Where Is Everything In The Universe Going?

[Music] in the 1970s astronomers discovered that our Milky Way galaxy is moving drawn by great invisible forces we were being pulled towards something but we couldn't see what a final destination was hidden by the zone of avoidance a region of the sky obscured by the gas and dust of the galactic dis like a tiny rra to drift in a vast ocean on a moonless night we were caught up in the current heading towards who knows where and we weren't alone for it wasn't just the Milky Way that was in motion but all of our neighbors

two astronomers arand Tully and J Richard Fischer were using the parks radio telescope in Australia to conduct a survey of distant galaxies attempting with their meager observations to reconstruct their movements and around the same time multiple teams of astronomers were observing the cosmic microwave background the bath of radiation that survives as a relic from the early days of the big bang and independently both groups found the first hints of this great Cosmic [Music] flow the galaxies that tul and Fisher mapped seem to share a common Locus they reconstructed velocities all roughly pointing in the same

direction as for the cosmic microwave background its temperature across the sky revealed a bias it was slightly hotter in One Direction and slightly cooler in the other much of this discrepancy could be eliminated by considering the motion of the sun around the core of the Milky Way But even after that subtraction a residue remained an unexplained source of motion relative to the ultimate Cosmic reference frame a speed amounting to hundreds of kilometers per second it appeared as if the Milky Way and all the other galaxies in our nearby vicinity of the Cosmos were being drawn

to a particular spot a specific location in the universe as if Tied by great invisible chains stretching tens of millions of light years we couldn't see it couldn't map it couldn't figure out what it was for decades the best we could do was simply name it the great attractor a great source of inexorable motion a persistent sink of gravity a single point in the course Mor that pulls and pulls and pulls our entire galaxy and thousands of others home to hundreds of billions of stars and countless planets drawn to the great attractor like helpless moths

to a flame and yet no matter how odd this may seem this is not an unusual situation in the cosmos for the universe is far from static every object within the universe is in a state of restless motion from the orbit of the Earth around the Sun to the sun's drift within our galaxy to the hurtling of the Milky Way towards the greater tractor and that's not even the largest example in the universe for the greater tractor turned out to be just the tip of a far grander Cosmic Iceberg flowing across the sky vast Cosmic

structures and motions dwarfing anything we had ever seen before and so nothing is still everything is going somewhere the question is where on the 23rd of September 1999 the Mars climate Orbiter lost contact with NASA as it approached the planet the mission was totally lost and it later turned out to have been down to a mistake converting metric to Imperial units even multi-billion pound projects that are supposed to work seamlessly can fail and that can also be incredibly frustrating when it comes to stuff you use every day which is why our sponsor today raycon are

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case cover is also a great stylish bonus and especially useful for me as I'm always losing earbuds and it supports wireless charging so head over to by ron.com hotu today to get to 50% off sitewide thanks to rayon for supporting educational content on YouTube our universe is defined by motion and one way to describe the history of science is through our increasing awareness of the restlessness of the cosmos for Millennia the brightest scientific Minds in Europe and the Middle East believed that the Earth was perfectly still and that the heavens revolved around it those early

astronomers busied themselves with attempts to explain and predict the motion of other objects the Sun the moon each of the known planets and the stars and their predictions worked surprisingly well but their cosmological system of motion wasn't perfect in fact it was an ungainly mathematical mess relying on small circular orbits nested within larger ones with some centered on the earth and some centered on other points and so on his deathbed in 1543 the Polish astronomer Nicolas kernus published on the Revolutions of the Heavenly spheres a radical reformulation of the old system that put the Sun

at the center of the universe still and motionless with the Earth set in motion around it along with all the other planets reaction to the work of Cernic's was mixed on one hand it was a bold reshaping of the universe on the other it was arguably just as messy as the ancient system it was trying to replace and on top of this it introduced more than a few questions that had no easy answers first and foremost if the Earth was moving how could we tell we know we are moving on the surface of the Earth

through a variety of ways we can feel the wind against our face when we run or watch as a distant goal draws nearer so why don't we feel a great Rush of wind as the Earth orbits around the Sun or why aren't we flung off into the void of space due to the incredible rotation of our planet it took centuries of Science and the development of Isaac newson's theory of gravity for the full picture to come together today we know that we don't feel the motion of the Earth because we are in motion along with

