The Great Enigma: Where Are We Really in the Universe ? | Space Documentary

[Music] where does the human being stand in the middle of this Cosmic immensity man is a living species among millions of others on the planet Earth throughout his Evolution he has distinguished himself by his ability to modify the environment and to shape nature to adapt it to his needs it is developed complex Societies in diverse cultures that reflect its way of living and interacting place on Earth is unique and considered as dominant man is a product of biological evolution that is developed on a planet among millions of others in a galaxy among billions of others within a universe that is in constant expansion [Music] if we look at things from this angle man becomes a relatively insignificant being in the immensity of the universe however he has had the ability and intelligence to make sense of the cosmos and to try to understand its Mysteries thanks to scientific research knowledge about our planet has increased the Earth belongs to the solar system this solar system is part of a galaxy called the Milky Way which itself is attached to a superstructure called the local group the local group is only a small part of a supercluster of galaxies called laniacaya and all this small world is concentrated in a universe with immeasurable borders match if we reduce the universe to the scale of our planet Lani Ikea would be a continent the local group our country the Milky Way our region the solar system our city and the Earth our apartment the power of the man becomes then very relative dear traveler welcome today we are going to explore the immensity of space to answer the dizzy in question where are we in the universe but before leaving for a new adventure think of liking the video and subscribing to the channel to not miss anything thank you and have a nice trip [Music] the planet earth was formed within the solar system this solar system is a precious territory more than 4 billion years old and includes the Sun the eight known planets as well as many small bodies of rock and Ice called asteroids and comets solar system is divided into several zones the inner Zone consists of the so-called caloric planets Mercury Venus Mars and of course the Earth these four planets are rocky and metallic their size is relatively small during their formation the heat of the sun has driven the gases from this area to concentrate dense elements Beyond Mars there is a belt of asteroids these are millions of blocks of rock waste products are the formation of planets from this asteroid belt we enter the domain of the giant planets Jupiter Saturn Uranus and Neptune in this external zone of the solar system the lower temperature during the formation of our solar system allowed the existence of volatile elements the planets are larger in size than the terrestrial planets and are composed of Light Elements such as hydrogen and helium the formation of the solar system took place after a nebula gradually collapsed on itself following the explosion of a supernova the Primitive nebula flattened under the effect of its rotation the central part of the nebula heated up and formed a proto-sun dust rich in carbon ice metals and minerals have then clumped together this phenomenon is called accretion these blocks met until they form protoplanets and then a few million years later the planets in their current size [Music] if we start from the Sun the Earth is the planet that is in third position it is the only planet in the solar system with liquid water on its surface seventy percent of the globe is covered with ocean several tens of kilometers deep its atmosphere is composed mainly of nitrogen and oxygen the conditions found on this terrestrial planet have allowed life to develop and evolve in a complex manner currently no other planet is known to Harbor life the Earth has always been subject to vigorous volcanic activity it has a diameter of almost 13 000 kilometers or about 8 000 miles [Music] the Earth has a very particular composition since to date is the only toleric planet that has four distinct layers including a core in two parts on the outside the Earth's crust is 5 to 80 kilometers or three to fifty miles thick it is mostly composed of rocks derived from volcanism under the crust is the mantle although it is hot and malleable it remains solid and extends to almost 3 000 kilometers or 1900 miles deep it is composed of minerals such as oxygen silicon iron and magnesium at the center of the earth is the core which is divided into two parts the outer core is composed of metallic elements its liquid structure is traversed by electric currents that create the magnetic field the solid inner core composed of iron and nickel is subject to a phenomenal pressure and a temperature reaching 6000 degrees Celsius or 10 800 degrees Fahrenheit the Earth's atmosphere contains very little carbon dioxide because it dissolves in the oceans nitrogen dominates our atmosphere followed by oxygen Argon some other gases and water vapor the gases present are transparent whereas water vapor is visible when it condenses into a cloud the ladder can cover up to 60 percent of the Earth's surface in the solar system the atmosphere most similar to that of the earth is that of Titan a moon of Saturn the atmosphere of Mars is 100 times less dense than that of the earth and that of Venus is 100 times more dense ozone is a molecule that contains three oxygen atoms the gas present in the atmosphere absorbs the harmful ultraviolet rays of the sun allowing life to thrive on the surface the Earth is different from other planets because of its geology and its complex climate another of its characteristics is that its crust is divided into tectonic plates that are Mobile in relation to each other the other teluric planets are called monoplate because they have only one crust this division of the crust into tectonic plates gives rise to teluric movements if seen from the sky the earth looks like a blue planet it is because two-thirds of its surface is covered by oceans and that erosion has erased the craters of asteroids and comets that may have hit its surface [Music] next to the Earth is the Moon its satellite it is the fifth largest satellite and the only moon in the solar system to be called Moon the Moon is devoid of atmosphere in life there has never been liquid water on the moon meteorite impact crater is an ancient volcanic eruption shape its surface seen from Earth the moon offers two types of very contrasting terrain with dark and light areas the latter called continents are massive areas riddled with asteroid impact craters that formed in the first billion years of the Solar System's history the dark areas are called Seas they are vast planes of lava emitted by volcanoes the moon exerts a significant attraction on the earth although it has a weak