It is not always that people, looking at the sky, can imagine the true size of the Sun. What can I say, even the size of the Earth itself is difficult to imagine when you stand on its surface. People are accustomed to the fact that bugs, cats and dogs are small, but they themselves are big and strong, perhaps a little smaller than elephants, but still big. On a cosmic scale, a person cannot even be compared with a bacterium. If we consider that our planet accommodates 7.7 billion people living on 30% of its territory (the rest is occupied by the World Ocean), then each person individually already resembles a grain of sand. But the Earth is not even the largest planet in the solar system. But if I now tell you the figure of 2.4 billion kilometers, then you can hardly imagine how much or how little it is. Therefore, we will begin to consider the largest objects in the Universe from the very accessible to man examples so that you have something to compare with.
You and I all know that beetles are small insects, no larger than a fingernail. However, some types of beetles can reach 15-17 centimeters in length. For example, the body length of titan lumberjacks varies between 8-17 centimeters, but according to some data it can reach 21 centimeters. The average height of a person ranges from 170 to 180 centimeters. This means that people are only 10 times larger than small bugs, and this is nothing on the scale of the Universe, and you will soon see this. By the way, the largest working phone on Earth is a copy of the Samsung SCH-R450, created by Cricket. The phone dimensions are 4.5×3.5×0.74 meters. The largest land animal in the world is the African elephant. Males of this species reach from 6 to 7.5 meters in length and up to 3.8 meters in height. And the blue (or blue) whale is considered the largest living creature on our planet. The size of the animal reaches 30 meters in length, and its weight reaches 200 tons. That is, to get the length of a whale you need approximately seventeen people.
The tallest building in the world is located in Dubai, United Arab Emirates. Burj Khalifa (that's the name of the building) rises 828 meters above the ground. No matter how long you count, that’s about 28 whales or 480 people. IN Saudi Arabia At the moment, construction is underway on the Burj Jeddah building, the height of which will be 1,007 meters. If we take ten thousand of these towers and stack them on top of each other, we get the length Russian Federation from west to east, namely 10,000 kilometers. This is greater than the radius of our planet, whose standardized equatorial value is 6,378 km. The length of the equator (an imaginary line passing through the middle Globe, and dividing it into two hemispheres) - 40,075 kilometers.
Now we're getting to the fun part. Our solar system consists of more than just the sun and planets. Someone, of course, will immediately add that there are also satellites and asteroids. And those who have been following astronomical discoveries and disputes over the past decades also know about the existence of dwarf planets. But we will analyze everything in detail. Let's start with the fact that in 1801 the Italian astronomer Giuseppe Piazzi discovered the dwarf planet Ceres. It was mistakenly considered a full-fledged planet for a whole decade, then it was classified as an asteroid, and only in 2006 did it take its place among the dwarf planets. Ceres was previously considered the largest asteroid. The diameter of this dwarf planet is 945-950 kilometers. Now the largest asteroid solar system Vesta is considered to have a diameter of 525.5 km.
Pluto, unlike Ceres, which received a “promotion” in the 21st century, has a sadder history. From its discovery in 1930 until 2006, Pluto was believed to be the ninth planet in the solar system. However, the International Astronomical Union decided to reconsider the concept of "planet" in the middle of the first decade of the 21st century. According to the new classification, Pluto became the largest dwarf planet along with Eris. The diameter of the two objects is 2,376 and 2,326 kilometers, respectively. For comparison: the diameter of the Moon is 3,474 kilometers. The largest satellite in the solar system revolves around Jupiter and is called Ganymede. This is one of four moons discovered by Galileo Galilei in 1610. Its diameter is 5,268 kilometers.
But all the objects discussed above, as you understand, are even smaller than the Earth, and yet we have collected them here to learn about the largest objects in the Universe. Let's start with Jupiter, the largest planet in the solar system. The diameter of this gas giant is approximately 139,822 kilometers. Determining the largest exoplanet (the so-called planets that are located outside the solar system) in the Universe is a rather difficult task, since some gas giants are so large that they look like stars, but their mass is insufficient to support nuclear reactions of burning hydrogen and turning into a star . Discovered in 2013, HD 100546 b is believed to be the largest exoplanet known, with a diameter 6.9 times that of Jupiter. The diameter of the Sun, the closest star to Earth, is ten times the diameter of Jupiter (or 109 times the diameter of Earth)—1.392 million kilometers. The mass of the Sun is 99.866% of the total mass of the entire Solar System.
