Our Universe is truly huge. Pulsars, planets, stars, black holes and hundreds of other objects of incomprehensible size that are found in the Universe.
And today we would like to talk about the 10 biggest things. In this list, we've put together a collection of some of the largest objects in space, including nebulae, pulsars, galaxies, planets, stars, and more.
Without further delay, here is a list of the ten biggest things in the universe.
The most big planet in the Universe - this is TrES-4. It was discovered in 2006 and is located in the constellation Hercules. The planet, called TrES-4, orbits a star that is about 1,400 light-years away from planet Earth.
The planet TrES-4 itself is a ball that consists primarily of hydrogen. Its dimensions are 20 times greater than the size of the Earth. Researchers claim that the diameter of the discovered planet is almost 2 times (more precisely 1.7) larger than the diameter of Jupiter (this is the largest planet in the solar system). The temperature of TrES-4 is about 1260 degrees Celsius.
To date the most a big star is UY Scutum in the constellation Scutum at a distance of about 9,500 light-years from us. This is one of the brightest stars - it is 340 thousand times brighter than our Sun. Its diameter is 2.4 billion km, which is 1700 times larger than our star, with a weight of only 30 times the mass of the sun. It’s a pity that it is constantly losing mass; it is also called the fastest burning star. This may be why some scientists consider NML Cygnus the largest star, and others consider VY Canis Majoris.
Black holes are not measured in kilometers; the key indicator is their mass. The largest black hole is in the galaxy NGC 1277, which is not the largest. However, the hole in the galaxy NGC 1277 has 17 billion solar masses, which is 17% of the total mass of the galaxy. By comparison, our Milky Way's black hole has a mass of 0.1% of the galaxy's total mass.
7. Largest galaxy
The mega-monster among the currently known galaxies is IC1101. The distance to Earth is about 1 billion light years. Its diameter is about 6 million light years and holds about 100 trillion. stars; for comparison, the diameter of the Milky Way is 100 thousand light years. Compared with Milky Way IC 1101 is more than 50 times larger and 2000 times more massive.
Lyman-alpha blobs (drops, clouds) are amorphous bodies resembling amoebas or jellyfish in shape, consisting of a huge concentration of hydrogen. These blots are initial and very short stage the birth of a new galaxy. The largest of them, LAB-1, is more than 200 million light years wide and is located in the constellation Aquarius.
In the photo on the left, LAB-1 is recorded by instruments, on the right is an assumption of what it might look like up close.
A radio galaxy is a type of galaxy that has much greater radio emission compared to other galaxies.
Galaxies, as a rule, are located in clusters (clusters), which have a gravitational connection and expand with space and time. What is located in those places where there are no galaxies? Nothing! Regions of the Universe in which there is only “nothing” and is emptiness. The largest of them is the emptiness of Bootes. It is located in close proximity to the constellation Bootes and has a diameter of about 250 million light years. Distance to Earth approximately 1 billion light years
The largest supercluster of galaxies is the Shapley supercluster. Shapley is located in the constellation Centaurus and appears as a bright clump in the distribution of galaxies. This is the largest array of objects connected by gravity. Its length is 650 million light years.
Most large group quasars (a quasar is a bright, energetic galaxy) is Huge-LQG, also called U1.27. This structure consists of 73 quasars and has a diameter of 4 billion light years. However, the Great GRB Wall, which has a diameter of 10 billion light years, also claims primacy - the number of quasars is unknown. The presence of such large groups of quasars in the Universe contradicts Einstein’s Cosmological Principle, so their research is doubly interesting for scientists.
If astronomers have disputes about other objects in the Universe, then in this case almost all of them are unanimous in the opinion that the largest object in the Universe is the Cosmic Web. Endless clusters of galaxies surrounded by black matter form “nodes” and, with the help of gases, “threads”, which in appearance are very reminiscent of a three-dimensional web. Scientists believe that the cosmic web entangles the entire Universe and connects all objects in space.
Our Solar System is one of the components of the Galaxy. Right here Milky Way extends over hundreds of thousands of light years.
The central element of the Solar System is the Sun. Eight planets revolve around it (the ninth planet Pluto was excluded from this list, since its mass and gravitational forces do not allow it to be on the same level as other planets). However, each planet is different from the next. Among them there are small and truly huge, icy and hot, consisting of gas and dense.
