Back in 1932, the young Soviet theoretical physicist Lev Davidovich Landau (1908-1968) concluded that superdense neutron stars exist in the Universe. Imagine that a star the size of our Sun would shrink to a size of several tens of kilometers, and its matter would turn into neutrons - this is a neutron star.
As theoretical calculations show, stars with a core mass more than 1.2 times solar mass, after the exhaustion of nuclear fuel, they explode and with great speed reset the failures of the outer shells. And the inner layers of the exploded star, which are no longer hindered by gas pressure, fall to the center under the influence of gravitational forces. In a few seconds, the volume of the star decreases by 1015 times! As a result of the monstrous gravitational compression, free electrons are pressed into the nuclei of atoms, as it were. They combine with protons and neutralize their charge to form neutrons. Deprived electric charge, neutrons under the load of the overlying layers begin to approach each other rapidly. But the pressure of the degenerate neutron gas stops further compression. A neutron star appears, almost entirely composed of neutrons. Its dimensions are about 20 km, and the density in the depths reaches 1 billion tons/cm3, that is, it is close to the density of the atomic nucleus.
So, a neutron star is like a giant nucleus of an atom, supersaturated with neutrons. Only unlike the atomic nucleus, neutrons are held not by intranuclear forces, but by gravitational forces. According to calculations, such a star cools rapidly, and within a few thousand years that have elapsed after its formation, the temperature of its surface should drop to 1 million K, which is also confirmed by measurements made in space. Of course, in itself this temperature is still very high (170 times higher than the temperature of the surface of the Sun), but since the neutron star is composed exclusively dense matter, then its melting temperature is much higher than 1 million K. As a result, the surface of neutron stars must be ... solid! Although such stars have a hot, but solid crust, the strength of which is many times greater than the strength of steel.
The force of gravity on the surface of a neutron star is so great that if a person still managed to reach the surface of an unusual star, he would be crushed by its monstrous attraction to the thickness of the trace that remains on an envelope from a postal item.
In the summer of 1967, a graduate student at the University of Cambridge (England), Jocelina Bell, received very strange radio signals. They came in short pulses exactly every 1.33730113 seconds. The exceptionally high accuracy of the radio pulses led me to think: are these signals being sent by representatives of civilization to the mind?
However, over the next few years, many similar objects with fast pulsating radio emission were found in the sky. They were called pulsars, that is, pulsating stars.
When radio telescopes were aimed at the Crab Nebula, a pulsar with a period of 0.033 seconds was also found at its center. With the development of extra-atmospheric observations, it was found that it also emits X-ray pulses, and X-ray radiation is the main one and is several times stronger than all other radiations.
Soon, researchers realized that the reason for the strict periodicity of pulsars is the rapid rotation of some special stars. But such short periods of pulsations, which range from 1.6 milliseconds to 5 seconds, can be explained by the rapid rotation of only very small and very dense stars (centrifugal forces will inevitably tear a large star apart!). And if so, then pulsars are nothing but neutron stars!
But why do neutron stars spin so fast? Recall: an exotic star is born as a result of a strong compression of a huge luminary. Therefore, in accordance with the principle of conservation of angular momentum, the speed of rotation of the star must increase sharply, and the rotation period must decrease. In addition, the neutron star is still strongly magnetized. The strength of the magnetic field on the surface is a trillion (1012) times greater than the strength of the Earth's magnetic field! A powerful magnetic field is also the result of a strong compression of the star - a decrease in its surface and a thickening of magnetic field lines. However, the true source of activity of pulsars (neutron stars) is not the magnetic field itself, ci is the rotational energy of the star. And losing energy to electromagnetic and corpuscular radiation, pulsars gradually slow down their rotation.
If radio pulsars are single neutron stars, then X-ray pulsars are components of binary systems. Since the gravitational force on the surface of a neutron star hurts billions of heaven than on the Sun, it "draws on itself" the gas of a neighboring (ordinary) star. Particles of gas are pushed at high speed onto a neutron star, heated up when they hit its surface, and emit X-rays. A neutron star can become a source of X-rays even if it "wanders" and a cloud of interstellar gas.
What is the mechanism of the pulsation of a neutron star? It should not be thought that the star is simply pulsating. The case is quite different. As already mentioned, a pulsar is a rapidly rotating neutron star. On its surface, apparently, there is an active region in the form of a "hot spot", which emits a narrow, strictly directed beam of radio waves. And at that moment, when that beam is directed towards the earthly observer, the latter will mark the radiation pulse. In other words, a neutron star is like a radio beacon, and the period of its pulsation is determined by the period of rotation of this "beacon". Based on such a model, one can understand why, in a number of cases, at the site of a supernova explosion, where the pulsar must certainly be, it was not detected. Only those pulsars are observed whose radiation is successfully oriented with respect to the Earth.
About the planets, about the structure of space, about the human body and deep space. Each fact is accompanied by a large and colorful illustration.
The mass of the Sun is 99.86% of the mass of the entire solar system, the remaining 0.14% are planets and asteroids.
Jupiter's magnetic field is so powerful that it enriches our planet's magnetic field with billions of watts every day.
The largest basin in the solar system, formed as a result of a collision with a space object, is located on Mercury. This is Caloris Basin, whose diameter is 1,550 km. The collision was so strong that the shock wave passed through the entire planet, drastically changing its appearance.
A solar substance the size of a pinhead, placed in the atmosphere of our planet, will begin to absorb oxygen at an incredible speed and in a split second will destroy all life within a radius of 160 kilometers.
1 plutonic year is 248 Earth years. This means that while Pluto makes only one complete revolution around the Sun, the Earth manages to make 248.
Things are even more interesting with Venus, 1 day on which lasts 243 Earth days, and the year is only 225.
The Martian volcano Olympus (Olympus Mons) is the largest in the solar system. Its length is more than 600 km, and its height is 27 km, while the height of the high point on our planet, the peak of Mount Everest, reaches only 8.5 km.
An explosion (flash) of a supernova is accompanied by the release of a gigantic amount of energy. In the first 10 seconds, a supernova that explodes produces more energy than the Sun in 10 billion years, and in a short period of time produces more energy than all objects in the galaxy combined (excluding other exploding supernovas). The brightness of such stars easily outshines the luminosity of the galaxies in which they flared up.
Tiny neutron stars, whose diameter does not exceed 10 km, weigh as much as the Sun (recall fact #1). The force of gravity on these astronomical objects is extremely high and if, hypothetically, an astronaut lands on it, then his body weight will increase by about one million tons.