However, if you think that the Sun is a large object, then I will disappoint you. The largest known star in the Universe is the red hypergiant UY in the constellation Scutum (UY Scuti). This star has a diameter of 2.4 billion kilometers, which is 1,700 times larger than the Sun! Imagine that you drew a circle with a diameter of 1 mm on the asphalt with chalk (think of it as just putting a dot), so the UY Shield will be represented by a circle with a diameter of almost two meters. If you place UY Scuti at the center of the Solar System, its photosphere (the radiating layer of the stellar atmosphere) will encompass the orbit of Jupiter. But there's another one here interesting fact. The radius of the red hypergiant NML Cygnus is estimated from 1,642 to 2,755 solar radii, which means that in theory this star could be one and a half times larger than UY Scuti.
But why argue about which star is bigger, if it's still crumbs compared to black holes - regions of space-time whose gravitational attraction is so strong that even objects moving at the speed of light cannot leave them. In 2018, an object was discovered that received the rather complex name SDSS J140821.67+025733.2. In fact, this is a quasar - quasi-stellar radiosource, which translated into Russian means “star-like radio source.” Quasars are at the center of active galaxies and are among the brightest objects known in the Universe, emitting a thousand times more energy than, for example, the Milky Way (the galaxy in which we live). At the center of quasars are supermassive black holes that absorb surrounding matter, forming an accretion disk, which is the source of radiation. The diameter of SDSS J140821 is 1.17 trillion kilometers, or about one-tenth of a light year.
I remembered the astronomical unit “light year” not by chance, but so that you can at least roughly imagine the following quantities. Our Milky Way galaxy has a diameter of 105,700 light years, which is a million times larger than the diameter of SDSS J140821. Now look at the picture above, because it shows the largest currently known galaxy in the Universe, IC 1101. Its diameter is between 4 and 6 million light years. Galaxy IC 1101 is located approximately one billion light years away. It contains about 100 trillion stars, while our galaxy may contain between 200 and 400 billion stars. Galaxies, in turn, are combined into clusters.
First, a little background. Scientists have long noticed that our galaxy is moving at high speed in a certain direction, presumably under the influence of the gravitational forces of some massive cluster of objects. It was decided to conditionally call this cluster the “Great Attractor”. However, it was not possible to examine this region for a long time due to the fact that it was hidden behind the plane of the Milky Way. Only with the advent of X-ray telescopes were astronomers able to study the location of the Great Attractor. It turned out that there are much fewer galaxies there, which means much less mass to create the necessary gravitational forces to attract the Milky Way and nearby galaxies. Scientists began to peer further. And at a distance of 500-600 million light years from Earth, they found a supermassive structure in the region of the Shapley Supercluster, which is the most massive of the 220 known superclusters of galaxies in the observable universe. It contains about 10,000 times the mass of the Milky Way and 4 times the mass observed in the Great Attractor region. However, even this finding cannot fully explain the movement of the Milky Way. So, probably, the data of scientists is still not complete. An important role is also played by the incompletely studied distribution of dark matter (the center of gravity of its clusters may not coincide with the center of gravity of the local supercluster), which determines the large-scale structure of the Universe.
In any case, reading such figures, it is already difficult to say that man is a big creature, right? But even these meanings will seem childish to you after the end of this paragraph. The fact is that in space there are such formations as voids (from the English void - “emptiness”). These are vast areas between galactic filaments in which there are no or almost no galaxies and clusters, that is, relatively empty areas of space. Scientists believe that voids make up up to 50% of the volume of the Universe, and this percentage, in their opinion, will continue to grow due to super-strong gravity, which attracts all the matter surrounding them. The largest such object recorded by mankind is located in the southern part of the constellation Eridanus. The dimensions of Supervoid Eridani are 1.8 by 3 billion light years. According to some physicists, such relic cold spots could be a reflection of another universe, caused by quantum entanglement between universes.
