97% of Galaxies Are Moving Faster Than Light, HOW IS THIS POSSIBLE?

[@Everyyoueverymiau]

This video makes me happy and very sad at the same time.

[@AquarianSoulTimeTraveler]

watch my videos about accelerating expansion of the universe and how it is dark matter creating an illusion of accelerating expansion by absorbing energy that pass through the dark matter and increasing its matter exponentially causing the illusion of accelerating expansion!

[@MegaSolidninja]

@@AquarianSoulTimeTraveler 😂😂😂 no thanks

[@AquarianSoulTimeTraveler]

@@MegaSolidninja enjoy your comfort bubble...

[@robertimmanuel577]

@@AquarianSoulTimeTraveler gae

[@augmentedkeys5971]

Why?

[@upsilonalpha3982]

We all need some relative distance during this quarantine.

[@KokoJeuru]

A few KZbin videos tells us that Andromeda galaxy will still be in close proximity with our Milky way galaxy and in a very far distant future, the new Earth inhabitants(if they survive) can actually see & observe a real neighboring galaxy full of stars... How's that possible if we should be moving away from each other because the universe is expanding more like exponentially?

[@sindhuaggarwal4846]

@@KokoJeuru for andromeda galaxy it is relatively closer to milky way, space is expanding but for this case gravity causes there collision.

[@leeg8461]

So, gravity only works in our part of the universe?

[@sindhuaggarwal4846]

@@leeg8461 No no it is just that andromeda is close enough that gravity wins over expansion.

[@AquarianSoulTimeTraveler]

watch my videos about accelerating expansion of the universe and how it is dark matter creating an illusion of accelerating expansion by absorbing energy that pass through the dark matter and increasing its matter exponentially causing the illusion of accelerating expansion!

[@gaurav_0369]

I can't believe this is the first time I have learned the difference between observable universe and sphere of inaccessibility Or even if their was a difference You're awesome 🙌

[@DylanBegazo]

Gaurav chauhan Put another example be a grenade where everything inside it is the matter that makes up our universe. The grenade itself explodes Matter is scattered everywhere. The matter that makes up the universe that we can see and interact with becomes the galaxies and super galaxies in clusters and everything else in our universe. Immediately after the grenade explosion the area within the blast radius is hot just like our universe during and after the Big Bang as the explosion continues outward things cool down. The outside environment ITSELF that our grenade exploded WITHIN in the first place IS the Antimatter itself. The matter that ends up making galaxies are all spread apart within the expansion of the grenade’s explosion. Assuming the Grenade’s explosion expansion speed is made to be equal to the expansion of the universe after the Big Bang. Does my grenade model work?

[@erwanregy6494]

@@DylanBegazo no sry I think thats a bad anology. I can think of a few things that dont work e.g. space is acceleratingly expanding after the big bang whereas a grenade explosion comes to a halt.

[@AquarianSoulTimeTraveler]

watch my videos about accelerating expansion of the universe and how it is dark matter creating an illusion of accelerating expansion by absorbing energy that pass through the dark matter and increasing its matter exponentially causing the illusion of accelerating expansion!

[@MDProgramming]

Exactly 👍

[@captainjackpugh6050]

*there

[@ScopeofScience]

The light finally reaches the lenses of the telescopes of the *semi-intelligent* apes. lol. Well, you're not wrong, Dom.

[@amodgawade4323]

love you kurtis!!!! when will you come back to youtube?

[@user-wy4mp9ts3u]

If a tree falls at the other end of the Universe and no one see it did it happen.Without conscience nothing means anything therefore we are really important because if we did not exist, no life to appreciate it,wow wouldn't that be strange.

[@colinp2238]

Ooooo ooooooo oooo aaaaahhh ahhhhhhh

[@rodneyboehner3007]

Unfortunately, this all flawed science. The so-called "observable universe" (AKA the cosmic event horizon) is also shrinking, AND is within the Hubble horizon IF the rate of expansion is speeding up. The only way the far edges of the universe interacts with us is through photons, which propagate at the speed of light. Thus, if those edges beyond the point where the universe is receding away from us faster than the speed of light, then that light will never reach us. Therefore this video is flawed in its reasoning. IF we presume the rate of the expansion of the universe is speeding up, then the light of everything beyond the cosmic horizon (which is within the Hubble horizon since those distant point will be caught up by a recession speed that is faster than light) will never reach us and will no longer be part of our observable universe. Even Wikipedia agrees with me. (See en.wikipedia.org/wiki/Hubble_volume ).

[@Only_God_Is_Allah_SWT]

We are not apes.

[@stza16]

I would like to attend one of these anteater parties.

[@AquarianSoulTimeTraveler]

watch my videos about accelerating expansion of the universe and how it is dark matter creating an illusion of accelerating expansion by absorbing energy that pass through the dark matter and increasing its matter exponentially causing the illusion of accelerating expansion!

