November 30, 2011 14:12
In our Galaxy, and in others, too, the stars are sometimes collected in the form of giant stellar swarms with hundreds of thousands of stars. This globular clusters, which move in elongated orbits, sometimes moving away from the center of the enormous distances. For this reason, most of my life, they are far from the galactic center. That brought together a bunch of stars in a small volume of space?
A team of researchers from the Lick Observatory in the U.S., studying one of the globular clusters located in a cluster of Pegasus, were able to penetrate as close to the center, as no one before them. And what they "see"? The closer they came nearer to the core cluster, the greater the number of stars they could count. Supervisor Puradzhra Guhathakurta believes that monstrous concentration of stars is because they are under the influence of supermassive object — a black hole, which itself is not visible.
In space, as on Earth — a strong win the weak?
And another fact is associated with the more massive the inhabitants of the universe — galaxies, which has hundreds of families — another billion stars. By studying 27 such semeek located from our neighborhood, scientists from the University of Michigan have found that every galaxy has a supermassive black hole. Moreover, the greater the mass of the galaxy, the greater the mass and the heavenly "monster." Very interesting and a model that explains how the central parts of galaxies appears that — something unusual. First black hole was small and. It was at the dawn of youth of any galaxy. But over time the growing appetite of the black hole and it absorbed so much gas and dust, which turned into a giant cluster that — a bit of heaven Gargantua. But still these monsters never been able to absorb all the matter of the "parent."
So, two seemingly terrible fact. In nature there are any — that objects called black holes that threaten the whole of the surrounding matter (gas, dust, stars and their planets, and, consequently, with creatures like us) of its voracity — a sort of celestial piranhas. What is a black hole? Do not consume us, if not tomorrow, then the day after, what — some space robber?
White and black in space
Color of the stars, like human skin is determined by the way they are born. The hotter the star, the more pigeons. In the colors of the stars represented all colors of the rainbow. But here's the "death" of stars brings the whole palette of colors to just two — white and black. This attempt will resemble an episode of Tales of Lewis Carroll's "Alice in Wonderland" in which Alice King asks:
— Look — ka on the road! Who do you see there?
— No one, — said Alice.
— I have a vision! — Said the King with envy. — See No one! Yes, even at this distance.
See black holes directly, or through a telescope to capture them in the photo is not possible for the reason that due to the strong gravitational nothing, not even light can not escape from the influence of black holes. True, this is only true for black holes, which do not rotate or spin very slowly.
How, then, can prove the existence of such objects in the universe? And how can imagine what is happening around or inside black holes? This can help the theoretical concepts being developed by scientists.
In addition, black holes do not exist in isolation from other bodies — they interact with dust, gas of interstellar space, galaxies, other stars, create a field in the surrounding area of unusual structure.
A bit of history
The history of black holes, which the American physicist Carl Thorne called "monsters of the Universe," a very long, because their prediction was made by the French mathematician and astronomer P.S.Laplasom back in 1795 in his book "The presentation of the world."
It created the first scientific cosmology of the planetary system, wrote that "shining star with a density equal to the density and diameter of the Earth is 250 times the diameter of the sun, does not give any light beam to reach us because of its gravity, so it is possible that the brightest celestial bodies in the universe are invisible for this reason. "
But whether such a body, the surface of which the escape velocity equals the speed of light? If so, then the gravitational field of the object nothing is able to leave, because one must have a velocity greater than the speed of light. Hence, the black hole does not let even light outside, and this means that an object no one can see the part! It turns out that in the space as it is formed hole, however, it is better not to fall!
Where did the strange term "black hole"? With his accent a person associates something very unusual and not very pleasant. The concept of the "black hole" appeared earlier arguments Laplace in 1757 in Calcutta. Ruler of Bengal, Nawab Siraj — Uddaulah by force would resolve a dispute with the British East India Company _. Small garrison could not withstand the 50000th Army Nawab, who lost thousands of lives — for the desperate resistance of the defenders of the fort. Survivors waited nightmare: a room of 5 to 6 meters Bengal government ordered cram 146 prisoners. 10 hours in the night from 20 to 21 June, the hottest time in India 123 prisoner died. This camera, which has two small windows, and called the "black hole of Calcutta." Objects in the Universe, present, in particular, one of the final stages of the life of stars, in 1968 the American astrophysicist John Wheeler and called "black hole." So what is too much in a celestial black hole?
The sun will be white
What makes the nature very close to the star itself, that is to become isolated object? The reason for the "disappearance" of the body to the outside world is the manifestation of the forces of gravity. This force, while inside the star are thermonuclear reactions, opposes the gas pressure and radiation. But the "fuel" to each star a limited amount and the time comes when it can no longer be the conversion of hydrogen into helium. And then reduce the gas pressure, which comes from — for the loss of energy star (because it continues to shine!) Unable to resist the force of gravity. Star is compressed! And the dimensions of an object moving from one state to another, reduced by hundreds and thousands of times. It all depends on what the initial mass of the star.