On February 5, 1843, astronomers discovered a comet, which was given the name "Great" (aka the March comet, C / 1843 D1 and 1843 I). Flying near the Earth in March of the same year, she 'lined' the sky in two with her tail, the length of which reached 800 million kilometers. Earthlings watched the tail trailing the Great Comet for more than a month, until, on April 19, 1983, it completely disappeared from the sky.
The energy of the sun's rays that warms us now originated in the core of the Sun more than 30 million years ago - most of this time it took her to overcome the dense shell of the celestial body and only 8 minutes to reach the surface of our planet.
Majority heavy elements contained in your body (such as calcium, iron and carbon) are the by-products of the explosion of a group of supernovae that began the formation of the solar system.
Researchers from Harvard University found that 0.67% of all rocks on Earth are of Martian origin.
The density of 5.6846×1026 kg Saturn is so low that if we could put it in water, it would float on the very surface.
Jupiter's moon Io recorded ~400 active volcanoes. The rate of emissions of sulfur and sulfur dioxide during the eruption can exceed 1 km / s, and the height of the streams can reach 500 km.
Contrary to popular belief, the cosmos is not a complete vacuum, but it is close enough to it, because. There is at least 1 atom per 88 gallons (0.4 m3) of cosmic matter (and as is often taught in school, there are no atoms or molecules in a vacuum).
Venus is the only planet in the solar system that rotates counterclockwise. There are several theoretical justifications for this. Some astronomers believe that this is the fate of all planets with a dense atmosphere, which first slows down and then twists. heavenly body in the opposite direction from the initial circulation, while others suggest that the cause was the fall of a group of large asteroids onto the surface of Venus.
Since the beginning of 1957 (the year the first artificial satellite"Sputnik-1"), humanity managed to literally seed the orbit of our planet with a variety of satellites, but only one of them was lucky enough to repeat the "fate of the Titanic". In 1993, the satellite "Olympus" (Olympus), owned by the European Space Agency (European Space Agency), was destroyed in a collision with an asteroid.
The largest meteorite that has fallen to Earth is considered to be the 2.7 meter Hoba, discovered in Namibia. The meteorite weighs 60 tons and is 86% iron, making it the largest piece of naturally occurring iron on Earth.
Tiny Pluto is considered the most cold planet(planetoid) solar system. Its surface is covered with a thick crust of ice, and the temperature drops to -2000 Celsius. Ice on Pluto has a completely different structure than on Earth and is several times stronger than steel.
Official scientific theory says that a person can survive in open space without a space suit for 90 seconds, if you immediately exhale all the air from the lungs. If a small amount of gases remains in the lungs, they will begin to expand with the subsequent formation of air bubbles, which, if released into the blood, will lead to embolism and inevitable death. If the lungs are filled with gases, then they will simply burst. After 10-15 seconds of being in outer space, the water in the human body will turn into steam, and the moisture in the mouth and before the eyes will begin to boil. As a result of this, soft tissues and muscles will swell, which will lead to complete immobilization. This will be followed by loss of vision, glaciation of the nasal cavity and larynx, blue skin, which in addition will suffer from severe sunburn. The most interesting thing is that the next 90 seconds the brain will still live and the heart will beat. In theory, if during the first 90 seconds an unlucky cosmonaut, exhausted in outer space, is placed in a pressure chamber, he will get off with only superficial injuries and a slight fright.
The weight of our planet is a variable value. Scientists have found that every year the Earth recovers by ~40,160 tons and dumps ~96,600 tons, thus losing 56,440 tons.
Earth's gravity compresses the human spine, so when an astronaut goes into space, he grows about 5.08 cm. At the same time, his heart contracts, decreasing in volume, and begins to pump less blood. This is the body's response to an increase in blood volume that requires less pressure to circulate properly.
In space, tightly compressed metal parts spontaneously weld together. This occurs as a result of the absence of oxides on their surfaces, the enrichment of which occurs only in an oxygen-containing environment ( good example Earth's atmosphere can serve as such a medium). For this reason, NASA specialists ( National Administration US Aeronautics and Research outer space(Eng. National Aeronautics and Space Administration)) process all metal parts spacecraft oxidizing materials.
Between the planet and its satellite, the effect of tidal acceleration occurs, which is characterized by a slowdown in the rotation of the planet around its own axis and a change in the orbit of the satellite. Thus, every century the rotation of the Earth slows down by 0.002 seconds, as a result of which the duration of the day on the planet increases by ~15 microseconds per year, and the Moon annually moves away from us by 3.8 centimeters.
"Cosmic whirlpool" called a neutron star is the fastest spinning object in the universe, which makes up to 500 revolutions per second around its axis. In addition, these cosmic bodies are so dense that one tablespoon of their constituent matter will weigh ~10 billion tons.
The star Betelgeuse is located at a distance of 640 light years from Earth and is the closest supernova candidate to our planetary system. It is so large that if placed in the place of the Sun, it would fill the diameter of Saturn's orbit. This star has already gained enough mass for the explosion of 20 Suns and, according to some scientists, should explode in the next 2-3 thousand years. At the peak of its explosion, which will last at least two months, the luminosity of Betelgeuse will be 1,050 times greater than that of the sun, making it possible to observe its death from Earth even with the naked eye.
Our nearest galaxy, Andromeda, is 2.52 million years away. The Milky Way and Andromeda are moving towards each other at tremendous speeds (Andromeda's speed is 300 km / s, and milky way 552 km / s) and most likely will collide in 2.5-3 billion years.
In 2011, astronomers discovered a planet made up of 92% superdense crystalline carbon, diamond. The precious celestial body, which is 5 times larger than our planet and heavier than Jupiter, is located in the constellation Serpens, at a distance of 4,000 light years from Earth.
The main contender for the title of a habitable planet outside the solar system, "Super-Earth" GJ 667Cc, is located at a distance of only 22 light-years from Earth. However, the journey to it will take us 13,878,738,000 years.
In the orbit of our planet there is a dump of waste from the development of astronautics. More than 370,000 objects weighing from a few grams to 15 tons revolve around the Earth at a speed of 9,834 m / s, colliding with each other and scattering into thousands of smaller parts.
Every second, the Sun loses ~1 million tons of matter and becomes lighter by several billion grams. The reason for this is the stream of ionized particles flowing from its crown, which is called the "solar wind".