it and since the vacuum of space is just that a vacuum there's nothing for us to push against and betray that motion and so how can we guarantee the that the Earth truly is in motion is there a standard reference indeed Newton assumed that such a standard existed that there was a fixed frame of universal reference from which all motion could be measured in crafting relativity Einstein rejected the concept of a fixed Universal ruler against which we could judge all motion instead all inertial motion was relative the only way to measure motion is in reference

to something else and from this fundamental idea the rest of Relativity blossoms the fabric of SpaceTime the equivalence of mass and energy the limitations of the speed of light all of it imagine cruising in an unpowered rocket ship and encountering your friend doing the same in the opposite direction you are both in an inertial frame of reference moving at a fixed speed a you cross paths you may declare that you are moving and they are staying put but in relativity they have just as equal right to state that they are moving and you are the

one that is standing still these two perspectives are equally valid despite this we can tell that the Earth is spinning because of the coris force which twists airst streams around to form hurricanes and typhoons and so even if our skies were completely blank with not a single star to be seen in the sky with nothing left to measure except what we have right in front of us we could still deduce the motion of the rotation of the Earth but the movement of the earth throughout the greater universe is another matter Al together for that we

need to identify some other frame of reference some other yard stick for us to measure from otherwise we could rightfully claim just like any other object in the universe that we are motionless and that the rest of the cosmos every planet and star and Galaxy moves around and about us and thankfully the universe itself gives us exactly the tools we need the trick is that we don't live in a static universe but an expanding one the cosmos changes from day to day in the past it was smaller and in the future it will be larger

and it is this that allows us to write down a preferred frame of reference one that expands along with the universe allowing us to measure motion relative to that in other words at large scales the universe is expanding on average galaxies are getting farther away from each other with time we can then Define motion on top of that General expansion anything that deviates from the general outward flow of the universe is special and unique in the Palance of cosmology this is known as peculiar velocity and these velocities can range from a few hundred to a

few thousand km/s and armed with this mathematical toolkit cosmologists can begin to understand not just the rotation of the Earth or the orbit of our planet around the Sun but the movement of our solar system within the Galaxy and the action of the Milky Way within the wider universe and so without even feeling it without even taking a single step you will move an incredible distance through your life first there is the rotation of the earth depending on where you sit on the globe you could be whipping around at up to, 1600 km every hour

of course if you happen to be standing on either geographic pole your rotational velocity will be exactly zero for most of humanity which lives somewhere in the mid latitudes between the poles in the Equator the typical everyday velocity is around 1,000 kmph for typical human lifetime time of around 80 years or 700,000 hours that gives a lifetime movement of around a billion kilomet just due to the rotation of the Earth but the Earth is also orbiting the Sun with an average speed of 30 km/ second over your lifetime that adds up to around another 80

billion kilm of total movement though of course most of that is in a rough Circle so it's not like you're going anywhere with it and the orbit of the earth is not the end of our motion the Sun along with all the planets asteroids comets and all the other denisons of the solar system moves within the Milky Way most of that motion is a simple orbit around the galactic center a journey that takes 230 million years to complete a single Revolution but in that time the sun travels an enormous distance giving it an average speed

of around 230 km per second and interestingly that number is also profound evidence for the existence of dark matter within the Milky Way when we add up the mass of all the Luminous objects within the orbit of the sun even including generous allowances for all the stars and clumps of gas that we can't directly observe there still isn't nearly enough material to keep the sun in a steady orbit if there was no additional source of mass the sun's current speed should have assured that it would have been completely ejected from the Milky Way billions of

years ago but yet the Sun is still here still orbiting trained to the Milky Way by some invisible form of matter dark matter that lends its weight to the Galaxy and glues everything together in addition to its orbit around the center The Sun Also lazily Bobs up and down like a boy in a dark ocean a byproduct of the unstable gravitational influences of all its neighbors over the course of millions of years the sun rises thousands of light years above the galactic plane before plunging through it reaching a minimum and starting the cycle a new

currently the sun is plunging through a region known as the local bubble a cavity blown out of the interstellar medium by a supernova detonation that went off millions of years ago this bubble has a density less than 1/10th the average for the Milky Way which is already low enough that it would register as a vacuum in a laboratory on Earth our solar system entered the bubbles somewhere between 5 and 10 million years ago and will continue to cross its thousand ligher expanse for millions of years to come and yet that is far from the end