If the star's mass is less than 1.4 solar masses, the compression can stay out — for the fact that he resists the helium gas. The matter density is increased a million times! One cubic centimeter of this star is hundreds of tons of material. And at such densities matter behaves differently! Objects of this type have been called a white dwarf, and they are open for a long time: a satellite brightest star Sirius, the sky was even captured a short distance away. White dwarfs can shine, cooling down, many billions of years, is turning into cold bodies, which could be called black dwarfs.
Signals "green" little people
In the early 60's discovery astronomers were thrilled almost all — have been detected signals from space, which varied with strict regularity. Not only as what — that civilization gives to know about your existence. Their so called "green" man! But it was much easier — Macka unusual in space were small in diameter, about 15 kilometers stars that rotate rapidly. And the lighthouse has been associated with such an object? What is this light? Astronomers have to remember that in the early 1930s, our compatriot Landau predicted the existence of such objects — neutron stars. They — and should have the small size of the — for that, after the exhaustion of the star of "fuel" also began to shrink, but from — and its mass, this compression is stopped, when the star "at the moment" has become a white dwarf.
It lasted as long as the material of the star has become so dense that was nearly the density of atomic nuclei. For this reason, neutron stars have such small mass. Incidentally, — for the variability of beacons on these stars were named pulsars. Now they found a few hundred. Our sun will never be out of a pulsar — the smallness of its mass. Now, if it was two times on — solid, that is another matter! To show off in our sky very young star, but it is very hot.
The fate of very obese stars
And if the star is more massive, well, for example, more than 3 times the mass of the sun, then what? As an obese person is hard to keep himself on his feet, and the "fat" star only to a certain time can be in equilibrium. Ends when the internal heat of fusion in these stars, they are as white dwarfs, neutron stars, or both begin to shrink. But in this case, the compression will be a catastrophe — the star tends to occupy as little space in the space!
And what — what the compression stage star seems to disappear for an external observer. So there are black holes? If you could shrink to the size of the sun is 6 km, it would be a black hole.
How to see the invisible?
The hero of the famous novel by HG Wells' Man — Invisible "to live among the people, winding himself with gauze. However, then instead of a face you could see that — that strange, but, at least palpable! And black holes — that they "see", they should also be less than — that shrouded.
Solitary black holes are very difficult to detect, although they fall interstellar dust and gas atoms. But the energy they give off a little bit, so that they are too weak SOS calls. True, supermassive black holes and find, but these objects are not "relatives" of the stars. In the nuclei of galaxies, these objects can contain within itself as the substance from which it was possible to be "blind" hundreds of millions and billions of ordinary stars.
And where is the black hole that was once a star, may drop as much stuff as it will be able to "reveal" themselves? Of course, in that case, if there is another star. Space monster literally tore off part of a normal star of its substance, which, with increasing speed falls into the black hole, while warming up to temperatures of millions of degrees! This one — the gas and light! Thus in our galaxy discovered several black holes. How many of them can be? The answer to this question depends on what the fate of the star's dog. Now, almost no one knows what will happen in the future with black holes. Indeed, in principle, all the matter in the Universe must become white dwarfs, neutron stars and black holes. But we, you and I can see the sky in stars. So, with stellar 'corpses' what — what is it that allows them to turn into the usual stuff out of which there are new generations of stars. But what?
Was a star, and there is none
If we take a dozen stars and watch them, be sure what — some of them will turn into a black hole. Why, from a truly titanic work for decades in our galaxy is open only a few black holes? Maybe a picture of extinction star is transparent to the outside world? In fact of the matter is that before you go to the other world star undergoes tremendous catastrophe in their lives — it explodes, sometimes dropping most of its substance. But of the remaining stellar matter as it leaves behind a tombstone in the form of a black hole. But we know that outbreaks of stars are rare. And if you like to know which of them is in heaven will know about his death a grand firework display, it would be possible to observe the birth of the empty space and in space and time. Why a hole in space — it is clear, but why and time?
Recall that in moving time goes wrong, how on earth — it slows down. The closer the rate of contraction of the star to the speed of light, the slower time passes there. It seems to freeze, if the star crosses the gravitational radius. Time for a black hole ceases to flow — is not a hole in time! It turns out that we should not notice the transition stars in oblivion?
The light from the star will fade out — for that matter the black hole as it moves away from us with ever greater speed. That is what will lead to the fact that the contracting star disappear for this world long before it becomes a real black hole.
If we had the equipment that can monitor millions of stars simultaneously, the detection of stars, which parted with its friends to stop sending them the light, it would be long overdue. It may be that just the other day we hear about the opening of such a phenomenon. American scientists have put into operation a system by which they monitor the state of the sky. The purpose of this system is very practical — early detection of objects that may collide with Earth. But it is also suitable for opening the black holes!
"Black holes have no hair"
Described the properties of black holes by Wheeler, keeping in mind that the two black holes would be very difficult to distinguish from each other. Of the various properties of stellar objects will only mass, electric charge and spin. Imagine gatherings of black holes: it would be very boring, they would all be one "face." Imagine that two very different object, say, Quasimodo and Narcissus falling into a black hole. After some time, to distinguish them from each other for will be impossible.