At the same time, not only empty spaces are huge in the Universe, but also supermassive clusters filled with light. Discovered in 2012, the Huge-LQG Huge Quasar Group, U1.27, is the largest cluster and contains 73 quasars. The diameter of this object is 4 billion light years. If that tells you anything, it's approximately 38 trillion kilometers. This cluster is one of the largest structures in the observable Universe. 5 billion light years. This is exactly the diameter of the Giant Galactic Gamma Ring (Giant GRB Ring). Astronomers studying gamma-ray bursts (huge bursts of energy that result from the death of massive stars) discovered a series of nine bursts, the sources of which were at the same distance from Earth, that formed this structure. The “ring” itself is just a term that describes the visual representation of this phenomenon when observed from Earth. Most likely, the giant gamma ring is a projection of a certain sphere around which gamma radiation emissions occurred over a relatively short period of time (about 250 million years). Now try to relax a little, because we are approaching the most incredible object, so huge that even supervoids seem small against its background.
The largest structural object in the Universe was discovered by astronomers while observing gamma radiation and received one of the most poetic names: The Hercules–Corona Borealis Great Wall. The most interesting thing is that the object received this name thanks to a Filipino teenager who simply entered it into Wikipedia immediately after the news about the discovery of the “wall” in November 2013. The Great Wall of Hercules - Corona Borealis is a galactic filament or wall consisting of groups of galaxies connected by gravity, measuring 10 billion light years in its greatest direction. In fact, this structure occupies about 10% of the visible Universe. Its discovery completely crossed out the existing cosmological principle of the homogeneity of the Universe. This is the basic position of modern cosmology, according to which each observer at the same moment in time, regardless of the place and direction of observation, discovers on average the same picture in the Universe. The scale over which homogeneity should appear is 250-300 million light years. After discovering a huge group of quasars measuring 4 billion light years, which is 13.5 times larger than the indicated value, scientists became wary. However, the existence of the Great Wall of Hercules – Corona Nord, which is larger than the established scale by more than 30 times, did call the cosmological principle into question. In addition, we see this wall as it was about 10 billion years ago, that is, 3.79 billion years after the Big Bang. The presence of such a huge and massive structure at such an early stage is impossible, based on the current model of the formation of the Universe. This means that scientists still know nothing about the world in which we live.
Although the Great Wall of Hercules - Corona Borealis is the largest structural object in the Universe, our article is not yet complete. In astronomy there is such a thing as the Cosmic Web. It is believed that all the largest structures, such as filaments, voids, superclusters, walls, and so on, form a single structure, so to speak, the “skeleton of the Universe.” In 2014, the work of researchers was published who managed to observe a thread of the cosmic web at a large cosmological distance, “illuminated” by a quasar. That is, the light emitted by the black hole “warmed up” the matter of the thread and made it glow. The web turned out to be approximately ten times more massive than theoretically expected, and explanations this fact could not be found. It is believed that the threads of the Cosmic Web are a kind of bridge for gravitational interaction between galaxies.
But you and I will most likely never know whether there are larger objects in the Universe, because people cannot look beyond the boundaries of the observable Universe. Currently, the comoving distance (the distance that does not change over time due to the expansion of space) to the most distant observable object (the surface of the last scattering of the CMB) is approximately 14 billion parsecs or 46 billion light years. Therefore, in fact, the observable Universe for humanity is a ball with a center in the Solar System, the diameter of which is approximately 93 billion light years.
If we draw a rough analogy, then our planet is just one atom of a small cog in the seat of a tanker floating in the ocean. So, the Earth is a small planet in the solar system, which, in turn, is part of the Milky Way. Further, our galaxy, together with the Andromeda galaxy and the Triangulum galaxy, form the Local Group of galaxies. More than 100 groups and clusters of galaxies are part of the Virgo Supercluster, which is part of the wall or complex of the Pisces–Cetus Supercluster Complex. All this is theoretically connected by the Cosmic Web and, together with the cosmic voids, makes up the Universe we observe.
The universe is something that our minds cannot comprehend. Some scientists call the entire Universe material world, surrounding us. The human mind is simply not able to understand and analyze its true dimensions.
Nobody knows whether the Universe is finite or not, but it is scientifically proven that it is constantly expanding. This place brings together amazing objects such as nebulae, galaxies, quasars, star clusters, black holes, quasars. Let's talk about the largest objects in the Universe.
