What the Milky Way Really Looks Like?

according to the dominant scientific hypothesis today around 13.8 billion years ago there occurred to the tremendous event dubbed the big bang which created our universe it is likely that incredibly powerful gravity waves compressed primary gas into gigantic clumps while unrelenting gravity forces ignited thermonuclear fire in their depths thus lighting the universe with the first stars these forces also grouped the stars into large scale clusters which were later to unite into yet more complex structures of colossal proportions billions of years later one of them became the cradle of an amazing phenomenon life and even though mankind is still confined to our native system we have found out a lot about our own galaxy what is it that we already know about the milky way [Music] long before telescopes had been invented people could observe a light strip crossing the heavens the fascinating and mysterious phenomenon prompted a multitude of legends but it took thousands of years of scientific progress to finally account for it it turned out that the milky way wasn't a path of gods what it is is the dissipated light of billions of stars too remote to distinguish each one separately the idea of the stars around us making our part of a single structure of enormous dimensions was first suggested by emanuel kant back in 1755. he also assumed that some nebulae discovered by scientists could in fact be remote star clusters that is other galaxies this ingenious gas was well ahead of its time with the philosopher's contemporaries initially dismissing it only in the early 20th century do the progress of observation equipment enable scientists to confirm the existence of other galaxies and in 1936 edwin hubble devised the classification system many of its principles are still referred to by scientists today according to the system the milky way falls into the category of barred spiral galaxies although it took a long while before it had assumed this today's looks our galaxy is quite an old one since the stars in its central globular clusters were born as far back as around 13 billion years ago at the same time there are some areas in the milky way where stars are actively born which means that there is always a fresh supply of young stars the collected data points to the fact that the milky way is a comparatively large galaxy in astronomical terms the diameter of its disk measures as much as two hundred 000 light years with a halo reaching out into space much deeper yet our galaxy is home to at least 200 billion various stars as well as 25 to 100 billion brown dwarfs in addition it contains over a trillion planets countless small celestial objects as well as clouds of cosmic dust and interstellar gas which may reach gigantic dimensions at the same time regular mata accounts for a small ratio in the galaxy around 90 percent of the milky way's overall mass is the so-called dark matter the amount of light emitted by this mysterious and widespread substance is negligible however dark matter plays an active role in gravitational interaction even though most of the galactic mass remains invisible we can still calculate it to that end scientists refer to star's trajectories of movement around the center of the milky way according to the estimates the overall mass of our galaxy reaches 0.8 to 1.5 trillion solar masses the structure of the milky way is quite elaborate we'll start our journey today from its center this area of the galaxy is shrouded in massive clouds of gas and dust but by a happy chance we can observe it through the so-called bardes window an area of space with lower amounts of dust just like most spiral galaxies the milky way has a supermassive black hole in its center which is surrounded with an accretion disk with a radius roughly three light years dubbed sagittarius star it is the closest object of this class to us its mass is 4.3 million solar masses and its radius isn't over 16 million kilometers which is three times smaller than mercury's orbit the first data about the nature of the object in the center of our galaxy was acquired in the course of long observations and thorough calculations only as recently as on may 12 2022 was it possible to get the first image with the help of the eht network of radio telescopes and so the earlier hypotheses were confirmed the area in the center of our galaxy is highly populated more than 6 000 stars have already been detected within three light-years from the black hole with the orbits of some of them defined rather accurately for example there is a white blue star designation s62 which is 17.8 astronomical units away from the black hole on its closest approach to it while moving at 6.7 percent the speed of light classical mechanics laws are inadequate for description of the trajectory of movement of a star as swift as that because of relativistic effects just to illustrate the axis of its orbit shifts by 75 angular minutes with every completed orbit besides when crossing this area in space we can see several large star clusters with a total mass of around 1 million solar masses and slightly further roughly 200 light years away another massive black hole is likely to be lurking whose mass should be around a hundred thousand times that of the sun traveling further on we will reach the central molecular cloud in a regularly shaped area measuring sixteen hundred to nineteen hundred light years whose mass is over sixty million solar masses there are great many stellar nurseries and gas nebulae as well as protostars and remnants of supernovae most of the clouds mata is dense hydrogen whose temperature fluctuates between 50 and 600 kelvin which corresponds to 223 degrees celsius below zero to 327 degrees celsius above zero spectral analysis shows the gigantic nebula to contain carbon monoxide methyl alcohol and hydrocyanic acid in addition to hydrogen having receded from the milky way's center a bit we will see that it is encompassed by a bulge a bright and massive formation of an elliptical shape with its length reaching 10 000 light years its transverse diameter is roughly 7 light years the total mass of the bulge is as much as 10 billion times that of the sun the exact number of the stars cannot be calculated because their radiation blends and renders any estimates unrealistic being elongated the bulge forms the so-called bar stretching for approximately 13 000 light years and serving as the base for spiral galactic arms it is here at one of its ends that we can see the star cluster stevenson ii containing the largest known star today its designation is stevenson 2-18 and its radius is 2150 times that of the sun unfortunately chances of finding exoplanets orbiting this outstanding object are quite minuscule even if planets did exist at some point in the past the hypergiant would have swallowed them up while it was expanding the galaxy's center is home to billions of stars and apparently a great number of exoplanets chances of encountering a potentially habitable world among this great multitude are much lower than in less populated areas of the galaxy this is due to the fact that when a big number of stars are located close together