Journey to the Edge of the Universe [4K]

thank you we live in a vast open

universe

full of trillions of galaxies, each with hundreds of billions of stars, space is so enormous that we can never hope to know every galaxy, but with telescopes like Hubble and James Webb we have mapped the positions of billions. and we have looked to the farthest corners of the cosmos, today we will use this wealth of understanding as we embark on the ultimate Journey that will take us through all of space and time, we will venture beyond our galaxy to the farthest Horizons. taking stock of the most impressive and significant milestones along the way this is our

journey

a

journey

to the

edge

of the

universe

before we begin our Cosmic Journey it is important to know where we are headed and where the

edge

of the universe actually lies When people When talking about space most of the time it refers to the observable universe, also known as the Hubble volume.

It is a geocentric spherical portion of space surrounding the Earth and containing all the galaxies and matter that can be observed by our instruments due to its light. The emissions have had time to reach the solar system, as we know, light travels omnidirectionally into space from a luminous source at a finite speed of just under 300,000 kilometers per second and, while this is exceptionally fast on terrestrial scales in the greater cosmic distances, it is agonizing. slow and any significant intergalactic distance beyond the Milky Way generates a substantial delay in light emissions reaching Earth, this makes objects appear younger and is why astronomers find so much utility in using light years as unit of measurement if a galaxy is a billion light away. years of Earth we will see it as it was a billion years ago and in this sense the edge of the universe is as much a temporal barrier as anything limited by its finite age of 13.8 billion years.

The Hubble volume only contains galaxies whose light has had to travel less than 13.8 billion light years to reach Earth and the galaxy's father, the closer it appears to be to the birth of the universe 13.8 billion light years ago. years and therefore a journey to the edge of the universe is also a journey back to Since the beginning of the universe there is an old saying that a telescope is a time machine and a telescope like James Webb is a TARDIS whose eyes Ultra-sharp infrared rays are at this very moment peering deeper into space than ever before, allowing us to know the cosmos at every moment.

In a single stage of its life and throughout this life cycle the universe has been expanding in volume and we can see evidence of this rooted in the light that reaches us from space which arrives elongated and reddened due to a phenomenon known as redshift which occurs when patterns of photons traveling towards Earth experience a decrease in wavelength in this case because they are being separated by the expansion of space as empty space inflates like a balloon. Creating new space everywhere gently widens the gaps between objects, including light waves traveling over very. At large distances this has the effect of causing visible lights to turn red, but the phenomenon applies to all types of electromagnetic radiation and is therefore a useful corroborator of intergalactic distances.

The redshift value of a given object, denoted by the letter Z, provides us with the perfect scale with which we can begin our cosmic journey. Our journey begins on Earth, a small speck of space indistinguishable even compared to the rest of the world. solar system and much less with the rest of our galaxy. The Sun is just one of at least 100 billion stars, many of which it will host. planetary systems like our own, but the true and terrifying scale of the universe does not begin to become apparent until we escape the confines of the Milky Way.

Our galaxy is the second largest member in a small, sparse pocket of space known as the local group. Containing more than 30 galaxies and hundreds of smaller satellite galaxies, the local group extends about 10 million light years, although its most important galaxies are all relatively close by; In fact, the three largest members of the group appear to be on a collision course as they are attracted by gravity that overcomes the weak expansion of the universe, so we don't notice any kind of redshift until we travel beyond the local group outside its boundaries, we drift toward the broader local volume, another smaller geocentric portion of local space encompassing all galaxies within about 30 million light years of Earth extending to a redshift of 0 .02.

This volume contains us and the rest of the local group along with more than 500 other fascinating nearby galaxies, each arranged in their own local aggregations. One of those not-so-local groups is the Council of Giants, a ring of 12 galaxies roughly the size of the Milky Way or larger that appear to surround our local group, being so large and massive that many of these galaxies also host their own extragalactic neighborhoods. smaller ones, such as the group of sculptors organized by the Council of The giant sculpting galaxy, officially designated NGC 253, is located about 11 million light years from Earth and is classified as a starburst galaxy, a galaxy that passes through a vigorous period of star formation, making it one of the most intrinsically luminous galaxies within our local portion, surpassed only by our neighbor the Andromeda galaxy and the more distant Messier Hat Galaxy 104, but best known for its bulge and dust galactic hat-shaped galaxy, it is a strange and unique galaxy of unclear morphology.