of it for against the backdrop of the expansion of the universe our galaxy is also on the move and it's headed right for our nearest neighbor [Music] billions of years from now our Sky will be unrecognizable the moon will be smaller fainter and more distant the sun will be larger and brighter all the familiar constellations will be gone replaced with a new generation of stars in our Solar neighborhood and in that nighttime sky One Singular object will reign supreme greater in Majesty than any nebula star or Planet the Andromeda galaxy right now Andromeda is large

but not noticeably so taking up as much of the sky is a fist held at arms length within 2 and A2 billion years however Andromeda will dominate our Knights almost completely filling the sky and it will not look like the Andromeda that we know today in the far future it will be distorted its previously simple shape Twisted by tremendous forces of gravity as it begins to tangle with the Milky Way a billion years after that the sky filling Andromeda will be Ablaze with giant stars as the gravitational interactions between the two galaxies will ignite a

new round of star formation and it will be billions of years after that long after our sun has breathed its last that the merger process between Andromeda and the Milky Way will end the core of this new Galaxy will glow with ghostly prominence in the sky brighter than any other nighttime object if our planet survives huddled against the meager glow of our Sun's white dwarf we will see the sky slowly fade first into redness and then finally as the last of the visible stars disappear into Blackness it was in the 1920s that Edwin Hubble made

the remarkable discovery that the Andromeda nebula which had long befuddled astronomers was actually an island Universe in its own right an entire galaxy sitting 2 and 1 half million Li years away over 10 times more distant than the furthest object astronomers had hypothesized could exist but measuring the speed of Andromeda was not a straightforward exercise Andromeda is simply too big training a telescope on it only revealed a small portion with wildly different velocity measurements and so it took until 1957 for the Dutch astronomer Henrik Vander hulst to finally provide a robust number he examined the

faint radiation emitted by neutral hydrogen something known as 21 cm radiation with careful radio measurements astronomers like Vander hulst could build up crude maps of the feeble signal sent out by this neutral hydrogen and examine any shifts in its Spectrum a red shift from the expected wavelength would indicate movement away from us while a blue shift would signal motion towards us and it was via this method that Vander Holst arrived at an average speed of Min - 296 km/s with an uncertainty of around 10 km a clear indication that andrometer is moving towards us but

to further complicate matters that measurement didn't just include the motion of our galaxies moving together but also the movement of the sun around the galactic center that must be subtracted to get give the true Galactic motion and that number is right around 100 km/s but of course now that we know the number there is freedom to choose the frame of reference we could say that the Milky Way is still and that Andromeda is racing towards us or that the Milky Way is rushing towards it at a great speed but in the frame of reference that

respects the expansion of the universe our two galaxies are actually both moving towards each other heading towards a common gravitational Center but this motion didn't necessarily mean that we would definitely Collide astronomers can typically only measure the radial motion of a galaxy the component of its velocity that is pointing either towards us or away from us lateral or side to side motion is much more difficult to measure indeed it wasn't until 2012 when a team of astronomers led by sangos used the Hubble Space Telescope to measure the velocities of thousands of Stars within Andromeda that

we had our first clear picture of its true three-dimensional course and it was then that we realized we really were on a collision course the fun begins in as little as 2 billion years as our galaxies draw closer their immense gravitational interactions will begin to distort and reshape them the cause is the same physics that governs the ocean tides on the Earth Earth the parts of each Galaxy that are nearest to each other will receive a stronger gravitational pull than the rest while the parts on the opposite sides will receive the weakest gravitational pole this

causes a tidal force that will stretch each Galaxy sometimes entire spiral arms can detach from a Galaxy causing a phenomenon known as a tidal tail an expanse of intense star formation stretching tens of thousands of light years and between the galaxies a bridge of gas and stars often develops as if the galaxies are reaching for each other but when the merger event finally happens in roughly 5 billion years it will not be like a sudden car crash most of the volume of each Galaxy is nearly empty space consisting of nothing more than a thin spread

of plasma stretched between the Stars while the gas Tangles up on itself forming shock fronts and complex waves of disturbances the Stars simply pass by each other like two giant swarms of bees but that doesn't mean that the Stars will go unharmed in the midst of a galaxy merger Stars will come dangerously close to each other not enough to pair off and merge together but more than close enough to disrupt their orbits in short everything will become chaos the flat plane of the galactic discs replaced with a tangled mass of complex overlapping orbits most stars

