Galaxies, also known as the universe island, originated from the Greek "galaxies", which has a huge exponentialStellar systemandInterstellar dustOperating system composed of.Galaxy is the basic unit of the universe.Referring to the Milky Way, it is a galaxy that contains stars, gasesCosmic dustanddark substanceAnd is bound by gravity.
Typical galaxies, from those with only tens of millions of starsDwarf galaxy, to a trillion starsElliptical galaxyYes, they all revolve around a center of mass.In addition to individual stars and thin interstellar matter, most galaxies have a large number of multi star systemsclusterAnd variousNebula。
In the observable universe, the total number of galaxies may reach 100 billion (10eleven）Above.[1]Most galaxies are between 1000 and 100000 in diameterSecond gapThe distance between them is the order of magnitude of the difference of millions of seconds.[2]The intergalactic space (the space between galaxies) is full of extremely thin plasma with an average density of less than one atom per cubic meter.Most galaxies will be organized into larger groups, becoming galaxy clusters or clusters, and galaxy clusters will converge into larger supercluster clusters.These larger groups are often called large-scale fiber structures, which are distributed around the huge holes in the universe.
NGC 4414, located in the constellation Cassiopeia, is a typical spiral galaxy.
Galaxies vary greatly in size。The diameter of elliptical galaxies ranges from 3300 light-years to 490000 light-years;The diameter of the spiral galaxy ranges from 16000 light years to 160000 light years;Irregular galaxies are between 6500 and 29000 light-years in diameter.
The mass of galaxies is generally between 1 million and 1 trillion times the mass of the sun.
The stars in the galaxy are movingThe galaxy itself is also rotating, and the whole galaxy is also moving in space.Traditionally, astronomers believe that the ratio of clockwise and counterclockwise rotation of galaxies is the same.But according to a galaxy classification, the distributed participation projectGalaxy ZooAccording to our observation, there are more galaxies rotating counterclockwise.
Diagram of galaxy redshift.
Most galaxies havered shiftphenomenon, indicating that these galaxies are getting farther and farther away from the Earth in the direction of space line of sight.This is also a strong evidence of the Big Bang theory。
The distribution of galaxies is nearly uniform on a large scale；But on a small scale, it is very uneven.for exampleLarge Magellanic GalaxyandMagellanic galaxyThey form double galaxies, and they form triple galaxies with the Milky Way.
historically,Galaxies are classified according to their shapes(usually referring to their visual shape).The most common isElliptical galaxy: They have a bright oval shape;spiral galaxy It is the shape of the disc plus the bendingVortex arm；Irregular galaxies are usually the result of the influence of other nearby galaxies.The interaction between neighboring galaxies may lead to the merger of galaxies or a large number of starsproduce, become the so-calledStarburst galaxy [3]。Small galaxies without organized structure will be calledIrregular galaxy。[4]
Although human beings are currentlydark substanceLittle is known about, but it occupies about90%Quality of.Observed data displaySupermassive black holeExists in the core of most galaxies, which are considered to beActive galactic nucleusThe main cause of.Galaxy - Earth andsolar systemThe galaxy where it is located - there is at least one such star in the core（Sagittarius A*）。
In the universe, a combination of two or more stars in rotational motion is called a galaxy.There are two types of star rotation: one is that many small stars circle the center of large massstarRotation, such as many planets andcometEqual rotation around the sun;Second, two or more planets around the commoncentroidRotate each other.Most galaxies belong to the former.
structure
Announce
edit
Few galaxies exist alone. Many galaxies are bound by gravity with a certain number of galaxies.A group containing about 50 galaxies is called a galaxy group, and a larger group containing thousands of galaxies is called a galaxy group, which spans millions of seconds.Galaxy clusters are usually governed by a huge elliptical star systemTidal forceIt will destroy nearby satellite galaxies and add mass to the galaxies.The super galaxy cluster is a huge collection, with tens of thousands of galaxies, including galaxy clusters, galaxy clusters and some lonely galaxies;At the scale of super galaxy clusters, galaxies will be arranged in thin sheets and filaments, surrounded by huge holes.In the above scale, the universe is isotropic and homogeneous.[5]
The Raniakia supercluster is the largest known cosmic structure.