gravity field and is rather far from the planet combined with the attraction of the Sun the influence of the Moon causes the tides which result in the rise and fall of the Waters of the oceans during a full or new moon when the moon the Earth and the Sun are aligned the forces of gravity add up to create the high tides the high tides are then very high and the low tides very low when only a quarter moon appears the Earth to Moon and Earth to Sun axes are at right angles and the forces of gravity partially cancel each other out the tides called neap tides are then reduced [Music] the one who Reigns Supreme in this gigantic domain and without whom the Earth and consequently man would be nothing is the Sun this giant ball of hydrogen and helium contains 99.9 percent of the total mass of the solar system the sun is a star although it seems huge to us it is medium size with a diameter of almost 1 million four hundred thousand kilometers or 870 000 miles the sun is in the middle of its life cycle since it is already used up between 35 and 45 percent of its hydrogen Reserves in about 6 billion years the hydrogen will be totally consumed and the sun will start to expand it will then become a sub-giant star brighter but less hot a billion years later the star will become a red giant growing even larger it will then eject its outer layers into space until its core curls up into a white dwarf it is within its core the central region of the Sun that nuclear reactions occur the energy release Rises to the surface and Escapes in the form of light and radiation it is thanks to this same energy that life on Earth is possible the atmosphere acts as a shield it allows the solar energy to penetrate and prevents the heat from escaping while preventing the dangerous solar radiation from reaching the planet this effect is called the greenhouse effect the atmosphere Keeps Us comfortably warm day and night human beings are entirely dependent on the sun which is involved in the entire life cycle the star heats the land oceans and Air when the water evaporates clouds form within these clouds water droplets are formed as the water vapor cools they will then fall back down as rain humans animals and plants benefit from this water plants also use sunlight for photosynthesis they convert carbon dioxide and water into carbohydrates necessary for their development in return they release the oxygen that living things need to breathe Mercury is the closest planet to the Sun it looks like a ball of iron surrounded by a thin Rocky mantle its surfaces like that of the Moon covered with impact craters the caloris Basin is one of the best known impacts so large that it could contain almost the whole of Texas apart from the craters and plains compression faults appear which form Cliffs and which can reach three kilometers or two miles in height having no atmosphere or liquid water Mercury's only erosion comes from the impact of meteorites asteroids and comets mercury has no moon its proximity to the sun results in an average ground temperature of 430 degrees Celsius or 800 degrees Fahrenheit it also experiences great temperature contrasts since when its hemisphere is plunged into the night the temperature decreases to about minus 200 degrees Celsius or minus 328 degrees Fahrenheit it is smaller than the Earth but so dense that it certainly has an important iron core Venus is the closest planet to Earth it is about the same size as Earth but is far from being its twin a thick atmosphere of carbon dioxide covered with clouds of sulfuric acid obscures its surface the pressure exerted on the ground is equivalent to that of a deep sea of 900 meters or 3000 feet while it is farther from the Sun than Mercury the average ground temperature of Venus is warmer and reaches up to 490 degrees Celsius or 914 degrees Fahrenheit the surface of Venus is covered with volcanic edifices such as pancake domes which are circular and flatten reliefs formed by a gas-rich lava this lava spreads like a pancake batter then solidifies and breaks the highest volcano on Venus is mottmans which Rises to 8 000 meters or 26 000 feet its lava flows can reach hundreds of miles and miles in length Mars comes in forth from the Sun its diameter of just over 6 700 kilometers or 4 200 miles is twice as small as Earth's it has a thin atmosphere containing mainly carbon dioxide its unstable climate leads to the formation of ice caps many extinct volcanoes culminate on its surface including Olympus Mons it is one of the highest known landforms in the solar system with a peak reaching over 21 000 meters or 69 000 feet it seems that liquid water in the form of real Seas covered its surface in the distant past the first geological hours of Mars were marked by meteoric bombardment and strong volcanism the ancient craters thus eroded by water gave birth to rivers there was then at that time a hydrodynamic cycle the climate should be mild and stable thanks to the presence of oceans allowing the water cycle nevertheless the weak mass of the planet could not allow to retain the gases of its atmosphere and the cycle of the water dissipated the water would then have evaporated and been absorbed within porous rocks [Music] the density of Mars is lower than that of the Earth because its smaller Mass compresses its deep layers less it is called a red planet because of a thin layer of red dust composed of iron oxide that covers its surface most of the southern hemisphere is covered by high plateaus riddled with impact craters in the north there are basins and large volcanoes Mars has two moons Phobos and Daimos these are asteroids that have been captured by its gravity field they are riddled with craters and have irregular shapes both are small with modest diameters of 27 kilometers or 17 miles for Phobos and 15 kilometers or nine miles for Daimos the distance between Daimos and Mars is such that it is in synchronous orbit with the planet the Moon is always at the vertical of the same place [Music] a cluster of asteroids circulates between the orbits of Mars and Jupiter irregularly shaped they can reach sizes ranging from a small Stone to a mini planet the largest of them Ceres has a diameter of about 950 kilometers or 590 miles it was even classified as a dwarf planet asteroids are composed of minerals metal or carbon they are riddled with impact craters they could not aggregate to form a planet because the gravity field of Jupiter disrupted and Scattered the blocks these Rocky bodies orbit the Sun but their small size prevents them from being classified as planets the majority of asteroids are located in the main belt its thickness measures between 100 and 300 million kilometers or between 60 and 190 million miles asteroids are classified into three distinct families according to their chemical composition and morphological characteristics we find the