[@eeka_droid]

This was the most amazing video i've ever seen about observable universe, dark energy and expansion, light doppler effect and those other "basic things" to understand the universe but nobody seem to be able to come up with simple and ilustrative examples like this one. Thank you so much for this information!

[@kaitlynhollinger7526]

Thank you, this was the most understandable explanation of this concept that I’ve seen.

[@AquarianSoulTimeTraveler]

watch my videos about accelerating expansion of the universe and how it is dark matter creating an illusion of accelerating expansion by absorbing energy that pass through the dark matter and increasing its matter exponentially causing the illusion of accelerating expansion!

[@methodinsane]

Amazing dissemination of knowledge in a nice tidy understandable "bite size" chunk. The bun analogy was great. Thanks for this. I was talking to my kids at dinner about this the other day and I sent this video to them and they loved it. Turns out they knew or your channel already although I only recently found it. Great channel. Again thanks.

[@diorynovis]

While our body's ability to travel is shrinking due to covid lockdown, this video makes our imagination expand.

[@onlypranav]

@Want some corona ? I know you are trying to be funny with that username. But it's not really And yes, I am throwing some shade your way

[@AquarianSoulTimeTraveler]

watch my videos about accelerating expansion of the universe and how it is dark matter creating an illusion of accelerating expansion by absorbing energy that pass through the dark matter and increasing its matter exponentially causing the illusion of accelerating expansion!

[@brendawilliams8062]

Kirchhoff ‘s law can give you a challenge. Lol

[@joesong4700]

My waist is expanding faster than 97% of other humans.

[@skb4all]

Ganja is the solution.

[@VeriVeronika]

Its so painfully tragic how the more of the universe we can see, the less we can ever hope to even signal. Very humbling.

[@smokey04200420]

What’s painful is the inaccuracy of this video.

[@Monduras]

@@smokey04200420 how so?

[@zealandia5668]

According to an estimate done by the scientists, there are approximately 71 planets hosting intelligent life in the Milky Way Galaxy, including us. If each intelligent life has a life span of 10,000 years, on average, we could be able to communicate with one alien intelligent life one time during our life span (if we are lucky to find one soon). So basically, the interstella communication would be something like this: Earthings: Hello, we are humans. We come from Earth. Alien intelligent life: What's up, bro? End of conversation.

[@ringoisacandyapple]

Like a big joke 😭

[@korakys]

And now you have blown my mind too with that information about more and more of the universe becoming observable.

[@pandabutter1266]

I love these videos because I can never wrap my head around this kind of stuff

[@AquarianSoulTimeTraveler]

watch my videos about accelerating expansion of the universe and how it is dark matter creating an illusion of accelerating expansion by absorbing energy that pass through the dark matter and increasing its matter exponentially causing the illusion of accelerating expansion!

[@xanamata5386]

-what is faster than the speed of light ? -space of course -and where is this light travel ? -ehm , then the only thing left since light ca not catch up with space , is time

[@GamesBond.007]

And how exactly does light travel in a space that expands faster than the speed of light ? How can that light ever reach us if space moves the light away from us as it expands ? If a car travels with 100kmh on a road that is expanding with a speed >100km/h in the opossite direction, will that car ever get to the end of the road ?

[@charlessnyder1839]

It makes me sad that E. T. could never phone home, thanks to the expansion of the universe. 😢

[@daviddavidson2111]

Good point. There's no hope for us, we can't even get trains to run on time.

[@zealandia5668]

According to an estimate done by the scientists, there are approximately 71 planets hosting intelligent life in the Milky Way Galaxy, including us. If each intelligent life has a life span of 10,000 years, on average, we could be able to communicate with one alien intelligent life one time during our life span (if we are lucky to find one soon). So basically, the interstella communication would be something like this: Earthings: Hello, we are humans. We come from Earth. Alien intelligent life: What's up, bro? End of conversation.

[@muhllandschaft]

So the rate of expansion is 70*10^3 (m/s)/Mpc That gives the distance of the galaxies moving at exactly the speed of light away from us as c/(70*10^3 (m/s)/Mpc)=1.4*10^10 ly (1Mpc = 3.26*10^6 ly) The volume of the sphere of accessibility is V1=4/3*pi*(1.4*10^10 ly)^3=1.15*10^31 ly^3 The volume of the observable universe is V2=4/3*pi*(45*10^9 ly)^3=3.82*10^32 ly^3 (V1/V2)*100=3% which is the part of the observable universe that is accessible to us. If we assume that galaxies are distributed equally in the observable universe, then 97% of them are inaccessible.

[@f.jideament]

Which is why I'm here to say F you to all of you, because you all so special for me.

