Let's Find Out - The Macroscopic Universe | ASMR

Episode Date: September 26, 2019

These podcasts are just the audio from my Youtube videos. If you'd like to see visuals too, visit my channel, Let's Find Out: https://www.youtube.com/channel/UC7FOVZ1xTzKav7TVTATIcxQ An overview of the entire macroscopic, observable universe, from the cosmic microwave background and galactic superclusters to our local star, the sun. Part 2 will concern the microscopic universe: atoms, subatomic particles, electromagnetic/strong/weak/gravitational forces, relativity, and how structures emerge out of the quantum sea of probabilistic energy fluctuations.

You're about to embark on an unforgettable journey, setting off from the heart of the solar system to the outer limits of the known cosmos in all its awe-inspiring wonder. Other books describe various aspects of space. This book shows you, taking you on a dazzling visual exploration of every type of astonishing feature and the library. This one certainly takes the cake in being the most dense, densely informative, and visually stunning, accessible, accessible in bounds, giving information to the layman. Now where it stands our place. A hundred years now of deep, scientifically rigorous investigation into the cosmos. So let's find out what we know about our place in the universe. This sums it up appropriately here.

You're about to embark on an unforgettable journey, setting off from the heart of the solar system to the outer limits of the known cosmos. This book reveals space in all its awe-inspiring wonder. Other books describe various aspects of space. This book shows you, taking you on a dazzling visual exploration, exploration of every type of astonishing feature.

The reason I chose this book for this huge undertaking was really this first image here sums it all up and immediately absorbed me into the it convinced me of the merits of this book. It's just fun to see a three-dimensional representation that you usually don't get. When looking at Earth, we have the billowing clouds.

Right here, in the Pacific Ocean, above the water, are clouds of water vapor in a volcanic ash plume, a reminder of the continuing geological activity of the planet's interior. This does. There's so many different perspectives about space we can take. Going out 90 million miles from the planet's interior. the earth we have the sun as in this is just a first few pages are a nice

introductory immersion getting our toes wet give you guys a brief idea because just so packed we got cosmic models of the predicted evolution of the universe at the large hat-tron collider and diagrams explaining relativity observatory. All these things we'll be getting into, breaking down the physics, the science, the observations, and the deductions of what we know about the universe.

The Sun dominates our solar system, our chief source of light and heat, and the rest of the planets in their order. This ultraviolet image here shows a reveals the dynamic activity in the ultra-hot corona. surface. Just imagine being close enough studying astronomy in the 17 and 1800s. And never always wondering what these black dots are on the surface of the sun. And now we're privileged enough to have experience and hard work

in the results of hundreds of years, if not thousands, of technological labor and innovation, to be able to give us a beautiful, ridiculously close-up view of the sun like this. We could see the little pockets. Each of these pockets of bubbling plasma are probably wide as our earth, and darker than the rest of the sun surface. Speaking about the sunspot, are sustained by strong magnetic fields, penetrating and twisting and...

being distorted within and through and around the sun. Some sunspots are large enough to engulf the entire Earth. They vary in cycles that take about, on average, 11 years to complete. And peaks in the cycle coincide with disturbances, such as aurora in our own atmosphere. And that's to say that the sun is a... collection of billions of nuclear nuclear bombs second a source of central source of all the energy and it billows out and actually billows out to such an extent that it creates a well it can be destructive is ejected precisely at our planet it's interestingly and

paradoxically maybe also very protective almost like how about parent can discipline their children, yet be the thing that protects them from all the dangers of the outside world. It envelops the solar system in a bubble, a protective bubble through its solar winds. And the Voyager spacecraft actually hit. Once it pierced through that layer, it instantly was in the interstellar medium of the galaxy, the Milky Way galaxy, which... Just a current, a wild set of currents of interstellar winds.

And we have the planet Jupiter's great red spot here. The gas giant Jupiter is more massive than all the other planets in the solar system combined, including Saturn. Its mysterious swirling vortex, the great red spot, has been known since the 17th century. But our knowledge of Jupiter has improved greatly since then. It was visited by uncrewed spacecraft in the 70s. This image of the Great Red Spot was taken in 1979 by the Voyager. One of two that has since left our own solar system headed out into the galaxy. Here is using filters that exaggerate its colors for easy,

comprehension by our human eye in the outer planets now we have stars and galaxies briefly the Orion Nebula it's actually part of a much larger region of the galaxy which on the edge of which which we are star and thus our solar system actually lies and nebula is visually interesting bright active part of a nebula that almost like a region, you might say, a big bubble in the galaxy. But this picture right here depicts the most active star-forming region. Each little nodule here is dense area of gas, interstellar gas, then has begun to collapse, and as it collapses on itself,

it begins to be set in rotation. And as it rotates, it increasingly gets, It gets closer and closer together gets more dense until at the center of it, enough matter, enough gaseous material has accumulated to be put under tremendous strain. Tremendous strain. And ultimately, the collapsing particles just like the transition from potential energy of an object being dropped off a cliff,

accelerating towards the center of mass of Earth. Earth, all these particles are releasing their potential energy that gravity has given them and turning it into heat and friction, which is kinetic energy. And as they all jumbled together, they bounce off one another in this torrent current of fluctuations and speed and rotation, they start to release a bunch of infrared heat. We can... After that, they get more and more dense, more hot, more pressure is imposed on them by the gravity of incoming. The pressure has exceeded a threshold, strong nuclear force, and fuse.

Fused together to release vast amounts of energy fusion, billows out and into the galaxy for itself. There's a really cool snapshot of one of the closest star-forming areas in the galaxy to us. We can see starbirth on all its stages of evolution. We have stars that have already been born. We have dense regions to fully collapse, but are still emitting infrared light. And then we have more nebulous areas to be shocked. of send an impulse of energy through like waves and so therefore the further we go out into the universe the further back in time we can look as it takes light to distances this image is of galaxies about nineers for the light to reach us and therefore we're seeing it all these galaxies as they existed as they looked nine billion years ago brimming with stars in the process of formation,

some 9 billion light years away, are seen in this image, taken at near-infrared wavelengths. The pierce, visible light often can't penetrate. So that's why they choose to see the more permeable. They stand out in the image because energy from the new stars has caused oxygen in the gas around them

to light up like a neon sign. This phase of rapid star birth is thought to represent an important stage in the formation of dwarf galaxies. The most numerous type of galaxy in the universe. Three-dimensional, I guess, representation of galaxy superclusters. It was generated here, this image, plotting the positions, thousand galaxies, features of our cosmic environment. to about 700 million light years. The yellow blobs are super clusters of galaxies which are interspersed with black of light years across. Tens of millions.