GalaxyIt is a member of the local galaxy group.The local galaxy group is relatively a small galaxy group with a diameter of about 1022 million seconds.[6]The Milky Way and Andromeda are the two largest galaxies in this group, and many other dwarf galaxies are satellite galaxies of these two galaxies.The local galaxy group is based onVirgo Galaxy ClusterIt is a part of the collection of giant galaxy clusters and galaxy clusters at the center.[7-8]
Galaxies are distributed in a network in the universe.On a large scale, galaxies are surrounded by empty areas like bubbles, forming a spider web or neural network structure as a whole, which is called the large-scale distribution of the universe.[9]
Wheel galaxy, which is formed by two galaxies colliding head-on.
There are two theories of galaxy formation.One theory holds that galaxies were formed in a big bang 13.7 billion years ago.Another theory is that galaxies are formed from dust in the universe.Originally, there were a lot of globular clusters in the universe. Later, these stars collided with each other and destroyed, leaving tiny dust.These particles combine to form galaxies.
Although today, aboutGalaxy formationMany people question his knowledge.At present, the Big Bang is one of the most popular explanations.
The cosmic microwave background radiation is usually considered as the afterglow of the Big Bang.
according toBig BangIn theory, the first generation galaxies probably formed inbig bangA billion years after it happened.At the first moment of the birth of the universe, there was an explosion of primitive energy.With the expansion and cooling of the universe, gravity began to play a role, and then the infant universe entered a short stage called "inflation".The small fluctuations in the original energy distribution have also expanded sharply from the micro scale with the expansion of the universe, thus forming some "trenches" along which galaxy clusters are formed.[10-11]
Illustration of the Big Bang.
With the rapid inflation, the universe returned to the usual expansion rate as seen today.In the first second after the birth of the universe, with the continuous expansion and cooling of the universe, a large number ofproton、neutronAnd electrons condense from the background energy.One hundred seconds later, protons and neutrons begin to combine into heliumNucleus。In less than two minutesatomThe ingredients of.After another 300000 years or so, the universe will have cooled to the point where hydrogen and helium nuclei can capture electrons and form atoms.These atoms slowly coalesce into huge fibrous clouds under the action of gravity.Soon, galaxies formed in it.A billion years after the Big Bang, hydrogen and helium clouds began to gather under the action of gravity.As the clouds grow, the nascent galaxiesProtogalaxyStart to form.At that time, the universe was small, and the protogalaxies were relatively close together, so the interaction was strong.As a result, some smaller clouds condense in the thinner and larger clouds, while the rest are absorbed by adjacent clouds.At the same time, the protogalaxy gradually increased due to the continuous fall of hydrogen and helium.[12]
The more massive the protogalaxies become, the more gas they attract.The motion of each cloud cluster and the interaction between them finally makeProtogalaxyStart to rotate slowly.These clouds are further influenced by gravityCollapse, some clouds with fast rotation form a disk;The rest are roughly ellipsoidal.After obtaining enough material, these primitive galaxies began to form stars in them.At that time, the universe was almost the same as it is today.Galaxies are clustered together, like islands in the ocean of the earth, embedded in the vast gas clouds in spaceGalaxy clusterandIntergalactic gasStretching into a fibrous structure, the length can reach hundreds of millions of light years.The clusters of galaxies of such a large scale are spherical in the vast space.[13]
The first telescope in the world was made by Galileo in 1609.
In 1610,GalileoHe used his telescope to study the bright ribbon in the sky, which was known at that timethe galaxyAnd found that it was formed by a large number of dim stars.In 1755,Emmanuel KantWith the help of earlierThomas White The sketch map of the completed work speculates that the galaxy may be composed of a large number of stellar rotatorsgravityThe pulling force of is gathered together, just like the solar system, but it is much larger.
On April 4, 2023, an international team of astronomers published two papers in the journal Nature Astronomy, pointing out that they had discovered four of the oldest known galaxies by using the James Webb Space Telescope, one of which formed 320 million years after the Big Bang, when the universe was still in its infancy.[48]
Distinguish galaxies
A sketch of the spiral galaxy in 1845.
The first astronomer to try to describe the shape of the Milky Way and the position of the sun wasWilliam Herschel In 1785, he carefully calculated the number of stars in different regions of the sky, and obtained the image of the elliptical galaxy in the center of the solar system, which was similar to that in 1920CaptanThe results obtained are very similar, but smaller (about 15,00 seconds difference in diameter).[14-15]Herschel made the largest telescope at that time and discovered Uranus.He also focuses on the world of stars.After years of observation, he drew a structural map of the Milky Way in 1785 according to the number of stars in all directions of the sky.Since it is impossible to measure the distance of distant stars, Herschel assumed that all stars in the sky have the same luminous ability, and estimated their distance to the earth according to the actually observed brightness of stars.The "portrait" of the Milky Way he got was flat and flat, with an irregular outline, and the sun was in the center of the Milky Way.Herschel confirmed the hypothesis that the Milky Way is a flat disk for the first time by statistical method, thus initially establishing the concept of the Milky Way.