The largest planet in the Universe is TrES-4. It was discovered in 2006 and is located in the constellation Hercules. The planet, called TrES-4, orbits a star that is about 1,400 light-years away from planet Earth.
The planet TrES-4 itself is a ball that consists primarily of hydrogen. Its dimensions are 20 times greater than the size of the Earth. Researchers claim that the diameter of the discovered planet is almost 2 times (more precisely 1.7) larger than the diameter of Jupiter (this is the largest planet in the solar system). The temperature of TrES-4 is about 1260 degrees Celsius.
According to scientists, there is no solid surface on the planet. Therefore, you can only immerse yourself in it. It is a mystery how the density of the substance that makes up this celestial body is so low.
Jupiter
The largest planet in the solar system, Jupiter, is located at a distance of 778 million kilometers from the Sun. This planet, the fifth in a row, is a gas giant. The composition is very similar to that of the sun. By at least, its atmosphere is predominantly hydrogen.
However, under the atmosphere, the surface of Jupiter is covered with ocean. Only it does not consist of water, but of boiling hydrogen rarefied under high pressure. Jupiter rotates very quickly, so fast that it elongates along its equator. Therefore, unusually strong winds form there. Because of this feature, the appearance of the planet is interesting: in its atmosphere, the clouds lengthen and form varied and colorful ribbons. Vortexes appear in the clouds - atmospheric formations. The largest ones are already more than 300 years old. Among them is the Great Red Spot, which is many times more sizes Earth.
Earth's Big Brother
It is worth noting that the planet’s magnetic field is huge, it occupies 650 million kilometers. This is much larger than Jupiter itself. The field partially extends even beyond the orbit of the planet Saturn. Jupiter currently has 28 satellites. At least that much is open. Looking into the sky from Earth, the farthest one looks smaller than the Moon. But the largest satellite is Ganymede. However, astronomers are especially actively interested in Europe. It has a surface in the form of ice, and is also covered with stripes of cracks. Their origin still causes a lot of controversy. Some researchers believe that under balls of ice, where the water is not frozen, there may be primitive life. Few places in the solar system are worthy of such an assumption. Scientists plan to send drilling rigs to this satellite of Jupiter in the future. This is necessary just to study the composition of water.
Jupiter and its moons through a telescope
According to the modern version, the Sun and planets were formed from one gas and dust cloud. Jupiter accounts for 2/3 of the total mass of the planets in the solar system. And this is clearly not enough for things to happen in the center of the planet. thermonuclear reactions. Jupiter has own source heat, which is associated with the energy from compression and decay of matter. If heating came only from the Sun, then upper layer would have a temperature of about 100K. And judging by the measurements, it is equal to 140K.
It is worth noting that Jupiter's atmosphere consists of 11% helium and 89% hydrogen. This ratio makes it look like chemical composition Sun. Orange color obtained due to compounds of sulfur and phosphorus. They are destructive for people, as they contain acetylene and poisonous ammonia.
Saturn
It is the next largest planet in the solar system. Through the telescope it is clearly visible that Saturn is more flattened than Jupiter. There are stripes on the surface parallel to the equator, but they are less distinct than those of the previous planet. The stripes show numerous and subtle details. And it was from them that the scientist William Herschel was able to determine the period of rotation of the planet. It's only 10 hours and 16 minutes. The equator diameter of Saturn is slightly smaller than Jupiter. However, it is three times less massive than the largest planet. In addition, Saturn has a low average density - 0.7 grams per square centimeter. This is because giant planets are made of helium and hydrogen. In the depths of Saturn, the pressure is not the same as on Jupiter. In this case, the surface temperature is close to the temperature at which methane melts.
Saturn has elongated dark stripes or belts along the equator, as well as light zones. These details are not as contrasting as those of Jupiter. And individual spots are not so frequent. Saturn has rings. Through the telescope, “ears” are visible on both sides of the disk. It has been established that the rings of the planet are the remains of a huge circumplanetary cloud that stretches for millions of kilometers. Stars are visible through the rings that revolve around the planet. The internal parts rotate faster than the external parts.
Saturn through a telescope
Saturn has 22 satellites. They have the names of ancient heroes, for example, Mimas, Enceladus, Pandora, Epimetheus, Tethys, Dione, Prometheus. The most interesting of them: Janus - it is the closest to the planet, Titan - the largest (the largest satellite in the Solar system in terms of mass and size).