[@PrivateSi]

Gravity and dark energy could be two sides of the same coin. The more mass is concentrated, the more voids expand. Growing galactic black holes are the main cause of void expansion in the model. Great Attractors that pull many galaxies to a point amplify the effect.

[@adamghosh4010]

Things to use to work this out (I think): -Time since big bang -Red-shifting of light -Shrinking sphere of inaccessibility -The fact that distance of galaxies from us can be measured through red-shifts -Expansion rate of space (70 km/s) idk what to do with these facts but I'm pretty sure that these are needed (apart from maybe sphere of inaccessibility)

[@AquarianSoulTimeTraveler]

watch my videos about accelerating expansion of the universe and how it is dark matter creating an illusion of accelerating expansion by absorbing energy that pass through the dark matter and increasing its matter exponentially causing the illusion of accelerating expansion!

[@DMSJagXK]

Some people think that light can travel faster than c (300,000,000m/s). If light travelled faster than c, then it would violate one of Einstein's postulates within his Theory of Special Relativity. In free space, wherever you are, the velocity of light is c. 2 stationary objects can have a velocity of 0m/s and yet move further apart if the space between those 2 objects is expanding. The expansion of space has no effect on their velocity since velocity is displacement from its original point divided by time. Since it has not moved from its original point, even though its position has changed relative to things around it, its velocity is zero since relative to its own position it has not moved. Now if we had an observer looking at those 2 stationary objects, they would have a relative velocity to the observer because they are moving relative to them, even though both objects still have a velocity of 0m/s. This is the exact same for light, the expansion of space has no effect on the velocity of light. The reason why some people think that it is possible for light to travel faster than c is to do with their confusion with the apparent velocity of light to an observer, rather than the actual velocity of light. If we consider objects that were actually moving within an expanding space, or just relatively moving to each other as a result of the expansion of space, then we would also have to take into account Special Relativity, since such objects will experience time dilation compared to time on Earth. The velocity of light would still be c. Time travels more slowly on moving objects, but in 1 second of wherever you are in the Universe, light will travel 300,000,000 metres. Did you know that there isn't enough energy in the Universe to get even a single electron to reach the velocity, c, of light?

[@jamesdodd2977]

@@DMSJagXK Have you seen the new pictures? Venus is blue!

[@sikharintonkladkhem745]

Your channel deserved more views.

[@MATropez]

In distant future though won't expansion of observable universe hit the end when light from distant galaxy will not be fast enough to overcome expansion of space between photon and earth ?

[@mehmetugur2924]

yeah i wonder too

[@kimjunguny]

Yes there is a point where our universe stops expanding. Only in 62 billion years. And eventually one day the only thing in our observable universe will be the milky way around us. Of course that's a time very far away.

[@TheZenytram]

Seach for Big Rip.

[@TheZacdes]

@@kimjunguny There is no way to predict this:/ Let alone in 62 billion years:/ The space between galaxies is expanding at a faster and faster rate the farther you go out. Just because just about everything has receded past the observation horizon does not mean it will stop expanding,lol. Just because it is no longer visible to "us" means nothing as far as the universe is concerned. Eventually things will be spread out over such a huge area that the Milky way will be all we can see. The universe will keep going till all the hydrogen is used up making stars, they die out, leaving cold cinders. It will just be VERY much larger by then:/

[@philipthompson117]

@@TheZacdes how do we know that it is still expanding if we can't see it. Might it be like an elastic band which stretches to a certain point and then snaps back. If it collapses back faster than the speed of light we will never see it coming!

[@steelersgoingfor7in2024]

How can they be moving away from us faster than light? If the way they appear changes at all, wouldn't that mean we are still receiving light from them? Otherwise, they would appear as a still image before ultimately disappearing.

[@sebastianclarke2441]

Thanks for a brilliant vid!! It really helped to improve my understanding of the differences between the "cosmic event horizon" and the "particle event horizon"

[@ArabPrinceKing]

It’s good that there are places in the universe we can never reach because if we reached it we’d pollute it and ruin it. Let it be pristine, let it be free. Whether we’d know it or not it’d still be mesmerising and beautiful.

[@buckanderson]

I think that what's been said in the end isn't too sad, because there just always seems to be something that makes things we previously thought were completely impossible just possible. If we start to understand things better, we might find a way around the limit of the speed of light (e.g. Alcubierre Warp Drive or something not yet invented/found out about). I think whats really interesting is the rate of what we know, what we can achieve in comparison to the rate the universe makes itself harder to access. Maybe our knowledge increases less than the universe gets harder to access so we will be stuck forever. Or we might be always very slightly ahead and figure something out to overcome the problems...

[@joyhouse4625]

Still will take trillions of years for different galaxies to be out of light speed ✨️ ? Humanity maybe lucky because we're still in a period of time where you can traveller across the universe see different galaxies. ✨️

[@NondescriptMammal]

It amazes me how optimistic people are about human interstellar travel. It. Will. Never. Happen. Emphasis on the word "never". For reasons that should be obvious to anybody who gives it some serious, realistic thought.