In 1906, the Dutch astronomer Captan proposed the "constituency plan" to re study the structure of the Milky Way.His model of the Milky Way is similar to Herschel's: the sun is in the middle, the stars in the center are dense, and the edges are sparse.
In 1918, Shapley proposed that the Milky Way is a lenticular star system with its center in the direction of Sagittarius, not the solar system.Later observations gradually proved that Shapley's model was closer to the real Milky Way, so it was still used today.[16]
Categorical galaxy
Hubble is observing.
In 1936, astronomersHubbleA classification of galaxies, now known as the Hubble sequence and still in use today, has been developed.[17]
In 1944, Hendrik Hurst predictedhydrogen atomIt will emit microwaves of 21cm wavelength. It was found in 1951 thatinterstellarThe radiation of a hydrogen atom.[18]This radiation line allows a deeper study of the galaxy, because it will not be absorbed by interstellar dust, and the Doppler shift from it can reflect the movement of gas in the galaxy.From this, scientists can distinguish the bar structure in the center of the galaxy, and with the help of radio telescopes, hydrogen atoms in other galaxies can also be traced.In 1970, Vera Rubin's research found thatTotal mass(Stars and gases) cannot properly describe the rotational speed of gases in star systems.A large number ofdark substanceAlready used for explanationGalaxy rotationQuestion.[19-20]
Since the 1990s,Hubble Space TelescopeIt improves the efficiency of observation, especially it confirms the mysteriousdark substanceIt can't be a faint small object in a galaxy.Hubble deep fieldIs to expose an area of the sky for an extremely long time.[21]It provides possible evidence that there may be as many as 175 billion galaxies in the universe.Improvements in spectral detection technology for invisible light (radio telescope, infrared cameraX-rayTelescope), allowing humans to see other galaxies that cannot be seen even by the Hubble Space Telescope.In particular, the survey of galaxies in the hidden zone of the sky (the part of the sky covered by the Milky Way) revealed a considerable number of new galaxies.[1][22]
This "Hubble" ultra deep field photo on the right shows a small part of the sky area of the Heavenly Throne. It was taken from September 24, 2003 to January 16, 2004, with a cumulative exposure time of 11.3 days. It is the most profound cosmic image ever obtained by mankind.The picture shows the universe more than 13 billion years ago, in which there are nearly 10000 galaxies, aged between 400 million and 800 million years.[23]
Hubble classifies galaxies according to the estimation of ellipticity of elliptical galaxies, from E0, a nearly circular galaxy, to E7, a very slender galaxy.These galaxies, regardless of the line of sight angle, have an oval appearance.They don't seem to have any structure, and the composition of interstellar matter is relatively small.Usually these galaxies have a small number ofOpen clusterAnd a small number of newly formed stars, more of which are old, and mainly mature stars that rotate around the center of the galaxy in various directions.Some of their properties are similar to those of smallerGlobular cluster。[25]
Most galaxies are elliptical galaxiesMany elliptical galaxies are formed by galaxy interactions, collisions or mergers.Huge elliptical galaxies often appear in the central region of galaxy clusters.Starburst galaxy yesGalaxy collisionThe latter result may lead to the formation of giant elliptical galaxies.
spiral galaxy (Spiral Galaxy, S-type Galaxy)VorticalExtragalactic galaxyIt is called spiral galaxy and is represented by S in Hubble's classification of galaxies.The spiral shape of spiral galaxies was first observed in 1845Hound galaxyM51.The central region of spiral galaxies is lenticular, surrounded by flat disks.A number of spiral arms extend from both ends of the bulged core sphere and are superimposed on the galactic disk.Spiral galaxies can be divided into normal spiral galaxies and barred spiral galaxies.Normal spiral galaxies can be divided into three subtypes: a, b and c: The Sa type has a large central area and sparsely distributed tight spiral arms;Sb type has a smaller central area and a larger and more developed swivel arm;The Sc type central region is a small bright nucleus with a large and relaxed rotating arm.In addition to high luminosity O, B type stars, supergiant starsionizationOutside the hydrogen region, there are also a lot of dust and gas distributed on the galactic disk.Seen from the side, it appears as a narrowDust belt, there is obvious extinction phenomenon.