The largest asteroid in the Universe
The largest asteroid is called Vesta, and it is recognized as the brightest visible asteroid that can be seen in the starry sky even without a telescope or spotting scope. The dimensions of the asteroid are 578x560x478 kilometers. It has a slightly elongated asymmetrical shape and can even be classified as a dwarf planet such as Mercury. The asteroid is located in the belt between Jupiter and Mars. Discovered celestial body was in 2010 using the Dawn apparatus. It is worth saying that the asteroid does not pose a threat to the Earth due to the high gravity acting on it from Jupiter.
The largest planet
The championship of the largest planet in the solar system is held by Jupiter, which contains hundreds of planets such as the earth. But in the depths of the visible Universe, a real monster lurks.
If we talk about exoplanets that could hypothetically harbor life, one of the largest planets in the Universe is Gliese 581, which was discovered in 2007 at a distance of 20 thousand light years from the earth at the Chilean La Silla Observatory using Doppler shift.
Biggest star
Interesting:
Are there stars that do not shine at all in the visible range?
The largest black hole
The largest supermassive black hole in the visible Universe was discovered in the constellation Perseus at a distance of 228 light years from Earth. This black hole is located in the galaxy: NGC 1277. This black hole contains a simply gigantic amount of matter, which is approximately twelve billion times the mass of our Sun.
It turned out that this black hole weighs about 15 percent of the mass of the entire galaxy, although black holes usually weigh no more than one and a half percent. By the way, such a small black hole is also located in the center of our Milky Way. Scientists agree that a galaxy in which there is a supermassive hole is very strange, since the nature of the formation of such an object is incomprehensible to physicists.
Largest galaxy
The largest galaxy in the Universe is called IC 1101. It is a large supergiant that is located in the center of the Abell 2029 galaxy cluster. The galaxy is located at a distance of one billion light years from Earth in the constellation Virgo. It is a CD class galaxy with a diameter of 7 million light years. The object is considered the largest among the known galaxies that have been discovered throughout cosmological research.
The galaxy IC 1101 contains more than one hundred trillion stars. If this galaxy were located in the place of the Milky Way, then it would absorb not only it, but also the Andromeda Nebula, the Triangulum Galaxy, the Large and Small Magellanic clouds.
Interesting:
Why does the sun shine?
Shapley Supercluster
The Shapley Supercluster is a huge cluster of stars that was discovered in 1989. It has a high density of stars. In total, according to preliminary calculations, the Shapley Supercluster contains a concentration of stars more than 500 million light years away. It also contains large galaxies A3560, A3558 and A3559. In total, there are about twenty-five galaxies in the Shapley Supercluster.
The largest pulsar
The largest pulsar, which is a bright pulsating star with a super-dense mass, was discovered in the region of the Tarantula Nebula. It was discovered using a powerful gamma-ray telescope 165 thousand light-years from the Milky Way galaxy. A pulsar was formed after a star exploded, and its core became a powerful neutron star. With a diameter of a couple of kilometers, the pulsar has a mass of twenty solar masses. Its gamma-ray emission is five times higher than that of the famous pulsar from the Crab Nebula. The pulsar rotates at a speed of twenty revolutions per second, emitting powerful gamma radiation.
Space is not easy great nothingness, endless space without oxygen and sounds. Unusual and amazing objects are hidden in its depths, about which humanity still knows nothing.
However, scientists manage to discover something, and among the finds there are truly impossible ones: what about the whole huge cloud of alcohol or a foam planet?
He collected the most amazing planets, nebulae, and other cosmic finds that will surprise anyone simply by the very fact of their existence. Just look:
1. “Pan” - a real space dumpling
This is a satellite of Saturn, which has “rings”, from our star system. Just a couple of years ago it was believed that it was spherical in shape, but in reality everything turned out to be different.
When Pana was photographed by the Cassini 7 probe from a distance of 24.5 km, the photo showed that it was flattened and had a belt. It looks like a real dumpling or, if you prefer, ravioli.
2. The Sombrero Galaxy with a black hole in the very center
This galaxy is 28 million light years away from us. It seems to be far away, but from Earth it is quite visible. And in general, this is not one galaxy, but two. That's why the form is like this.