they destabilize exoplanets orbits while their powerful radiation is lethal to all living things that is why a special area in the galaxy is defined as the habitable zone it looks like a ring with a radius measuring 22 to 29 000 light years and contains star systems with the most favorable conditions for the genesis of biological life worlds encompassed by the ring languish in exposure to excessive radiation while beyond the ring there's a lack of heavy elements however mathematical modelling shows that stars within galaxies are able to migrate thousands of light years away thus either leaving the habitable zone or entering it consequently with an exoplanet lying within the zone it does not automatically suggest favorable conditions on it moving on away from the center of the milky way we will have a chance to check out its most impressive part the galactic disk it is made up of two components with different properties the first one known as the thin disc measures one thousand to one thousand three hundred light years in thickness and its visible radius measures as much as fifty thousand light years on the edge it gradually dissipates with the outermost stars lying up to a hundred thousand light years away from the galaxy's center this part of the milky way contains around 80 percent of the galaxy's visible mass and in fact it was the last component to have formed as for the thick disc its diameter is comparable to that of the thin disc but it's four times a stick and is much more rarefied it is made up of old stars and is practically devoid of interstellar gas observations of some stars in the milky way as well as mathematical modelling show our galaxy to have swallowed up another one in the period from 11 to 8 billion years ago this hypothetical cosmic structure was dubbed gaia enceladus it is thought that it contributed several billion stars to the milky way as well as great amounts of interstellar gas and dark matter it is thanks to this tremendous event that most of our galaxies thick disk formed and an additional supply of gas led to a stellar baby boom there is no doubt that spiral arms are the most noticeable structural elements of our galaxy's disk usually two major ones are singled out the scutum centaurus arm and the perseus arm and two minor ones the norma arm and the carina sagittarius arm sometimes a fifth large arm is taken into account named after the cygnus constellation galactic arms are areas of especially high star count most of interstellar gas is also concentrated here which is why the rate of star formation in the arms is three to five times higher than in the galaxy on average they spend the first millions of their lives in open clusters but gravity forces are too weak to hold the stars close together for a long time this destabilizes the clusters and young stars gradually drift away from each other traveling along the carina sagittarius arm we will reach a fork that links it to the perseus arm the length of this stellar structure reaches 11 000 light years and its width measures roughly 3 500 light years it is referred to as the orion arm and it is here 27 000 light years away from the galaxy's center that the solar system is located from our planet's perspective the galaxy's center is seen as a dark abyss this is the grey drift an area of space that shuts out the greater part of the milky way from our gaze it is filled with massive clouds of interstellar gas and dust and its total mass is as much as a million times that to the sun even though the great drift is practically not transparent in the optical range its matter actively emits radio waves and thermal energy spectral analysis data reveals that the clouds are mostly made up of hydrogen with a small percentage of more complex compounds ammonia alcohols and amino acids the great drift is thought to be a potential stellar nursery but it is going to take a while until the first stars light up in that area while it is still not quite active let's move on beyond the galaxy disk even though its bright and clearly defined arms attract a lot of attention there is more to the milky way than that if we look closer we will see the vastest and the most terrified of its components the halo its visible part spherical in shape stretches for up to 260 thousand light years away from the galaxy's center but accounts for just a few percent of the total mass the halo contains a great number of globular clusters made up of remarkably old stars over 12 billion years of age and several tremendous stellar streams the sagittarius stream for example made up of several thousand stars encompasses our galaxy in an elongated ellipses which is almost perpendicular to the main plane modelling shows that all these stars are highly likely to have been gravitationally captured by the milky way from a dwarf satellite galaxy designation sagittarius deg it lies 500 000 light years away from the milky way's center and is going to be swallowed up by it completely within several billion years another dwarf galaxy has already met a similar fate lying in the canis major constellation it was almost destroyed by the milky way which pulled out millions of its stars by gravity forces stretching for 200 000 light years and mixing with other stars this string of stars with a total mass of roughly 100 million solar masses has already wrapped around our galaxy three times apart from bright but rare stars and clusters the halo contains great amounts of gas whose temperature reaches millions of kelvin also great amounts of dark matter are thought to be scattered in the vicinity of the milky way forming the so-called dark halo stretching for up to 2 million light years it hardly emits any electromagnetic radiation and can be detected only by gravitational interaction the dark halo remains an unsolved mystery yet it greatly contributes to the global stability of our galaxy the milky way is just one of the countless structures of the universe together with other galaxies it forms the local group which in its turn is part of the virgo supercluster galaxy clusters group into filaments which form still larger scale structures cosmic scales are so stupendous that they can hardly be appreciated by the human mind still our knowledge about the universe gets more and more accurate with every passing day and mysteries of the cosmos succumb to the human tenacity one after another this is the power of the human mind and progress and we are proud to be part of it feel free to give us a like if you are ready to conquer the mysteries of the universe alongside cosmo let's keep in touch [Music] you

Channel: Kosmo

Views: 259,590

Keywords: milky way, the milky way, our galaxy, galaxy, what our galaxy looks like, what was discovered in the milky way, what is in the centre of the galaxy, orion's arm, where is the solar system, bulge, bar, arms, geography of the milky way, stephenson 2-18, great rift, how many galaxies are there in the universe, closest galaxies, space, cosmos, universe, stellar stream, galaxies colliding, science, film, video, cosmo, kosmo, film about space, planets, black hole, sagittarius a

Id: 8WfPamf1WXw

Length: 17min 7sec (1027 seconds)

Published: Wed Aug 10 2022