Shows how galaxies outside the Milky Way are distributed in clusters in filamentary structures. The galaxies are color-coded according to brightness with the bright ones in blue and the faint ones. by observing the universe in different wavelengths, which we'll get into more in the future here. The massive cluster of galaxies is one of the most distant known to astronomers, astronomers, some 8.5 billion light years away, superimposed on the optical picture here behind it,

this kind of purply blob, an x-ray image revealing hot gas shown in purple that pervades the cluster. So there's so many things is revealed to us that we otherwise wouldn't be able to detect with visible telescopes. Brief and scales, just a quick clean. Another awesome image. We could see again a better, everything's better visually seen, observed, than just just describe. It's always hard to describe it, but this image here is a beautiful depiction of just how strong the solar winds, which are just the energy waves created by the atomic blasts, nuclear explosions created from the pressure to itself.

Once that energy hits the exterior of the surface of the star, it gets released into the void, the near void of space, and it creates spherical of energy that shock the surrounding gas molecules and it creates almost like a shield, a bubble, and ejecting. Here's a quote by the famous astronomer of cosmologist Stephen Hawking. There are grounds for cautious optimism

that we may now be near the end of the search for the ultimate laws of nature. He really thought that we and we might be and obviously his speculation is much more accurate and informed. So it's really it is encouraging to know that

he felt one of the leading scientists and just minds in general of our time really was convinced and so inspired by just how much we're able to explain about the universe that he felt were on the verge of understanding the distances. Laws of physics to the extent that we are is really truly remarkable.

And something to definitely revel in. The universe is all of existence. And remember, that means us too. I love Carl Sagan's and his understanding of the universe and as us as the actual embodiment of the universe being created from the carbon and nitrogen and iron in our blood, you know, ejected in the space from supernova billions of years ago, which ultimately years of evolution on Earth, cognizant, and evolved this consciousness, completely out of this material, amitists, and inquisitive people,

the universe is unknowably vast and ever since it formed, carrying distant regions apart at speeds up to and in some cases possibly even exceeding light. The universe encompasses everything from the atom to the largest galaxy cluster. So we're going to answer some of the questions that cosmologists, you know, and all the variations of people who study everything outside. Old is it? And how does it work? Even on the grandest of scales.

First, we gotta put things into perspective of distance and understand the scale of the universe. Everything in the universe is part of something larger. I mean, fundamentally, we are made up of systems. You know, you are a system of cells. Together into certain systems that we call organs, like kidneys and, you know, GI tracks and your heart and your bloodstream and your limbic system and your nervous system is a part to live in a system of social relationships

where your mind is influenced and influences other minds. We call friendships and family and loving relationships, and then we exist in societies and nations interact with one, another, that's not to even mention the symbiosis and other biological life on Earth. Groups of stars that float around the lazy river of our Milky Way galaxy orbiting it every 200. And then we have systems of galaxies that float of the universe together as well. So where is our place? The scale of the Earth and its moon may be relatively easy for the human mind to grasp,

being a few thousand miles across and the moon being about 220,000 miles away. You know, even that is kind of hard to comprehend. But once we get bigger than that, the nearest star is unimaginably remote Alpha Centauri. Four light years. It takes only eight minutes for light to reach Earth from the sun. It takes four years for our sun's light to reach the nearest star. And then the farthest galaxies are billions of times more distant than that even. Yet, so cosmologists who study the size and structure of the universe use mathematical models

to build a picture of the universe's vast scale. urge for this book to be so much and yet it also loves to speculate i think really fills the the journey the voyage of through you know of our understanding the adventure science is that the possibilities fun to speculate on what all that we know about it could actually mean And here they're talking about how for all that we know, we actually aren't 100% certain about the characteristics of the universe on the largest scales. It could be infinite. Alternatively, it might actually have a finite volume, but even a finite universe would have no center or boundaries and would curve in on itself. So, paradoxically, an object traveling off in one direction would eventually reappear from an opposite direction,

like traveling around the earth. But a person traveling around the earth being kind of just on the two-dimensional surface of a three-dimensional object, they're talking about the universe, all three dimensions itself would be curving. Space itself would curve. So eventually we would reappear from the opposite direction. But what is certain, though, is that the universe is expanding and has been doing so since its origin. So we know it's been expanding since its origin about 14 billion years ago. 13.7 to be, I guess, the most specific estimate currently.

By studying the patterns of radiation left by the Big Bang, called the cosmic microwave background a steady stream of microwave wavelength, which are wavelengths. A chaotic jumble before, right after the Big Bang before everything kind of cooled off. Scientists have been able to estimate that some parts of the universe must be separated by at least ten. Here, From our local to our farthest perspectives of distance, we have the Earth and the Moon system. Then it goes very, very small part of our solar system size. It means that the sun is just one of billions of stars, rotating galactic nucleus.

Closest star to our sun, Alpha Centauri, lies 4.35 light years away. or 25 trillion miles. That's 25,000. Within 20 light years of the sun are 79 different star systems containing 106 stars. The total includes binary stars, which actually happen to be the most frequently forming, which actually happen to be not as rare as you would do.

think. In fact, they're almost as common as single star systems. Stars of some of our local, most local nearby stars are actually serious, the brightest star in the sky. Part of a disk of now 200 galaxy, which is all the more reason to believe that there's definitely got to be different solar systems out there with life. It's really true. just a matter of wondering what level of intelligence and evolution and consciousness that life has had the opportunity to reach at the moment. Isn't just stars, of course. Like we said, when we're looking at this image here of the Orion Nebula, the Milky Way is new stars, and it's not going to diminish and dissipate into nothingness anytime soon.

for you know trillions of years really or at least hundreds of billions of years that are just just waiting to be you know shocked into or you know catalyzed into collapsing on itself just all it needs is a little nudge a little infusion from a nearby supernova or even a smaller regular nova to collapse and so we have yet to see all of the stars able to form in our Milky Way. Milky Way itself, and here's actually pretty cool, almost overlooked, three-dimensional representation showing you the, you know, how far off the galactic, ecliptic, some of these stars lie up. There's our Sun, Sirius, Alpha Centarius, pretty darn close. Galaxies. Galaxies. Galaxies.

scientists are very practically minded so that's exactly what they called our neighboring us and our neighboring galaxies it's called the local group and that includes the other biggest one is andromeda which has just like we we have satellite galaxies satellite dwarf galaxies or even what's called globular clusters of stars orbiting our galaxy. There's tons of other smaller galaxies orbiting Andromeda and the third largest galaxy in our local group Triangulum. A region about 10 million light years across. Andromeda is about 2 million light years away. And again, I love the three-dimensional depiction. So it gives us, you know, the regular Cartesian X, Y, coordinate system.