Its galactic halo shines with starlight brighter than the sculpting galaxy despite being only half the galaxy. Large in size and located three times farther from Earth, it belongs to a series of approximately a hundred small galaxies known as the Virgo 2 cloud, which emerges from the most important Virgo cluster found within the constellation of Virgo. name and which is located slightly beyond the local volume with a redshift of 0.039. The Virgo Cluster is a galaxy-packed structure in the center of the city containing more than 1,500 in what is the largest aggregation in our immediate intergalactic neighborhood. Near its heart we find a truly iconic Titan of the Messier 87 cosmos.

This supergiant elliptical galaxy is home to several billion aged evolved stars and more than 15,000 globular clusters spread over an area much larger than our Milky Way galaxy, and in its core we find its central supermassive black hole with a mass more than 6 billion times that of our sun. black hole that dazzled the world in 2019 as the first to be imaged by the Event Horizon Telescope's decade-long quest to reveal one. This black hole is also a keen target for radio astronomers, as it emits a stream of high-energy plasma to thousands of light years into space, which is one of the most prominent extragalactic sources in the radio sky, this galaxy appears. along with the surrounding Virgo cluster and the branching clouds of Virgo 2, as well as us and over a hundred additional large galaxy aggregations and groups.

To feed an even larger intergalactic structure that takes us beyond the 0.01 redshift limit, around 150 million light years, the Virgo supercluster, as it is known, is home to thousands of galaxies spread over an area exceeding The 100 million light years and the scale of aggregations within the cosmic web does not even seem to end there. The Virgo Supercluster is just one of four lobes within an even larger apparent network of galaxies defined by the speeds and motions of their flows through space. This supercluster of higher-order galaxies is known. such as Laniakia contains more than 100,000 galaxies and extends more than 500 million light years through space, while these galaxies are not gravitationally bound and therefore are not able to overcome the expansion of the universe to gather the combined gravitational potential from within this network. induce some surface motion in its constituent galaxies analogous to the way photosynthetic sheets extend toward sunlight, but for a long time we did not know where these galaxies extended, since Laniakia's apparent gravitational basin is located in a region of the sky that is obscured by the galactic plane of the Milky Way, therefore the source of this so-called great galaxy attractor remained a mystery for many decades, but fortunately, new exploration capabilities have since helped illuminate this zone of avoidance hidden behind the Milky Way, unlike visible light.

X-rays and infrared emissions can pass through the thick dusty disk of our galaxy, allowing us to detect superclusters that lie beyond where we find the source of the largest tractor located deep in the Hydrocentaris supercluster, within this supercluster, 250 million light to use from Earth. at a redshift of 0.018 we find the Norma cluster, the apparent heart of the larger tractor toward which Laniakia's massive outflows appear to be angled, but this galaxy cluster alone is not substantial enough to explain the velocity which galaxies seem to be attracted to this basin, something significant. Larger also exerts an influence and lies far beyond the limits of Laniakia, more than 650 million light years from Earth we find the Shapley Supercluster, an exceptionally compact massive concentration of superclusters containing thousands of condensing galaxies bound gravitationally. and a little further, more than 870 million light.

Years from Earth we found the Valor supercluster and these two more substantial superclusters of galaxies are now thought to be exerting gentle influences on the Laniakia galaxies from afar, amplifying the potential of the Norma cluster, which explains what makes the gravity of the biggest tractor is so big. Great, as we mentioned, the Laniakia supercluster is not gravitationally bound unlike the Shapley cluster and neither are other Virgo supercluster galaxies, so it's hard to say if we can really call these types of higher-order aggregation structures. ; However, propagations in the cosmic web can reach even larger scales than a supercluster known as a filament galaxy.

Galaxy filaments are the largest type of cosmic structure that manifest as chains of superclusters of galaxies that assume galaxy-shaped formations. threads at distances exceeding 250 million light years and some can grow even further to a billion light years from Earth. At a redshift of 0.074 we find the Sloan Great Wall, a truly colossal filament-like structure identified from data recorded by the Sloan digital Sky survey. This structure constitutes a giant arc formation of galaxies within a fairly dense region of space. It contains several packed superclusters of galaxies, the largest being. of which sci-126 can be found near its center, the entire structure measures over 1.3 billion light years at its largest extent, although in later years it has been argued that this enormous scale may actually be the result of three superclusters and filaments of galaxies aligned.