Film about Saturn
All of the planet's satellites, with the exception of Phoebe, orbit in the forward direction. But Phoebe is moving in orbit in the opposite direction.
Uranus
The seventh planet from the Sun in the solar system, therefore it is poorly lit. It is four times the diameter of the Earth. Some details on Uranus are difficult to distinguish due to their small angular dimensions. Uranus rotates around an axis, lying on its side. Uranus orbits the Sun every 84 years.
The polar day at the poles lasts 42 years, followed by night of the same duration. The composition of the planet is a small amount of methane and hydrogen. By indirect signs there is helium. The planet's density is greater than that of Jupiter and Saturn.
Journey to the planets: Uranus and Neptune
Uranus has planetary narrow rings. They consist of individual opaque and dark particles. The radius of the orbits is 40-50 thousand kilometers, the width is from 1 to 10 kilometers. The planet has 15 satellites. Some of them are external, some are internal. The most distant and largest are Titania and Oberon. Their diameter is about 1.5 thousand kilometers. The surfaces are pitted with meteorite craters.
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My sister was lucky - she was given a real telescope for her birthday. Of course, it doesn’t increase it too much, but is that really that important? I myself looked at the starry sky for about forty minutes without stopping. And I even recognized one of the small round spots, which, in fact, is the largest planet in the Solar System.
Which planet is the largest in the Solar System?
Most major planet is Jupiter. It is more than 11 times larger than our Earth.
Jupiter also has many more satellites than our planet. You and I can only boast of having one and only one Moon.
At Jupiter same on this moment counted as much 69 satellites- more than any other planet in the solar system. Of course, I won’t list them all. But I’ll still name the most famous:
- Callisto.
- Ganymede.
- Europe.
This magnificent quartet of Jupiterian moons discovered by Galileo, and did it whole 407 years ago.
Why is it difficult to fly to Jupiter?
The first reason is that it is located quite far from earth. Distance varies from 588.5 to 968.6 million km. Why such a large spread? The fact is that the planets, revolving around the Sun, cyclically approach and then move away from each other. So in order to fly faster, you need to guess the moment when the planets will be well located relative to each other.
The second problem is landing. The space probes that are sent to explore this cosmic behemoth can not Fine sit on its gas surface. All they have to do is immerse themselves in the atmosphere - and enormous pressure planets flatten the probe into a cake.
Yes and radiation near Jupiter also greatly interferes with the operation of spacecraft, often leading to severe malfunctions or even large losses of collected data.
However, despite such enormous difficulties, Jupiter and its moons are being carefully studied. Some of moon gas giant attracts special attention - there, presumably, there is an ocean, which means she could life arises. It is unlikely that it will be intelligent, but even the very fact of its discovery will make humanity understand that we are not alone in space.
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When I was little, I stubbornly believed that the largest planet in the solar system was the large red and yellow ball at its center. Only later, when I entered school, did the teachers explain to me that this “planet” is the main star of our system - the Sun. This news made me continue to search for the largest planet in the solar system.
The planet is a giant
If you put planets in order of increasing mass, then the list will look like this:
- Mercury - 3.3·10^20 kilograms;
- Mars - 6.4·10^20 kilograms;
- Venus - 4.9·10^21 kilograms;
- Earth-6.0·10^21 kilograms;
- Uranium - 8.7·10^22 kilograms;
- Neptune - 1.0·10^23 kilograms;
- Saturn - 5.7·10^23 kilograms;
- Jupiter - 1.9·10^24 kilograms.
As seen , The largest planet in the solar system is Jupiter.Diameter of this planet at the thickest part, at the equator, 11 thousand times larger than the diameter of the Earth. Of course, this size is much smaller than the diameter of the Sun, approximately 10 diameters of Jupiter will be equal to the diameter of the Sun. Proportional to its size, the mass of Jupiter is very large. If you put all the planets of the Solar System and their satellites on a scale (of course, “cosmically” huge) and compare their weight with the weight of Jupiter, then Jupiter will easily outweigh it all. If only increase the weight of the planets and their satellites by 2.5 times, the scales will balance.
