An INCREDIBLE journey to DISCOVER the Milky Way's neighboring GALAXIES | Space Documentary

foreign [Music] what are the other galaxies in the universe like are they so different from ours what if we went to explore the galaxies closest to the Milky Way especially those that are part of the local group galaxies that are far away on our scale and yet so close to ours such as the Andromeda galaxy the triangulum Galaxy or the great magellanic Cloud Galaxy but so many other Galactic objects which although very modest in size play a fundamental role in our understanding of the universe what is the composition of these galaxies what is their history or their future evolution dear traveler welcome today we leave for an incredible journey to the galaxies closest to the Milky Way and discover these distant but fascinating lands our Galactic traveler has prepared a tour for you to discover these Cosmic monsters according to their different categories once you are comfortable we will go from Galaxy to Galaxy to discover these unusual worlds get ready to live an unforgettable experience but before taking off if you haven't already done so remember to like the video and subscribe to the channel so you don't miss anything thank you have a nice trip let's start our adventure let's leave behind our solar system and quickly cross our Milky Way I suggest you start with the second most important member of the local group The Andromeda Galaxy also known as Messier 31 [Music] the Andromeda Galaxy with its one thousand billion stars is often considered the twin sister of our Milky Way measuring 220 000 light years in diameter Messier 31 is a huge celestial object the furthest from Earth that can be observed with a naked eye under clear skies even though it is 2.5 million light years away the first observations of this luminous spot go back to the dawn of time but the first written records date back to 964. they are due to Al Sophie a Persian astronomer the Andromeda galaxy located in the constellation of the same name is easily recognized by its oval and diffuse shape with a bright core the ladder of yellow color contrasts with the dark dust bands and the large arms that Trace their way around this is a spiral galaxy the closest to our galaxy which offers us a breathtaking spectacle in its Meander as we can see clusters of blue stars but also nebulae of reddish color the total mass of the Andromeda galaxy estimated at 1230 billion solar masses against 1900 billion solar masses for the Milky Way does not prevent it from containing a considerable number of stars more in the heart of its bowels is a supermassive black hole estimated at 140 million solar masses which is much larger than the one in our galaxy which is estimated at only 4 million solar masses Andromeda has two companions Messier 32 and Messier 110 both of much smaller size the first Messier 32 is a compact elliptical galaxy its greatest length not exceeding 8 000 light years distant from the Sun by 2.5 million light years it is an elliptical dwarf Galaxy with a mass of only 3 billion solar masses although it may seem insignificant it contains a central bulge whose characteristics are comparable to that of its host M31 with a mass of about 100 million solar masses it is estimated that approximately 5 000 Stars per cubit parsec are rapidly rotating around a central supermassive object it is mostly composed of old stars and has a high surface brightness all indications are that Messier 32 was once much larger but that its outer star population in globular clusters were considerably absorbed by its giant host the Andromeda Galaxy but what about this giant second companion Messier 110. is it as impacted by its proximity to the Andromeda Galaxy [Music] like Messier 32 it is an elliptical dwarf Galaxy which does not appear to contain a supermassive black hole its diameter is 17 000 light years twice that of Messier 32. it is smooth and almost featureless with no arms or star-forming regions but it does contain a population of young blue stars in its Center there are 10 billion of them as well as eight globular clusters that are visible in its Halo as you can see Messier 110 unlike its companion does not appear to be at the end of its activity these three Cosmic monsters are far from evolving alone the Andromeda galaxy and its two smaller sisters are accompanied in their astral Dance by many smaller galaxies these form the subgroup of Andromeda [Music] there are at least 14 dwarf galaxies that belong to the Andromeda Galaxy subgroup of course there is Messier 32 and Messier 110 whose discoveries date back to the 18th century but since the 1970s new Galactic objects have been discovered one after the other thanks to technological advances thus the galaxies Andromeda one two and three all distant between 2.1 and 2.4 million light years from our sun were discovered in 1972 by Sydney Vandenberg a Canadian astronomer this scientist also discovered Andromeda 4 at the same time if he believed at first that it was an irregular galaxy belonging to the subgroup of Andromeda the measurements made in 2000 with the Hubble Space Telescope place it rather between 16 and 26 million light years this galaxy would then be largely outside the local group in 1998 the Galaxy Andromeda 5 joined the subgroup of spherical dwarf galaxies of Andromeda it is 2.6 million light years away from our solar system also in 1998 it was the turn of the spheroidal dwarf Galaxy of Pegasus or Andromeda 6 and the dwarf Galaxy of Cassiopeia Andromeda 7 to be revealed the distance of the former is still poorly defined but it could be between 2.5 and 3.1 million light years while the latter is estimated at 2.5 million light years we will not continue this list which extends to Andromeda 33 a dwarf galaxy of the same type as its consorts and discovered in 2013 thanks to the pan stars 1 astronomical survey program that uses a panoramic survey telescope and rapid response system located on the Hawaiian archipelago among the main members of the local group other Cosmic monsters although less imposing are just as marvelous and reserve us an extraordinary show this is notably the case of a Duo of dwarf galaxies separated by only 75 000 light years these are the famous magellanic clouds these two galaxies very close to our galaxy are remarkably visible to the naked eye from the southern hemisphere appearing as two milky spots in the Deep sky and resembling fragments of a cloud of stars that would have broken away from our galaxy it is not known when the first observations of these two celestial objects date back