Unlike A Long Unbroken Chain, but the Sloan Great Wall was instantly crowned the largest known cosmic structure upon its discovery in 2003. A title it would hold for around a decade. As we pass through the Sloan Great Wall we reach the 0.1 redshift limit. about 1.38 billion light years from Earth. Beyond this point our light delay approaches and exceeds one and a half billion years, so from this distance we begin to see objects more characteristic of the youngest universe billions of years ago, galaxies like the Milky Way. and M31. still undergoing major evolutionary changes when they collided with galaxies near Nabis combining their stars and gas, these mergers flooded the cause of the galaxies with an abundance of star-forming gas that was strengthened by the contrasting tidal influences associated with the merger and when As a large amount of gas accumulates in the center of a galaxy, particularly around its black hole core, all sorts of weird and wonderful electromagnetic processes can arise when a galaxy's central black hole interacts with this gas.

We call it an active galactic nucleus because it invariably leads to the release of an enormous amount of radiant energy that amplifies the luminosity of the galaxy in at least some electromagnetic wavelengths, for example in the radio spectrum, radio galaxies are one such type of active galactic nucleus that invariably occurs within elliptical galaxies like m87, since the gas thatorbits the nucleus of this galaxy it becomes ionized and subatomic particles are trapped inside. The black hole's magnetic field and are channeled toward its polar axes. This matter is then ejected from the Event Horizon at speeds close to the speed of light by a pair of twin relativistic Jets that transport the material at high energies thousands of light years into space.

The ejector glows with high radio intensity synchrotron radiation, and these emissions can sometimes reach scales much larger than the optical emissions from the underlying host, so radio galaxies are much more detectable at higher redshifts than galaxies. increasingly weaker optical emissions from silent radio galaxies outside the redshift.1 we find 3c327 one of the thousands of known radio galaxies and around one and a half billion light years further away we find the largest Alcionius radio galaxy currently known, its emissions extend by a whopping 16 million light years in length, but between these two objects with a redshift of 0.158 we find 3c273 but this is not just a radio galaxy, it is a quasar, the brightest and most energetic type of active galactic nucleus, a unlike a radio galaxy that is propelled by jets emanating from the nucleus.

A quasar's emissions are further driven by the accretion disks surrounding it. The black hole inside a rotating accretion disk, subatomic particles race at extraordinary speeds, collide with other particles and release thermal energy through friction. This friction superheats the material in the disk to millions of Kelvin and often even more, causing it to radiate electromagnetic energy and illuminate some 50 times more efficiently than the nuclear fusion reaction that enables Sunshine, this gives as resulting in the release of unfathomable amounts of luminous radiant energy almost uniformly across the electromagnetic spectrum. Quasar galaxies shine hundreds of thousands of times brighter than the Milky Way, so powerfully that they can impersonate the stars of our galaxy from billions of light years beyond Earth; in fact, they were only discovered due to their prominence at other wavelengths, specifically the unusual radio and ultraviolet emission profile of 3c273 for what was once thought to be an ordinary star, but Quasar galaxies tend to 3c273, which are seen fairly infrequently within this redshift band, found about 2.5 billion light-years away, but the vast majority are found much further back at a time when space was generally more suitable for ignition of these ultra-bright intergalactic beacons, in addition to requiring copious amounts of gas.

Orbiting a galactic nucleus, a black hole needs to be a particular size to drive a quasar's emissions. If a supermassive black hole is too massive like the monster at the heart of m87, then it will be too big to shred the gas inside. The ergosphere tends to swallow material rather than chew it, and it is this chewing motion, the tidal gradient exerted on objects by smaller black holes, that spaghettizes the gas and separates it into subatomic particles that feed its secretion disk, So in the early Universe, when the cores of black holes were generally smaller, we see many more of these intergalactic wells of light spread across space, but to see quasars in their greatest abundance.

We need to venture much further into space across the redshift one boundary, just under 8.4 billion light years away. When the Earth was considerably younger and smaller, less than half its current age, at this depth quasars begin to appear at a substantially higher rate, which is convenient given that most of the lights in galaxies Ordinary rays at these distances are too faint and weak to study in detail, but the quasars that shine since the peak of the Quasar Epoch just under 10 billion years ago are capable of elucidating the filaments of the Galaxy above the that once shot up like LED lights around the branches of a Christmas tree and are approaching 9 billion light.