will survive in this new reality but some will be scattered Ed receiving boosts of energy from nearby encounters flung away from their Galactic homes forever the first merger pass will take more than 100 million years to complete and will repeat several times over a few hundred million years with each cycle of collision interaction and separation growing progressively shorter indeed each one of these interactions will lead to a fresh round of star formation as gas compresses and fragments at its peak the star formation process in the merged Galaxy could reach over a thousand times its present

day rate and so for a brief moment it will be beautiful the merged Galaxy adorned with millions of newborn Stars blazing bright white and blue a dazzling release of the Titanic energies that powered the Collision but then sadly comes the tragic end Galaxies have only limited supply of gas to turn into new generations of stars left alone a Galaxy like the Milky Way can steadily sip on its reserves for over a 100 billion years but the act of the Collision Burns far too hot quickly depleting Reservoir after reservoir of gas in the intense rounds of

star formation once those Stars burn out there will be relatively little left to form new ones and the only remaining Stars within the Galaxy will be the longlived dwarf stars small and dim and red the merged Galaxy some astronomers call it mil comoda will become a giant elliptical a large red ooid incapable of substantial star formation and doomed to Simply pass the days watching its population of stars drop one by one of course this is all hypothetical our best guess as to how this massive event will unfold and some of the most recent simulations have

raised the possibility that it may not happen for another 8 billion years if at all astronomers can't watch Galaxy mergers play out in real time as the process takes hundreds of millions of years to complete instead what we have are snapshots the beginning of a merger here or the end result there a kaleidoscope of catastrophes caught in this specific moment in time take the m galaxies a pair of interacting galaxies sitting 290 million light years away so named because their long tiddled Tales make them look like two mice nestled together the Galaxies have just begun

the merger process and the ensuing gravitational distortions and in 2023 astronomers used the James web Space Telescope to observe ARP 220 a pair of galaxies caught mid merger sitting 250 million light years away the merger triggered a round of star formation so intense that the Galaxy now shines over a 100 times brighter than the Milky Way But already star formation has shut off what we are currently seeing is the Afterglow of the already ignited Stars throughout the Universe astronomers see countless galaxies interacting in a variety of different ways there are galaxies colliding headon and others

just glancing by each other sometimes they are perpendicular and sometimes they are slamming their spiral arms against each other sometimes more than two are caught in a struggle for gravitational dominance and so the process of Galaxy merges began billions of years ago even before the galaxies themselves arose and it will continue long into the future for the Journey of the Milky Way does not end in its merger with Andromeda our motion through the universe is far from over and it's towards a direction that we barely [Music] understand sometimes mathematics can be a crystal ball that

lets the careful Observer peer through the distant reaches of space and time and sometimes that crystal ball begins its own story in a space and time far far removed from Modern Day cosmology take the wide reaching consequences of the work of the French mathematician Gaspar MJ although he didn't know it at the time instead as minister of the Navy in Revolutionary France in 1792 he was more interested in working out optimization problems in the transportation of goods several decades later the great Pioneer Andre Marie on took M's work and expanded on it generating an equation

that has since found use in a variety of economic settings for example in figuring out the most efficient way to move resources between mines and factories and in the midst of World War II the Soviet mathematician Leonard canovic took the work of M andare to the next level extending and applying their equations to the thorny logistical problems faced by the Soviet War Machine but finally in a beautiful example of the universality of physics in the 1970s Canadian American cosmologist Jim Peebles realized that the same equations could be used to describe the efficient movement of mass

in the assembly and formation of galaxies coming from a humble background the son of a Grain Exchange worker and a homemaker Jim would go on to study at Princeton University and eventually become a giant in the field of cosmology though in the early days of his research in the 1960s cosmology was not widely considered a serious field of study we knew that the Universe was expanding and that the Big Bang picture was likely correct but there was so little observational data available that most astronomers considered the field a dead end with no serious future but

Jim pushed on and pioneered almost every aspect of modern physical cosmology from the growth of structure to the earliest moments of the Big Bang work that would earn him a Nobel Prize in physics in 2019 and completing the circle it was two astronomers the French Roya mahay and the Russian Andre seski who followed up on Jim's pioneering work and finally turned the so-called M jeon canovic equations into a cosmological crystal ball they found that they could take the present day positions of galaxies and combine that with limited information on their velocities to transport these galaxies

back in time the trick behind this approach is that we know how galaxies move they're influenced by their Mutual gravitational attraction and we know how gravity works so this technique allows cosmologists to take the current state of a collection of galaxies and compute where they should have been in the past it's not perfect by any means every step backwards in time introduces ever larger uncertainties and the technique can't go all the way back to the Big Bang but it does work with this method Brent Tully who first identified the beginnings of the great ATT tractor