to but it is in 924 that the large magellanic cloud is described for the first time in the literature by the Persian astronomer al-sufi even if their identification was formalized during The Voyage of Ferdinand Magellan in the 16th century but what makes these two galaxies even more Curious is a kind of bridge that seems to connect them to each other let's get a little closer to this strangeness let's start by observing the large magellanic Cloud which is a dwarf Galaxy of The Bard spiral type it is located in the constellations of the Dorado and the table its disc shape is characterized by the presence of a single spiral arm and a large bar that were discovered long after the Galaxy itself which explains why it was first cataloged as an irregular galaxy the large magellanic cloud is 163 000 light years distant from our solar system but more importantly it occupies the 4E position in the local group in terms of mass after the Andromeda galaxy The Milky Way and the triangulum Galaxy several hundred thousand giant and supergiant stars are counted there as well as 60 globular clusters 400 planetary nebulae and 700 open clusters among the very many celestial objects it contains we can note two high mass Stellar black holes both in the form of binary systems we can also observe a soft gamma-ray booster the first object of this type to be discovered it is a source of gamma rays with Violet and recurrent episodes of emission but regular and most probably corresponding to Young neutron stars with intense magnetic field one of the youngest pulsars probably about 1 650 years old with a rotation period of 50.3 milliseconds can also be seen these last two objects are both located in the aftermath of supernovas these explosions of stars that give us a show of beauty we can thus see that an intense activity Reigns in the interstellar median of the large magellanic cloud where the quantities of gas and dust are colossal this explains why an important quantity of new stars emerge in its heart the largest and most active region of the local group is the tarantula nebula this galaxy is the most active of any region in our galaxy and has a star birth rate like no other in fact the tarantula nebula is the largest nebula known to date but what makes the large magellanic clouds so special is the link it has with its fellow Traveler indeed the southern bar of the large magellanic cloud is connected to the small magellanic Cloud by a bridge of gas and stars known as the magellanic bridge this structure which is due to the tidal forces linking the magellanic clouds and perhaps also to those of the Milky Way is mainly composed of neutral hydrogen however it is home to a few stars that must have formed within it the small magellanic cloud is an ancient barred dwarf spiral galaxy which has become an irregular galaxy due to the inexorable tidal forces around it distant from our sun by about two hundred thousand light years its diameter is half that of its Big Brother reaching 7 000 light years for those who have the opportunity to observe it from the southern hemisphere it occupies in the night sky the value of 10 full moons which made it in the first Polynesian or Australian Aboriginal cultures an indispensable tool for Navigators this visibility to the naked eye is mainly due to its small distance from our sun although it is one of the most distant objects that can be observed without instruments if the small magellanic cloud is considered small compared to other galaxies it would nevertheless contain no less than three billion stars we can also admire in the heart of this small Galaxy many objects all more luminous and colorful than the others including star clusters that shine brightly Supernova remnants or magnificent nebulae where the occurrence of new stars is particularly intense let's move on to the third galaxy of the local group the triangulum Galaxy also known as Messier 33 which lies in the northern constellation of triangulum located about 2.7 million light years from Earth it is over 50 000 light years in diameter and hosts more than 40 billion stars it is a regular spiral galaxy which means that it is unbarred without Rings it is in the form of a galactic disc that surrounds a central bulge the mass of this Galactic Monster is estimated at 60 billion solar masses which is still far less than our Milky Way and the Andromeda galaxy which are both at the top of the podium in terms of size Messier 33 represents only five percent of the mass of the Andromeda Galaxy estimated at 1230 billion solar masses the triangulum Galaxy is very different from the Milky Way which you have certainly visited it is larger flatter and brighter it also has a large number of spiral arms rather open each containing billions of stars and gas clouds the absence of significant interaction of this Galaxy with other massive objects allows it to maintain its beautiful spiral structure a relatively symmetrical overall shape and therefore does not experience major alterations like its larger sisters it has a large amount of gas and dust which makes it an ideal place for the formation of stars and planets as you travel through the triangulum Galaxy you can see many types of stars including red dwarfs red giants binary stars and massive stars in fact astronomers count more than 500 active regions of infrared radiation that are massively concentrated in its Center and along its spiral arms among the brightest regions of the Galaxy are its main nebulae NGC 588 NGC 592 NGC 595 and NGC 604 the latter also called the triangle nebula is the brightest of all and extends over nearly 1500 light years it is the second most luminous region of ionized hydrogen in the local group thanks to the Hubble telescope we know that it hosts about 200 young and hot Stars distributed in at least two clusters their masses vary between 15 and 60 solar masses moreover it is in the southern spiral arm that the rate of explosion of supernovas is the most important there would be on average every 147 years which explains the hundred of supernova remnants that could be identified there there are also many other interesting phenomena such as Jets of matter expelled by some supermassive black holes in summary the triangulum Galaxy is a Place full of discoveries and wonders of nature it's an incredible sight to see isn't it among the main members of the local group I invite you to discover now NGC 185 and NGC 147 two galaxies that belong to the great majority that compose the local group namely the dwarf spheroidal galaxies however as you will see these two dwarf Galaxies have