And then it adds the Z axis, which is depth. So we can see which easily are comprehensible perspective of where the galaxies lie and respect to us. It contains about 50 known galaxies. The galaxies are spocal group is, of course, systems and systems. It's like the Russian nesting doll. We're a part of a larger cloud. called the local super cluster of galaxies. We see different scales.

So to give you an idea of each coordinate, each grid, each time or distance step, each of these grid lines. On the local group it was 250,000 light years. This is 10 million light years now. So our whole local group fits with the local group within one of these grids. These little squares.

The local group of galaxies, together with some nearby galaxy clusters, such as the giant Virgo cluster, is contained within a vast structure called the Virgo supercluster. And that's 100 million light years across, including dwarf galaxies. That's about 10. that's on the order of tens of thousands of galaxies. Supercluster.

Galaxy superclusters clumpet and knots. They extend as filaments. That can be billions of light years long, with large voids separating them. However, at the largest scale, the density of galaxies, and thus all visible matter, is actually uniform. Spider's web. Locally the more you zoom in, it does look like it's pretty

heterogeneous, but the more you zoom out, you recognize that the voids and the filaments are on average, on average, pretty equidistant from one another, so it ends up looking much more homogenous. I'm going to show you much more close up because this is one of the many cool things I was about to say the coolest, but it's just any cool things. that makes me so just amazed, just filled with such a sense of this galaxy cluster. We'll certainly be getting into more detail later, but I just want to briefly show you these lines right here. They aren't warping in the lens of the telescope. This is actually what's called gravitational lensing. And what that means is there is a galaxy gravity,

There's a galaxy in front of a galaxy's light is being warped by the gravity of that galaxy in front of it. And what that comes out to us, 2 billion years away from it, the light, we can see here in the galaxy. The galaxy's light can be completely distorted into a ring-like shape around a set of galaxies. So on the fastest scales of the universe we have these filament-like structures we can see down here it really does look like some effervescent web, translucent spindling but each of these millions of light years across tens or even hundreds stranger than fiction and it's just beautiful to be actually remember the reality of the situation that we're in and remember reality of the situation that we actually live with no bigger adventure

than studying reality cognitive history and archaeology of religion and the emergence of consciousness the most complex thing in the world and the universe really past distances the overwhelmingly bewilderingly large and small scales that we have been able to probe the universe on. So we are in one large mysterious thing that just incredibly visualizations that we get with this book. It's showing two people, two observers surrounded by a sphere and that sphere is meant to represent the distances, the furthest distances at the sea because we understand based on a lot of complex observations in a long history of observing space itself expanding the evolution

of galaxies and recognize that the largest structures including you know made up of galaxies had to have arrived at where they are from a certain starting point at least that's what the the evidence observed evidence the red shifting of galaxies which means that they're traveling increasingly further away. And what Einstein and Hubble and many other brilliant genius observers of the universe have concluded was that space itself in between the galaxies is expanding the often mentioned, you know, raisin bread. If the bread starts to bake and has raisins roughly uniformly. smattered throughout, the distance between each raisin is going to increase as the entire loaf itself expands. Whether away you are from a particular raisin, if you're within the loaf looking,

you know, trying to observe other raisins, the faster those other raisins are going to expand or appear to be expanding it, definitely. So these two observers, um, They have a little bit of an overlapping field. I guess the point demonstrate that the universe might look like this for us, but if there's another intelligent observer from a planet in a galaxy 10 billion years away from us or closer to our visible universe, if you will, then that person, his horizon of observable, phenomena in the universe is going to be shifted by another 10 billion light years.

So he's going to be able to observe galaxies and phenomena much more distant than we can. And likewise, we can look at things that will be beyond his visible horizon as well. So that's all to say that we think the universe is about 13.7. billion years old, but that doesn't... that's much smaller than the actual distance in light years that we think the universe is, because not only does it take... because not only does it take 13.7 billion years

for light to reach us from other distant galaxies, the most distant of galaxies, but the space has expanded so much in that 13 billion years that the galaxies we can see well beyond our event horizon or observable cosmological horizon i guess it might be called so i believe the current estimate for the diameter of the universe is something like 95 billion light years across which is just astounding. So let's move on to take a look at observed what makes them stars and the planets. Larger scale structures such as galaxies and clusters and all the things that, like black holes,

in dark matter and dark energy, the driving forces. More interesting than that, we're going to delve into the true, physics the physics underlying all the understanding behind the interstellar, intergalactic, all the cosmic phenomena that we know about. Because of course the universe,

what it's so, so cool is to have a system, you know, a superimposed set of hierarchy system, hierarchical systems that are within universal hierarchy, create these structures, that dwarf us in an unimaginable sense.

So it's fascinating to know that we have the large that are created. We are right in the middle in states of stars like plasma. How we analyze light is just a form of radiation along the electromagnetic. It consists of energy, space through space as single atoms or simple gas molecules. Other matter clumps into islands. of material, from dust modes to giant suns, or they even implode to form black hole, largest of which we call supermassive that lie at the center of galaxies. Gravity all these objects into great clouds and disks of material known as galaxies. Galaxies in turn fall into clusters

and finally form the biggest celestial objects of all super clusters. Gas, dust, and particles are the most important aspects of the universe, because they are what become the stars and the black holes in the galaxies themselves. Much of the ordinary matter of the universe exists as a thin and tenuous gas, within and round, galaxies and even as thinner gas between galaxies. So the gas is made mainly of hydrogen and helium, the most abundant atoms elements in the universe, just mainly because they're the simplest. They were the first form after the Big Bang being the simplest.

hydrogen having just one proton associated electron and helium having just two protons with in the nucleus with of course the neutrons to follow in different isotopes so those are the most abundant and lightest elements but of course some clouds inside galaxies may contain atoms of heavier chemical elements and even simple molecules. Mixed in with the galactic clouds is dust. Tiny solid particles of carbon or substances such as silicates, compounds of silicone and oxygen. Within galaxies, the Gas and dust, they make up what's called the interstellar medium. So between all the stars of the Milky Way galaxy in particular, because that's the one that we live in, and that's the one we can best study.

Stream this current, just dispersed gas, waiting again to be collapsed into newly formed. The visible clumps of this medium may, many of them, the sites of star formation are called nebulae. Some, called emission nebulae, actually produce a brilliant glow as their constituent atoms absorb radiant energy from the stars and they re-radiate it as light. So they become these glows. As we can see here, nebula.