And this space object is also cool because inside it there is a supermassive black hole, which has a mass of 1 billion of our Suns.
3. Huge “Foam Planet”
An exoplanet called Kepler-7 b was discovered using the Kepler telescope. It has an abnormally low density: 30 times lower than that of water on Earth.
A cubic meter of the substance from which this celestial body is made weighs only 30 kg. The polystyrene foam we use to insulate our houses weighs about the same. Hence the name.
4. Gas nebula called “Soap Bubble”
A beautiful symmetrical nebula floats in the field of the constellation Cygnus. It was discovered only a few years ago, so it is not in many astronomical atlases.
What is most surprising is the shape and appearance nebulae. It resembles a real soap bubble, and this is exactly the nickname scientists gave it.
5. Tethys - a huge eye in outer space
Another satellite of Saturn, and it resembles a huge eye that watches us from the distant expanses of space. Meet Tethys.
The iris and pupil on the satellite are a huge crater in the middle of it. It was filmed by the Cassini probe just two years ago, in 2017.
6. The most expensive planet made from real diamond
The planet is called 55 Cancri e. It orbits a star that resembles the Sun in the constellation Cancer. A year on it is equal to our 18 hours.
The temperature at the surface of the planet reaches 1,648 degrees Celsius. It is twice the size of the Earth and one third consists of diamond. Imagine how much it could cost.
7. The oldest cosmic cloud “Himiko”
One of the oldest objects in space
This is one of the most interesting phenomena in space that is known to our scientists. The cloud, which consists of three young galaxies, formed 800 million years after the Big Bang.
This seems like a huge amount of time. But by cosmic standards this is not much. By observing Himiko, scientists can provide a large number of answers to questions about the universe.
8. An ominous nebula called "Witch's Head"
The nebula's real name is IC 2118. It is located in the southern constellation Eridanus at a distance of 1,000 light years from the Sun. What is most surprising is its outline.
We see the nebula from behind the star Rigel. Due to its radiation, the outlines of the “Witch’s Head” are reflected and visible in telescopes from Earth.
9. Rum and raspberry flavored dust cloud
We won't be able to try it.
It is located in a region of space called Sagittarius B2. It was discovered about ten years ago, and thematic media immediately began to insist that this object must have a raspberry flavor.
Scientists assure that the molecules that were discovered in the cloud are indeed similar in structure to rum molecules. But trying all this won’t work, at least because of other dangerous chemical compounds.
10. Incredibly large space ocean
An ocean that is made of steam
At a distance of 12 billion light years from Earth there is a quasar called APM 08279 + 5255. Its brightness is 100 billion times greater than the Sun. But that's not what we're interested in.
Several years ago, huge reserves of water were discovered around it. They are 140 trillion times larger than the volume of Earth's oceans. Surprisingly, it’s still too far for us to fly there.
11. “Prometheus” - a real space potato
Potatoes with potatoes
This satellite of the same Saturn has an irregular and uneven shape, dotted with craters. Therefore, it resembles a real potato.
Prometheus is called the shepherd moon. It attracts cosmic dust and other objects that form one of the planet's rings.
12. The Loneliest Planet Known to Humans
A planet that walks on its own
The planet is called PSO J318.5-22 and is located 80 light years from Earth. It is six times larger than Jupiter and does not obey any star.
Yes, usually planets are tied to a celestial body, but this one prefers to walk on its own. This is a unique phenomenon, but it proves that this is even possible.
13. The huge “Great Wall of Hercules - Northern Crown”
Our scientists have not yet found anything larger in space
When scientists observed gamma radiation in the Universe, they discovered the largest cosmic object known to our science.
Its size is 10 billion light years, and its name was invented by a Filipino teenager. He described the object on Wikipedia before scientists did, and they did not change his name.
14. This is the largest star known to science
Simply huge!
It is called VY Canis Majoris, and its diameter is 1,500 times larger than the Sun. Compared to this star, our planet is nothing at all. Our science does not yet know more about the star.
However, it is impossible to say that this is the largest star in the Universe, because a couple of hundred years ago our Sun was considered the largest star.
15. The most famous red dwarf “Proxima Centauri”
We'll move here someday
Its ecosystem contains the exoplanet Proxima b. It is located at such a distance from the star that it could theoretically harbor life.