a small peculiarity apart from belonging to the Andromeda subgroup let's start with NGC 185 a dwarf spheroidal galaxy located about 2.1 million light years from our sun it is remarkable for its small size and low mass which is approximately one-tenth that of the Milky Way if like all galaxies of this type it contains few stars and gas because of its Advanced age on the other hand its surface of a very high luminosity and its extremely bright and compact nucleus place it in the category of Seafort galaxies of type 2. this type of nucleus represents one of the largest known sources of electromagnetic radiation in the universe would it hide a supermassive black hole in its Center therefore it arouses our curiosity especially since it displays a notable proximity to a neighboring Galaxy NGC 147 like its companion NGC 147 is a dwarf spheroidal galaxy located about 2.2 million light years from our solar system it also contains few stars and gas but what makes it intriguing is its particular location near its neighbor it seems that these two galaxies form a gravitationally stable binary system these galaxies may not look as impressive as the large spiral galaxies but they are interesting to study because of their interaction and proximity especially since a third object the recently discovered pale dwarf Galaxy Cassiopeia 2 may also be part of the satellite system of the Andromeda Galaxy it may well be that these three Galactic objects are part of the same Cosmic dance but to confirm this we will have to examine their choreography for some time foreign let's continue our exciting Journey Through the Barnard Galaxy this galaxy is shyly located in the constellation of Sagittarius about 1.5 million light years from the Milky Way it hides its irregular shape behind a screen of dust and closer Stars which explains why it was only discovered in the 1880s by Edward Emerson Barnard its appearance is not unlike that of the small magellanic cloud is it not its largest diameter reaches 7 000 light years and although it does not shine like the biggest divas of the local group it is full of young blue stars although it does not have Splendid spiral arms it is surrounded by a necklace of purple nebulae where intense activity heats the surrounding hydrogen during star formation as a proof we can sometimes see a brood of massive stars that ejects with an unheard of violence the matter literally blowing the interstellar gas this small galaxy has nothing to Envy to the larger ones showing signs of an obvious star formation activity [Music] let's visit the last of the main members of the local group the Galaxy named IC 1613 located in the constellation of cetus the sea monster and distant a little more than 2.3 million light years from our sun we owe its Discovery to the German astronomer Max wolf in 1906. but it was in 1928 using a powerful 2.5 meter or eight foot telescope at the Mount Wilson Observatory that his compatriot altar bod successfully visualized its individual Stars once again this is a dwarf Galaxy with low surface brightness but our journey to it is not by chance this Galactic neighbor unlike its fellow galaxies has made a clean sweep what we want to explain to you is that it contains very little Cosmic dust allowing it to reveal the Wonders it contains this phenomenon is quite rare and therefore worth observing no dark trail of SideReel dust opaque and swirling is visible among the gas and stars that populate this galaxy which appears clean as a whistle [Music] two types of stars can be seen pulsating at their own pace cepheid variables and RR Illyria variables because of its unusual appearance the ic1613 Galaxy offers great opportunities for observations despite its small size it has helped scientists understand and use variable stars to map our universe so it is not the largest objects that hold all the keys to the cosmos [Music] I now propose you to visit the dwarf spheroidal galaxies which compose the subgroup of the Milky Way and to which they are gravitationally linked they can be observed in this small corner of the universe within a radius of 1.5 million light years around our galaxy [Music] let's start with a huge Galaxy that has been hidden for a long time behind the galactic disc of the Milky Way in the constellation of antlia at a distance of 422 000 light years its existence was detected in 2018 by the Gaia satellite let me introduce you to the anthalia 2 Galaxy this Galaxy with nearly 9 500 light years in diameter is relatively similar to the large magellanic cloud but unlike the latter its brightness is 10 000 times less it even appears 100 times more diffuse than the so-called Ultra diffuse galaxies whose Luminosity is very low making it the least luminous of all the galaxies known to date this characteristic is also the reason why it is called a ghost Galaxy although its size is one-third of that of the Milky Way in short it is a Galaxy that is either too dark for its size or too large for its brightness one of the most interesting features of antilia 2 is that it is also rich in dust clouds which are regions where new stars and planets form these dust clouds are visible due to their absorption of light from the background Stars forming dark regions called Dark dust clouds antalia 2 is rich in young stars and gas this means that there are many new stars forming in this galaxy in fact it is estimated to be about 10 times more active in Star formation than the Milky Way therefore as you can see there are many Star clusters in antlia2 these clusters are groups of thousands of stars that have formed together from a single cloud of gas some of these clusters are very young and still contain stars in the process of forming another particularity is noteworthy its mass appears well below the first estimates made on the basis of its size could it be the consequence of incessant dismantling caused by the galactic tides of the Milky Way moreover this galaxy whose age is about 11.2 billion years raises another problem for scientists a problem of size in theory galaxies that are devoured by another Galactic Monster see their size reduced antilia 2 is huge and seems to be growing rather than shrinking it seems that this Phantom galaxy has not yet revealed all its Secrets which makes it even more fascinating another galaxy is the Talk of the scientific community it is the Sagittarius dwarf Galaxy which has been the subject of debate since its Discovery in 1994. it is considered by some as a spheroidal Galaxy and by others is an elliptical galaxy be careful not to confuse it with the irregular dwarf