Nebulae. These are visible only as smudges that block out starlight. starlight. Here's an example. Dust in dense gas, Barnard 68 is an example of a dark nebula. The thick dust obscures the rich starfield behind it. And they know that, which is super, super cool. I love it, that they can pierce in this dark veil. It's very opaque, light transferable clouds of dust and gas. and that's able to look at x-rays or microwaves or infrared, ultraviolet wavelengths, anything that's other than visible light, oftentimes they're able to see exactly, exactly what's behind that cloud. To me, that is so, so amazing.

Just one more example of how we can slowly, you know, step by step, incrementally, pierce, the veil, a mysterious veil that the universe has laid before us. You can peel it back and behind the universe. Energetic subatomic particles traveling at high speeds throughout the cosmos. And again, we can, with the right instruments, we can also detect cosmic rays. A nebula, which, this is a beautiful picture right here, is a beautiful picture right here. giant cloud of gas in the southern hemisphere. It is visible to colors in this image represent different variations in temperature. Versus light of course energy through

sometimes occur in pairs or even in clusters. Depending on their initial mass, stars varying color, surface temperature, brightness, and lifespan. The most massive stars known as giants and super giants even are the hottest and brightest but as you might imagine because they're so bright and have such enormous pressure condensing and compressing all the matter inside the star it's going to burn it much more quickly and so these things they last our star our sun last on the order of five to ten billion years that's a fairly average fairly main sequence star these large super giants they burn out in sometimes less than 10 million years one-tenth of a billion years relatively fast compared to most stars and of course as soon as they

burn out they go into either supernova or just nova and they release and they spew out their material again to be captured so much and so quickly that it no longer can hold the gravitational forces compressing it at bay

and it collapsed down the pressure the inside kind of rebounds and reverberates that energy and swells up again and this happens

a couple times to the point where the star expands, as it undergoes a reactionary expansion, so much that it almost becomes too big to no longer hold external atmosphere, and that starts to dissipate. The process is continually going on all throughout the galaxy, constantly renewing impulses and adding to the chaos of energy. solar winds if our spacecraft if they travel out there they're gonna be able to detect much solar wind but if they like the voyager spacecraft go much much beyond our solar system because they they don't burn as brightly and as hotly so generally red is much more cooler than blue very white hot blue stars are the hottest. And so these ones creating fusion are at pace. They don't have as much pressure collapsing in on the core of the

stars to inch the, and so they live for much longer up to, you know, tens of billions of years even. These are called generally red dwarfs. Smaller still are even brown dwarfs. These are actually failed stars. These are like very, very large Jupiter's. Maybe if Jupiter had ten times its mass, it would be a brown, not massive or hot enough to sustain the type of fusion that occurs in stars. And they emit only much of the, it's so big star system here, a binary system, is our, is consisting of a bright yellow-orange primary star,

star in a dimmer bluish companion. And here is a small insert of the globular clusters, which are not quite galaxies, but they are clusters and oftentimes very, very ancient clusters that are made of very, very old stars, tens of thousands of them, clustered together, ancient objects that orbit galaxies, This has quite a bit actually about half a million.

There is the brown dwarf. We're actually able to see the dot to the right of the center of this picture is a brown dwarf called Glees 229. The letter usually indicates its secondary or if it's a tertiary component of a star system. brighter object is the red dwarf star glees 229 forever even the smallest ones longest lived eventually do fade away stars of medium mass such as the sun expand into large low density stars called red giants before they blow off most of their outer layers They then collapse to form white dwarf stars that gradually cool and fade. The expanding shells of blown off matter surrounding the such stars are called planetary nebulae. Not because of anything to do with the planet, but actually because the original discoverer and namer of these objects was Herschel,

William Marshall, a famous 17th century astronomer, and he thought, rather than being in their death throes, they were actually proto-planetary systems. And perhaps there were young stars with, surrounded with spheres of opaque matter and gas that had yet to collapse into the disks that would eventually coalesce into planets.

So he named them planetary nebula. stars may be obscured as yet unformed planets things that were named long ago they have since been found to be much different than the thing that were they were originally named after but the name stuck and so we still call them more massive stars have even more spectacular ends disintegrating in explosions called supernovae the expanding shale of ejected matter may be seen for thousands of years. It is called a supernova remnant. Actually, there's one that we observed in maybe a thousand years ago.

I believe it's the crab, the crab nebula, that the Chinese and some other civilizations actually were able to record. And it's pretty cool that they actually saw the supernova itself. and it was so bright they could see it in the daytime sky and now a thousand years later we're able to see the remnants that our ancestors recorded which is a beautiful connection between the history it's awesome some of the larger stars that do collapse in the supernova it's kind of where they collapse in on themselves and it creates a chain reaction you think of it as when you have a big enough star with enough material, the gravity created by such a large amount of mass in one central location is so immense that the actual pressure, even the pressure of billions of nuclear bombs pushing outward can't stop the collapse. And so once the things kind of, the pressure of gravity,

surges the core with even more energy than it had before and that fuses even more atoms that otherwise would have been left and so in these last moments the core of the star star is big enough to create supernova at least they have a cataclysmic chain reaction of explosions that very counter to the much more mild mild diffusion of material in a pretty concentric ring of the planetary nebula.

These create cataclysmic explosions that can be seen across millions and millions of light years and they can even from the largest stars outshine the light, temporarily at least, of an entire galaxy of billions, hundreds of billions of stars. So for the largest of these stars, they create temporarily at least an immense illumination that outshines even the hundreds of billions of stars that make up galaxies that they might be in. So here in the Veil Nebula is the shockwave from a star that exploded anywhere from 5 to 15,000 years ago. It's 2,600 light years away from us, and its material may one day. You can see this collapsed nebula here.

It may one day spark the growth of new stars. Because what happens, like we touched upon before, this is a really good example. And you can see the curvature here exactly matches what you would expect from a concentric radially emitting sphere of ejected material from such a powerful explosion in space as a supernova would be. This material isn't necessarily from the nova itself, but it's actually just nebulous, molecules and elements, atoms floating in the void that are roughly compact, floating amongst themselves. And it's near enough to the supernova explosion that the energy, the shock waves, emitted. A solar explosion, I guess you might say. This cloud and compressed as it travels.

pressed all these atoms together and once they're compressed together they threw friction and all the motion amongst them they start to emit light in infrared and then visible wavelengths so here we can see the whole cloud itself is kind of thrown and pushed by the shock waves to perhaps create a whole new star system or multiple star systems. And just like the smaller stars before it, even supernovas do leave behind cores in remnants of materials.

A part of the core collapses into a compact, extremely, extremely dense object known as a neutron star. These, as you might figure out, by the name, their primary characteristic is that they are composed entirely of neutrons as opposed to protons, neutrons, and electrons, that are the constituents of what we normally think of as atoms.