Moreover, scientists generally believe that it is in the red dwarf ecosystem, which is 4.22 light years away from us, that in the future it may run over humanity.
16. There is a planet made of hot ice in space
This ice is called "Ice X"
It is called Gliese 436 b and is located 33 light years away. It is classified as a hot Neptune because of the substances it consists of.
Judging by the density, it contains water molecules. Due to the size of the planet, which is 4.5 times larger than the Earth, the liquid remains crystallized even at 300 degrees - it is ice, but hot.
17. The planet with the worst weather in the Universe
OMG: it's raining glass here
It is called HD 189733 b. At first glance, it resembles Earth. The same blue dot in the infinitely black depths of space. But that's where the similarities end.
The wind speed on this planet reaches 8,700 km/h. At the same time, it constantly rains on it, but not from water, but from molten glass.
18. A huge cloud of alcohol in the middle of outer space
There is no such thing as too much alcohol
A huge cloud of alcohol is located at a distance of 6,500 light years from Earth. It consists of almost only ethanol, with a length of approximately 482,803,200,000 kilometers.
Scientists specify that about 189,270,589,200,000 liters of beer could be produced from such a volume of alcohol. But these calculations may not be 100% accurate.
19. Amazing part of the Carina Nebula “Finger of God”
The Carina Nebula, which NASA was able to photograph, can take on the most bizarre shapes. Some see in its parts a hand with an outstretched finger - hence the name.
20. The real “Death Star” in orbit of Saturn
Tell me, it really looks like it!
A few years ago, the Cassini spacecraft managed to photograph another satellite of Saturn, called Mimas. It was immediately dubbed the “Death Star”.
The oceans are, of course, vast, and the mountains are impressive in their size. 7 billion people is also not a small number. Since we live on planet Earth (which has a diameter of 12,742 km), it is easy for us to forget how tiny we truly are. To realize this, all we have to do is look at the night sky. Looking into it, it becomes clear that we are just a speck of dust in an unimaginably vast universe. The list of objects below will help put human greatness into perspective.
10. Jupiter
Largest planet (diameter 142.984 km)
Jupiter is the largest planet in the solar system. Ancient astronomers called Jupiter the king of the Roman gods. Jupiter is the 5th planet from the Sun. Its atmosphere consists of 84% hydrogen and 15% helium with small additions of acetylene, ammonia, ethane, methane, phosphite and water vapor. The mass of Jupiter is 318 times greater than the mass of the Earth, and its diameter is 11 times greater than that of the Earth. The mass of Jupiter is 70% of the mass of all other planets in our solar system. Jupiter's volume can accommodate 1,300 Earth-sized planets. Jupiter has 63 satellites (moons) known to science, but almost all of them are very small and dim.
9. Sun
The largest object in the Solar System (diameter 1,391,980 km) 
The Sun (yellow dwarf star) is the largest object in the Solar System. Its mass makes up 99.8% of the total mass of the Solar System, and Jupiter's mass takes up almost the rest. At the moment, the mass of the Sun consists of 70% hydrogen and 28% helium. All other components (metals) occupy less than 2%. The percentages change very slowly as the Sun converts hydrogen into helium at its core. Conditions in the Sun's core, which occupies approximately 25% of the star's radius, are extreme. The temperature reaches 15.6 million degrees Kelvin, and the pressure reaches 250 billion atmospheres. The solar power of 386 billion megawatts is provided by nuclear fusion reactions. Every second, about 700,000,000 tons of hydrogen are converted into 695,000,000 tons of helium and 5,000,000 tons of energy in the form of gamma rays.
8. Solar system
Our solar system consists of a central star (the Sun) and nine planets: Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, Neptune and Pluto, as well as numerous moons, millions of rocky asteroids and billions of icy comets.
7. VY Canis Major(VYCMa)
The largest star in the Universe (3 billion kilometers in diameter) 
The star VY Canis Majoris (VY Canis Majoris) is the largest and also one of the brightest stars known at the moment. It is a red hypergiant in the constellation Canis Major. Its radius is 1800-2200 times greater than the radius of the Sun, and its diameter is 3 billion kilometers. If it were placed in our solar system, its surface would extend beyond the orbit of Saturn. Some astronomers disagree with this statement and believe that the star VY Canis Majoris is actually much smaller, only 600 times larger than the Sun, and would only stretch to the orbit of Mars.