Galaxy of Sagittarius about 10 000 light years in diameter it is approximately 50 000 light years from the center of the Milky Way which makes it also one of its satellites its population of old and metal poor Stars makes it possible to establish that it is an old Galaxy especially since it has little Interstellar dust we can think that it was at the base of a dwarf spheroidal Galaxy which would have suffered the consequences caused by tidal forces of the Milky Way especially since a significant number of its Stars and a stream of gas appears scattered throughout its orbit moreover the dwarf Galaxy of Sagittarius seems to disturb intermittently the outer disk of the Milky Way to which it is a little too close since five or six billion years producing numerous filamentary structures if at the moment of these structures of filamentary and spinning appearance are not yet explained by astronomers several theories are emerging in particular that of the remains of fossil spiral arms whatever the case these structures are certainly related to past interactions with a Milky Way the interactions between the Sagittarius dwarf Galaxy and our galaxy are not going to get any better since its trajectory indicates that it should cross the Milky Way Galactic disk within 100 million years it will thus probably be absorbed entirely by our galaxy through a long process of Destruction and restructuring in the category of spheroidal dwarfs we can continue our journey towards the dragon dwarf Galaxy located in the constellation of the dragon at about 260 000 light years from the Earth its Discovery dates back to 1954 by Albert George Wilson of the Lowell Observatory it is globular in shape and extends from 2700 to 1800 light years making it one of the smallest galaxies known it is also very faint in terms of luminosity it is one of the least luminous Companions of our galaxy this object that orbits our galaxy also seems to contain large amounts of dark matter this mysterious matter still hypothetical and whose existence has not yet been proven directly it has thus become an ideal candidate for the scattering phenomenon and could be very useful for scientists working to understand Cosmic mechanisms however more than 260 variable Stars accumulate at its Center and despite its small size and Luminosity the dragon dwarf Galaxy is rich in Old stars and metals such as iron calcium and magnesium the ancient Stars probably form billions of years ago the presence of these old stars and metals indicates that the dragon dwarf galaxy has experienced a lot of star formation activity in the past it also contains several red giants which are low Luminosity Stars these stars have exhausted their nuclear Fuel and consequently have stopped Shining these stars are very enriching because they contain information about the history of the Galaxy they are also potential candidates for the search for extrasolar planets who knows maybe one day we will be able to detect the presence of potentially habitable planets in this region of the cosmos among other deep Sky objects we can also explore the dwarf galaxy of the Little Dipper which can be reached in the constellation of the same name its average distance from our sun is 205 000 light years while it is only 1.4 million light years from the center of the local group its size 45 times smaller than the Milky Way is estimated at 2200 light years discovered under the same conditions as the dragon dwarf Galaxy the findings seem identical it is similarly a Galaxy that could contain a large amount of dark matter indeed the velocity dispersion does not decrease with the distance to the center of the Galaxy moreover 94 bright stars have already been identified in the bowels of this object whose radial velocity brings it closer to our solar system at a speed of 247 kilometers per second or 153 miles per second this is a new Galaxy with many suns which seems to be expanding do you think that it may have a few planets where extraterrestrial life could have developed and why not but do you know which is the first dwarf Galaxy that was discovered orbiting the Milky Way well it's the sculptor dwarf Galaxy first described in 1937 by astronomer Harlow shapley since then many other observations have been made notably thanks to the Gaia study of the European space agency and observations made with the Hubble Space Telescope the galaxy has among other things allowed scientists to determine how individual stars move through a galaxy of this type they are now able to confirm that their change in position is Tiny even over long reference periods of about 10 years the proper motions of about a hundred stars have been measured and coupled with the radial velocity the motion of the Stars could be reconstructed in three dimensions this is the first time that such a reconstruction could be performed for a dwarf Galaxy the sculptor dwarf Galaxy thus plays a crucial role in the astronomers sphere who can now study the impact that the gravity of Dark Matter this elusive matter can have on the motion of other objects such as stars or galaxies let's now take the direction of the Sextant constellation where the ninth satellite of the Milky Way is hidden the Sextant dwarf Galaxy or Sexton's one this galaxy of spheroidal type was detected in 1990 by Mike Irwin as part of a comprehensive Sky survey plate monitoring program United Kingdom Schmidt telescope with the application performance monitoring measurement machine in Cambridge UK the distance of this object is estimated to be only 280 000 light years from the Sun its apparent magnitude is 10.4 which makes it one of the least luminous galaxies among the closest to our Milky Way as you can see it is also an elliptical galaxy with a red shift as it moves away from us at a constant speed of 224 kilometers per second or 140 miles per second it is small and its diameter measured along its main axis does not exceed 8400 light years as you can see its population consists of old Stars pore in metals the in-depth study of this galaxy allows us to question the hierarchical formation scenario this Theory According to which Galactic Monsters such as our Milky Way would have been created mainly by absorbing other Galactic objects over time cannot be affirmed when we study more closely the chemical composition of the dwarf galaxies that surround it indeed compared to our galaxy Sexton's one presents a deficit of the most primitive Stars this indicates that the fossil content of the Primitive epics the Epic that precedes the Assembly of galaxies between them is not similar thus neighboring