Typical example of spiral galaxy: M101 windmill galaxy
In spiral galaxies, the shape of spiral arms is similarLogarithmic spiralIt is theoretically shown that this is an interference mode caused by the consistent rotation of a large number of stars.[26]Like a star, the spiral arm rotates around the center, but the angular velocity of rotation is not constant, which means that the star will pass through the spiral arm, which is a high-density area or density wave.[27]As stars enter the spiral arms, they slow down, creating higher density.The spiral arm can be seen because the high density promotes the birth of stars here, so there are many bright and young stars on the spiral arm.[28]
Vortex galaxies usually have a halo with sparse structure covering the whole, calledGalactic halo。MainlyStar Family IICelestial objects, typicallyGlobular cluster。A medium mass spiral galaxy often has 100-300 globular clusters, which are randomly scattered in the space around the galaxy disk.Further out, there may be more sparse gas spheres, called galactic halos.The mass of the spiral galaxy is one billion to one trillion solar masses, and the corresponding luminosity is - 15~- 21 absolute magnitude.The diameter range is 5~50Kpc.The total number of Sa type galaxiesSpectral typeK, F-K for Sb and A-F for Sc.Existing high luminosity of main celestial bodies producing total spectrumEarly type star, with high luminosityLate type star。Star Family ICelestial objects are composed of galactic disks and spiral arms, and the main components of star family II areGalactic nucleus, galaxy halo andGalactic corona。[25]
Barred spiral galaxy(Barred Sprial Galaxy, SB type Galaxy) YesIn the shape of a long bar in the centerSpiral galaxy。Bar spiral galaxyThe center of the rod is in the shape of a rod, and the two sides of the rod have spiral arms extending outward.About two-thirds of the spiral galaxies are bar spiral galaxies.Bars usually affect the motion of stars and interstellar gas in barred spiral galaxies, and they also affect the spiral arms.The spiral arms of barred spiral galaxies appear to emerge from the ends of short rods.In ordinary spiral galaxies, the stars are directly gushing from the core;In the galaxy taxonomy, it is represented by the symbol SB.[25]
GalaxyIt's a hugeGalactic diskA barred spiral galaxy with a diameter of about 30000 seconds or 100000Light year, the thickness is about 3000Light year；It has about 300 billion stars.
Dwarf galaxyIt is a relatively small galaxy composed of billions of stars.Many dwarf galaxies may revolve around a single large galaxy, and there are at least some such dwarf galaxies in the Milky Way.stayLocal galaxy groupThere are also many dwarf galaxies: most of these small galaxiesOrbiting large galaxies, like the Milky WayAndromeda galaxy, andTriangle galaxy。
The blue line to the right of the middle light spot is the huge jet of M87 nebula.
Some galaxies are classified as active galaxies.There is usually a supermassive black hole in the center of them, and the huge energy of its radiation is considered to be generated by matter falling into the black hole.
In the form of X-rays, galaxies emitting high energy are classified asSeyfert galaxy[30]、a quasar, orScorpio BLa quasar[31]。From the relative emitted from the coreJetActive galaxies emitting radio frequencies are classified as radio galaxies.stayUnified field theoryIn our galaxy model, these different types of galaxies are interpreted as the results obtained from different perspectives.[32-36]
Irregular Galaxy (Irr type Galaxy)The shape is irregular, without obvious nucleus and rotating arm.They are represented by the letter Irr.Irregular galaxies account for only 5% of the brightest galaxies in the sky.According to the classification of galaxies, irregular galaxies can be divided into Irr I type and Irr II type.Type I is a typical irregular galaxy. In addition to the above general characteristics, some have indistinctly visible irregular bar structure.Their mass is 100 million to 1 billion times that of the sun, and some can reach 10 billion times that of the sun.Their size is small, and the range of their long diameter is 2~9 thousand seconds.Irr I'sAstral familyComposition and Sc typespiral galaxySimilar, usually O-B starsIonized hydrogen region, gas and dust, etc.Irr II type has an amorphous appearance, can not distinguish the composition of stars and star clusters, and often has obvious dust belts.Some type II irregular galaxies may be exploding or post exploding galaxies, while others may be affected bycompanionA galaxy distorted by gravitational perturbations.So the origin of type I and type II irregular galaxies may be completely different.[37]
Other classifications
Announce
edit
Independent and dependent galaxies
The galaxies in the universe are divided intoIndependent galaxyandSubordinate galaxy。Running independently in space, it does not rotate around the centroid. Such a galaxy is called an independent galaxy.And the galaxies orbiting the centroid, such as the solar system orbiting the silver center, and the Earth Moon galaxy orbiting the sun, are called subordinate galaxies.