asteroids of type c called carbonaceous The Asteroids of Type S rich in silica and the asteroids of Type n said metallic about 75 percent of them are c-type asteroids they are lodged in the most distant regions of the asteroid belt and are the least luminous can These Lumps floating in the sky be made to crash into the Earth and become a threat to life some fragments of asteroids can head towards the Earth and collide with it they are called meteoroids if one of these meteoroids enters the Earth's atmosphere at high speed the friction creates heat so great that it burns the meteoroid to ashes and produces a Trail of Light across the sky if the meteoroid does not burn up completely the remaining piece can then touch the Earth it is then called a meteorite an impact with a large meteorite could obviously leave obvious signs on the surface of the Earth and cause dramatic consequences for life [Music] Jupiter is the largest planet in the solar system it could contain all the other planets in its interior its composition is almost entirely gaseous and consists mainly of hydrogen and helium Jupiter is more like a star than a real planet after Venus Jupiter is the most luminous planet it has a compact core of rock and ice formed of compressed hydrogen and helium this core represents about five percent of its mass it is a novella by a volatile elements buter is spectacular it has no solid surface and a dynamic atmosphere from the earth we can observe an alternation of dark belts and clear areas this banded Arrangement is due to its rapid rotation which stretches the disturbances around the globe and confines the clouds of its atmosphere and a set of parallel lines in the middle of these bands Cyclones and anti-cyclones are present the most famous of them is the Great Red Spot it owes its bright color to molecules containing phosphorus this anticyclone is larger than the Earth the Great Red Spot is constantly shrinking from forty thousand kilometers or 25 000 miles in 1930 to 16 000 kilometers or ten thousand miles long in 2014. and would disappear within 70 years Jupiter has a ring system that remains dark and is only visible when it is in the planet's shadow the planet is not only distinguished by its size it also has the largest number of moons to date 95 are known foreign is the second largest planet in the solar system but what makes it famous are the rings that surround it with the help of a small amateur telescope it is possible to observe them from Earth Saturn's rings are a world apart they are composed of many ice particles acting as an independent satellite some of them can reach the size of a house the particles in these rings are shiny coated or composed of Highly reflective ice Saturn's rings are brighter than those of other planets and reflect up to 60 percent of sunlight they are flattened although they measure 280 000 kilometers or 170 000 miles in diameter their thickness does not exceed a few meters or feet on average Saturn has a solid core of rock and ice its atmosphere contains mainly hydrogen and helium the clouds are deeply buried and their color blurred by layers of haze gives the planet a livid hue one of the characteristics of Saturn is that it has a flattened shape at the pole this is due to its extremely fast rotation on itself of less than 10 hours 30 for a complete turn Saturn imposing in terms of mass and gravity field has captured a large number of asteroids that have become its moons 83 known satellites are attributed to it today among them Titan has a diameter of more than five thousand kilometers or 3100 miles and is the second largest moon in the solar system Titan is surrounded by a thick layer of nitrogen being quite far from the Sun the temperature on its surface is extremely low [Music] by continuing to move away from the sun we can observe in the sky a ball with blue green Reflections it is the planet Uranus it is the third largest planet its diameter is four times that of the Earth its particular color is due to the presence of methane no details of its atmosphere are visible neither Cloud bands nor cyclonic formations unlike Jupiter and Saturn which are considered as gas giants Uranus is similar to an ice Giant it is much denser and its internal layers must contain elements heavier than hydrogen like ice Uranus goes around the Sun in a little more than 84 years this situation gives it strange seasons this is also explained by the fact that its rotation axis is almost lying in the plane of its orbit [Music] long periods of sunlight follow long periods of Darkness during the winter solstice the northern hemisphere is plunged in the night for 21 years the planet Uranus has rings 13 are currently known 11 located in the inner system and two in the outer system their capacity to reflect light is extremely low they are therefore difficult to see these rings are composed of dust particles with dimensions of the order of a centimeter they could have been formed by the fragmentation of a small Moon after a collision with a meteorite Uranus has so far 27 known moons five of them are large the others are only a few tens of kilometers in diameter the largest Titania measures 1580 kilometers in diameter but the strangest of the moons encountered so far is Miranda the fifth satellite of Uranus in size its surface shows complex and extraordinary geological formations one could compare it to a giant puzzle as if this Moon had been torn apart and then put back together it could be that Miranda was smashed during a collision and that the piece is in orbit around Uranus were then reassembled until the moon was reconstituted foreign is a gas planet unlike Jupiter and Saturn its solid core is larger than its total mass Neptune's atmosphere is characterized by Strong Winds of over 2 000 kilometers per hour or 1200 miles per hour and large cyclonic formations that persist for long periods the most visible large dark spot is as large as the Earth the last planet in the solar system glows with a beautiful Azure color this Hue is explained by the presence of methane in its atmosphere which absorbs red radiation and lets only blue radiation filter through its atmosphere is composed in addition to methane of hydrogen and helium Neptune has an important internal heat Source since it emits a quantity of energy equivalent to almost three times that received from the Sun five rings surround Neptune they are composed of ice covered with a large carbonaceous dust and remain very difficult to detect because of its remote distance from the Sun the number of Neptune's moons remains poorly known Triton is the largest of Neptune satellites known to date this moon has Canyons craters Peaks and very long fissures forming a most amazing landscape it also has very strange volcanoes on its surface it seems that Triton's volcanoes look like geysers that emit jets of