dwarf galaxies do not have the same characteristics as the Halo of our Milky Way its oldest part moreover the Sextant one Galaxy like many other galaxies of the same type lacks very low iron Stars unlike our Galactic Halo here is another dwarf spheroidal Galaxy the Karina dwarf Galaxy also named PGC 19441 it is found in the constellation Karina this satellite of the Milky Way is about 330 000 light years away but is gradually moving away at a speed of 230 kilometers per second or 140 miles per second its size is estimated to be 75 times smaller than our galaxy with a diameter of 1600 light years it is part with the lion 2 galaxy of the smallest known galaxies it is home to a majority of stars whose formation dates back approximately 7 billion years which means that they appear less ancient than those of other satellite galaxies the Karina dwarf Galaxy may be more recent than its Twin Galaxies although it has also experienced other peaks of star formation notably 13 and 3 billion years ago another satellite galaxy of the Milky Way attracts our curiosity this time in the constellation of the Furnace it is the dwarf galaxy of the Furnace distant from 450 000 light years from the Sun it is like almost all nearby dwarf galaxies composed mostly of old Stars called population 2. it has a recession of 53 kilometers per second or 33 miles per second moving further and further away from our Milky Way its low surface brightness makes it unattractive at first sight however it contains several Treasures including a planetary nebula and five globular clusters the largest of which named NGC 1049 was discovered a century before its host by the British astronomer John Herschel in 1835 this cluster contains a large number of stars which makes it brighter than the Galaxy itself as proof its distance of 444 000 light years does not make it invisible with a medium-sized telescope unlike the Galaxy that hosts it this cluster and its companions have been the subject of numerous observations it appears that they are very similar to those existing in our Milky Way this observation challenges the main theories on the formation of these clusters which should be surrounded by large quantities of old Stars however we see that this is not the case here as is often the case in astronomy a new observation even if it opens a little more the door of our knowledge puts in questions some theories leading to new questions let's now look at the last two spheroidal dwarf galaxies belonging to the Milky Way subgroup the Leo one Galaxy and its twin the Leo 2 Galaxy also named Leo one and Leo 2. their simultaneous Discovery is attributed to Robert Georges Harrington and Albert George's Wilson in 1950 like the Karina Galaxy their diameter does not exceed 1600 light years which makes them the smallest known galaxies of the Milky Way subgroup the first the Leo one Galaxy is 800 000 light years away from our sun the second slightly closer is seven hundred thousand light years away the latter is made up of stars 8 billion years old it does not produce any more new stars except in the center where we can see younger Stars Leo one however has captured the attention of researchers since it was found that it contains a relatively small amount of Dark Matter compared to its peers it was in 2021 at the McDonald Observatory and with the help of a supercomputer that a team from the University of Texas discovered that a supermassive black hole namely of 3.3 million solar masses rains at the heart of the Leo one Galaxy here is yet another mystery to be solved how can a black hole of this Mass exist in such a small Galaxy we have just visited the dwarf spheroidal galaxies belonging to the Milky Way subgroup however there are other dwarf spheroidal galaxies that are labeled as Ultra faint if you want let's go to meet them while staying in the constellation of Leo you the discoveries follow one another thanks to new technologies and numerous programs the Sloan digital Sky survey or sdss for short is a celestial object survey program using a dedicated 2.5 meter or eight feet diameter optical telescope located at the Apache Point observatory in Southern New Mexico USA this program which started in 2000 has allowed to count in 2006 about 24 dwarf companion galaxies of our Milky Way whereas half of them were counted until then one of these galaxies named seg-1 is 75 000 light years distant from the Milky Way a billion times fainter than our galaxy it appears to be composed mainly of dark matter with only a few hundred Stars scattered in its bowels seg-1 despite an extremely low Luminosity which does not exceed that of 300 Suns because of its practically insignificant number of stars is considered as a dwarf spheroidal Galaxy its mass corresponds to about six hundred thousand suns which is too large for a globular cluster especially since its stars are rather similar to those usually found in galaxies this lack of Luminosity associated with a very compact structure at a low concentration of metal seems to indicate that this is a very old celestial object which will probably have encountered during its Cosmic wanderings the gravitational disc of our galaxy but what remains a mystery is the mass of this object which cannot be explained by the presence of a black hole indeed the Stars present do not swirl ardently around an object that would be massive consequently seg-1 does not have a massive black hole in its Center which could explain this important Mass no other matter in sufficient quantity like hydrogen gas in astronomical accumulation or dust can explain this Mass seg-1 would thus be the only Dark Matter galaxy in the universe a little further away another galaxy was discovered during the same study program Sloan digital Sky survey in the Aries Galaxy the seg 2 Galaxy located at about 114 000 light years from the Sun this small Galaxy is approaching our sun at a speed of 40 kilometers per second or 25 miles per second its Stellar population is composed mainly of old stars formed more than 12 billion years ago no newly formed stars are present their metallicity is very low they would contain at least 100 times less heavy elements than our sun you are probably looking at the oldest stars in the universe seg 2 contains only a thousand stars and some dark matter that binds them together its luminous power is strongly impacted it is barely 900 times brighter than the sun which is ridiculously low compared to the Milky Way which shines 20 billion times brighter the seg 2 Galaxy is thus one of the famous galaxies known to date weighing at least 10 times less