Over time, planetary systems become extremely unstable. This happens as a result of the weakening of the bonds between the planets and the stars around which they revolve. In such systems, the orbits of the planets are constantly shifting and may even intersect, which will sooner or later lead to a collision of the planets. But even if this does not happen, then in a few hundreds, thousands, millions or billions of years the planets will move away from their star to such a distance that its gravitational attraction simply cannot hold them, and they will go on a free flight through the galaxy.
Often referred to as "dead" neutron stars are amazing objects. Their study in recent decades has become one of the most exciting and discoverable areas of astrophysics. Interest in neutron stars is due not only to the mystery of their structure, but also to their colossal density, and the strongest magnetic and gravitational fields. Matter there is in a special state resembling a huge atomic nucleus, and these conditions cannot be reproduced in terrestrial laboratories.
Birth at the tip of a pen
The discovery in 1932 of a new elementary particle, the neutron, made astrophysicists think about what role it could play in the evolution of stars. Two years later, it was suggested that supernova explosions are associated with the transformation of ordinary stars into neutron stars. Then, calculations were made of the structure and parameters of the latter, and it became clear that if small stars (such as our Sun) turn into white dwarfs at the end of their evolution, then heavier ones become neutron ones. In August 1967, radio astronomers, while studying the scintillations of cosmic radio sources, discovered strange signals - very short, about 50 milliseconds long, radio emission pulses were recorded, repeating after a strictly defined time interval (of the order of one second). It was completely different from the usual chaotic picture of random irregular fluctuations in radio emission. After a thorough check of all the equipment, confidence came that the impulses were of extraterrestrial origin. It is difficult to surprise astronomers with objects emitting with variable intensity, but in this case the period was so short, and the signals were so regular, that scientists seriously suggested that they could be news from extraterrestrial civilizations.
That is why the first pulsar was named LGM-1 (from the English Little Green Men - “Little Green Men”), although attempts to find any meaning in the received pulses ended in vain. Soon, 3 more pulsating radio sources were discovered. Their period again turned out to be much less than the characteristic oscillation and rotation times of all known astronomical objects. Due to the impulsive nature of the radiation, new objects began to be called pulsars. This discovery literally stirred up astronomy, and reports of the discovery of pulsars began to arrive from many radio observatories. After the discovery of a pulsar in the Crab Nebula, which arose due to a supernova explosion in 1054 (this star was visible during the day, as the Chinese, Arabs and North Americans mention in their annals), it became clear that pulsars are somehow connected with supernova explosions. .
Most likely, the signals came from the object left after the explosion. It took a long time before astrophysicists realized that pulsars were the rapidly rotating neutron stars they had been looking for.
crab nebula
The outbreak of this supernova (photo above), sparkling in the earth's sky brighter than Venus and visible even during the day, occurred in 1054 according to earth clocks. Almost 1,000 years is a very short time by cosmic standards, and yet, during this time, the most beautiful Crab Nebula managed to form from the remnants of the exploded star. This image is a composite of two images, one from the Hubble Space Telescope (shades of red) and the other from the Chandra X-ray telescope (blue). It is clearly seen that high-energy electrons emitting in the X-ray range lose their energy very quickly, therefore blue colors prevail only in the central part of the nebula.
Combining the two images helps to more accurately understand the mechanism of operation of this amazing cosmic generator that emits electromagnetic oscillations the widest frequency range - from gamma rays to radio waves. Although most neutron stars have been detected by radio emission, they still emit the main amount of energy in the gamma and x-ray ranges. Neutron stars are born very hot, but they cool quite quickly, and already at a thousand years old have a surface temperature of about 1,000,000 K. Therefore, only young neutron stars shine in the X-ray range due to purely thermal radiation.
Pulsar physics
A pulsar is just a huge magnetized top spinning around an axis that does not coincide with the axis of the magnet. If nothing fell on it and it did not emit anything, then its radio emission would have a rotation frequency and we would never hear it on Earth. But the fact is that this top has a colossal mass and high surface temperature, and the rotating magnetic field creates an electric field of enormous intensity, capable of accelerating protons and electrons almost to the speed of light. Moreover, all these charged particles rushing around the pulsar are trapped in a trap from its colossal magnetic field. And only within a small solid angle near the magnetic axis, they can break free (neutron stars have the strongest magnetic fields in the Universe, reaching 10 10 -10 14 gauss, for comparison: the earth's field is 1 gauss, the solar field is 10-50 gauss) . It is these streams of charged particles that are the source of that radio emission, according to which pulsars were discovered, which later turned out to be neutron stars. Since the magnetic axis of a neutron star does not necessarily coincide with the axis of its rotation, when the star rotates, a stream of radio waves propagates in space like the beam of a flashing beacon - cutting through the surrounding darkness only for a moment.
X-ray images of the Crab Nebula pulsar in active (left) and normal (right) states
nearest neighbor
This pulsar is only 450 light-years from Earth and is a binary system of a neutron star and white dwarf with a circulation period of 5.5 days. Soft X-rays received by the ROSAT satellite are emitted by polar caps PSR J0437-4715 heated up to two million degrees. During its rapid rotation (the period of this pulsar is 5.75 milliseconds), it turns to the Earth with one or the other magnetic pole, as a result, the intensity of the gamma-ray flux changes by 33%. The bright object next to the small pulsar is a distant galaxy, which for some reason is actively glowing in the X-ray part of the spectrum.
Omnipotent gravity
According to modern theory massive stars end their lives in a colossal explosion that turns most of them into an expanding gaseous nebula. As a result, from the giant, many times the size and mass of our Sun, there remains a dense hot object about 20 km in size, with a thin atmosphere (made of hydrogen and heavier ions) and gravitational field, 100 billion times greater than the earth. They called it a neutron star, believing that it consists mainly of neutrons. The substance of a neutron star is the densest form of matter (a teaspoon of such a supernucleus weighs about a billion tons). The very short period of signals emitted by pulsars was the first and most important argument in favor of the fact that these are neutron stars, which have a huge magnetic field and rotate at breakneck speed. Only dense and compact objects (only a few tens of kilometers in size) with a powerful gravitational field can withstand such a rotation speed without breaking into pieces due to the centrifugal forces of inertia.