Nuclear Rotating Galaxies and Nuclear Non rotating Galaxies
According to whether the central star rotates, it is divided intoNuclear rotating galaxyandNuclear non rotating galaxy。In the universe, the core of an independent galaxy rotates and does not rotate.The nucleus of the subordinate galaxy is rotating.
Intragalactic and cosmic galaxies
According to the spatial location of the galaxyIntragalactic galaxyandCosmic galaxy。All galaxies moving in the galaxy are called intragalactic galaxies;All galaxies that move independently in extragalactic space are called cosmic galaxies.
Older and younger galaxies
According to the age of galaxy formationOld galaxyandYoung galaxy。Those galaxies that have been formed for a long time in space or within galaxies are called old galaxies. Most of the old galaxies have evolved into more regular galaxies;Some galaxies in the universe or in the interior of galaxies have just formed or have not formed long ago. Such galaxies are called young galaxies. Most young galaxies are irregular.
Central galaxy and companion galaxy
The Large Magellanic Galaxy is one of the companion galaxies of the Milky Way.
According to the relationship between stars in the galaxyCentral galaxyandCompanion galaxy。Galaxies composed of small mass stars moving around large mass stars are called central galaxies, such as the solar system, the Milky Way, etc;The galaxy composed of two stars moving around each other's central particle is called companion galaxy, such as the Earth Moon galaxy composed of the Earth and the Moon.
There are also some galaxy classification methods: the Dworkler classification system, the Yerkes classification system and the Vandenberg classification system are developed and refined on the basis of the Hubble classification method, using the central concentration or luminosity level of light as the parameters of galaxy morphology classification.Some scholars have proposed an unmodeled classification system and given several structural parameters that can directly measure the morphology of galaxies, such as the aggregation index C, asymmetry index A, clustering index S, Gini coefficient G and moment index Mtwenty。These parameters can reflect the history of galaxy formation, star formation, interaction with other galaxies, and merging activities that have occurred or are in progress.[38]
Galaxy
Announce
edit
A 360 degree panorama of the Milky Way taken by the European Southern Observatory.
GalaxyIs a barred spiral galaxy containing the solar system.[39]The diameter ranges from 100000 light years to 180000 light years.There are about 100 billion to 400 billion stars, and possibly 100 billion planets.The solar system is about 28000 light years away from the center of the Milky Way, at the inner edge of the spiral arm with dense gas and dust, known as the Orion Arm.In the position of the sun, the revolution period is about 270 million years.[40]Seen from the Earth, the Milky Way Galaxy appears as a band around the celestial sphere because it is seen from the inside of the disk structure.[39][41-42]
The Milky Way has several satellite galaxies, all of which are members of the local galaxy group[7], and isVirgo Supercluster Part of;And it is composed ofRanyakia superclusterPart of.The whole Milky Way is moving at a speed of about 600 kilometers per second to the reference coordinate system outside the Milky Way.
The artist's imagination of the Milky Way can see the clear stick shaped core.
The Milky Way is a galaxy composed of a disk of gas, dust and stars, surrounded by a central bar shaped core.The Mass Distribution of the Galaxy and the Classification of Hubble GalaxiesSbc typeVery similar, showing that this is a bar spiral galaxy with relatively loose spiral arms.In the 1990s, astronomers began to suspect that the Milky Way is a bar spiral galaxy rather than an ordinary spiral galaxy.Their suspicions were captured in 2005Spitzer Space Telescope Our observations confirm that this indicates that the bar at the center of the Milky Way Galaxy is larger than previously thought.[43]
The Milky Way is the second largest galaxy in the local galaxy group. The diameter of the star disk is about 100000 light-years, and the average thickness is about 1000 light-years.It ripples above and below the flat disk of the Milky Way, like a circular filament surrounding the stars around the Milky Way, which may belong to the Milky Way itself.If so, it means that the diameter of the Milky Way Galaxy is 150000~180000 light years.[44]
M31，Andromeda Galaxy.It is one of the few galaxies that is approaching the Milky Way.