and his collaborators have released continuously updated cataloges called Cosmic flows which map out tens of thousands of galaxies around the Milky Way along with their positions billions of years ago this information allows him and his colleagues to reconstruct the Motions of galaxies through Cosmic time not just into the past but into the future giving them the ability to predict where the Milky Way is headed and it's through this technique a combination of intense careful observations and clever mathematical crystal balls that we can finally understand the shape and influence of the great attractor and what our

ultimate fate in the universe will be the expansion of the universe allows us to construct a preferred frame of reference from which we can judge all motion its movement relative to the general expansion flow we can therefore create detailed velocity maps of nearby galaxies to attempt to ascertain that General flow a laborious and eraone exercise however thankfully the universe itself gives us a snapshot of that cosmological reference frame for confirmation of the great ATT tractor's existence came not from maps of local galaxies but from the ultimate source of light in the entire universe the cosmic

microwave background the CMB was generated when the universe was roughly 380,000 years old when the transition from a hot dense plasma into a slightly less hot but neutral gas flooded the cosmos with radiation that radiation has two very useful properties one it's literally everywhere every single cubic centimeter of space participated in the creation of the CMB and the formation of the CMB was relatively brief on the order of 10,000 years so the CMB is responsible for the vast majority of photons in the universe and we can see it in all directions in the sky everywhere

you go in the universe you'll always see the CMB and secondly the CMB is almost perfectly uniform with deviations in temperature no bigger than roughly one part in a million a reflection of the nearly pure homogeneity of the early Universe this means that we are surrounded on all sides by radiation that is almost perfectly smooth and was created in a single moment in the distant past it is a measurable snapshot of the cosmological reference frame any movement within the universe relative to that frame will distort our image of the CMB it would appear blue shifted

in our direction of motion and red shifted away from our direction of motion and that's exactly what we [Music] observe the cmbb is hotter by about 0.0035 5 Kelvin in the direction of the constellation Leo and CER by that same amount in the direction of the constellation Aquarius the only way to explain this temperature discrepancy known as a dipole is by our motion relative to the CNB and hence cosmical frame of reference to get this measured shifting our speed must be somewhere around 600 km per second of course some portion of that velocity is due

to the sun's orbit around the center of the Milky Way and some is due to our inevitable collision with Andromeda but even after subtracting that there's still a residue about 300 km/s and the direction of that movement after accounting for the orbit of the sun and the merger path of the Milky Way is straight towards the great attractor the grand structures of our universe a built from billions of years of restless ceaseless motion the Milky Way started out small just a few thousand stars huddled together in the dark but it was birthed in movement and

through successive mergers amassed itself to its present day status this same story has played out trillions of times across the visible Universe creating Galaxy after Galaxy this is the story of hierarchical structure formation how our universe built itself like a towering Lego Masterpiece Brick by solitary brick and and so there are hierarchies of structure in the universe galaxies groups clusters and superclusters and along with that hierarchy of structure comes a hierarchy of movement the galaxies already assembled from countless merges in the past groups like The Local group that contains the Milky Way Andromeda triangulum and

a host of smaller dwarf galaxies are still in the process of collapse and merger indeed roughly 100 billion years after the Milky Way and Andromeda meet each other the other members of the local group will collapse in with them forming a single Mega Galaxy these groups of galaxies like the local group are in motion as well trekking along through the expanses of the universe towards their local centers of gravitational attraction the clusters of galaxies the nearest cluster to us is the Virgo cluster already home to thousands of galaxies and drawing tens of thousands more towards

it in addition to the motion of the Milky Way towards Andromeda as a group we are also Falling Towards Virgo this process was set in motion during the earliest moments of the Big Bang but only ramped up a few billion years ago as clusters like Virgo grew they exerted more gravitational influence on their surroundings this pulled more material onto them which increased their mass and increased their gravity long ago the nent Virgo cluster started weakly tugging on the local group and as the cluster grew that gentle tug turned into a mighty force and this growth

through gravity does not just stop at the scale of clusters though clusters are the largest gravitationally bound structures in the universe for the Clusters themselves participate in yet another level of growth one that is not quite finished the building of superclusters superclusters have always had a loose definition in astronomy usually referring to anything vaguely resembling a coherent structure on scales larger than clusters as far back as 1863 astronomers William and John hersel noted an excess number of nebula which were really galaxies in the direction of the Virgo cluster in the 1950s the astronomer Gerard deer