Here, the pressure leaves behind a core so dense and so compact that the protons and electrons, positive and negatively charged normally have fused together to form a neutral neutron normally what's called neutron beta decay is where a neutron and we'll get to that couple pages here it's created of I believe an up and two down quarks there's three subatomic particles within it Neutron can compose or decay into a proton and an electron and then an anti-neutrino. Because like Einstein's equations dictate, it's equivalent where it's a matter's mass is going to be directly proportional to the energy created when that mass decays.

And so I guess a neutron is normally a little bit heavier. than a proton. So that means it has some extra mass there. And when it decays into a relatively proportionally sized proton, and a much smaller mass-wise electron, there's even some mass left over. And this turns into what scientists call an anti-neutrino. And so I think I believe the the coolest description of the sheer density of what a neutron star actually is. It's these compact things, so we generally think of the atom as being a very, very, very tiny, but massive atomic core. Have a nucleus with protons and neutrons. It defines what the element is, and it is surrounded by a concentric fuel.

field I guess because there are no electrons or protons it's just neutrons they actually butt up and they're electrically so they won't actually electrically repel or attract one another they're just so dense and so tight up next to one another that the plasmic so what this actually means that one spoonful of this stuff There's a spoon sturdy enough to hold it. Would weigh as much as a mountain, a large one like Everest. This stuff is...

And then lastly, that's the last step before we hit the most interesting remnant of all star stellar explosions, a black hole. Anything beyond a star big enough to create a supernova and leave beyond a neutron star has its core. anything larger than that is going to create a black hole. This is... This is a star so large that trying to make sense

of that amount of matter in that small of a space creates a singularity and physicists believe that Einstein's equations say that all that matter not be able to hold its structure its actual physical structure and it will collapse into a volumless point in space it'll warp the fabric and the actual universe around it to an equation that yields an infinitely small point

were actually means but we actually observed creetian disk melting illuminating radiating matter surrounding a black hole in the heart of the galaxy

M87 and so we do know that these black holes do exist and we even have one in the center of our galaxy as well so these things heavy and dense

and they actually break what we classically understand as matter in space to define. And that's what's left by the heaviest of stars or planets. The solar system, our own star being the sun, and all the planets, asteroids, dwarf planets, clouds of small objects in the orc cloud and its perimeters, is thought to have formed from dust and gas that condensed into a spinning disk called a protoplanetary disk. Scientists aren't really sure exactly how our solar system started, of course, because it's five, at least five billion years. But they think they have a pretty good understanding based on observing, you know, the multitude,

millions of other stars that are similar in mass composition in our galaxy. They think that, like we said, with supernova's bursting forth plumes of energy, that send shockwaves through otherwise pretty inert clouds, pretty stagnant, pretty motionless relatively, clouds of interstellar molecules, then certain areas of those clouds. All it takes is a little bit, a slightly denser patch of those clouds. For a feedback loop,

initiate which creates a new center of gravity towards which all the other molecules, or many at least, in the cloud gravitate. And once that happens, of course, the three-dimensional, spherical cloud that starts to coalesce and collapse, picks up a rotation, an angular velocity, and just like the sun and the Earth have a little slight bulge around its equator, the point most perpendicular to the axis of rotation. These clouds also, these protoplanetary nebulae, the initial stages of our own solar system's formation,

it too began to collapse into a more two-dimensional spherical disk-like shape. And when it did heavier elements like iron and such metals, silver and gold, and all the elements much heavier than hydrogen and helium, they were the first to outside of the sun to coalesce into bodies small bodies that just like the rings of Saturn have little moons that clear the entire ring of that same distance away the same radius away from Saturn that's what creates the little ring shapes and these bodies they eventually gather enough mass and to the point where they become the sole attractor for all the elements, all the particles of matter within that same orbital distance, orbital field. I may actually maybe drawing very three-dimensional over time more disk-like shape increases with an angular velocity. has an increasing angular velocity so in that same way there would be starting to form because once a couple rocks hit together they smash into each other and perhaps with

enough velocity they melt together and they create magma and then before you know it you have a little rock that's you know a mile wide and then maybe a couple miles and it's a runaway feedback loop. All it takes is that initial area that's just slightly more massive than the other areas. And basically clearing the field around their same orbital distance from whether it's the sun, planets clearing the field around the sun or clearing the field.

Let's see, the sun was made out of a group. Perhaps it formed out of an entire stellar nursery, much like we see with the Orion Nebula, it has many, many stars forming, and they almost, they form in groups. Of course, a few hundred orbits, a few hundred two million, two hundred million year-long orbits, a rocky way galaxy, the groups might begin to disperse. But initially, the first things to collapse would be the large, stars that would form out of it. They would compose most of the matter out of the nebula. Their life cycles are, like we said, the shortest, but they do gain the initial mass,

most of it, maybe 80% of it, and the rest of the stars are much less massive. They have much less material now in the nebulous cloud to draw off of. So they become more average sized main sequence sun-like stars but nonetheless the the sun we think was formed in this in this manner you know out of an interstellar nursery of molecules that was maybe initiated into collapsing in the local areas of very dense matter and of course once that happens just like a black hole, a very mild version of a black hole. All matter is attracted to it. That's why we think supermassive black holes might be the, in many ways, the driver, galaxy structures, and dynamics.

Because once you have a black hole form, if it's near enough to other matter, it will inevitably draw it in into its orbit, if not completely beyond its event horizon. So our star formed the percentage of the mass of the initial nebulous material that out of which our star and our whole solar system is derived ends up being about 99.8. or 9% So that's saying that 99 out of every thousand particles

in the entire solar system protoplanetary mass of material was ultimately became and was drawn in to our sun

and that's an incredible percentage of the material that's It just gives you a good perspective of just how massive and therefore gravitationally dominant our sun really is in the solar system. Now from there, the remaining tenth of a percent, 90 percent of that resides entirely in just Jupiter and Saturn alone. and as you might begin to suspect the remaining 84% of that matter outside of the sun and Jupiter and Saturn actually resides entirely 84% of the remainder resides entirely in Uranus and Neptune so you can imagine where the earth lies on that I think it's something of the order of

3 millionths of a percent of the sun's mass, which is roughly of the whole solar system. So that's one way of looking at the Earth and put ourselves in perspective of just our own solar system, let alone the galaxy and not even touching upon the universe and the size that it truly is. So as this disk is starting to form, we have the sun at the center, of course,

and all the material in the orbits closest to it, Mercury right there. Just like in a cup, if you pour, you know, a styrofoam and sand, and water and oil and all segregate themselves within Earth's or due to Earth's gravitational influence from heaviest at the bottom to lightest which would really be the atmosphere or the gas the gaseous air at the top and it's in very similar fashion because of course the same laws of physics apply here on Earth, as they do elsewhere in the universe, everywhere else as far as we know. All the inner planets here, they are composed. They all have iron cores. They have a lot of

metallic constituents. Asteroid belt, maybe. I'm way trying to draw this to scale. I mean, this is not even anywhere near scale, but I think if that were truly the size of the earth Jupiter might be like something like a quarter of the size of this entire page but out here Jupiter

with its many moons and slightly smaller Saturn with its rings and many moons they are made of mostly lighter things and in fact Jupiter's made of

much the same light elements as the sun is. And perhaps that's because hydrogen and helium and lithium, all those lighter elements are less massive and are maybe move and swarms quicker and they were able to condense and collapse much quicker than all the heavier elements. And so the sun drew in mostly hydrogen in helium, those are the most abundant elements in the universe, after all.