A neutron star consists of a neutron liquid with an admixture of protons and electrons. "Nuclear liquid", very reminiscent of the substance from atomic nuclei, 1014 times denser than ordinary water. This huge difference is understandable, since atoms are mostly empty space, with light electrons fluttering around a tiny, heavy nucleus. The nucleus contains almost all the mass, since protons and neutrons are 2,000 times heavier than electrons. The extreme forces that occur during the formation of a neutron star compress the atoms so that the electrons pressed into the nuclei combine with protons to form neutrons. Thus, a star is born, almost entirely composed of neutrons. The superdense nuclear liquid, if brought to Earth, would explode like a nuclear bomb, but in a neutron star it is stable due to the enormous gravitational pressure. However, in the outer layers of a neutron star (as, indeed, of all stars), pressure and temperature drop, forming a solid crust about a kilometer thick. It is believed to consist mainly of iron nuclei.
Flash
The colossal X-ray flash on March 5, 1979, it turns out, occurred far beyond our Galaxy, in the Large Magellanic Cloud, a satellite of our Milky Way, located at a distance of 180 thousand light years from Earth. Joint processing of the gamma-ray burst on March 5, recorded by seven spacecraft, made it possible to accurately determine the position of this object, and today there is practically no doubt that it is located in the Magellanic Cloud.
The event that happened on this distant star 180 thousand years ago is hard to imagine, but it then flared up like as many as 10 supernovae, more than 10 times the luminosity of all the stars in our Galaxy. The bright dot at the top of the figure is the long-standing and well-known SGR pulsar, while the irregular contour is the most probable position of the object that erupted on March 5, 1979.
Origin of the neutron star
A supernova explosion is simply the conversion of some of the gravitational energy into thermal energy. When the old star runs out of fuel and thermonuclear reaction can no longer heat its bowels to the required temperature, a kind of collapse occurs - the collapse of a gas cloud onto its center of gravity. The energy released at the same time scatters the outer layers of the star in all directions, forming an expanding nebula. If the star is small, like our Sun, then a flash occurs and a white dwarf is formed. If the mass of the star is more than 10 times that of the Sun, then such a collapse leads to a supernova explosion and an ordinary neutron star is formed. If a supernova erupts in place completely big star, with a mass of 20-40 solar, and a neutron star with a mass greater than three suns is formed, then the process of gravitational compression becomes irreversible and a black hole is formed.
Internal structure
The hard crust of a neutron star's outer layers is made up of heavy atomic nuclei arranged in a cubic lattice, with electrons flying freely between them, much like Earth's metals, only much denser.
Open question
Although neutron stars have been intensively studied for about three decades, their internal structure is not known for certain. Moreover, there is no firm certainty that they really consist mainly of neutrons. As we move deeper into the star, pressure and density increase, and matter can be so compressed that it breaks up into quarks, the building blocks of protons and neutrons. According to modern quantum chromodynamics, quarks cannot exist in a free state, but are combined into inseparable "triples" and "twos". But, perhaps, at the boundary of the inner core of a neutron star, the situation changes and quarks break out of their confinement. To better understand the nature of a neutron star and exotic quark matter, astronomers need to determine the relationship between a star's mass and its radius (average density). By examining neutron stars with companions, one can accurately measure their mass, but determining the diameter is much more difficult. More recently, scientists using the capabilities of the XMM-Newton X-ray satellite have found a way to estimate the density of neutron stars based on gravitational redshift. Another unusual feature of neutron stars is that as the mass of a star decreases, its radius increases - as a result, the most massive neutron stars have the smallest size.
Black Widow
The explosion of a supernova quite often informs a newborn pulsar of considerable speed. Such a flying star with a decent magnetic field of its own strongly perturbs the ionized gas that fills interstellar space. A kind of shock wave is formed, running ahead of the star and diverging in a wide cone after it. The combined optical (blue-green part) and X-ray (shades of red) image shows that here we are dealing not just with a luminous gas cloud, but with a huge flux of elementary particles emitted by this millisecond pulsar. Line speed The Black Widow is equal to 1 million km / h, it makes a rotation around its axis in 1.6 ms, it is already about a billion years old, and it has a companion star circling around the Widow with a period of 9.2 hours. The pulsar B1957 + 20 got its name for the simple reason that its most powerful radiation simply burns its neighbor, causing the gas that forms it to “boil” and evaporate. The red cigar-shaped cocoon behind the pulsar is the part of space where electrons and protons emitted by the neutron star emit soft gamma rays.
The result of computer simulation makes it possible to visualize, in a section, the processes occurring near a fast-flying pulsar. The rays diverging from a bright point are a conditional image of that flow of radiant energy, as well as the flow of particles and antiparticles that comes from a neutron star. The red border on the border of the black space around the neutron star and the red glowing plasma puffs is the place where the stream of relativistic particles flying almost at the speed of light meets with the interstellar gas condensed by the shock wave. When decelerating sharply, the particles emit X-rays and, having lost their main energy, do not heat up the incident gas so much.
Convulsions of the giants
Pulsars are considered one of the early life stages of a neutron star. Thanks to their study, scientists learned about magnetic fields, and about the speed of rotation, and about future fate neutron stars. By constantly observing the behavior of a pulsar, one can determine exactly how much energy it loses, how much it slows down, and even when it ceases to exist, having slowed down enough to not be able to emit powerful radio waves. These studies confirmed many theoretical predictions about neutron stars.
Already by 1968, pulsars with a rotation period of 0.033 seconds to 2 seconds were discovered. The frequency of the radio pulsar pulses is maintained with amazing accuracy, and at first the stability of these signals was higher than the earth's atomic clock. And yet, with the progress in the field of time measurement for many pulsars, it was possible to register regular changes in their periods. Of course, these are extremely small changes, and only over millions of years can we expect a period to double. The ratio of the current rotation rate to the rotation deceleration is one way to estimate the age of a pulsar. Despite the astonishing stability of the radio signal, some pulsars sometimes experience so-called "disturbances". For a very short time interval (less than 2 minutes), the pulsar rotation speed increases by a significant amount, and then after some time returns to the value that was before the "violation". It is believed that the "violations" may be caused by a rearrangement of mass within the neutron star. But in any case, the exact mechanism is still unknown.