In the 1920s, the American astronomer HubbleAndromeda Galaxy A kind of“Cepheid variable”To calculate the distance of the nebula, and finally confirm that it is outside the Milky Waysphere systems , call them "extragalactic galaxies".Extragalactic galaxies, which are located outside the Milky Way, consist of billions to hundreds of billions of stars, nebulae andInterstellar matterA celestial system composed of.The reason why they are called extragalactic galaxies is that they all exist outside the Milky Way, that is, all celestial systems outside the Milky Way are called extragalactic galaxies.The Milky Way and extragalactic galaxies form the highest name of astronomy for celestial bodies——Total galaxy。And the Milky Way is just an ordinary galaxy in the total galaxy。It is estimated that the total number of celestial bodies and celestial systems in extragalactic galaxies is more than one trillion. They are like islands in the vast ocean, so they are also called "cosmic islands".
The discovery of extragalactic galaxies can be traced back to more than 200 years ago.At that time, French astronomersmessier (Messier Charles)CatalogueThe nebula M31 is located in theHistory of AstronomyIt has an important position.On the night of early winter, people familiar with the stars can find it with the naked eye in Andromeda - a fuzzy spot, commonly known asAndromeda Galaxy 。
Since 1885, many new stars have been discovered in the Andromeda Nebula, which leads to the conclusion thatAndromeda NebulaNot the usual, passiveReflected lightIt must be a system composed of many stars, and the number of stars must be huge, so it is possible to have so manyVariable star。If we assume that the brightness of these variable stars at their brightest is the same as that of other variable stars found in the Milky Way, we can roughly infer that the Andromeda Nebula is very far away from the Earth, far beyond the scope of the known Milky Way.But due to the use ofVariable starThe measured distance is not very reliable, so it has also caused controversy.
It was not until 1924 that American astronomer Hubble used the world's largest 2.4 meter telescope at that time to find the Cepheid variable star called the "sky ruler" at the edge of the Andromeda NebulaPhotoperiodThe exact distance of the Andromeda Nebula can only be determined by the corresponding relationship with the luminosity, which proves that it is indeed outside the Milky Way, and like the Milky Way, it is a huge and independent star group.
From the discovery of extragalactic galaxiesGalaxy: It is just an ordinary galaxy, a member of the trillion galaxy family, an island in the ocean of the universe, and a very small part of the infinite universe.[45]
In January 2012, an international astronomical research group led by American scientists also announced in the British journal Nature that the oldest galaxy was discovered using the Hubble Space Telescope, which was born inBig BangThe first 480 million years, while the newly discovered ancient galaxy was born in the first 200 million years of the Big Bang, 280 million years older than the former.This galaxy was discovered by a research team led by John Richard of the Lyon Observatory of the University of Lyon in FranceSpitzer Space Telescope Discovered the galaxy, and then used HawaiiKeck Observatory The distance from the galaxy to the earth measured by the instrument of the Milky Way is 12.8 billion light years, which indicates that the galaxy was born at least 12.8 billion years ago.Further research on the spectrum of the galaxy shows that the earliest stars in the galaxy have a history of 750 million years, so researchers concluded that the galaxy was born 13.55 billion years ago.This achievement was published in the Monthly Journal of the Royal Astronomical Society.[46]
The farthest galaxy
The research team led by Nicholas Lapel of the University of London College published a paper in the recent Astrophysical Journal that they captured the shape of galaxy A2744_YD4 13.2 billion years ago, which is the farthest object discovered by 2020.This achievement also means that astronomers have obtained important clues to study the birth of stars in the original galaxies of the universe.
Using the high sensitivity Alma astronomical telescope in Chile, the research team found the radio waves emitted by the dust and oxygen of galaxy A2744_YD4. After detailed analysis, it calculated that the galaxy is 13.2 billion light years away from the Earth.According to the analysis of the total amount of dust detected and the birth of celestial bodies, it is believed that the galaxy was active in star building 13.4 billion years ago.The same results were confirmed by the research team using the large optical infrared telescope of the European Southern Observatory.
According to the observation results, the research team calculated that the total amount of dust in A2744_YD4 is about 6 million times that of the sun, and the total mass of the planet is 2 billion times that of the sun.At the same time, it is found that there are 20 solar sized gas clusters forming stars in this galaxy every year.This means that the planet birth of A2744_YD4 is 10 times more active than that of the Milky Way.[47]