than previous estimates for such objects this is a new challenge to the theoretical understanding of structure formation in the universe let's now visit the great dog dwarf Galaxy which is our closest neighbor and is located on the periphery of our solar system it is about 25 000 light years from the Sun and 42 000 light years from the center of the Milky Way it is located as its name suggests in the constellation of the great dog it is a small irregular galaxy whose mass is equivalent to nearly 1 billion solar masses long hidden behind the plane of the Milky Way hidden by the dust and gas trapped in its disk it was discovered only recently it is thanks to an infrared survey allowing astronomers to see many regions of space well beyond the disk of our galaxy that it was detected for the first time in 2003 dethroning then the dwarf Galaxy of Sagittarius of its status of closest galaxy rather elliptical in shape but irregular it is home to a billion stars including a large number of red giants which in fact represents only a small percentage compared to the Milky Way its main body of jagged and fragmented appearance is thus of irregular shape this degradation seems to be the consequence of the accretion to the Milky Way that it inexorably undergoes undergoing the tidal forces of the latter it is literally torn apart leaving in its wake a long filament of stars it is so long that it goes three times around the Milky Way taking the form of a ring known as the unicorn ring it looks like there are other remnants that have not yet been completely swallowed up there are several globular clusters which have been discovered in different constellations the dove the hair the stern and the Karina and which would have been separated from their host I propose you now to join the constellation of the Great Bear you know this immense constellation which decorates our Starry Sky with a famous big pan adorned with countless Stars it is home to a magnificent planetary nebula but above all there are no less than 50 galaxies including the Big Dipper one Galaxy also called Ursa Major 1. this Galaxy with low surface brightness is 316 000 light years away from our sun it is one of the three least luminous galaxies recorded to date in comparison it is less luminous than the star deneb which is in our Milky Way it is made up only of population 2 stars that is to say old stars with low metallicity you can find similarities with the dwarf Galaxy Sextant one it is like its cousin old and poor in metals and measures only a few thousand light years in diameter let's take the opportunity to visit the Great Bear 2 dwarf Galaxy also known as Ursa Major 2 or uma2 discovered at the same time as the previous Galaxy it is about 30 KPC from the Sun or about 97 800 light years its Luminosity is about 4 000 times that of the sun which is well below the vast majority of globular clusters that we can admire it is even less luminous than some stars in our galaxy such as canopy for example the majority of the stars in this galaxy are population two stars that is stars of advanced age the formation of these Stars probably dates back to more than 10 billion years they're relatively low metallicity index is estimated at more or less 0.06 which means that they contain 300 times less metal than our sun however its total mass is equivalent to nearly 5 million solar masses if we count baryonic matter and dark matter its mass to Luminosity ratio is then of the order of 2000 which seems to be strongly overestimated especially since its irregular shape shows that it is strongly perturbed by the galactic tidal forces induced by the Milky Way unfortunately this satellite which is one of the smallest and weakest orbiting our galaxy is approaching our sun at a speed of 116 kilometers per second or 70 miles per second the Big Dipper 2 is inexorably subject to tides that cause strong disturbances over time even irreversible dismantling we could continue our journey through many such galaxies including the Wilman one Galaxy also located in the constellation the Big Dipper the Bouvier dwarf Galaxy the Berenice hair dwarf Galaxy the Hercules dwarf Galaxy the Pisces two dwarf Galaxy or the Aquarius II dwarf Galaxy if all these Galaxies have many points in common I propose however that we linger with the reticulum 2 Galaxy which is located in the southern constellation of reticulum halfway to the magellanic clouds its recent discovery dates back to 2015 and was only possible through the exploitation of data collected by the Des Dark Energy survey which is an international Optical and near-infrared Survey research program but reticulum 2 did not reveal itself alone it was spotted along with eight other dwarf satellite galaxies orbiting the Milky Way this discovery surprised astronomers who did not expect to find so many satellites in such a small area of the sky reticulum 2 which is probably spheroidal is only 104 000 light years away from our solar system making it one of the closest Milky Way satellite galaxies this object called Ultra pale like all the ultra faint spheroidal dwarf galaxies we have just visited contains very little observable manner this small structure probably contains no more than five thousand stars themselves representing little more than one percent of the observable matter composed essentially of dark matter which itself is only detectable by its gravitational attraction this galaxy is a billion times darker than our galaxy and a million times less massive If You observe it closely you can see how it is being torn apart by the massive tidal forces it is undergoing as it comes into contact with a Milky Way the discovery of these dwarf satellites in a handkerchief of pocket proves to be disconcerting and questions once again the scientists are they ancient satellites that orbit the magellanic clouds and were ejected by the interaction between the small and large magellanic clouds or were they originally part of a gigantic group of galaxies destined like the magellanic clouds to be devoured by our own Galaxy what about you what do you think [Music] the vast majority of spheroidal dwarf galaxies occupy a position in space quite close to the two main members of the local group namely the Milky Way and the Andromeda Galaxy to which they are gravitationally bound most of them are gathered in a perimeter of only 7 million light years however some dwarf spheroidal galaxies prefer to play solitary these galaxies which seem to have stepped out of line are called isolated galaxies what might an isolated Galaxy look like how does it behave in the