Thus, the Vela pulsar is subjected to large “violations” about once every 3 years, and this makes it a very interesting object for studying such phenomena.
magnetars
Some neutron stars, called SGRs, emit powerful bursts of "soft" gamma rays at irregular intervals. The amount of energy emitted by SGR during a typical flash, lasting a few tenths of a second, the Sun can radiate only for a whole year. Four known SGRs are within our Galaxy and only one is outside it. These incredible explosions of energy can be caused by starquakes - powerful versions of earthquakes, when the solid surface of neutron stars is torn apart and powerful streams of protons escape from their interiors, which, bogged down in a magnetic field, emit gamma and X-rays. Neutron stars were identified as sources of powerful gamma-ray bursts after a huge gamma-ray burst on March 5, 1979, when as much energy was thrown out in the first second as the sun emits in 1,000 years. Recent observations of one of the most "active" neutron stars at present seem to support the theory that powerful bursts of gamma and X-rays are caused by starquakes.
In 1998, the well-known SGR suddenly woke up from its "slumber", which had not shown signs of activity for 20 years and splashed out almost as much energy as the gamma-ray flash on March 5, 1979. What struck the researchers most when observing this event was a sharp slowdown in the speed of rotation of the star, indicating its destruction. To explain powerful gamma-ray and X-ray flares, a model of a magnetar, a neutron star with a superstrong magnetic field, was proposed. If a neutron star is born spinning very fast, then the combined influence of rotation and convection, which plays an important role in the first few seconds of the existence of a neutron star, can create a huge magnetic field through a complex process known as an “active dynamo” (the same way a field is created inside the Earth and the Sun). Theorists were amazed to discover that such a dynamo, operating in a hot, newborn neutron star, could create a magnetic field 10,000 times stronger than the normal field of pulsars. When the star cools down (after 10 or 20 seconds), convection and dynamo action stop, but this time is quite enough for the necessary field to appear.
The magnetic field of a rotating electrically conductive ball can be unstable, and a sharp restructuring of its structure can be accompanied by the release of colossal amounts of energy (a good example of such instability is the periodic transfer magnetic poles Earth). Similar things happen on the Sun, in explosive events called " solar flares". In a magnetar, the available magnetic energy is enormous, and this energy is quite enough for the power of such giant flares as March 5, 1979 and August 27, 1998. Such events inevitably cause a deep breakdown and changes in the structure of not only electric currents in the volume of a neutron star, but also its solid crust. Another mysterious type of object that emits powerful X-rays during periodic explosions are the so-called anomalous X-ray pulsars - AXP. They differ from ordinary X-ray pulsars in that they emit only in the X-ray range. Scientists believe that SGR and AXP are life phases of the same class of objects, namely magnetars, or neutron stars, which emit soft gamma rays, drawing energy from the magnetic field. And although magnetars today remain the brainchild of theorists and there is not enough data confirming their existence, astronomers are stubbornly looking for the necessary evidence.
Candidates for Magnetars
Astronomers have already studied our own galaxy, the Milky Way, so thoroughly that it costs them nothing to draw a side view of it, marking the positions of the most remarkable neutron stars on it.
Scientists believe that AXP and SGR are just two stages in the life of the same giant magnet - a neutron star. For the first 10,000 years, a magnetar is an SGR - a pulsar visible in ordinary light and giving repeated flashes of soft X-rays, and for the next millions of years it, already like an anomalous AXP pulsar, disappears from the visible range and puffs only in X-rays.
The strongest magnet
An analysis of the data obtained by the RXTE (Rossi X-ray Timing Explorer, NASA) satellite during observations of the unusual pulsar SGR 1806-20 showed that this source is the most powerful magnet known to date in the Universe. The magnitude of its field was determined not only on the basis of indirect data (on the deceleration of the pulsar), but also almost directly - on the measurement of the rotation frequency of protons in the magnetic field of a neutron star. The magnetic field near the surface of this magnetar reaches 10 15 gauss. If it were, for example, in the orbit of the Moon, all magnetic information carriers on our Earth would be demagnetized. True, given that its mass is approximately equal to that of the Sun, this would no longer matter, because even if the Earth had not fallen on this neutron star, it would have revolved around it like crazy, making a complete revolution in just an hour.
Active dynamo
We all know that energy loves to change from one form to another. Electricity is easily converted into heat, and kinetic energy into potential energy. Huge convective flows of electrically conductive magma, plasma or nuclear matter, it turns out, can also convert their kinetic energy into something unusual, such as a magnetic field. The movement of large masses on a rotating star in the presence of a small initial magnetic field can lead to electric currents, which creates a field in the same direction as the original one. As a result, an avalanche-like growth of the own magnetic field of a rotating conductive object begins. The greater the field, the greater the currents, the greater the currents, the greater the field - and all this is due to banal convective flows, due to the fact that hot matter is lighter than cold, and therefore floats
Restless Neighborhood
The famous Chandra space observatory has found hundreds of objects (including in other galaxies), indicating that not all neutron stars are destined to live alone. Such objects are born in binary systems that survived the supernova explosion that created the neutron star. And sometimes it happens that single neutron stars in dense stellar regions such as globular clusters capture a companion. In this case, the neutron star will "steal" matter from its neighbor. And depending on how massive the star will keep her company, this "theft" will cause different consequences. Gas flowing from a companion with a mass less than that of our Sun, on such a "crumb" as a neutron star, will not be able to immediately fall due to its own too large angular momentum, so it creates a so-called accretion disk around it from the "stolen » matter. Friction during winding around a neutron star and compression in a gravitational field heats up the gas to millions of degrees, and it begins to emit X-rays. Another interesting phenomenon associated with neutron stars that have a low-mass companion is X-ray bursts (bursters). They usually last from a few seconds to several minutes and, at their maximum, give the star a luminosity nearly 100,000 times that of the Sun.
These outbursts are explained by the fact that when hydrogen and helium are transferred to a neutron star from a companion, they form a dense layer. Gradually, this layer becomes so dense and hot that a thermonuclear fusion reaction begins and a huge amount of energy is released. In terms of power, this is equivalent to the explosion of the entire nuclear arsenal of earthlings on every square centimeter of the surface of a neutron star within a minute. A completely different picture is observed if the neutron star has a massive companion. A giant star loses matter in the form of a stellar wind (a stream of ionized gas emanating from its surface), and the enormous gravity of a neutron star captures some of this matter for itself. But here the magnetic field comes into its own, which causes the falling substance to flow along lines of force to the magnetic poles.