gas and dark carbon compounds from underground Pluto was considered the ninth planet in the solar system in 2006 it was reclassified as a dwarf planet dwarf planets are considered to be Stars orbiting a star more or less spherical and often found in the vicinity of many other large objects such as asteroids comets or other dwarf planets as their name indicates these planets are small they cannot exert the gravitational forces necessary to attract and hold objects in their orbit [Music] with its 2300 kilometers or 1430 miles in diameter Pluto is smaller than the moon and yet the largest and second most massive dwarf planet it's essentially Rocky core occupies the majority of the planet's volume its surface consists of planes and mountains covered with a thick layer of ice probably water mixed with traces of methane nitrogen and carbon monoxide it takes almost 250 years for Pluto to go around the Sun [Music] Beyond Pluto a vast region of comets opens up comets are visible to us as they approach the Sun as they develop a glowing tail but billions of invisible comets stay at the edge of the solar system comets are classified into two families long period comets that Circle the sun in more than 200 years and short period comments the long period comets have orbits inclined with respect to the circulation plane of the planets their trajectories are varied suggesting that they belong to a vast spherical Cloud that envelops the solar system like a cocoon the Kuiper belt is the source of short period comets it is located around 30 astronomical units and extends to hundreds of astronomical units it is home to hundreds of icy objects some of which reach the size of large asteroids [Music] extending over a few tens of billions of kilometers it is a thousand times smaller than the ort cloud the ort cloud is the reservoir of long period comets it extends over distances between thirty thousand and one hundred thousand astronomical units this spherical cloud is hypothetical since it could not be observed directly as it is beyond the reach of our instruments the knowledge of its existence is based on the analysis of the orbits of several comets in 1932 the first astronomer postulated that comets orbiting for long periods of time came from a large Cloud located beyond the limits of the solar system about 20 years later another astronomer put forward a theory According to which meteorites could not have formed in their current orbit because of the astronomical phenomena that govern them he deduced that they must be stored in a large Cloud the ort cloud [Music] a comet that passes near the sun loses part of its mass volatilized into gas and dust one might think that in a few tens of thousands of years a comet should have completely melted however the solar system has always been full of comets there is in fact a vast reservoir of comets hibernating around the Sun [Music] as the sun moves through the Milky Way It Is subject to Tidal forces as it passes near other stars comets can then be dislodged from the Oort cloud and directed towards the interior of the solar system comets are bodies composed of a head which includes a nucleus surrounded by a luminous hair of gas the nucleus of the Comet presents different colorations varying from black to gray through red [Music] the nucleus is composed of common silicate and molecules composed of carbon oxygen nitrogen and hydrogen when it is far from the Sun the comet is invisible like many other small celestial bodies as the comet approaches the inner regions of the solar system the heat produced sublimates some of the ice present in the nucleus which mixed with other gases forms the hair and the tail as the comet passes through the solar system the material of which the short period comet is composed is depleted and transforms it into a tiny body among others it happens that the Earth during its own rotation around the Sun crosses the dust or gases that have been left behind by a comet these materials while crossing our atmosphere create magnificent swarms of meteors that are called shooting stars during the formation of the comet's hair carbon dioxide and carbon monoxide first evaporate then it is the turn of the ice the emitted gas disperses in space and is replaced by new matter the vaporization takes place only on the side facing the sun where the comet is active the material emitted from the nucleus can spread out into space for hundreds of thousands of miles and miles [Music] when the comet shines and becomes visible its tail can be seen which comes from the gases in the hair a comet has in most cases at least two tails one is composed of ionized gas and the other of dust the latter are not always visible the gas tail is bluish in color because of the presence of carbon monoxide it can measure up to several hundred million kilometers in miles they are always straight and consist of structure node and condensation the sudden separation of the tail from its hair is one of the most spectacular phenomena [Music] man from his planet Earth seems infinitely small when placed on the scale of the solar system and yet the universe is far from stopping there the solar system is located in the Galaxy called the Milky Way it is a huge disk of stars in motion that measures nearly 1 000 million billion kilometers in diameter along its diameter one could line up 130 million solar systems and yet the Milky Way is one Galaxy among many [Music] galaxies are gigantic clusters of stars that can extend over hundreds of thousands of light years presenting a wide variety of sizes and shapes galaxies are classified into two main families elliptical and spiral galaxies spiral galaxies are further subdivided into simple spiral barred spiral and lenticular galaxies elliptical galaxies are the most massive the spiral and lenticular galaxies can reach diameters similar to the large elliptical but are less massive because they are flattened spiral galaxies represent 60 percent of all cases and 30 percent are elliptical the best known Remain the spiral galaxies among them we find barred spiral galaxies which have a thick bar of stars crossing their heart and extending by an arm at each end and normal spiral galaxies which see their arms emerging directly from the heart of the Galaxy spiral galaxies are flattened like a disc with a central bulge of old red stars the disc at the periphery contains clouds of gas and dust that will serve to form new stars spiral galaxies are rotating resulting in density waves that compress the gas and dust to form bright blue stars that illuminate their arms a spherical Halo of globular clusters containing up to a million old red stars surrounds spiral galaxies the so-called elliptical galaxies of a slightly flattened oval shape they have three axes of different lengths the lenticular Galaxies have as for them a lens shape they remind