And the remainder, the heavier elements, out of the remainder, rather, the heavier elements sank towards the interior we call the inner solar system. And out here, all of this and beyond, would be the outer planets or system, Saturn, Uranus Neptune, they're all gas giants, as I describe, you know, talk endlessly about in my gas giants video. They're mostly lighter elements. We don't know for sure what's at their core, but we know they're much, generally much lighter, made of much lighter elements than the inner planets, Mercury, Venus, Earth, and Mars.

and we have outside of that we have what's called the Kuiper Belt which is on the innermost side of which is Pluto and it's which is pretty much another planet a dwarf planet orbiting it

so it's almost like a binary dwarf planet system the Kuiper Belt is a series of icy worlds and comets and asteroids that are orbiting way beyond Neptune even, the last of the planets. And then way, way, way beyond that, the Kuiper belt, at the furthest extent of the solar systems,

the sun's gravitational dominion in the galaxy is the Oort cloud. If it says anything about the Oort Cloud, if it says anything about the Oort Cloud. True material became the Sun, while the other outer material matter, matter formed planets and other small cold objects further away from the sun of course the generally colder the objects get a planet is a technically as humans define it a sphere a heavenly celestial sphere that's at least a thousand miles across orbiting the star and unlike brown dwarfs they don't produce nuclear fusion. So if Jupiter were maybe ten times its size, so maybe the Sun only was composed of 99% of the total solar systems matter and Jupiter got about nine or ten times more access to matter than it does, maybe it would actually be big enough

to apply enough pressure at its very core to initiate nuclear fusion. And this then it would be the lower most, lower most, limit, massive limit of a star. Of course, it's not, so it remains just a very large. Since planets and protoplanetary disks are found orbiting stars elsewhere in our galaxy, it's probable that the solar system is actually pretty typical in that planets are very common.

in the universe and in fact we've found many exoplanets as the years go on and we search for gravitational perturbations due you know around other close nearby stars due to these large and even smaller um earth size planet and then we see the star itself wobble due to another planet you know one of its planets tugging on it gravitationally or if we happen to be perfectly lined up to where the we're not looking at it from this view but instead we happen to see perfectly dead on one of its own planets orbit right in front of it might see the light of the star dip a little bit just to dim just a few you know millions of a percent

But that's all we need to actually, for our very, the most advanced instruments we have, to detect a slight in the solar system, the planets are either gas giants, Saturn and Jupiter, Uranus and Neptune, or the inner planets, the rocky, worldly terrestrial planets, planets that aren't defined by their atmospheres but more so by the crust that surrounds their molten cores. Mercury, Venus, Earth. Still smaller objects fall into about five categories. Moons are objects that don't orbit the Sun exclusively, but they orbit planets orbiting the Sun. Sun. Asteroids, which could be trapped and become moons, asteroids are rocky bodies about 150 feet, all the way up to about 600 miles across. Comets further to differentiate from asteroids, there are chunks of

ice and rock. Oftentimes asteroids are close enough to the sun where the ice would have long ago melted off their surface. So they might, in some cases, be ancient comets that have been trapped in the inner solar system. Of course, comets being ice, that mainly means that they're all the way out at the far reaches, in the Kuiper belt, in some even in the orc cloud. Then we have ice dwarfs, which are similar,

but are up to a few hundred miles. miles across. And that would be the ice dwarf planet Pluto, which we would define as not quite a planet anymore because it's so, so small and so distant. You have meteorites are the remains of shattered asteroids or simply dust from common. Imagine in 1610 over 400 years ago, Galileo was one of the first people. He might be the the first to look up with these glass lenses that were able to magnify whatever object you were looking at and he looked at Jupiter and saw that it looked like it had a series of string that are pretty much in a straight line of stars around it again it really does look very much like that you see Jupiter it maybe you see a wispy band if you have a little better telescope, you might be able to see the faintest outline of the great red spot. But then you really

just see outside of it these tiny little dots. And those are its moons. Galileo was able to see four moons, the largest of Jupiter's moons. Io, Europa, Ganymede, and Callisto, all Greek names. Here we have Achaia Zeng, a few comets traveling. orbits that bring them close to the sun frozen chemicals in the comet then vaporize as they get close and get bombarded by the heat and radiation off the sun they always if they do get vaporized and as they get towards the roughly about three earth distances from the sun, the comets begin to project a tail out of the coma, which would be the nucleus here. You can see you have a dust tail and a gas tail.

And the tail kind of counterintuitively, or very much actually, unlike what you would think of as maybe a tail wind, coming off something on earth, maybe out of a jet engine or something, they don't always follow, they don't always point directly away from the motion of the comet. In fact, if a comet's coming in like this way, the tail, even though the comet might be going that way, the tail is going to be, or maybe, so instead of the comet's tail being following the exact opposite direction of the trajectory, it's of its velocity, its tail is actually going to be directly opposite the solar wind. It might be moving this way, but its tail is going to be

all the particles blasted off by the solar wind. So the direction of the solar wind, of course, emanating directly out from the sun. Move up in the unirical. In the unirical. The uniron universal cosmic ladder and talk about galaxies and much larger scale objects much more massive much more gravitationally dominant in the largest players in the cosmic celestial bodies we'll start with the primary players constitute much of what we know even though well not not the majority of it and we'll get to with dark matter and dark energy. So up next is galaxies.

