attempts of our “centrism”: geocentrism, heliocentrism, galaxycentrism. We ourselves, like our Earth, like the Solar System, like the Galaxy, are just “particles” of the structure of the Universe, unimaginable in ordinary scale and in complexity, called the “Metagalaxy”. It includes many galaxy systems of varying complexity (from “binaries” to clusters and superclusters). Agree that at the same time, awareness of the scale of one’s own insignificant size in the vast mega-world does not humiliate a person, but, on the contrary, elevates the power of his Mind, capable of discovering all this and understanding what was discovered earlier.
It would seem that it is time to calm down, since the modern picture of the structure and evolution of the Metagalaxy has been created in general terms. However, firstly, it conceals a lot of fundamentally new things, previously unknown to us, and secondly, it is possible that, in addition to our Metagalaxy, there are other mini-universes that form the still hypothetical Big Universe...
Maybe we should stop there for now. Because now, as they say, we would like to figure out our Universe. The fact is that at the end of the twentieth century it presented astronomy with a big surprise.
Those who are interested in the history of physics know that at the beginning of the twentieth century, some great physicists thought that their titanic work was completed, because everything important in this science had already been discovered and explored. True, a couple of strange “clouds” remained on the horizon, but few imagined that they would soon “turn into” the theory of relativity and quantum mechanics... Is something like this really awaiting astronomy?
It is quite likely, because our Universe, observed with the help of all the power of modern astronomical instruments and seemingly already quite thoroughly studied, may turn out to be just the tip of the universal iceberg. Where is the rest of it? How could such a daring assumption arise about the existence of something huge, material and completely hitherto unknown?
Let us turn again to the history of astronomy. One of her triumphant pages was the discovery of the planet Neptune "at the tip of a pen." The gravitational effect of some mass on the movement of Uranus prompted scientists to think about the existence of a still unknown planet, allowed talented mathematicians to determine its location in the solar system, and then tell astronomers exactly where to look for it on the celestial sphere. And in the future, gravity provided similar services to astronomers: it helped to discover various “outlandish” objects - white dwarfs, black holes. So now, the study of the movement of stars in galaxies and galaxies in their clusters has led scientists to the conclusion about the existence of a mysterious invisible ("dark") matter (or perhaps some form of matter unknown to us), and the reserves of this "matter" should be colossal.
According to the most daring estimates, everything that we observe and take into account in the Universe (stars, gas-dust complexes, galaxies, etc.) is only 5 percent of the mass that “should have been” according to calculations based on laws of gravity. This 5 percent includes the entire megaworld we know, from dust grains and cosmic hydrogen atoms to superclusters of galaxies. Some astrophysicists even include all-pervasive neutrinos here, believing that, despite their small rest mass, neutrinos with their countless numbers make a certain contribution to the same 5 percent.
But perhaps the “invisible matter” (or at least part of it, unevenly distributed in space) is the mass of extinct stars or galaxies, or such invisible cosmic objects as black holes? To some extent, such an assumption is not without meaning, although the missing 95 percent (or, according to other estimates, 60-70 percent) will not be made up. Astrophysicists and cosmologists are forced to consider various other, mostly hypothetical, possibilities. The most fundamental ideas boil down to the fact that a significant part of the “hidden mass” is “dark matter”, consisting of elementary particles unknown to us.
Further research in the field of physics will show which elementary particles, other than those that consist of quarks (baryons, mesons, etc.) or are structureless (for example, muons), can exist in nature. It will probably be easier to solve this mystery if we combine the forces of physicists, astronomers, astrophysicists, and cosmologists. Considerable hopes are placed on data that can be obtained in the coming years in the event of successful launches of specialized spacecraft. For example, it is planned to launch a space telescope (diameter 8.4 meters). It will be able to register a huge number of galaxies (up to 28th magnitude; recall that luminaries up to 6th magnitude are visible to the naked eye), and this will make it possible to construct a map of the distribution of “hidden mass” across the entire sky. Certain information can also be extracted from ground-based observations, since the “hidden matter,” having high gravity, should bend the rays of light coming to us from distant galaxies and quasars. By processing images of such light sources on computers, it is possible to register and estimate the invisible gravitating mass. Similar reviews of individual areas of the sky have already been made. (See the article by Academician N. Kardashev “Cosmology and SETI problems”, recently published in the popular science magazine of the Presidium of the Russian Academy of Sciences “Earth and the Universe”, 2002, No. 4.)
In conclusion, let us return to the question formulated in the title of this article. It seems that after all that has been said, it is unlikely that one can confidently give a positive answer to it... The oldest of the most ancient sciences, astronomy is just beginning.