both spiral galaxies and elliptical galaxies they have like spiral galaxies a disc with a central bulge that houses clouds of gas and dust they differ by the absence of spiral structure they do not have young blue stars and host only old red stars there are two theories explaining how galaxies are formed according to the first Theory galaxies formed from huge clouds of gas that collapsed in on themselves by gravity the second theory suggests that galaxies would have assembled from smaller objects both processes could have been at work when the Galaxies formed more than 10 billion years ago [Music] just one or two billion years after the big bang the universe then consisted of a vast expanse of hydrogen and helium some parts of this universe denser than others attracted matter thanks to their gravitational forces these regions individualized into huge clouds that would later become future galaxies these different clouds were brought to meet and thus form even denser sets during the collisions shockwaves stirred up the gas and caused it to collapse into stars and star clusters it seems that in earlier times the universe contained a higher proportion of spiral galaxies than today this change in the appearance of the universe is due to repeated collisions between galaxies indeed when spiral galaxies Collide they emerge to give elliptical galaxies the merger thus explains their large size and why they contain so little gas and so many red stars from our human eye is in the night sky the Milky Way appears as a whitish molten band crossing the celestial sphere it takes the form of a ring of which only a part is revealed from the earth its brightness is weak and diffuse in reality we can only see the side of the galactic disc composed of an endless string of stars that the human eye is unable to distinguish many stars planets and nebulae populate the Milky Way a star is a ball of ionized gas made up primarily of hydrogen and helium the two most abundant elements in the universe Stars tend to collapse into their own weight this is called gravitational contraction the nuclear reactions that occur within the star also exert pressure from the inside out the balance between these two forces gives Stars their own dimension the core of the star is subjected to high temperature and pressure the hydrogen nuclei Collide and form helium nuclei thanks to these reactions a stark and Shine for billions of years its surface temperature will depend on its color our sun is a yellow star of average size [Music] stars are born in molecular clouds these are large areas of gas inside which some regions are denser than others and attract by gravity the gases present around a globule is then formed and contracts until it becomes a protostar the contraction causes an increase of the rotation as well as an increase of the temperature and the pressure the thermonuclear reactions start the star is born the North and South Celestial poles are the extension of the Earth's axis to infinity and are the only two immobile points in the sky the North Star indicates almost exactly the North Pole it is not very bright since it is only the 48th star in the sky in order of brightness but it is one of the most important landmarks since it does not move and always indicates North thanks to it it is possible for us to orient ourselves at night from Earth without a compass or GPS [Music] 200 billion stars populate the Milky Way and only 3 000 of them are visible to the naked eye the closest star system to us is Alpha Centauri it is a complex system composed of three stars the two largest form a double Star located 4.37 light years from the solar system their size and color resemble those of the Sun they are accompanied by Proxima Centauri it is a tiny star a brown dwarf measuring one and a half times the size of Jupiter Proxima Centauri is a little closer to us than the main components of Alpha Centauri since it is 4.24 light years away from Earth Alpha Centauri shines with an impressive brightness it is the third brightest star in the sky with the help of a telescope the two main components of Alpha Centauri form a beautiful double star several types of stars populate the Milky Way binaries multiples and variables almost half of the stars in our galaxy are binaries binary and multiple stars are stars that orbit a common center of gravity and are bound together by gravitational attraction binary stars form within the same cloud of matter which during its collapse splits into two pockets some clouds split into multiple parts and can group up to six stars [Music] a variable star sees its brightness change for several reasons when a star passes in front of another for example it will modulate the amount of light we receive the periodic pulsations of the star's surface can also change its brightness the light emitted is a function of the surface of the star S at the end of their life expand and contract Stars can undergo unpredictable variations in brightness due to gas eruptions or other cataclysmic phenomena sheliak is an eclipsing binary star which is very surprising it consists of two stars so close to each other that they exchange matter and deform each other the larger of the two loses the equivalent of the mass of the Sun every fifty thousand years is located in the constellation of lira if our planet were positioned near this infernal Stellar couple the inhabitants would see huge perturbances tear away from the larger one to wrap around the smaller one but from the earth we only notice the brightness of sheliak diminished as soon as the smaller star passes in front of the larger one a set of neighboring Stars can sometimes present a figure on the celestial sphere these are the constellations from the earth man can observe different figures drawn by stars like Orion the Big Dipper or the Southern Cross the stars have their own movement but they are so far away from us that they seem fixed their Position will change gradually to the point that our familiar constellations will become totally unrecognizable in the distant future the Big Dipper is the most famous constellation in the northern hemisphere it is close enough to the celestial Pole where the North Star is located that it never disappears below the Horizon whatever the time of night or the season the seven brightest stars of The Big Dipper form a distinctive saucepan shape most of its stars are less than a hundred light years away and belong to an open cluster that is almost completely dislocated many Legends have been associated with this constellation according to Greek mythology it represents the nymph Callisto changed into a bear by Hera the wife of Zeus after her husband fell in love with her Zeus would then have raised the bear to the Heavens to place it near the sun Arcus whom he had with Callisto and who is also transformed into a little