The solar system occupies just a tiny part of our enormous disk-shaped structure of stars, gas, and dust we call the Milky Way. Truly astounding is that we really only about 100 years ago were able to develop, again, through the scientific method that really truly kicked off only. about 400 years ago, the tools to enable us to really get an accurate perspective of ourselves

along the scale of distances and volume of the universe and recognize that the galaxy we live in is really only just one of hundreds of billions, if not trillions, of other galaxies. massive groups of billions of stars themselves drifting in along these large filaments we call galactic superclusters it's really discover this really blessed to be in this age you know we've had a lot of

incredibly sad disasters of human conflict in the 20th century the World War among the foremost of them. But we've also, alongside that, have had an incredible advancement in technology and therefore our ability to probe

and understand our place in the universe. So really until 100 years ago, our galaxy was thought to comprise the whole universe. We thought every single star we saw in the sky, even with the largest telescopes, was all part of the same kind of local group, maybe a few tens of thousands of light years across. And it was just a matter of, you know, categorizing and cataloging them

and, you know, discovering the local universe. You know, that wasn't everybody, but we're, when we speak of we and what we thought at certain points in human history, we generally just, We discuss what the average educated person might believe. There were, of course, many people from ancient astronomers to classical modern philosophers like Kant in the 1700s, who came up with hypotheses that there were, in fact, different universes, which we now call properly galaxies, drifting amongst themselves, much like this picture here depicts

but yeah we really thought that was just it we it was really just a failure of imagination at its heart and we couldn't really imagine anything outside a limit of local stars

and groups today we know that just the observable part of the universe contains more than a hundred billion separate galaxies and I think this book might be up to about 15 years old so I think that number's gotten into the trillions now and we don't know where it will ultimately lead

we really don't they vary in size from dwarf galaxies a few hundred light years across to and then containing a few million stars to giants spanning several hundred thousand light years containing several trillion stars so we're closer to a giant than we are a dwarf globular you know cluster dwarf galaxy we are in the center of the mass around which many dwarf galaxies themselves

orbit and group as we saw. We're only second to the large Andromeda galaxy. But, so as well as stars, galaxies do contain clouds of gas and dust and dark matter, all held together by gravity. So we'll tackle dark matter in just a little bit. And like all science, we astronomers love categorizing the galaxies into easily identifiable shapes and structures. So we have a spiral, which we think ours is, I believe. We got barred spiral, which is we have pictured here.

radiate from the ends of the central bar-like structure rather than from the nucleus. We have elliptical, which is more like spherical or football-shaped, much like the sombrero galaxy. Lenticular, which means lens-shaped. I don't know if they have an example here. And then, of course, much like the duck-built platypus, we have to have an irregular category, a category into which we put, it's kind of a junk drawer category, put all the ones that don't fit there. Astronomers identify galaxies by their number

in one of several databases of celestial objects. For example, NGC 1530 indicates Galaxy 1530 in a database called the new General Catalog. And here we have Galaxy M81, which was an older catalog invented by the, or initialized I guess, by the astronomer Messier. So these M stands for Messier, and he just listed them at, I don't, know if there is any particular order or if it was just he started numbering them as he found them but we have m81 this image taken by the spitzer space telescope shows a nearby spiral galaxy m81 the sensor captured infrared radiation rather than visible light and the image highlights dust in the spirals, the galaxy's nucleus in spiral arms. It's really cool. You can see a lot more in the

infrared spectrum than the visible light. Now to galaxy clusters before we get to black holes. Galaxies are bound by gravity to form clusters of about 20 to up to several thousand. They vary from 3 to 30 million light years across. Some have a concentrated concentrated central core in a well-defined spherical structure of galaxies forming the outer circumference of the sphere. Others are irregular in shape and structure, probably meaning that they're more chaotic in their motions. To me, it's really cool to perceive what we look at as these beautiful pictures of galaxies. that look like they're really just some stationary wallpaper like backdrop of the cosmos.

They're so large on such an unimaginably large scale and massive scale too that they seem motionless to us. And for all intents and purposes, they really are. But what's really cool to remember is that we're just taking a snapshot every time we literally take a picture all that is is a moment in time and the temporary location that they're at amongst a you know billion year long dance with the other objects and that they're surrounded by so here this central image is really symbolic of the dynamic constant incessant movement of these galaxies and the fact that they like we are just nothing but an accumulation

with our brains being an emergent structure that comes out of trillions of atoms galaxies are really nothing amongst themselves but a structure composed of billions and billions of stars And so here we have what looks like the result. The Tadpool galaxy lies 420 million light years away. Like any galaxy, it's a vast spinning wheel of matter bound together by gravity. The streamer of stars emerging from this galaxy is thought to have been torn out by the gravity of a smaller galaxy passing through it. Really, really awesome to remember that, that, you know, our galaxy might have, most likely is the result of, you know, a few dozen smaller dwarf galaxies merging and merging over billions of years until we finally have arrived at a largely stable, very large structure full of hundreds of billions of stars. And it just adds to the wonder

at a certain particular point in their trajectory on the weight of their ultimate fate. If we can even talk about galaxies with words like the neighboring Virgo cluster is a large irregular cluster of several hundred galaxies lying about 50 million light years away. Chains of about about a dozen. About a dozen or so galaxy clusters are linked up loosely by gravity,

and they make up what we call superclusters, which can be up to superclusters or in turn, arranged in broad sheets and filaments, like you might see in a spider's web, separated by voids of about 100 million light years. Sheets and voids form a network that permeate, the entire observable universe. Compact group, this cluster includes a face-on spiral galaxy in the center of the image. Very, very cool. You can see that right. Abel 1689 is one of the most massive galaxy clusters that we know.

It's thought to contain hundreds of galaxies. The whole is a region of space containing at its center. some matter squeezed into a point of infinite density. We call this a singularity. This would be Einstein's equations amounting to dividing by infinity. Within a spherical region around the singularity, the gravitational pull is so great that nothing not even light is able to escape, essentially massless, and it doesn't have anything that goes.

in the universe faster than it. And so really black holes are one of the most unimaginable, hard to visualize, hard to even conceptualize objects in the entire universe. The cells don't emit light, but they certainly have a huge, they have a huge impact on matter all around them, in space itself, as we're going to find out later.

They can be detected, not directly, but very much indirectly. From the behavior of material around them, those discovered so far typically have a disk of gas and dust, spinning around the hole, throwing off hot, high-speed jets of material or emitting radiation such as x-rays, as the material falls beyond the event horizon, the point at which no light is going to escape.

So it just slowly fades into a black sphere, really. Even though the point, the singularity itself is supposedly without volume. There is no, it takes up no actual space. It's just a single point. The effect that it has on everything around it is going to be, you know, I don't know, maybe 10s of miles across. So anything within a couple astronomical units of the black hole is going to be so close to it that it's light. And every characteristic of it will not ever be able to be seen again from outside the event and horizon.

So there are two main types of black holes that we know about. Supermassive and smaller ones on the scale of stars. We call stellar. Supermassive black holes, which can have a mass equivalent to billion of suns, exist in the centers of most galaxies, including our own. Their exact origin is not yet understood. but they may be a byproduct of some process of galaxy formation. Stellar black holes form from the collapsed remains of super giant explosions.