Black holes can vary by the fact that one hole can rotate faster than the other, and for one moment, they can make hundreds of thousands of turns on its axis.
In addition, they can also be charged differently. The last property defines very exotic properties of black holes: they can glow! But this space is very weak flashlight.
Roller coaster near black holes
Thrill-seekers will be in the distant future to test your nerves, making travel in the vicinity of black holes. Sometimes in science fiction novels described a terrible situation capture spacecraft black hole: Once in the gravitational field of the monster ship uncontrollably falls in the "underworld". Chaos and confusion reigned then among zvezdoplavateley — they will inevitably have to be broken swings gravity in the gravitational field of a monstrous black hole. But this description is only partly true! Spaceship, coming up from far away to an orbit that has a radius twice the gravity, will turn around the black hole, and then fly off into space, of course, if the crew is not thirsty himself fall into the arms of a black hole! It will be captured, if close fit to the orbit of the measuring in two gravitational radius.
The above picture of the possible — due to the fact that the movement of the heavenly bodies around the black hole is an amazing way. Of Newtonian mechanics it is known that any body can move around each other, the more massive for a very limited number of curves — ellipse, parabola, or hyperbola. If the ellipse curve is closed, then the other two — open. Planets move around the sun in elliptical orbits — is known Kepler's first law, established back in 1609. It goes no body the solar system can not escape from the sun's gravitational. And any body flies past the Sun, for example, the comet can not be captured by them. This object needs to get rid of excess energy to go to the hyperbolic orbit into an elliptical. This means that the need to capture the presence of a third body. But the black hole circular motion for a long time can not be done, since every movement there is unstable. A small perturbation can "bring down" the body from orbit, so it will either fall into the black hole, or leave it outside.
Englishman Roger Penrose proposed a method of extracting energy from black holes. However, in this case the black hole must be rotating, but that the universe does not rotate. If the spacecraft gets into the sphere of influence of the black hole, the so-called ergosphere, which is a vortex gravitational field, including the engine there, the ship will depart from her, having more energy than had previously. The ship seemed to capture the energy of the "monster", thus reducing its mass. This property can be created unique objects, which were called gravity bombs. To create such a Unicum must surround an artificial black hole area and send in radiation. It can be enhanced by the black hole and go away, but it is hampered by the mirror surface of the sphere. A ray of light again return to the black hole, after interaction with which again will increase your energy, and so as long as the amount of energy will be so large that it will break the sphere. What is not a recipe for a fantastic thriller weapons against two civilizations! Make such a bomb is not possible, since we still do not know how to create a black hole and is unlikely to be able to do it soon. Fly is the nearest black hole, we can, too soon.
Journey through time?
Since black holes connected journey through time and space. According to ID Novikov collapsing matter without reaching zero volume can begin to expand, and the subject may appear again in the field of view of an external observer, but in a different universe. A Shklovsky believed that after passing through the gravitational radius of the observer will see in a short time the whole future of the universe! "Jumped" into the "new" universe traveler will see the entire past history of the new universe. True, recent studies show that if such transfers are possible, it is only in rare cases.
There just is no black holes!
Is there a limit to the mass of the black hole, that is, whether to meet space "monsters" to the masses, for example, thousands of times more solar. There are no restrictions for the mass of black holes there but as constraints on the minimum weight. Astronomers believe that they are a long time — long ago "discovered" black holes: sources of activity of some galaxies are supermassive black holes. Other explanations why quasars emit so enormous amount of energy from a small amount as the allocation of its surrounding matter in the fall, may even be as many as the stars in the supermassive black hole almost none. Even in the center of our own galaxy, scientists suspect the presence of a huge black hole.
Supermassive black holes are found in dozens, and where they just do not. Near the center of the globular cluster M15 in our galaxy stars move with unusually high velocities. This shows the enormous mass of the compact object around which the stars and have to bear the horrific imagination speeds to avoid falling into a black hole.
And the activity of many galaxies can not be explained without allowing their central regions the presence of very massive black holes. Masses of some of them are measured in billions of solar masses.
There are no nearby black hole?
About black holes is interesting to know, but being close to these "monsters of the Universe," as they called K. Thorne, their well-known researcher, not always safe. And whether nearby solar system similar object? This would not have been unusual, since black holes in our galaxy much. But no evidence of their close presence there. After all, before the advent of the black hole phenomenon to happen supernova. On record such bursts stars were seen, but these disasters have occurred far away from the Earth. There is evidence that 65 million years before dinosaurs died out — for the fact that close to the Sun which broke out — that star. Lethal radiation destroyed much of what existed in the world at that time. But where is the black hole that was left of it? Does not she now upon us?
We finish our story about black holes episode from the same book about Alice, who asks Kota "disappear and not appear so suddenly," because otherwise it makes your head spin. And then the cat was gone, but very slowly, and is the last smile disappeared. "It has long hovered in the air, when everything else is gone.
— Y-yes! — Thought Alice. — I seen cats with no smiles, but the smile without a cat! This in my life I have never seen. "