bear the universe favoring groupings the stars are often binary or multiple but on a larger scale larger groupings of stars are formed as open or globular star clusters globular clusters can contain from one hundred thousand to more than one million stars they are similar to Tiny elliptical galaxies they contain old stars of red color while the open clusters are populated by Young blue stars Within These clusters collisions are frequent leading to the formation of new stars called Blue Wanderers globular clusters orbit the center of the Galaxy and together form a spherical Halo the Milky Way contains nearly 150 globular clusters in its Halo one of the brightest clusters is Omega of The Centaurus it Peaks high in the southern Sky in March and April to the naked eye it looks more like a spot than a star through a telescope we can see that many small Stars dot its surface Omega Centauri contains nearly 10 million stars over 10 billion years old it is the largest globular cluster in the galaxy this cluster could be the remnant of a small Galaxy that was swallowed by our Milky Way nebulae are interstellar clouds that contain the raw material to make new stars these clouds come in a variety of sizes and colors the smallest nebulae are called globules their diameter is of the order of a light year and they look like dense and dark spots large molecular clouds contain enough material to make tens of millions of stars all clouds are composed of gas and helium as well as grains of carbon and silicon dust when a new star forms in an Interstellar Cloud the light ionizes the gases and creates luminescence some clouds do not emit their own light they reflect or scatter the light of nearby stars and nebulae the Orion Nebula is the closest to Earth it shines according to a phenomenon of fluorescence the atoms of the gas are stimulated by the ultraviolet radiation of bright stars which leads them to diffuse light in turn in this nebula many stars and planetary discs are forming it is easily observable from Earth simply with binoculars this nebula looks like a small cloud in which the central region appears greenish [Music] the Milky Way is a spiral galaxy it consists of a flat main body in the form of a disc with a diameter of more than one hundred thousand light years this disc contains the vast majority of stars it contains curved structures from the core that extend to the borders of the Galaxy these are the spiral arms inside these arms the matter reaches a high density and clouds of gas and Interstellar dust give birth to new stars in the center of the flattened disc we find the galactic nucleus which shelters the Halo a shell populated by the oldest stars in globular clusters representing the ancient Stellar systems of our galaxy globular clusters have an extremely high density and are extraordinary objects that we can contemplate through a telescope from Earth [Music] 27 000 light years away from the heart of the Galaxy we find the sun our star it is located on the periphery two-thirds of the galactic radius from the center we the inhabitants of the Earth travel in space following the movements of our planet with the whole solar system within the Milky Way these movements are imperceptible but they are similar to a crazy race of 600 kilometers per second or 370 miles per second the Milky Way rotates on itself in about 240 million years the sun orbits around its Center at a speed of about 220 kilometers per second or 136 miles per second The Starry Sky that illuminated the Earth at the time of the dinosaurs was therefore very different from the sky we can observe today during this time the sun has gone through at least one third of its revolution it moves in space with its own motion that is superimposed on the revolution around the galactic center the stars are subject to the local attraction exerted by the nearby Stars they have their own motion and move through the Galaxy the constellations that we observe did not exist at that time and they will not exist in the future one of the particularities of the Milky Way and of any other spiral galaxy is that its rotation occurs in a differentiated way the central stars and celestial objects have a shorter period of revolution than the more distant stars and objects the objects that populate the Milky Way such as open and globular clusters or nebulae move across the sky the movement of globular clusters is particularly remarkable these dense clusters are composed of hundreds of thousands of old stars that inhabit a spherical region around the nucleus and disk of the Galaxy they are Like Satellites and revolve around the galactic center in elliptical orbits more elongated and inclined than the disc their movement is very fast about 200 kilometers per second or 125 miles per second and they regularly cross the disk thanks to their density they remain stable however the interaction with the plane of the Milky Way leads to their disintegration the open clusters have a different motion containing only a few hundred or thousands of stars these clusters break up in the spiral arms Their Stars being less thick than those of globular clusters they tend to disintegrate over tens of millions of years therefore globular clusters can reach a lifetime of more than 10 billion years while open clusters are younger a large band of dust called the Great Rift splits the Milky Way into originally our galaxy was made up of stars and hydrogen clouds and we could see through them very well since then countless Stellar explosions have released dust that has accumulated inside completely changing its appearance when we look towards the interior of the Galaxy the Great Rift disposition between the constellation of cygnus and the southern constellation of Centaurus all spiral galaxies are now crossed by such dust bands the Milky Way belongs to a group of about 60 galaxies called the local group the Milky Way is not the only galaxy in the universe many small faint nebulae in the night sky are also galaxies they are distant from the Milky Way galaxies are not uniformly distributed in the universe they form groups more or less large galaxies are usually accompanied by dwarf satellite galaxies there are two that can be seen with a naked eye from Earth they appear as nebulae they are the magellanic clouds two dozen other dwarf galaxies of low brightness are next to them a little further away we find the great Galaxy of Andromeda itself surrounded by two other relatively large neighbors and many small satellite galaxies the Milky Way accompanied by the Andromeda galaxy and the triangulum Galaxy forms the local group with many other smaller galaxies counting also the dwarf galaxies the local group includes more than 50 members the three large spiral galaxies that are the Milky Way the Andromeda galaxy and the triangulum Galaxy are accompanied by dozens of