Years away from Earth, we are beginning to see quasar galaxies in numbers and formations that emulate vast cosmic structures like Sloan's Great Wall. Large quasar clusters are a variety of quasars dispersed over distances of billions of light years, and although the clusters themselves are not thought to be gravitationally bound. its aggregations still rank among the largest structures we have ever seen. 8.8 billion light years from Earth, we found the first of three groups of record-breaking u1.11 quasars. It contains 38 quasar galaxies spread over a distance of 2.2 billion light years. extension and then adjacent but somewhat further back with a redshift of 1.28 we find the Klaus campusano lqg, another cluster of 34 Quasar galaxies that also appears to span a distance greater than 2 billion light years and then, finally, around From that same distance with a redshift of 1.25 we find the largest group of them, all the enormous lqg, a variety of 73 Quasar galaxies spread over an area of ​​more than 4 billion light years;

In reality, none of these groupings are likely to be indicative of real structures and are more likely to be the product of random alignments within which we can see patterns, but in any case, scientists still classify these three groups of quasars among the list of structures. largest known cosmic phenomena, but the largest structure that displaced Sloane's Great Wall in 2013 is not a cluster of quasars, it is a gamma-ray burst. formation A gamma ray burst is the most powerful type of electromagnetic explosion, releasing as much energy as the entire life cycle of the sun in a matter of seconds, but unlike quasars and radio galaxies, gamma ray bursts do not tend to associate with active galactic nuclei. rather, they often occur as a result of exceptionally violent supernova explosions or when a pair of neutron stars collide to form a black hole.

In both cases a catastrophic amount of gamma radiation is released lasting from a few milliseconds to several hours, followed by a more persistent glow at longer wavelengths that allows us to map the positions of hundreds and lurking far beyond the clusters. of quasars with a redshift of 1.6, scientists found an apparent aggregation of gamma-ray bursts scattered over an extraordinary expanse of 10 billion light years called the Boreal Corona of Hercules. The Great Wall, while scientists consider this wall to be the largest cosmic structure, its concentration is not likely to be the result of an underlying superfilament, after all gamma-ray bursts, such as quasars, are an event intrinsic to a galaxy and therefore probably have little relevance to filament evolution in a broader context, yet simply trying to understand a distance of 10 billion light years is a mind-boggling task, it is inconceivable, it dwarfs our entire existence by orders of magnitude and makes our efforts here on Earth seem like nothing.

The Boreal Crown of Hercules. The Great Wall takes us to redshift 2. 11.2 billion light years from Earth, we arrive at the early universe in the midst of one of the busiest times of its life. Cosmic noon, the period when young star formation accelerates. The universe reached its peak about two and a half billion years after the Big Bang, we see the universe dotted by a flurry of young gaseous galaxies. Ten star factories, each producing the equivalent of three to four thousand new stars per year. Compared to the mere 10 solar rays produced by the much larger Milky Way, these early galaxies would have been hives of ubiquitous ionizing electromagnetic radiation, and luminous quasar galaxies still feature prominently throughout this redshift band, but at These insane depths we sometimes see the emissions of active and bright galactic nuclei obscured by walls of gas in the foreground anyone wants a hot dog, well, in this case a hot dog is a galaxy obscured by hot dust a luminous quasar galaxy of the Early universe glowing from within a thick shell of surrounding gas in 2010 NASA's wise telescope identified more than a thousand of these hot dogs between records 2 and 4.

Approaching 13 billion, it would seem to look back years from Earth However, at redshift 3, it becomes increasingly difficult to work with the lights from objects because around this distance some redshift models argue that the recession speed of galaxies begins to exceed the speed of light, as we mentioned, the inflation of all parts of space pushes galaxies further away from each other by widening the gaps between them and therefore eventually there comes a distance between two points where space will appear to expand. faster than the speed of light, but this does not break any laws of physics because nothing actually moves at the speed of light, but more than 12 billion light years from Earth objects are being moved so far away. quickly their emissions become incredibly weak and red-shifted, appearing to freeze. time, since their light cones are deprived of photons and strangled by the expansion of the universe, in fact, the redshift bands Beyond this distance were once thought to be largely inaccessible, but the next generation of Humanity's electromagnetic observatories, particularly aided by advances in the infrared field, are helping to bring the fading lights of this bygone era Out of the Shadows - in fact primordial galaxies are one of the main targets of the James Webb Telescope among The variety of reasons that make these galaxies so attractive to astronomers is their supposed population concentration of 3 stars, the universe's first generation of stars that emerged directly from the gas left by the Big Bang when these first stars began to shine in The cosmic dawn, triggered a period in the life of the universe that until now we have struggled to obtain clear information about the epoch of reionization. of two major phase transitions for the gas of the early universe after the Big Bang ended, its plasma was harvested to form the first neutral gas of hydrogen and helium, but when this host gave rise to the population of three stars, its emissions Radiating stars began to reverse this process by reionizing.