The reason for Jupiter's huge size
This planet formed in the early period of the solar system's development, like Saturn, during this period more materials (gases) were free to create planets, therefore the size of the planets of that period is simply huge. Heat+ a large amount of gas made the planet Jupiter so large. The remaining planets have much less gas left, so they look inconspicuous. Also about gases, Jupiter's atmosphere is very dense, so it is difficult to give an accurate estimate of its size. All that humanity can observe now are the clouds of Jupiter and nothing more.
Someone bigger
In our solar system, Jupiter is definitely a giant, but there are other systems where the gas giants are closer to the star than Jupiter is to the Sun, so the temperature of these giants is higher, and therefore their size exceeds the size of Jupiter. WITHThe largest planet known to mankind is TRES-4.
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A couple of years ago, my son returned from school with the question: “How many planets are there in the solar system?” Recently it turned out that Pluto is no longer considered a planet. Like, it's too small. It must be said that the debate on this issue continues to this day. Fortunately, there is no doubt about the most major planet in the solar system.
The largest planet in the solar system
Jupiter is often called a gas giant. It is the fifth planet from the Sun. Its diameter is about 143 thousand kilometers. Thus Jupiter is almost 11 times larger than Earth. Jupiter is so large that its mass is two and a half times greater than the combined mass of all the other planets in our galaxy. It is one of the few planets that can be seen without a telescope. That is why people in ancient times knew about the existence of this giant cosmic object, just like about the Sun, Moon and Venus. By sending a small telescope towards Jupiter, we will see an impenetrable layer of clouds 4 thousand kilometers thick and among them characteristic feature- large red spot. First time I saw him in 1665 French astronomer Giovanni Cassini. Its size is comparable to the diameter of planet Earth. The active movement of gases in the atmosphere of Jupiter occurs under the influence of winds whose speed reaches 600 kilometers per hour.
Diamond in the center of Jupiter
Scientists believe that under a thick layer of rapidly moving clouds, at a depth of about 40 thousand kilometers, the planet's core is stationary. Nothing is known about its chemical and physical parameters. There is a hypothesis that, under enormous pressure and temperature, the core could have formed either in the form of fossilized hydrogen with the properties of a metal, or in the form of coal with all the properties of diamond. Can anyone imagine diamond is three times larger than Earth?
Rings and moons of Jupiter
Jupiter also has rings, similar to Saturn. Despite the fact that the total width of the rings is about 6 thousand kilometers, few people know about them. In addition to all of the above, the fact that Jupiter has 67 moons. The largest of them are:
- Europe;
- Ganymede;
- Callisto.
Solar System Vacuum Cleaner
The presence of a large number of satellites is due to the fact that Jupiter creates very strong gravitational field. Therefore, this planetary ball can be called a vacuum cleaner of the Solar system. Numerous asteroids and comets are sucked into Jupiter's atmosphere. Thus, these space objects no longer pose a threat to planet Earth and humanity.
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Giant of the Solar System
Everyone knows that largest planet - Jupiter. Due to the fact that it can be observed almost all night, the planet has been known since ancient times. "Mulu Babbar"- that’s what his representatives called him ancient culture Mesopotamia, which means "star-sun". A significant breakthrough in the study of this planet occurred only in the middle of the 17th century.. He became the first celestial body to have satellites discovered, and this discovery was made by the great Galileo. This is truly a giant among planets, but is it a planet??
Planet or star
Some scientists at the beginning of the last century believed that the giant radiates own light , and some of its characteristics like the sun:
- consists of hydrogen;
- emits x-rays;
- emits radio waves;
- has a gigantic magnetic field.
Observant astronomers immediately noticed that all of the above characterizes the stars, and not planets. That’s why the question arose: maybe it’s not a planet, but a star? Jupiter has a slight nuclear energy emitter, however, science says the opposite: the planet should not have anything like this. Indeed, the planets are only reflect rays and energy, while the stars themselves generate both. And what’s most interesting is that the outgoing energy significantly exceeds that transmitted to the planet Sun.
Another important point- huge energy generation rate, which indicates that the planet is essentially "warming up". Observations made it possible to establish that, due to its gigantic mass, the planet absorbs particles "Solar Wind". As the number of captured particles increases, the mass of the planet itself increases, which is one of the main conditions for transformation into a star.
Scientists have calculated that in about 2 billion years Jupiter will catch up with the mass of the Sun, which will cause the emergence double solar system.