smaller galaxies the satellite galaxies are those present in greater numbers they swarm around the large spiral galaxies like mosquitoes around a lamp satellite galaxies are discreet agglomerations of several million stars of a few thousand light years in diameter [Music] the triangulum galaxy has no satellite galaxies while the Milky Way and the Andromeda galaxy are surrounded by many they probably grew by swallowing small satellite galaxies this process is still going on today for example the Sagittarius dwarf galaxy has been stretched by the tidal forces of the Milky Way and will eventually be swallowed by it the large magellanic cloud is about 15 000 light years in diameter it is composed of a few billion stars and is located 163 000 light years from Earth due to its high content of gas and Interstellar dust the level of star formation activity is very high the largest star-forming region of the large magellanic cloud is the tarantula nebula it is so bright that if it were located at the same distance as the Orion Nebula it would never be dark on Earth the large magellanic Cloud contains dozens of globular clusters hundreds of open Stellar clusters and planetary nebulae it contains many more heavy elements than the Milky Way these have been created over time by nuclear fusion reactions within the Stars themselves indicating that the magellanic clouds are younger than the Milky Way the brightness of the magellanic clouds is incomparable to that of the Milky Way from the Southern Hemisphere and in the absence of light pollution they appear distinctly to the naked eye the small magellanic cloud is located further away than its Big Brother two hundred thousand light years from Earth it contains fewer Stars only 3 billion it is less bright in the night sky but it is still recognizable to the naked eye the small magellanic Cloud contains a large number of cepheids these are stars whose brightness varies over a period of days or weeks foreign 2.5 million light years from Earth from the Northern Hemisphere on a moonless Autumn night and on a clear day the Andromeda galaxy appears as a diffuse patch of light it is one of the most distant objects in the universe that can be seen without the aid of optical instruments the Andromeda galaxy contains about one trillion stars at least twice as many as The Milky Way it is larger than the latter it is the largest galaxy in the local group however it seems to contain fewer star-forming regions the Andromeda galaxy was born 5.5 billion years ago from the collision and merger of two smaller galaxies the triangle Galaxy owes its name to the constellation in which it is located this spiral galaxy is located almost 3 million light years from Earth it has a low brightness nevertheless under extremely favorable conditions it is possible to see it with the naked eye from Earth the triangulum galaxy is the smallest of the three large galaxies in the local group it is half the size of the Milky Way contains about 40 billion stars and is about 50 000 light years in diameter the triangulum Galaxy is home to a large number of star-forming regions including the largest NGC 604 This Magnificent nebula and emission surpasses the brightness of Venus its gas is ionized by a cluster of massive stars at its heart distributed in at least two clusters there are about 200 stars with masses ranging from 15 to 60 solar masses the diameter of the triangle nebula reaches about 1500 light years [Music] in about 4 billion years the local group will see the Milky Way and the Andromeda galaxy collide 2 billion years later they will merge to form a single giant elliptical galaxy the Sun and its planets could be catapulted into space because of gravitational disturbances [Music] the triangulum Galaxy meanwhile May collide with the Milky Way a little earlier it may end up orbiting the giant elliptical galaxy that will form during the collision between the Milky Way and the Andromeda Galaxy [Music] Lani Ikea is a Hawaiian word meaning immense Celestial horizon or immeasurable Paradise it is a super cluster of galaxies that includes among others the Virgo supercluster which hosts the Milky Way and thus our planet Earth our local group forms with other galaxies a superstructure in a quasi-central position within the Virgo cluster the latter is like a vast and flat expanse including a small Central bulge that is called local supercluster the local cluster represents only one of the six million superclusters in the observable universe lania Kaya consists of three superclusters the Virgo supercluster of which we are apart the Hydra Centaur supercluster in which the great attractor is located and finally the Peacock Indian supercluster as in most Galactic clusters the space between the different galaxies is not really empty it is filled with a rarified gas mainly hydrogen and helium at a temperature of nearly 30 million degrees Celsius or 54 million degrees Fahrenheit lania Kaya extends over 500 million light years this super cluster contains more than one hundred thousand galaxies the mass of laniakea is estimated at about 100 million billion times that of the Sun each of the 100 000 large galaxies lack ours has an average of 100 billion stars and a million dwarf galaxies the local Group is located in the Virgo supercluster the Hydra Centaurus supercluster is the closest neighbor of the Virgo supercluster it is actually two superclusters the Hydra and the Centaur which are gravitationally connected the Peacock Indian supercluster contains three main clusters a bell 3656 a bell 3698 and a bell 3742 at the heart of the lania ks supercluster is the great attractor this gravitational anomaly in Intergalactic space demonstrates the existence of a local concentration of mass equivalent to tens of thousands of times the mass of the Milky Way our galaxy and all those in our supercluster are heading towards the great attractor [Music] if one imagines a picture from the sky that represents the distribution of all the superclusters in the observable universe the Milky Way is much too small to be visualized proportionally the solar system the Earth and man Can Only Be Imagined we are a tiny part of a speck of dust in this vast ocean this vast ocean in question represents in our eyes the so-called observable universe the further man looks into space the further he looks into the past the speed of light is not infinite but the finite speed of light combined with the finite age of the universe D limits an impassable border between which we cannot see this is the cosmological horizon even with the best telescope everything Beyond this limit remains undetectable light needs time to reach us but the possible travel time is limited since the universe is 13.8 billion years old thus the light from a galaxy located 20 billion light years away from us has not yet had enough time to reach