This means that X-rays are primarily generated in hot spots at the poles, and if the magnetic axis and the axis of rotation of the star do not coincide, then the brightness of the star turns out to be variable - this is also a pulsar, but only X-ray. Neutron stars in X-ray pulsars have bright giant stars as companions. In bursters, the companions of neutron stars are low-mass stars of low brightness. The age of bright giants does not exceed a few tens of millions of years, while the age of faint dwarf stars can be billions of years, since the former consume their nuclear fuel much faster than the latter. It follows that bursters are old systems in which the magnetic field has weakened over time, and pulsars are relatively young, and therefore magnetic fields they are stronger. Maybe bursters once pulsated in the past, and pulsars have yet to flare in the future.
Pulsars with the shortest periods (less than 30 milliseconds), the so-called millisecond pulsars, are also associated with binary systems. Despite their rapid rotation, they are not the youngest, as one would expect, but the oldest.
They arise from binary systems, where an old, slowly rotating neutron star begins to absorb matter from its already aged companion (usually a red giant). Falling onto the surface of a neutron star, matter transfers rotational energy to it, causing it to spin faster and faster. This happens until the companion of the neutron star, almost freed from excess mass, becomes a white dwarf, and the pulsar comes to life and begins to rotate at a speed of hundreds of revolutions per second. However, astronomers have recently discovered a very unusual system where the companion of a millisecond pulsar is not a white dwarf, but a giant bloated red star. Scientists believe that they are observing this binary system just in the stage of "liberation" of the red star from excess weight and transformation into a white dwarf. If this hypothesis is wrong, then the companion star could be an ordinary globular cluster star accidentally captured by a pulsar. Almost all neutron stars that are currently known have been found either in X-ray binaries or as single pulsars.
And just recently, Hubble noticed in visible light a neutron star, which is not a component of a binary system and does not pulsate in the X-ray and radio range. This provides a unique opportunity to accurately determine its size and make adjustments to the composition and structure of this bizarre class of burnt out, gravitationally compressed stars. This star was discovered for the first time as an X-ray source and emits in this range, not because it collects hydrogen gas as it moves through space, but because it is still young. Perhaps it is the remnant of one of the stars of the binary system. As a result of a supernova explosion, this binary system collapsed and former neighbors began an independent journey through the universe.
Little Star Eater
As stones fall to the ground, so big star, releasing its mass bit by bit, gradually moves to a small and distant neighbor, which has a huge gravitational field near its surface. If the stars did not revolve around a common center of gravity, then the gas stream could simply flow, like a stream of water from a mug, onto a small neutron star. But since the stars circle in a round dance, the falling matter, before it reaches the surface, must lose most of its angular momentum. And here the mutual friction of particles moving along different trajectories and the interaction of the ionized plasma forming the accretion disk with the magnetic field of the pulsar help the process of falling matter to successfully end with an impact on the surface of a neutron star in the region of its magnetic poles.
Mystery 4U2127 Solved
This star has been fooling astronomers for more than 10 years, showing a strange slow variability in its parameters and flaring up differently each time. Only latest research space observatory "Chandra" allowed to unravel the mysterious behavior of this object. It turned out that this is not one, but two neutron stars. Moreover, both of them have companions - one star, similar to our Sun, the other - to a small blue neighbor. Spatially, these pairs of stars are separated enough long distance and live independent lives. But on the stellar sphere, they are projected almost to one point, which is why they were considered one object for so long. These four stars are located in globular cluster M15 at a distance of 34 thousand light years.
Open question
In total, astronomers have discovered about 1,200 neutron stars to date. Of these, more than 1,000 are radio pulsars, and the rest are simply X-ray sources. Over the years of research, scientists have come to the conclusion that neutron stars are real originals. Some are very bright and calm, others periodically flash and change with starquakes, and still others exist in binary systems. These stars are among the most mysterious and elusive astronomical objects, combining the strongest gravitational and magnetic fields and extreme densities and energies. And each new discovery from their turbulent life provides scientists with unique information necessary for understanding the nature of Matter and the evolution of the Universe.
Universal standard
It is very difficult to send something outside the solar system, therefore, together with the Pioneer-10 and -11 spacecraft that went there 30 years ago, earthlings also sent messages to their brothers in mind. To draw something that will be understandable to the Extraterrestrial Mind is not an easy task, moreover, it was still necessary to indicate the return address and the date of sending the letter... It is difficult for a person to understand how intelligibly all this was done by the artists, but the idea of using radio pulsars for indicating the place and time of sending the message is ingenious. Discontinuous rays of various lengths, emanating from a point symbolizing the Sun, indicate the direction and distance to the pulsars closest to the Earth, and the discontinuity of the line is nothing more than a binary designation of their period of revolution. The longest beam points to the center of our Galaxy - the Milky Way. As a unit of time on the message, the frequency of the radio signal emitted by the hydrogen atom when changing the mutual orientation of the spins (direction of rotation) of the proton and electron is taken.
The famous 21 cm or 1420 MHz should be known to all intelligent beings in the universe. According to these landmarks, pointing to the "radio beacons" of the Universe, it will be possible to find earthlings even after many millions of years, and by comparing the recorded frequency of pulsars with the current one, it will be possible to estimate when these man and woman blessed the first flight. spaceship that has left the solar system.
Nikolai Andreev
A beautiful space spinning top could one day destroy the Earth with deadly rays, scientists report.
Unlike the Star Wars Death Star, which needed to get close to a planet to blow it up, this blazing spiral is able to burn worlds thousands of light-years away, much like the Death Galaxy already described on our website.
"I loved this spiral because of its beauty, but now looking at it, I can't help but feel like I'm looking down the barrel of a gun," said researcher Peter Tuthill, an astronomer at the University of Sydney.
At the heart of this fiery cosmic top are two hot, bright stars circling each other. In such mutual rotation, flashes of flowing gas escape from the surface of stars and collide in the intermediate space, gradually intertwining and twisting by the orbits of stars into rotating spirals.
A sequence of 11 images, combined and colorized, shows a spinning top formed by the double star Wolf-Raet 104. The images were taken in near-infrared by the Keck telescope. Peter Tuthill, University of Sydney.
Short circuit
Yula, called WR 104, was discovered eight years ago in the constellation Sagittarius. It circles "every eight months, with the precision of a cosmic chronometer," says Tuthill.
Both heavy stars in WR 104 will one day explode as a supernova. However, one of the two stars is a highly unstable Wolf-Rae-type star, which is in the last known phase of the life of heavy stars before going supernova.
"Astronomers think Wolf-Rae stars are ticking bombs," explains Tuthill. "This star's 'fuse' is almost - astronomically speaking - blown, and it could explode at any time within the next few hundred thousand years."