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In April of this year I observed one very bright object, lighting in my city is practically absent at night, so I was able to get a good look largest object in the solar system after the luminary itself - Jupiter. And it is not at all surprising that it was so clearly visible to the naked eye, because this planet superior our mass Earth a little more than 300 once. Accordingly, when she is at the point of opposition, the light reflected by her eclipses even Sirius.
The largest planet in the solar system - Jupiter and its origin
Jupiter located at a sufficient distance from the Sun to make it difficult for humanity to study it, and the atmosphere there is unfriendly, after all gas giant, after all. Showers of ammonia are hardly conducive to a comfortable immersion in the environment of any terrestrial device, especially since there is also no solid surface. No, it is quite possible that somewhere very deep there is core, but there is no hydrocarbon life there. The planet was formed due to large-scale phenomena, a series of chemical reactions and probably gravitational collapse, which marked the beginning of our system. Structurally Jupiter comprises:
- Multilayer atmosphere.
- Metallic hydrogen.
- The core, presumably stone.
Of course, it is not possible to obtain accurate data due to the peculiarities celestial body, but space devices, sent to direct closeness, allowed us to record more or less specific information at least about outer layer of the atmosphere.
Jupiter rotates around your axes just for 10 earth hours, which makes it in this regard not only the most massive, but also fast planet of the solar system. However, the orbit is so large that one a revolution around the Sun lasts 12 years. Due to its size, Jupiter has extremely powerful gravity, yes, approaching comet over a distance of 15 thousand kilometers was torn into many pieces. Plus, the planet has record number of satellites- about 70 objects.
Healthy 
Who is the largest in the solar system?
Largest planet in the solar system is gas giant -Jupiter. Jupiter known to ancient people as supreme deity Ancient Rome . What’s interesting is that she was God’s wife Juno. Namely, this is the name of the spacecraft that was sent to explore the planet. What amazes us about this gas giant:
- To fill all volume of Jupiter, need to 1300 planets Earth.
- If there were stocks hydrogen And helium was in 80 times more,Jupiter would become a star.
- Jupiter has a small copy of the solar system- 4 months and 67 small satellites.
And also, as it turned out, Jupiter shrinks by 2 cm every year. Scientists have discovered that after its “birth” the giant was much larger and hotter. And it was formed much earlier than Mercury, Venus, Earth and Mars. These four were formed from substances that gas planets were thrown into space.
The mystery of the planet - the big red spot
Jupiter It has amazing coloring. And all thanks to the winds that blow up 650 kilometers per hour. And here from the sky in the form of rain fall diamonds. Besides this wealth, on Jupiter constantly raging Hurricane, the diameter of which is 3 times the size of the Earth. From space it looks like giant red spot. It either increases or decreases, and its color still remains a mystery for scientists.
The giant's powerful magnetic field
A magnetic field this "god of the planets" exceeds the earth's by 20 thousand times. Electrically charged particles of this field are constantly at war with other planets, constantly attacking them. A Jupiter radiation may cause damage even good protected spacecraft. Jupiter also has three rings, although they are not as bright as Saturn's.
And also Jupiter like a real supreme god, protects planets from comets and asteroids. Its gravitational field affects asteroids and changes their orbits. Thanks to this, we are still alive.
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The seemingly inconspicuous UY Shield
In terms of stars, modern astrophysics seems to be reliving its infancy. Star observations provide more questions than answers. Therefore, when asking which star is the largest in the Universe, you need to be immediately prepared for answering questions. Are you asking about the largest star known to science, or about what limits science limits a star? As is usually the case, in both cases you will not get a clear answer. The most likely candidate for the biggest star quite equally shares the palm with its “neighbors.” How much smaller it may be than the real “king of the star” also remains open.
Comparison of the sizes of the Sun and the star UY Scuti. The Sun is an almost invisible pixel to the left of UY Scutum.
With some reservations, the supergiant UY Scuti can be called the largest star observed today. Why “with reservation” will be stated below. UY Scuti is 9,500 light-years away from us and is observed as a faint variable star, visible in a small telescope. According to astronomers, its radius exceeds 1,700 solar radii, and during the pulsation period this size can increase to as much as 2,000.
It turns out that if such a star were placed in the place of the Sun, the current orbits of a terrestrial planet would be in the depths of a supergiant, and the boundaries of its photosphere would at times abut the orbit. If we imagine our Earth as a grain of buckwheat, and the Sun as a watermelon, then the diameter of the UY Shield will be comparable to the height of the Ostankino TV tower.