6. Most large number water ever discovered
Astronomers have discovered the largest and oldest mass of water ever discovered in the Universe. The giant 12-billion-year-old cloud carries 140 trillion times more water than all of Earth's oceans combined. A cloud of water vapor surrounds a supermassive black hole called a Quasar, located 12 billion light years from Earth. According to scientists, this discovery proved that water has dominated the Universe throughout its existence.
5. Extremely huge supermassive black holes
(21 billion times the mass of the Sun) 
A supermassive black hole is the largest type of black hole in a galaxy, ranging in size from hundreds of thousands to billions of solar masses. Most, if not all, galaxies, including the Milky Way, are believed to contain a supermassive black hole at their center. One of these newly discovered monsters, weighing 21 billion times the mass of the Sun, is an egg-shaped swirl of stars. It is known as NGC 4889, the brightest galaxy in a sprawling cloud of thousands of galaxies. This cloud is located 336 million light years from the constellation Coma Berenices. This black hole is so big that our entire solar system would fit there about a dozen times over.
4. Milky Way
100,000-120,000 light years in diameter 
The Milky Way is a closed spiral galaxy with a diameter of 100,000-120,000 light years and containing 200-400 billion stars. It may contain at least that many planets, 10 billion of which may orbit within the habitable zone of their parent stars.
3. El Gordo "El Gordo"
Largest galaxy cluster (2×1015 solar masses) 
El Gordo is located over 7 billion light years from Earth, meaning it has been observed since birth. According to scientists involved in the study, this cluster of galaxies is the most massive, hottest and emits more X-rays than any other known cluster at this distance or even further.
The central galaxy in the middle of El Gordo is unusually bright and has amazing blue rays at optical wavelengths. The authors believe that this extreme galaxy was formed as a result of the collision and merger of two galaxies at the center of each cluster.
Using data from the Spitzer Space Telescope and optical images, it was estimated that about 1% of the cluster's total mass is occupied by stars, while the rest is hot gas filling the gaps between stars and visible to the Chandra telescope. This ratio of gas to stars is consistent with results obtained from other massive clusters.
2. Universe
Estimated size - 156 billion light years 
A picture is worth a thousand words, so look at this poster and try to imagine/understand how big our Universe is. The mind-blowing numbers are listed below. Here is a link to the full-size image.
Earth 1.27×104 km
Sun 1.39×106 km
Solar System 2.99×1010 km or 0.0032 light years
Solar interstellar space 6.17×1014 km or 65 light years
Milky Way 1.51×1018 km or 160.00 light years
Local Group of Galaxies 3.1×1019 km or 6.5 million light years
Local Supercluster 1.2×1021 km or 130 million light years
Universe 1.5×1024 km or 156 billion light years (but no one knows for sure)
1. Multiverse
Imagine not one, but many universes existing at the same time. The multiverse (or meta-verse) is a hypothetical collection of many possible universes (including the historical universe in which we exist). Together they form everything that exists and can exist: the community of space, time, matter and energy, as well as the physical laws and constants that describe them. But, again, there is no evidence for the existence of a multiverse, so it may well be that our universe is the largest.
The universe is huge. It is difficult for us to imagine its true size. Scientists say that from the moment big bang she has grown so much that she has... We cannot see the entire Universe, but those parts of it that are open to our eyes also contain many secrets, riddles and other unusual things. In the past we have already written about. Today we’ll talk about single ones: starting from the largest asteroid and ending with the largest galaxy in the visible space of space.
Looks creepy, right?
Reference: One light year is a unit of measurement of distance in astronomy, equal to the distance that light travels in a vacuum in one Earth year.
The largest asteroid in the solar system
Such an asteroid can do a lot of things.
Previously, the largest asteroid in the Solar System was Ceres. The diameter of the object is about 950 kilometers. The second largest was Pallas with a diameter of 512 kilometers. And Vesta occupied third place as the largest known asteroid in the Solar System, inferior in size to Pallas, but ahead of it in mass.