When Wolf Rae goes supernova, it “could throw a huge gamma ray in our direction,” says Tuthill. “And if such a gamma ray explosion occurs, we would really not want the Earth to get in its way.”
Since the initial blast wave will move at the speed of light, nothing can warn of its approach.
In the line of fire
Gamma ray bursts are the most powerful explosions known to us in the universe. In times ranging from a few milliseconds to a minute or more, they can release as much energy as our Sun in its entire 10 billion years of existence.
But the most eerie thing about this yule is that we see it as a near-perfect spiral, according to latest pictures the Keck telescope in Hawaii. “Thus, we can only see a binary system when we are practically on its axis,” explains Tuthill.
To our greatest regret, the emission of gamma rays occurs directly along the axis of the system. In fact, if a gamma ray release ever occurs, our planet could be right in the line of fire.
"It's the first object we know of that can fire gamma rays at us," says astrophysicist Adrian Melott of the University of Kansas at Laurence, who was not involved in the study. "And the distance to the system is frighteningly close."
Yula is about 8,000 light-years from Earth, about a quarter of the way to the center of the Milky Way galaxy. While that seems like a decent distance, "earlier studies have shown that a gamma ray burst could be detrimental to life on Earth - if we're not lucky enough to get in its way - and at that distance," says Tuthill.
Possible Scenario
Although the spinning wheel cannot blow the Earth to pieces like the Death Star and Star Wars - at least not from a distance of 8000 light years - it can lead to massive destruction and even the complete extinction of life, in forms known to us, on our planet.
Gamma rays can't penetrate Earth's atmosphere deep enough to burn the soil, but they can chemically alter the stratosphere. Melot calculated that if the WR 104 fired a burst of about 10 seconds at us, the gamma rays would deprive us of 25 percent of the ozone layer that protects us from harmful ultraviolet rays. In comparison, the human-induced thinning of the ozone layer, which created "ozone holes" over the polar regions, reduced the ozone layer by only 3-4 percent.
“Things will be very bad,” says Melot. Everything will start to die. The food chain can collapse in the oceans, there can be an agricultural crisis and famine.”
The release of gamma rays can also lead to sun-dark fog and acid rain. However, the distance of 8,000 years is “too long for the dimming to be noticeable,” Melot said. - I would say, in general, there will be less sunlight by 1-2 percent. The climate may get a little colder, but it should not reach a catastrophic ice age.”
The danger of cosmic rays
What is unknown about gamma rays is how many particles they spew out as cosmic rays.
“Typically, gamma ray bursts occur so far away from us that the magnetic fields of the universe pull off any cosmic rays that we might observe, but if the gamma ray burst occurs relatively close, all high-energy particles will rush through the magnetic field of the galaxy and hit us,” Melot says. “Their energy will be so high that they will arrive almost simultaneously with the light flux.”
“That part of the Earth that turns out to be facing the flow of gamma rays will experience something similar to that located not far from nuclear explosion; all organisms can get radiation sickness, Melot adds. Moreover, cosmic rays can exacerbate the effect of gamma rays on the atmosphere. But we simply don't know how many cosmic rays gamma rays emanate, so we can't assess the severity of the danger."
It is also not clear how wide the flow of energy released by the burst of gamma rays will be. But in any case, the cone of destruction emanating from the spinning top will reach several hundred square light-years before it reaches the Earth, according to Melot's calculations. Tuthill, on the other hand, states that "no one can fly a spaceship far enough not to hit the beam if it actually fires in our direction."
Fictional "Death Star" from "Star Wars"
Do not worry
Nevertheless, Tunhill thinks that the top may be quite safe for us.
“There are too many uncertainties,” he explains. “The radiation can pass by without causing us any harm if we are not exactly on the axis, and besides, no one is completely sure that stars like WR 104 are able to cause such a powerful burst of gamma radiation.
Further research should focus on whether WR 104 is indeed aimed at Earth and how supernova birth results in gamma ray bursts.
Melot and others have also speculated that gamma ray showers could have caused a mass extinction of species on Earth. But when it comes to whether the whirligig poses a real threat to us, Melot notes: "I'd rather be worried about global warming."
1. The mass of the Sun is 99.86% of the mass of the entire solar system, the remaining 0.14% are planets and asteroids.
2. The magnetic field is so powerful that it enriches the magnetic field of our planet with billions of watts every day.
3. The largest basin in the solar system, formed as a result of a collision with a space object, is located. This is Caloris Basin, whose diameter is 1,550 km. The collision was so strong that the shock wave passed through the entire planet, drastically changing its appearance.
4. Solar substance the size of a pinhead, placed in the atmosphere of our planet, will begin to absorb oxygen at an incredible speed and in a split second will destroy all life within a radius of 160 kilometers.
5. 1 Plutonian year is 248 Earth years. This means that while Pluto makes only one complete revolution around the Sun, the Earth manages to make 248.
6. Things are even more interesting with Venus, 1 day on which lasts 243 Earth days, and the year is only 225.
7. Martian volcano "Olympus" (Olympus Mons) is the largest in the solar system. Its length is more than 600 km, and its height is 27 km, while the height of the highest point on our planet, the peak of Mount Everest, reaches only 8.5 km.
8. An explosion (flash) of a supernova is accompanied by the release of a gigantic amount of energy. In the first 10 seconds, a supernova exploding produces more energy than in 10 billion years, and in a short period of time produces more energy than all objects in the galaxy combined (excluding other exploding supernovas).
The brightness of such stars easily outshines the luminosity of the galaxies in which they flared up.
9. Tiny neutron stars, whose diameter does not exceed 10 km, weigh as much as the Sun (recall fact No. 1). The force of gravity on these astronomical objects is extremely high and if, hypothetically, an astronaut lands on it, then his body weight will increase by about one million tons.
10. On February 5, 1843, astronomers discovered a comet, which was given the name "Great" (aka the March comet, C / 1843 D1 and 1843 I). Flying nearby in March of the same year, she ‘drawn’ the sky in two with her tail, the length of which reached 800 million kilometers.
Earthlings watched the tail trailing the Great Comet for more than a month, until, on April 19, 1983, it completely disappeared from the sky.
11. The energy of the sun's rays that warms us now originated in the core of the Sun more than 30,000 million years ago - most of this time it took her to overcome the dense shell of the celestial body and only 8 minutes to reach the surface of our planet.