universe but above all how did it form this is what we will try to elucidate by getting closer to some of them let's start by visiting the dwarf whale Galaxy which was long camouflaged in the constellation of the same name until its Discovery in 1999 by a member of Cambridge University it is respectively 2.46 million light years away from the center of the Milky Way and 2.2 million light years away from the center of the Andromeda Galaxy like its congeners it has a low surface brightness its Stellar mass is estimated at 2.6 million solar masses while it appears to be devoid of hydrogen so much so that this gas is not detectable its population of stars is relatively old they would have been formed 12 billion years ago during a short period of two to three billion years it is therefore 8 billion years since no new stars appeared in the heart of this galaxy which looks so peaceful the effective radius of this galaxy is barely 2300 light years its radial velocity of 87 kilometers per second or 55 miles per second brings it slowly closer to our sun while its dispersion velocity is about 17 kilometers per second or 10 miles per second if you take a few moments to contemplate it you will notice that it has a global orientation speed of about eight kilometers per second or five miles per second this group of old cold stars like a ghost ship carried by weak Cosmic currents seems to wander in the universe like a lost soul another cluster of small Stars very faint and devoid of gas was discovered in 1990 at the mount stromlow observatory in Australia this is the toucan dwarf Galaxy like the whale dwarf Galaxy its surface brightness is relatively low and its population of stars is comparable most of them 13 billion years old tiny spheroidal Galaxy smaller than the whale its effective radius being just over 926 light years it is about 2.8 million light years away from our galaxy and nearly 4.4 million light years away from the Andromeda Galaxy but what makes it even more special is its position in the local group if like isolated galaxies of the same kind it is at a certain distance from the two referent Galactic Monsters on the other hand it is located almost opposite most of the other members in relation to the Milky Way unlike many galaxies it has a positive radio velocity meaning that it is moving away from our sun at a speed of 194 kilometers per second or 120 miles per second with a low velocity rotary motion estimated at 16 kilometers per second or 10 miles per second in its outer regions among the isolated spheroidal dwarf galaxies we can also mention KKR 25 located in the dragon Galaxy the latter was discovered in 1999 by three researchers who gave it their name namely karachen Seva karachen Sev and Richter like the two previous galaxies it is characterized by its distance from the main members of a local group estimated at more than 6 million light years but especially by its isolation from any other Cosmic object another isolated Galaxy attracts the scientific Community the kks-3 Galaxy difficult the spot because of its low Luminosity it is barely 7 million light years away from the Milky Way its discretion is all the more important as its total mass is about 20 million times that of the Sun if it was detected in 2000 its isolation could be proven only in 2014 thanks to the Hubble telescope the majority of the stars that compose it are old stars formed probably 12 to 14 billion years ago devoid of gas since then it has not created stars for a long time it is therefore A Relic that greatly interests astronomers because of its great age but Above All Because of its isolation it is probably not undergone any change for a very long time which makes it an ideal research laboratory to understand the cosmic workings and the foundations of the universe the Hubble Space Telescope has been steadily revealing its findings since its launch in 1990. in 2018 it detected a Galaxy that until then had gone unnoticed as if forgotten and for good reason while scientists were observing the globular cluster NGC 6752 13 000 light years away from our solar system in search of its famous stars a never-before-detected dwarf Galaxy quietly appeared in the background in the constellation peacock in the form of a very dense and elongated collection of faint Stars distant by about 30 million light years the bed in one Galaxy was thus also the object of an accidental discovery hidden behind the bright stars of the cluster studied this spheroidal dwarf which places it in the category of isolated galaxies it is even to date the most isolated Galaxy of this type its closest neighbor is 2.12 million light years away NGC 6744 a large intermediate spiral galaxy also located in the constellation peacock for the time being it is not yet known whether these two galaxies are gravitationally bound nor whether NGC 6744 is its host but what makes bedden one even more spectacular apart from its isolation is its age examination of its light spectrum which is about a thousand times smaller than that of the Milky Way has led scientists to conclude that it has a very low concentration of metals [Music] this galaxy which was probably born during an explosion has not experienced any new period of star formation since then the stars in it are therefore very very old bed in one seems to be one of the oldest galaxies ever discovered and would be 13 billion years old if you add 0.8 billion years to it bed in one would be as old as the universe considered by astronomers as a kind of living fossil of the primordial Universe having undergone no interaction with other Cosmic monuments it looks like a time capsule its preservation of the conditions of the Primitive Universe should still be able to give us many Secrets concerning its creation New Generation telescope such as the W first telescope should in the near future bring to light many other galaxies of this type which have remained discrete for a long time because of their very low luminosity as you can see these objects have not finished to be talked about I propose to you now to be interested in another category of galaxies let's discover some of the most beautiful irregular dwarf galaxies that embellish the local group with their colorful twinkling let's first discover the ic10 galaxy located in the northern constellation of Cassiopeia about 2.2 million light years from our sun you immediately notice that it is much brighter than all the previous galaxies of course it does not Dazzle by its size its diameter being about 5 000 light years no it is by its different regions reflecting a reddish glow