The gas as its electrons were stripped by ultraviolet radiation that lasted approximately 150 million years and concluded with a redshift six. The epoch of reionization ended when most of the once-neutral gas had converted back to charged plasma. A key question for astronomers studying this era is: Was University reionization democratically shared among all galaxies or was it mostly driven by a few large galactic oligarchs who acted as ionization powerhouses to answer this question? Astronomers have tried to find the oldest and most distant galaxies after the cosmic dawn and in recent years we have managed to detect objects at astonishing depths of more than 13 billion light years within the constellation of Ursa Major, located at a depth of redshift of 11.1, we find gnz11, one of the oldest and most distant galaxies we know, from a small torrid pocket of gas and ancient stars, this faint blob is believed to have taken shape just 420 million years after the Big Bang , a remarkably rapid accumulation considering the stars probably didn't even exist for more than half that time. gnz11 held the title of the most distant galaxy detected only until recently. as 2022.

When astronomers at the University of Tokyo managed to bring back an even more remote and therefore earlier galaxy, this galaxy called HD1 is estimated to be at a staggering redshift of 13.27, which means which formed just 330 million years after the birth of the universe. and within a hundred million years of the first stars, however, this crazy distance is awaiting confirmation from the James Webb Telescope which, coincidentally, also saw its own ultra-distant primordial galaxy, recently glass z13, although not as distant as HD1, this Genesis galaxy is still found. In redshift band 13, 13.5 billion light years from Earth, it is difficult to comprehend such a large universal distance, but it becomes even stranger when we take into account the expansion of space. 13.5 billion light years is the distance at which these three galaxies were when they formed.

The first light was emitted. Current versionsof these galaxies will be far beyond having been ejected faster than the speed of light by the cosmic tide. The proper distance of these galaxies today is estimated to be more than 33 billion light years from Earth. so unfathomably remote that its light emissions would never have enough time to reach the solar system now as objects begin to fall off the grid this way we approach the edge of the universe at redshift 20 13.6 billion light years of the Earth our Optical view of the The universe ends with the light of the first population of 3 stars.

Beyond this, we enter one of the most mysterious moments in the life of the children's universe. It is the Dark Ages, the time that came after the Big Bang but before the cosmic Dawn, when there was no light emitting. The sources and space were completely dark, we know this because space itself is not black, it is colorless and transparent, and this blackness that we see undermining the deep fields captured by Hubble and Webb is actually a point in the life of the universe only a few million years after the big bang where there was no light and unfortunately this is as far as it is possible for us to look in the optical wavelengths, at least Beyond this limit no other photon has had time to reach the Earth, as they would have been more than 13.8 billion light away. years in which they were emitted as the universe ages, older lights will reach the solar system from even greater depths, growing our observable universe, but these galaxies will simply manifest as dark, elongated red shadows frozen in time and until then we are confined to the Hubble volume. segmented from the rest of the universe by the Cosmic Event Horizon, also known as the Particle Horizon, but this is not where the edge of our universe lies.

We have one last stop on this journey, from our point of view, the Dark Ages begins where Reionization ends at redshift 20, but extends to redshift 1090, where we find the oldest light in the universe, the glow from the Big Bang, but this glow has been so elongated by the expansion of the universe that they are no longer The photons of optical light have no longer moved into the radio spectrum, no matter where you point an antenna in the sky, there is always a microwave band constant static that sounds the same everywhere and, while most of this is due to terrestrial interference, a small portion originates from a much deeper Source the birth of the universe the last stop on our cosmic journey is photography itself from the University Baby a snapshot of the moment the Big Bang ended when it was just 379,000 years old.

This cosmic background radiation began its journey as optical light emitted by the fading high-energy plasma that condensed to form the first atoms, all the photons that came before this moment were absorbed by the primordial plasmid before it disappeared and are therefore undetectable to us today and therefore, for all intents and purposes, the cosmic. The microwave background is both the edge of the universe and the Twilight Curtain. The radius of our observable universe is measured by the distance traveled by its oldest photons of light. These CMB photons have been flowing freely for 13.8 billion years, but they have traveled as far as space. so far it has an expanded proper distance of about 46.5 billion light years and that is why you may have heard people say that the observable universe is 93 billion light years in diameter despite being less than 14 billion years old, however, this diameter is arbitrary to our observable field defined by our position in space the age of the universe and the travel time of light if we traveled billions of years through space our universe observable and particle horizon would change accordingly and then looking back the Milky Way would become a young redshifted Galaxy, unfortunately the edge of our observable universe is not the actual edge of the universe and most of the Scientists agree that there are many more lies hidden beyond the cosmic horizon, but the questions of how much and where the real edge is are completely different questions and in the next video we will try to answer these questions as we cross the particle horizon and venture into the darkness of the unobservable universe