And they actually may be more common than we previously thought in the galaxy. Here at the bottom, the black hole SS 433 is situated in the center of this false. colored x-ray image. It's detectable because it's sucking in matter from a nearby star and blasting out material and x-ray radiation. Visible here has two bright yellow lobes. Of course, this book is about 15 years old, so it's not going to have the new image from the galaxy Messier or M87 of the black hole that we just found. through the event horizon network of telescopes. But this one here from NGC-4438

is a really good depiction of the effect that black holes can have on the material surrounding them. You could think of the black. Say it's really, really hot, maybe a star, a remnant of a star falls in, and it's light, simply pulled by gravity all the way back in. If it were a little further out,

its light might get a little bit closer, but ultimately fall back in. If it were right here, right on the inside of the, if it were right on the inside of the horizon across which all events are no longer visible, then maybe it's light, momentarily pops out before it's completely again sucked back in but if it does or if it hasn't yet crossed that horizon then it's it's light might be bent but it will eventually escape get a

little maybe maybe that helps hopefully doesn't make it worse but your understanding of what it looks like when you see interstellar like black holes that are apparently very what you're seeing it's really hard it was hard for me to visualize exactly what was going on when we had this light from behind here because in the actual light that normally you know even our sun as massive as it is it doesn't really bend light that much it bends it I think someone said or I once read that it bends light and this is actually one of the first experiments that was able to conclusively prove Einstein's theory of relativity was accurate much more accurate than Newton's previously dominant

theory of gravity it bends light our sun does about the width of a human hair looked at from a distance of about 100 yards or 100 meters. The width of a human hair is the limit of perception, you know, held out at arm's length, let alone looking at it from, you know, that far of. I could imagine an object like a black hole massive than our sun. Just how much it's going to be bending light. So if you have light here, you know, trying to do. escape outside the event horizon and it hasn't yet fallen within that boundary of no return

which you know definitely undergo some bending and the closer it gets so if it shoots out this way it might not bend that far you know if it shoots this way like directly away from the event horizon maybe it only undergoes a slight bend. This slide is here, you know, all these photons, if we, like the event horizon, and I wanna do a separate video on the event horizon itself. Maybe I'll have it done by the time I post this one.

Um, it's just really amazing. It's just so baffling, it's so wonderful to be able to think about what that actually means when you're looking at the event horizon telescope pictures of the black hole being imaged. The light, even though it's a fuzzy patch, that is actual collected photons from the center of this galaxy that's millions of miles away and the light is a actually the light that's already, you know, that makes it our direction is light that has already been bent by the gravity of the black hole. It's been bent around. And if we're over here, you know, our little solar system millions and millions of light years away, but it eventually makes it to us, that's like that's probably, you know, came from the other side of the black hole.

so that is very awesome to think about i think we're going to end this first section about the you know i guess about the observable aspects of the universe before we get into matter relativity are our theories of forces and physical laws of the universe dark matter and dark energy it's kind of a as far as I know even in the last you know since this book has been written

in revised in the last 10 to 15 years dark matter and dark energy are still elusive underlying fundamental concepts that scientists have simply observed

and collected data on the effects of but don't quite know the causes, don't quite know, you know, the fundamental nature of. So there's far more matter in the universe than is contained in the stars, in other visible objects, all other visible objects. The invisible mass we just call dark matter. I heard Neil deGrasse Tyson say it best that they don't know what it is, so they just gave it the name dark matter, but that doesn't actually correlate with anything other than the fact that it's unobserved.

So they figure it doesn't put out light, so it's not white. It's dark. Its composition is unknown. Some might take the form of machos. Astronomers love ridiculous acronyms, by the way. massive compact halo objects, dark planet-like bodies. So they think maybe our galaxy is being affected gravitationally by very dark. Their planets or dwarf planets or dwarf stars even, failed stars that are massive enough and in a large enough quantity to have a gravitational impact on the Earth. the dynamics of our galaxy without being observable.

So they're not observable with regular telescopes. And even in the infrared, which, if they were producing radiative heat from nuclear fusion and they were just too dim to be noticed in the visible wavelength, you would think that we would be able to observe them with infrared and, ultraviolet wavelength detectors, but we can't. So not even with that, are they observable. Weekly interacting massive particles. These are exotic subatomic entities that scarcely interact with ordinary matter.

In the word massive, there's just to denote that they have a mass, even though it's on the subatomic scale, It's not to say that they're large objects. They're just objects with a mass, a detectable mass, maybe on the size of a proton or something, that just simply doesn't, much like a neutrino, interact with other matter in the universe, in a detectable way.

Evidence for dark matter includes the motion of galaxies in clusters. they move faster than can be explained by the gravity of visible matter. So there must be further mass present. And also there is, it seems even within our own galaxy, the outermost stars are propelled on by a gravitational force larger than the core of the galaxy. would be able to impart on them. Even if all the dark matter deduced from observations is included, though, in the scheme of the universe.

The density of the universe itself is not sufficient to satisfy theories of its evolution. And that's where dark energy comes into play here. To find a solution, cosmologists have proposed the existence of dark energy. They're saying that this is a force that counteracts gravity and causes the universe to expand faster than it otherwise would. And we'll be getting to the exact, you know, even though scientists don't know what dark matter is, at least they have two prime candidates, machos and whims. But yeah, with dark energy, it's entirely still speculative. They don't even know if there could be such a thing.

And I guess it would be as fundamental as gravity, maybe, because gravity, like we will discuss in the next part, discussing matter and the fundamental forces of matter is really elusive. Scientists still haven't uncovered a gravitron or graviton, a particle that, carries the force of gravity, like they have with the strong and weak and electromagnetic forces. In search of dark matter, down this little excerpt down here, says to find dark matter scientists are investigating several forms it could take.

Underground detectors search for evasive particles, such as whims and neutrinos, And neutrinos are so tiny. They were once thought to be massless. But they do actually have a minute mass. There are so many neutrinos in the cosmos that their combined mass would be about 1 to 2% of the universe's dark matter. Wimps, if detected, could account for far more. In the future about the methods and they're really important.

And they're really interesting how they actually, the length scientists go to try to detect these near massless particles. They're so in unreactive with other particles that it's like, I think they could travel through, you know, tens, 20 feet of solid steel with essentially no, deflection at all. So it's pretty amazing how that works. You're getting into much more, including neutrinos, dark energy, subatomic particles in the nature of the space time theories of matter and energy in the future, guys. So for now, I'll leave us with this, with this topic. So we'll call it quits for now. Thanks for watching guys.

I'll see you next time.