through intermediate dust clouds that it stands out unlike its fellow galaxies the ic10 galaxy has a large population of newly formed massive stars you are in front of the only Starburst Galaxy I.E a star-forming Galaxy belonging to the local group it contains more wolf Riot Stars hot stars of several tens of solar masses then the magellanic clouds although much smaller observe its central part where a large x-ray Source can be detected a high mass x-ray binary is located there it is composed of a wolf Riot star and a compact object which is none other than a stellar black hole whose Mass reaches several tens of solar masses look how these star formations punctuate the heart of this galaxy their production represents between 0.04 and 0.08 solar masses per year the interstellar gas that feeds these numerous outbreaks can probably last for several billion years what a magnificent sight now look at the hydrogen envelope that surrounds this Galaxy with its vaporous mantle look carefully its movement is different from that of the Galaxy itself surprising isn't it another isolated Galaxy intrigues the astronomer sphere this is the Leo 3 Galaxy also named Leo a as you have understood it is located in the constellation of Leo distant from 2.25 million light years from our sun it is also an irregular dwarf Galaxy whose Mass probably does not exceed 800 solar masses this gas-rich galaxy has a low Stellar mass and low metallicity its largest diameter is about 6 500 light years it contains stars of different ages the youngest are approximately 10 million years old while the oldest are up to 10 billion years old however over 90 percent of its stars were formed less than 8 billion years ago in total it hosts five star clusters two young low mass clusters and three older ones also low mass despite these mini Stars this galaxy is still eighty percent dark matter which is still a mystery you can admire its ancient Halo of stars which was discovered a few years later in 2004 take a closer look at this galaxy its internal ring structures remind you of the typical morphology of spiral galaxies its Stars extend beyond its gaseous envelope it thus resembles massive disc galaxies and proves that galaxies a very low Stellar Mass are just as capable of creating complex structures here is once again a galactic object that challenges the current understanding of Galaxy evolution our journey is coming to an end however I would like to allow you to discover two last galaxies which of course do not belong to the local group but which are so close to it that we cannot be satisfied with observing them from far it would be a shame to give up visiting them when we have never been so close to them wouldn't it [Music] among the galaxies that populate the near periphery of the local group I propose you to discover one of them long considered wrongly as an irregular galaxy let's go to the constellation of the sculptor where we can admire that Galaxy NGC 55 also named Cadwell 72 in the distance it hides behind its flattened shape making it look like a long graceful Comet with its disparate Tales in fact it only lets us admire its narrow profile extending over about 68 000 light years but look closely as we get closer to it we can change our angle of view isn't that wonderful look at this Galactic object that is slowly being revealed doesn't it look strangely like the large magellanic cloud you can now contemplate this galaxy which offers us a complete vision of its structure in reality Cadwell 72 is a barred spiral galaxy composed of a single arm it falls more precisely in the category of magellanic spiral galaxies however unlike the magellanic clouds which are about 180 000 light years away this small Galaxy is almost 7 million light years away from our solar system it is probably the closest galaxy to the local group known to date several hundred billion stars illuminate its flattened disc but you can see how much denser and brighter its Center appears this is its bulge characterized by this Central and spherical bulge this core particularly bright is crossed by clouds of dust in some places you can observe iridescent colored areas there are many regions of pink star formation but also young clusters of blue stars which testify to the activity that still Reigns within this small Galactic Monster [Music] not far from there another luminous object attracts our attention still in the constellation of the sculptor another spiral galaxy is next to the object NGC 55. it is the Galaxy NGC 300 or Caldwell 70. this one is also about 7 million light years away from our sun is a low surface brightness Galaxy it's light being spread over a larger apparent area if you look closely at its structure you will see that it is not unlike our Milky Way it's luminous Halo which extends over more than 55 000 light years is dotted with swarms of red giant stars that straddle its two spiral arms its bulb too has myriads of stars moreover this galaxy has been the subject of many studies it has even been portrayed this feat is the result of 50 hours of exposure spread over a number of nights of observation the wide field imager camera which has a very large field of view comparable to that of the apparent surface of a full moon was able to take a large number of pictures which once processed with special filters and assembled allowed the creation of a unique image in addition to mapping this galaxy which is comparable to our own and structure it has revealed that it Harbors a black hole of about 15 solar masses at its heart this black hole belongs to a binary system and is close to a hot and luminous wolf Riot star finally only one million light years seems to separate these two Cosmic objects namely NGC 55 and NGC 300. this Galactic pair is most likely gravitationally bound do you think that one of these galaxies is destined to devour its sister or will they both be absorbed by an even more powerful Galactic Monster

Channel: Wondody | The World of Odysseys

Views: 109,661

Keywords: wondodi, science, space, documentary, earth, space documentary, galaxy, milky way, universe, mars, nasa, extraterrestrial, alien, history, solar system, life, history of the earth, extinction of dinosaurs, history documentary, exoplanet, extraterrestrial planet, planet, documentary universe, discovery, doc, james webb, cosmos, universe documentary, 2023, cosmos documentary, extraterrestrial life, james webb documentary, documentary 2023, galaxy documentary, milky way documentary, galaxies, andromeda

Id: PoT0HF0FhtE

Length: 79min 6sec (4746 seconds)

Published: Sun Apr 23 2023