tentatively identified this excess of galaxies as a structure in its own right calling it The Local Super Galaxy which he later changed to local supercluster but because superclusters are not yet fully assembled they have no easily defined limits or boundaries initially astronomers believed that the Virgo cluster sat at the heart of the local super cluster also confusingly known as the Virgo super cluster a rough collection of around 100 Galaxy groups and individual clusters spanning over 100 million light years in breadth but beginning in 2014 Brent Tully along with collaborators elen ctoa Yehuda Hoffman and Daniel

pomed proposed a new definition of supercluster this definition was not based on spatial extent but on movement they employed the Monon canovic reconstruction technique to Spring their Galaxy surveys into life changing them from static snapshots of the present day Universe into living entities enabling them to see where these tens of thousands of galaxies near to us came from and discern where they're going and it was the Motions of these galaxies that revealed the true extent of our local supercluster it turned out what we thought was a supercluster was just a single Branch one of four

of a much larger assemblage an entity that Tully and his collaborators named lania a Hawaiian word that roughly translates to immense heaven or open Skies [Music] and so the Milky Way galaxy belongs to the local group because we are all moving towards a Common Center which would eventually become a gigantic singular Galaxy the local group belongs to the Virgo branch of our supercluster because we are all headed towards the Virgo cluster and the Virgo supercluster Branch belongs to Lan AA because we're all moving towards the center of Lan AA 100,000 galaxies in total spanning across

over 500 100 million Li years in length assembled on four separate branches each one considered superclusters in their own right all headed for a single destination the Beating Heart of lanaka the local Center of Attraction of this portion of the universe the final assembly point of a construction process that began billions of years ago and will take hundreds of billions of years to complete the center of it all the greater tractor our portrait of the greater tractor is hazy at best because it lies within the zone of avoidance the direction in the universe obscured by

our own Galaxy's dust but some wavelengths of light can penetrate that dust and surveys taken with radio infrared and x-ray have shown us glimpses of what lies Beyond the Veil and what might be sitting within the greater tractor's region as best we can tell the heart of lanaka the focal point for the great migration of 100,000 galaxies including the Milky Way is the Norma cluster named for the constellation we must peer through to see it it is several times larger than a typical Galaxy cluster and sits about 220 million Li years away from us and

so even at a speed of over 100 km/s the normal cluster is so far away that our journey towards it would take over a 100 billion years Norma began life just like any other Galaxy cluster the result of countless merges and Relentless gravitational attraction but it happened to sit at the bottom of an immense gravitational well the single point of Attraction for this entire local region of the universe indeed over time noral will only grow more immense as it continues to collect more material within it but recent surveys again using the M Jean canovic reconstruction

technique have revealed that our motion towards the greater tractor that is the Norma cluster is still not the end of the story for one even though our understanding of Norma is vague at best it appears to be a little too small even adding in the contribution of its Dark Matter Norma's gravitational pull is not quite large enough to account for the speed with which we are moving towards the great ATT tractor in other words the great ATT tractor isn't quite as great as it initially appears there seems to be an additional source of Attraction sitting

even further beyond the Norma cluster for Norma 2 appears to be in motion an entity even larger even greater than the greater tractor sitting over 650 million light years away the structure was first observed by harlo shapley of the Harvard College observatory in 1930 who could only dimly perceive a distant nebulosity but we now know it to be another supercluster the next nearest neighbor to our own lanaka and from what we can tell it's a supercluster even larger than our own the incredible mass of the shapley supercluster is influencing every Galaxy every group and every

cluster around it for hundreds of millions of light years indeed if we were to give the universe enough time and for all this motion to continue unabated the Lano would transform into a single compact object a much more immense version of the normal cluster that currently sits at its heart and that object would eventually make its way to a similar one situated at the center of the shapley supercluster and there are even hints of additional motion on even greater scales in 2008 NASA astronomer Alexander kashlinsky was observing a subtle signal found in the cosmic microwave

background known as the kinematic siav zeldovich effect it's a tiny imprint caused when light from the CMB passes through a Galaxy cluster on its way towards us by comparing these signals in different regions of the sky kashlinsky found that there appeared to be a large flow of clusters towards a direction on our Sky between the constellation curus and V this apparent dark flow as kashlinsky nicknamed it was between 600 and 1,000 km/s faster than our own motion towards the great ATT tractor and that motion caught up a significant portion of clusters in the universe and