12. Most of the heavy elements in your body (such as calcium, iron, and carbon) are by-products of the supernova explosion that started the formation of the solar system.
13. Researchers from Harvard University found that 0.67% of all rocks on Earth are of origin.
14. The density of 5.6846 × 1026-kilogram Saturn is so low that if we were able to place it in water, it would float on the very surface.
15. Saturn's moon Io has ~400 active volcanoes. The rate of emissions of sulfur and sulfur dioxide during the eruption can exceed 1 km / s, and the height of the streams can reach 500 km.
16. Contrary to popular belief, space is not a complete vacuum, but close enough to it, because. There is at least 1 atom per 88 gallons of cosmic matter (and as we know, there are no atoms or molecules in a vacuum).
17. Venus is the only planet in the solar system that rotates counterclockwise. There are several theoretical justifications for this. Some astronomers are sure that such a fate befalls all planets with a dense atmosphere, which first slows down and then spins the celestial body in the opposite direction from the initial rotation, while others suggest that the reason was the fall of a group of large asteroids to the surface.
18. Since the beginning of 1957 (the year of the launch of the first artificial satellite Sputnik-1), mankind has managed to literally seed the orbit of our planet with a variety of satellites, but only one of them was lucky enough to repeat the 'fate of the Titanic'. In 1993, the satellite "Olympus" (Olympus), owned by the European Space Agency (European Space Agency), was destroyed in a collision with an asteroid.
19. The largest meteorite that has fallen to Earth is considered to be the 2.7 meter Hoba discovered in Namibia. weighs 60 tons and is 86% iron, making it the largest piece of naturally occurring iron on Earth.
20. is considered the coldest planet in the solar system. Its surface is covered with a thick crust of ice, and the temperature drops to -200 0C. Ice on Pluto has a completely different structure than on Earth and is several times stronger than steel.
21. The official scientific theory says that a person can survive in outer space without a spacesuit for 90 seconds if he immediately exhales all the air from his lungs.
If a small amount of gases remains in the lungs, they will begin to expand with the subsequent formation of air bubbles, which, if released into the blood, will lead to embolism and inevitable death. If the lungs are filled with gases, then they will simply burst.
After 10-15 seconds of being in outer space, the water in the human body will turn into steam, and the moisture in the mouth and before the eyes will begin to boil. As a result of this, soft tissues and muscles will swell, which will lead to complete immobilization.
This will be followed by loss of vision, glaciation of the nasal cavity and larynx, blue skin, which in addition will suffer from severe sunburn.
The most interesting thing is that the next 90 seconds the brain will still live and the heart will beat.
In theory, if during the first 90 seconds an unsuccessful cosmonaut who has been tormented in outer space is placed in a pressure chamber, then he will get off with only superficial injuries and a slight fright.
22. The weight of our planet is a variable value. Scientists have found that every year the Earth recovers by ~40,160 tons and dumps ~96,600 tons, thus losing 56,440 tons.
23. Earth's gravity compresses the human spine, so when an astronaut hits, he grows by about 5.08 cm.
At the same time, his heart contracts, decreasing in volume and pumping less blood. This is the body's response to an increase in blood volume that requires less pressure to circulate properly.
24. In space, tightly compressed metal parts spontaneously weld. This occurs as a result of the absence of oxides on their surfaces, the enrichment of which occurs only in an oxygen-containing environment (the earth's atmosphere can serve as a good example of such an environment). For this reason, NASA specialists The National Aeronautics and Space Administration is an agency owned by the US federal government, reporting directly to the Vice President of the United States and funded 100% from the state budget, responsible for civil space program country. All images and videos obtained by NASA and its affiliates, including those from numerous telescopes and interferometers, are published in the public domain and may be freely copied. treat all metal parts of spacecraft with oxidizing materials.
25. Between the planet and its satellite, the effect of tidal acceleration occurs, which is characterized by a slowdown in the rotation of the planet around its own axis and a change in the orbit of the satellite. So, every century the rotation of the Earth slows down by 0.002 seconds, as a result of which the duration of the day on the planet increases by ~15 microseconds per year, and annually moves away from us by 3.8 centimeters.
26. ‘Cosmic whirlpool’ called a neutron star is the fastest spinning object in the Universe, which makes up to 500 thousand revolutions per second around its axis. In addition, these cosmic bodies are so dense that one tablespoon of their constituent matter will weigh ~10 billion tons.
27. The star Betelgeuse is located at a distance of 640 light years from Earth and is the closest candidate for a supernova to our planetary system. It is so large that if placed in the place of the Sun, it would fill the diameter of Saturn's orbit. This star has already gained enough mass for the explosion of 20 Suns and, according to some scientists, should explode in the next 2-3 thousand years. At the peak of its explosion, which will last at least two months, the luminosity of Betelgeuse will be 1,050 times greater than that of the sun, making it possible to observe its death from Earth even with the naked eye.
28. The nearest galaxy to us, Andromeda, is at a distance of 2.52 million years. The Milky Way and Andromeda are moving towards each other at tremendous speeds (Andromeda's speed is 300 km/s, and the Milky Way is 552 km/s) and will most likely collide in 2.5-3 billion years.
29. In 2011, astronomers discovered a planet made up of 92% superdense crystalline carbon – diamond. The precious celestial body, which is 5 times larger than our planet and heavier than Jupiter, is located in the constellation Serpens, at a distance of 4,000 light years from Earth.
30. The main contender for the title of a habitable planet in the extrasolar system, "Super-Earth" GJ 667Cc, is located at a distance of only 22 light-years from Earth. However, the journey to it will take us 13,878,738,000 years.
31. In the orbit of our planet there is a landfill from the waste of the development of astronautics. More than 370,000 objects weighing from a few grams to 15 tons revolve around the Earth at a speed of 9,834 m / s, colliding with each other and scattering into thousands of smaller parts.
32. Every second the Sun loses ~1 million tons of matter and becomes lighter by several billion grams. The reason for this is the stream of ionized particles flowing from its crown, which is called the "solar wind".
33. Over time, planetary systems become extremely unstable. This happens as a result of the weakening of the bonds between the planets and the stars around which they revolve.
In such systems, the orbits of the planets are constantly shifting and may even intersect, which will sooner or later lead to a collision of the planets. But even if this does not happen, then in a few hundreds, thousands, millions or billions of years the planets will move away from their star to such a distance that its gravitational attraction simply cannot hold them, and they will go on a combined flight through the galaxy.