To fly around such a star at the speed of light it will take as much as 7-8 hours. Let us remember that the light emitted by the Sun reaches our planet in just 8 minutes. If you fly at the same speed as it makes one revolution around the Earth in an hour and a half, then the flight around UY Scuti will last about 36 years. Now let’s imagine these scales, taking into account that the ISS flies 20 times faster than a bullet and tens of times faster than passenger airliners.
Mass and luminosity of UY Scuti
It is worth noting that such a monstrous size of the UY Shield is completely incomparable with its other parameters. This star is “only” 7-10 times more massive than the Sun. It turns out that the average density of this supergiant is almost a million times lower than the density of the air around us! For comparison, the density of the Sun is one and a half times higher than the density of water, and a grain of matter even “weighs” millions of tons. Roughly speaking, the averaged matter of such a star is similar in density to a layer of atmosphere located at an altitude of about one hundred kilometers above sea level. This layer, also called the Karman line, is the conventional boundary between the earth's atmosphere and space. It turns out that the density of the UY Shield is only slightly short of the vacuum of space!
Also UY Scutum is not the brightest. With its own luminosity of 340,000 solar, it is tens of times dimmer than the brightest stars. A good example is the star R136, which, being the most massive star known today (265 solar masses), is almost nine million times brighter than the Sun. Moreover, the star is only 36 times larger than the Sun. It turns out that R136 is 25 times brighter and about the same number of times more massive than UY Scuti, despite the fact that it is 50 times smaller than the giant.
Physical parameters of UY Shield
Overall, UY Scuti is a pulsating variable red supergiant of spectral class M4Ia. That is, on the Hertzsprung-Russell spectrum-luminosity diagram, UY Scuti is located in the upper right corner.
On this moment the star is approaching the final stages of its evolution. Like all supergiants, it began actively burning helium and some other heavier elements. According to modern models, in a matter of millions of years, UY Scuti will successively transform into a yellow supergiant, then into a bright blue variable or Wolf-Rayet star. The final stages of its evolution will be a supernova explosion, during which the star will shed its shell, most likely leaving behind a neutron star.
Already now, UY Scuti is showing its activity in the form of semi-regular variability with an approximate pulsation period of 740 days. Considering that the star can change its radius from 1700 to 2000 solar radii, the speed of its expansion and contraction is comparable to the speed of spaceships! Its mass loss is at an impressive rate of 58 million solar masses per year (or 19 Earth masses per year). This is almost one and a half Earth masses per month. Thus, being on the main sequence millions of years ago, UY Scuti could have had a mass of 25 to 40 solar masses.
Giants among the stars
Returning to the disclaimer stated above, we note that the primacy of UY Scuti as the largest known star cannot be called unambiguous. The fact is that astronomers still cannot determine the distance to most stars with a sufficient degree of accuracy, and therefore estimate their sizes. In addition, large stars are usually very unstable (remember the pulsation of UY Scuti). Likewise, they have a rather blurry structure. They may have a fairly extensive atmosphere, opaque shells of gas and dust, disks, or a large companion star (for example, VV Cephei, see below). It is impossible to say exactly where the boundary of such stars lies. After all, the established concept of the boundary of stars as the radius of their photosphere is already extremely arbitrary.
Therefore, this number can include about a dozen stars, which include NML Cygnus, VV Cephei A, VY Canis Majoris, WOH G64 and some others. All these stars are located in the vicinity of our galaxy (including its satellites) and are in many ways similar to each other. All of them are red supergiants or hypergiants (see below for the difference between super and hyper). Each of them will turn into a supernova in a few millions, or even thousands of years. They are also similar in size, lying in the range of 1400-2000 solar.
Each of these stars has its own peculiarity. So in UY Scutum this feature is the previously mentioned variability. WOH G64 has a toroidal gas-dust envelope. Extremely interesting is the double eclipsing variable star VV Cephei. It is a close system of two stars, consisting of the red hypergiant VV Cephei A and the blue main sequence star VV Cephei B. The centra of these stars are located from each other at some 17-34 . Considering that the radius of VV Cepheus B can reach 9 AU. (1900 solar radii), the stars are located at “arm’s length” from each other. Their tandem is so close that whole pieces of the hypergiant flow at enormous speeds onto the “little neighbor”, which is almost 200 times smaller than it.