After scientists transferred it to the category of dwarf planets, Pallas began to occupy the top line of the largest (by size) asteroids in the Solar System. However, astronomers clarified the size of Vesta and it turned out that it is larger than Pallas. The diameter of Vesta is 530 kilometers. Thus, Vesta became not only the largest, but also the most massive asteroid in our solar system.
The largest satellite of the planet in the solar system
Comparative sizes of Ganymede with other satellites of the solar system and the Earth
Gas giant Jupiter's moon Ganymede is the largest moon in the solar system. Its diameter is 5268 kilometers.
Ganymede is one of the four largest moons of Jupiter, which, along with Io, Europa and Callisto, were first discovered by the Italian mathematician, philosopher and astronomer Galileo Galilei. The name Ganymede was not used until the mid-20th century. Galileo called the satellites he discovered “Medici planets,” and Ganymede himself called Jupiter III or “the third satellite of Jupiter.”
Scientists believe that under the surface of Ganymede, which contains much more water than on Earth.
The largest satellite of an exoplanet
The star WASP-12, located 870 light-years away, hosts an exoplanet. Recall that exoplanets are planets that are located outside the solar system.
In 2012, the planet WASP-12b was explored by Russian scientists. They assumed that she had a companion. This possibility was based on an analysis of the brightness (brilliance) of the star. Based on the characteristics of brightness changes, it is possible to calculate what fraction of the star’s disk area is covered by the satellite. Scientists believe that the satellite has a radius of 0.57 of the radius of Jupiter (it is 6.4 times the size of Earth). Such a large size allowed us to assume the existence of a satellite.
The largest planet in the solar system
Comparison of the sizes of Jupiter and Earth.
With a diameter of 142,984 kilometers, Jupiter is the largest planet in the solar system. Along with Saturn, Uranus and Neptune, Jupiter is classified as gas giant.
Jupiter's mass is 318 times that of Earth. It is 2.5 times heavier than all the other planets in the solar system combined. The giant is located at a distance of about 770 million kilometers from the Sun and makes a complete revolution around the star in approximately 11.9 Earth years.
Perhaps the most famous feature of Jupiter is its (BKP) - a hurricane that has continued on the planet for more than 300 years. The diameter of the Spot is greater than the diameter of the Earth.
Largest rocky exoplanet
Artist's representation of planet BD+20594 b
The largest rocky exoplanet was discovered by the Kepler space telescope in 2016 in the constellation Aries, which is 500 light years away. The object, designated BD+20594b, is about 16 times heavier than Earth and has a radius 2.2 times that of Earth.
Previously, Kepler-10 c was considered the largest rocky exoplanet. This planet was said to have a radius that is 2.35 times that of Earth, and its mass is about 17 times that of Earth. However, more accurate calculations conducted in 2017, it was possible to establish that the planet Kepler-10c is only 7.4 times heavier than Earth, and its composition is rather closer to gas giants.
The largest gas giant outside the solar system
The largest gas giant.
Determining the largest exoplanet of the gas giant class is not an easy task. Scientists need to take many things into account. For example, in space there are objects so huge that they can hardly be called planets. They are more like a star. At the same time, their mass is less than the minimum required to support nuclear reactions of hydrogen combustion and transformation into a star. Such objects are usually called substellar.
Presumably the largest gas giant exoplanet discovered to date is HD 100546 b, discovered in 2013. It is located 337 light years from Earth. Scientists believe that HD 100546 b is 6.9 times larger and 20 times heavier than Jupiter.
The largest star in the Universe
Deep bottomless space.
Currently, the largest star not only in our Milky Way galaxy, but also in the known Universe is the red hypergiant UY Scuti. It is located approximately 9,500 light years away. According to scientists, the radius of UY Scutum is equal to 1708 solar radii, but it is constantly changing and can reach 2100 solar radii. The diameter of the star is 2.4 billion kilometers.
Size of our Sun and star UY Scuti (magnified by 7 times)
To understand: if the Sun is drawn with a small circle with a diameter of 1 mm, then for the UY Shield you will need a circle with a diameter of 1.7-2.1 meters! If you place UY Scuti at the center of the Solar System, its photosphere (the radiating layer of the stellar atmosphere) will encompass the orbit of Jupiter.
According to modern estimates by astronomers, the star UY Scuti is 340,000 times brighter than our Sun.