the Earth it is beyond our cosmological Horizon it is comparable to the Horizon that Sailors see from the lookout of a ship the ocean continues just as the universe exists Beyond the cosmological Horizon we just can't see it [Music] the expansion of the universe is faster than the speed of light which is why galaxies are far apart Beyond 13.8 billion years telescopes do not show the world as it is but as it was when we look at the stars we are in fact looking into the past the farther we look into space the farther into the past we see this phenomenon gives us access to bodies or phenomena that no longer exist such as stars that exploded in supernovae galaxies destroyed by tidal forces or the first years of the universe white has a speed of three hundred thousand kilometers per second it takes time to reach us it takes about eight minutes for the light from the sun to reach us on Earth when we look at the sun it appears as it was eight minutes earlier when we look at the stars in the night sky they appear to us as they were tens or even hundreds of years earlier with the expansion of the universe the concept of distance loses some of its meaning when a galaxy is 10 billion light years away it means that it has been traveling through an expanding space for all that time before reaching us when this light was emitted the Galaxy was at a closer distance to us than when its Light reaches the Earth because of the expansion of the universe astronomers are able to determine the distance to the most distant galaxies in the observable universe the light that arrives from a Galaxy brings with it a suitcase full of information about the length of its Journey the most distant star ever observed is nicknamed Icarus this blue supergiant is located 9 billion light years away from us the Galaxy z8gnd 5296 is one of the most distant galaxies and one of the oldest currently known it would have formed some 700 million years after the big bang although it is 13.1 billion years old it is actually about 30 billion light years away from Earth due to the expansion of the universe this galaxy appears rich in metals and would generate 100 times more new stars than our Milky Way although lania Kea is a most impressive superstructure it represents only four percent of the observable universe so what would happen if we took into account the universe as a whole a long time ago men thought that our planet Earth was unique then we discovered that there were other planets orbiting a star the sun a long time ago people thought the sun was unique then we discovered the Milky Way and its hundreds of billions of suns a long time ago men thought that the Milky Way was unique today we know that the observable universe contains a hundred billion galaxies is it possible that humans will one day discover that there are other universes beyond the one we are able to observe [Music] to know our place beyond the universe we would already have to know what it contains however this area is currently inaccessible to us only hypotheses are put forward by scientists to explain what can be found Beyond the universe that we can observe from the earth is full of galaxies that extend in all directions we see them more than 10 billion light years away but the galaxies must extend much further on this subject speculations abound and address without complex the existence of parallel universes the string theory of particle physics approaches the notion of Multiverse the different universes of this Multiverse would each have unique properties they could exist in parallel to each other but in different dimensions [Music] science also allows us to imagine that beyond the observable universe space is infinite and Without Limits since its creation it has not stopped growing the cosmos could then extend perpetually hundreds of billions of light years away from us there may be another Universe similar to ours in this other parallel universe would life exist all research conducted to date in the areas we can reach remains unsuccessful beyond the Sun the Milky Way contains between 200 and 400 billion stars it is itself only one Galaxy among 100 billion other galaxies many stars are surrounded by A procession of planets the list of planetary systems discovered is growing every year a universe modestly filled with billions of billions of planets could well hide other places where the Miracle of Life could have taken place [Music] for more than half a century thanks to highly sensitive detectors and high-tech computers we have been sending mathematically coded messages to neighboring exoplanetary systems to let them know we are there but the cosmos remains desperately silent while it is possible that life is widespread in the universe complex life forms and intelligent civilizations would certainly be rarer perhaps we are a subject of observation for a scientific experiment conducted by an advanced alien life form or are we unable to understand them because their technology is much more advanced than ours or are we simply the only living beings in the universe the universe is extremely vast with billions of galaxies each containing hundreds of billions of stars seen from this eye man occupies a relatively insignificant place our planet Earth being only a small rocky planet orbiting a medium-sized star the sun located in a relatively quiet Galactic suburb although we have explored and observed much of the observable universe through technology our understanding remains Limited we know that the universe is expanding and that visible matter such as stars galaxies and planets is only a small fraction of the total matter in the universe man has not yet succeeded in fully understanding the immensity and complexity of the universe that surrounds him despite our modest place in the universe we have developed the ability to think reason and understand the physical laws that govern our environment we have created a technology that allows us to explore and study the universe in which we live our place seems small and yet we have a wealth we have the ability to understand and appreciate the beauty and complexity of the universe that surrounds us and to push the limits of our knowledge every day to discover more foreign

Channel: Wondody | The World of Odysseys

Views: 46,146

Keywords: wondodi, science, space, documentary, earth, space documentary, milky way, universe, history, solar system, history of the earth, history documentary, journey, documentary universe, doc, james webb, universe documentary, 2023, cosmos documentary, exoplanets documentary, galaxy documentary, milky way documentary, beyond milky way, planet documentary, where we are in the universe, where we are in the milky way, our place in space, our place in the universe, our place in the milky way

Id: oxTGc2AY04c

Length: 81min 3sec (4863 seconds)

Published: Mon Aug 14 2023