Looking for a leader
Under such conditions, estimating the size of stars is already problematic. How can we talk about the size of a star if its atmosphere flows into another star, or smoothly turns into a disk of gas and dust? This is despite the fact that the star itself consists of very rarefied gas.
Moreover, all the largest stars are extremely unstable and short-lived. Such stars can live for a few millions, or even hundreds of thousands of years. Therefore, when observing a giant star in another galaxy, you can be sure that a neutron star is now pulsating in its place or a black hole is bending space, surrounded by the remnants of a supernova explosion. Even if such a star is thousands of light years away from us, one cannot be completely sure that it still exists or remains the same giant.
Let us add to this the imperfection of modern methods for determining the distance to stars and a number of unspecified problems. It turns out that even among a dozen known largest stars, it is impossible to identify a specific leader and arrange them in order of increasing size. In this case, UY Shield was cited as the most likely candidate to lead the Big Ten. This does not mean at all that his leadership is undeniable and that, for example, NML Cygnus or VY Canis Majoris cannot be greater than her. Therefore, different sources may answer the question about the largest known star in different ways. This speaks less of their incompetence than of the fact that science cannot give unambiguous answers even to such direct questions.
Largest in the Universe
If science does not undertake to single out the largest among the discovered stars, how can we talk about which star is the largest in the Universe? Scientists estimate that the number of stars, even within the observable Universe, is ten times greater than the number of grains of sand on all the beaches of the world. Of course, even the most powerful modern telescopes can see an unimaginably smaller portion of them. In search " star leader“It also doesn’t help that the largest stars can stand out with their luminosity. Whatever their brightness, it will fade when observing distant galaxies. Moreover, as noted earlier, the most bright stars are not the largest (example - R136).
Let us also remember that when observing a large star in a distant galaxy, we will actually see its “ghost”. Therefore, it is not easy to find the largest star in the Universe; searching for it will simply be pointless.
Hypergiants
If the biggest star It’s impossible to find practically, maybe it’s worth developing it theoretically? That is, to find a certain limit after which the existence of a star can no longer be a star. However, even here modern science faces a problem. Modern theoretical model The evolution and physics of stars do not explain much of what actually exists and is observed in telescopes. An example of this is hypergiants.
Astronomers have repeatedly had to raise the bar for the limit of stellar mass. This limit was first introduced in 1924 by the English astrophysicist Arthur Eddington. Having obtained a cubic dependence of the luminosity of stars on their mass. Eddington realized that a star cannot accumulate mass indefinitely. The brightness increases faster than the mass, and this will sooner or later lead to a violation of hydrostatic equilibrium. The light pressure of increasing brightness will literally blow away the outer layers of the star. The limit calculated by Eddington was 65 solar masses. Subsequently, astrophysicists refined his calculations by adding unaccounted components and using powerful computers. So the current theoretical limit for the mass of stars is 150 solar masses. Now remember that R136a1 has a mass of 265 solar masses, almost twice the theoretical limit!
R136a1 is the most massive star currently known. In addition to it, several other stars have significant masses, the number of which in our galaxy can be counted on one hand. Such stars were called hypergiants. Note that R136a1 is significantly smaller than stars that, it would seem, should be lower in class - for example, the supergiant UY Scuti. This is because it is not the largest stars that are called hypergiants, but the most massive ones. For such stars, a separate class was created on the spectrum-luminosity diagram (O), located above the class of supergiants (Ia). The exact initial mass of a hypergiant has not been established, but, as a rule, their mass exceeds 100 solar masses. None of the Big Ten's biggest stars measure up to those limits.
Theoretical dead end
Modern science cannot explain the nature of the existence of stars whose mass exceeds 150 solar masses. This raises the question of how one can determine the theoretical limit on the size of stars if the radius of a star, unlike mass, is itself a vague concept.
Let us take into account the fact that it is not known exactly what the stars of the first generation were like, and what they will be like during the further evolution of the Universe. Changes in the composition and metallicity of stars can lead to radical changes in their structure. Astrophysicists have yet to comprehend the surprises that further observations and theoretical research will present to them. It is quite possible that UY Scuti may turn out to be a real crumb against the background of a hypothetical “king star” that shines somewhere or will shine in the farthest corners of our Universe.
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