the Intriguing puzzle with this dark flow is that the differences in density in the universe aren't large enough to explain the velocity there simply isn't enough material collected together in any one patch of the universe to explain such large scale Co erent motion although in 2013 scientists with the esa's plank satellite found no evidence for dark flow debate continues whether this dark flow is a real feature of our Cosmos or not there are still reverberations echoing from the distant past when the universe was only a few hundred thousand years old it was over aill million

times smaller than it is today and all its material was compressed into a hot dense plasma like any plasma sound waves crashed and echoed within it as waves of density surged back and forth and these sound waves have a name bionic acoustic oscillations when the universe expanded and cooled it transitioned from a plasma to a neutral gas releasing the cosmic microwave background and at that moment the bionic acoustic oscillations were frozen in place trapped in whatever position and state they were in when the plasma dissipated these oscillations persisted as Tiny fluctuations in density a series

of overlapping shells of slightly higher density than their surroundings over time along with the rest of the universe they grew accumulating more matter than average and after hundreds of millions of years more galaxies than average and today cosm ologists map the imprint of the acoustic oscillations in massive surveys of galaxies using them to test models of the history of the universe and in 2023 Brent Tully Colin howlet and Daniel pomed discovered that many nearby clusters walls and other structures of the cosmic web are arranged in the shape of a shell the radius of this shell

is over 400 million light years and it includes elements like the SLO Great Wall this CFA Great Wall and the Hercules complex all centered on the booti supercluster all enormous entities in their own right Tully and his collaborators believe that this structure is an individual bionic acoustic oscillation a remnant of the chaotic plasma era of the universe still echoing today appropriately enough they named it h Lana taken from a portion of a Hawaiian creation chant meaning from Deep Darkness came murmurs of [Music] Awakening and finally reverberations of Ages past are not the only forces at

play in the Deep Universe we are constantly pulled by gravity the gravity of Andromeda the gravity of the Virgo cluster the gravity of the great attractor the gravity of the shapley super cluster the gravity of H Lana but there are also pushes sources not of Attraction but of repulsion adding up all the known sources of mass in The Wider universe as deep and as far as our galaxy surveys will reveal to us is still not enough to fully account for the motion of the Milky Way galaxy there appears to be something else something on the

opposite side of the sky of the shapley supercluster something that we have not yet fully met or understood a great void a vast expanse of nothingness one of many that dominate the volume of the universe named the dipole repell void we did not yet have an accurate understanding of its shape size or Dimensions all we know is that it seems to participate in the great movements that Define life in the large scale universe and the important thing to realize here is that these great voids don't just let go of matter they actively push away the

galaxies at their edges because despite their emptiness they are filled to the brim with dark [Music] energy and eventually the repulsion of these voids will unwind the cosmic clock unravel the cosmic web and prevent us from ever reaching the great attractor [Music] it was perhaps the only time that Einstein didn't trust his own mathematics early in his career he had made a name for himself with his leaps of imagination and insight grounded in a deep understanding of the physical universe and the mathematics needed to bring his ideas to light indeed in a single year he

crafted the special theory of relativity discovered a foundational principle of quantum mechanics and conclusively demonstrated the existence of atoms but in 1917 Einstein tripped over himself he had just developed general relativity and found numerous applications for it and so decided to take these new found equations and use them to describe the entire universe after all gravity is the only force that operates at large scales across all objects and so the language of general relativity should have been more than capable of describing the evolution of the cosmos yet what he found surprised him his equations naturally

predicted a dynamic Universe one that was always in motion with all objects at large scales either collapsing together or expanding away from each other this went against the conventional wisdom at the time that while planets May orbit and stars may move here and there the large scale unit Universe was fixed and static for all eternity and so for whatever reason Einstein didn't want to disrupt the established order and he found an opportunity in the form of a cosmological constant a number that he could slip into his equations without breaking them in the solar system this

cosmological constant didn't affect any measurements but on large scales it would act to stabilize the universe overcoming the natural tendency of objects in the COS Moss to [Music] move unfortunately for this idea just a few years later Edwin Hubble would discover the expansion of the universe while Einstein never admitted it in public or in any letter his closest friends recalled that he would refer to the cosmological constant as his greatest blunder yet despite Einstein's regret the constant never quite went away eventually the great Soviet astrophysicist Yakov zeldovich recognized its importance when he equated the cosmological

constant to the vacuum energy of SpaceTime just two different expressions of the same fundamental concept and in 1998 astronomers realized that the expansion of the universe was accelerating the most likely culprit for this mysterious accelerated expansion the vacuum energy of space time and so in the span of only a few weeks cosmologists around the world dusted off their history books and reacquainted themselves with Einstein's greatest blunder and how that little innocent term in the equations just might be tearing the universe [Music] apart the local group the Virgo cluster the lanaka super cluster they were all

built atom by atom Galaxy by Galaxy they took billions of years of slow and steady movement to reach their current stunning Grand while the rest of the universe may be continually getting bigger and galaxies gently drifting away with the Hubble flow the galaxies of lanaka should always have been able to call it home until dark energy tipped the balance for 5 billion years ago the expansion of the universe diluted all its matter to a point where a new Force could emerge triumphant that force was always there waiting in the shadows part of the very fabric

of SpaceTime but it was weak and so it sat in the background content to let the forces of radiation and matter dominate the evolution of the cosmos until its time finally came we still don't definitively understand what dark energy is we merely know what it's doing it's causing the expansion of the universe to accelerate and its influence is only growing as the universe expands its matter contents get more and more spread out but that same expansion creates more Dark Energy whatever it is it appears to be related to the vacuum energy of SpaceTime if you

have a completely empty box devoid of all matter and radiation you were left with nothing but vacuum but quantum mechanics tells us that that vacuum is alive a roiling bubbling sea of fundamental particles constantly vibrating in and out of existence and dark energy appears to be a manifestation of that vacuum energy as the universe expands there's more empty space more vacuum and so more Dark Energy 5 billion years ago was the turnover point when the density of matter dropped for the first time below the density of dark energy and since then it's only gotten worse

at the present Epoch Dark Energy accounts for roughly 70% of all the contents of the universe in the future it will be 90% then 99% % then even more building up on itself as the universe continues to expand and as that expansion accelerates it only drives the creation of more Dark Energy a process that has no apparent end and shows no sign of slowing down Dark Energy will not let the universe come to rest and it's already begun its process of deconstruction in the voids the voids of our universe are by definition almost entirely empty

of matter only the occasional thin filament of ionized gas or small dwarf Galaxy they are almost entirely pure vacuum which means that they are filled with dark energy and driven to expand by the repulsive effects of that dark force the voids are therefore the precise locations within the universe where the accelerated expansion takes place as time goes on the voids will only get bigger and merge driving the galaxies at their edges away from each other faster than their gravitational attraction can keep them together the only objects that will survive the growing Darkness will be those

that are already gravitationally bound this means that our local group will survive although transformed as its individual member galaxies coales and it means that clusters like Virgo will also survive safe harbors for the thousands of galaxies that already call it home but the superclusters will not make it d AA shapley and all the millions of others that twist and wind their way to create the backbone of the cosmic web will not maintain their cohesion it is simply too late they simply did not have time to pull themselves close enough together before the forces of dark

energy began their work 5 billion years [Music] ago and finally we will never complete our journey the Milky Way will continue on its tragic course with Andromeda but the local group will never make it to the safe shores of the Virgo cluster let alone the great attractor or whatever lies Beyond billions of years from now our Passage through space towards the great attractor will slow down stop and reverse over the course of hundreds of billions of years we will see those distant clusters and galaxies dim and fade from view eventually slipping over our Co mological

Horizon caught up in the accelerated expansion driven by dark energy indeed after a long enough time trillions of years from now the Mega Galaxy that was once the local group will be isolated a drift in a sea of nothingness as every other Galaxy slips away but even then our motion will not cease gravitational interactions within the future Galaxy will cause stars to randomly scatter away and once they slip outside its Embrace they too will be caught up in the accelerated expansion flung away as if they were never there one by one star by star our

galaxy will diminish the same fate will apply to every macroscopic object hundreds of trillions of years from now each individual body will be completely and utterly isolated from everything else in the universe separated by vast Gulfs of faster than light expansion [Music] and so with nothing left in the wider Universe with no outside frames of reference with no stars to gauge motion against or Hubble flows to compare to with no other sources of attraction or repulsion the universe what's left of it will finally finally come to rest you've been watching the entire history of the

universe don't forget to like And subscribe and leave us a comment to tell us what you think thanks for watching and we'll see you next time [Music]