[@buckanderson]

@@NondescriptMammal What are these apparently obvious reasons?

[@NondescriptMammal]

@@buckanderson Well for starters, the nearest star from our sun is about 25 trillion miles away... at the fastest speed ever achieved by a manned spacecraft, that trip would take about 110,000 years. We haven't even put a man on the moon for 50 years... there is some optimism about sending humans to Mars, which remains to be seen... but even that is literally a million times closer than the nearest star. A spacecraft that could deliver an adult human to that nearest star within a typical lifetime would have to travel well in excess of 50 million miles per hour, and accelerate to that speed without killing the occupants. Those are only the fundamental problems that would have to be overcome, there would be any number of logistical details beyond that, many of which would be non-trivial in themselves...

[@NondescriptMammal]

... and even if that can be achieved, and all the problems worked out to do it safely and successfully... and that is a much bigger "if" than most space travel optimists are willing to admit.... the practical matter of the almost certainly enormous expense involved would also be a consideration not to be ignored.... How do you justify that expense, when only a select few guinea pigs... oops, i mean humans, sorry... would be able to make this perilous and risky and untested journey, meanwhile the political will would have to exist to force the rest of us to pay for it..... shall i continue? Would you like to explain the realistic side of the argument for being optimistic about it?

[@DrStench13]

what if speed of light and "time" is just slowing down? In other words, expansion is not taking place or at least not increasing in speed. And who says this doesn't have an oscilating quality. Say in that many billion years it will slow down again and shrink?

[@adrianbiber5340]

"So we'll be able to *see* more of the universe, but be *in touch* with less and less" Kind of like the story of technological progress... out of touch with Nature and each other, even though we have facetime and tele/micro-scopes.

[@AquarianSoulTimeTraveler]

watch my videos about accelerating expansion of the universe and how it is dark matter creating an illusion of accelerating expansion by absorbing energy that pass through the dark matter and increasing its matter exponentially causing the illusion of accelerating expansion!

[@BrightBlueJim]

Actually, the claim is that we'll see a greater VOLUME of space, but the farthest galaxies will wink out, one by one, as they cross the boundary of our observable universe. Which by the way, is bullshit. They would have to be moving faster than light, which would make their red-shift infinite, making them already invisible. You literally could not see something traveling away from you faster than light.

[@thesuncollective1475]

Nice you explained this fundamental conundrum pretty well it makes sense

[@jerwilliamsmith]

I was listening to this episode while cooking dinner, and I kept wondering why all of the aunts in the first example were named Ita 🤦🏼‍♂️

[@bornepayne242]

If the galaxies are moving away from us faster than light, does that mean matter CAN move faster than light? I mean, what is the difference between "object 1 and object 2 are moving away from each other" and "the space between object 1 and object 2 is increasing". I feel like those mean the same thing. It seems the assertion is that the objects aren't moving at all, and "new" space is being created between them, but how can that be proven? Is that just a convenient way to explain a phenomena that appears to violate our mathematical speed limit?

[@sax5055]

I was thinking the exact same thing. Sure would like to hear an explanation of how moving farther away at greater than the speed of light is not moving. Yeah, I saw the balloon…they’re still moving away 🤪 I’m old and retired and got into all of these concepts late in life. I love thinking of this stuff. I wish I had chosen this field to study when younger. But…we didn’t have awesome free YT explanations then. We had to use books LOL ;-)

[@richtourist]

I've never understood why when the space expands the measurement of space doesn't expand with it? I mean, if I had a long ruler (say one of those 100 parsec ones), and it was set with a convenient galaxy at each end, and then space expanded, why wouldn't my ruler expand along with everything else? If the space between big things is expanding, then why not the space between all things? Why not the space inside atoms; inside electrons? In other words, why not the space inside my ruler; which would mean that space would seem to be constant. I guess the speed of light would have to be changing, then?

[@muhammadharis9996]

YOU ARE THINKING WRONG IF YOU HAVE A RULER WITH A GALAXY AT EACH END THEN THE RULER 📏 WILL REMAIN AS LIKE THAT BUT THE GALAXIES ARE NOW BE FAR AWAY AND WILL BE NO EFFECT ON RULER BCZ GALAXIES ARE NOT LINKED JUST AS THE WHOLE RULER IS LINKED BY INTERMOLECULAR AND INTRAMOLECULAR FORCES BW THE ATOMS ,MOLECULES WHEN THE RULER WAS CONSTRUCTED ...IT CANT EXPAND GALAXIES will now not touching the edges of RULER but attained more distance as the space has expanded

[@muhammadharis9996]

Distance bw nucleus and electron doesn't increase although space expansion bcz there is electrostatic force of attraction bw them

[@universeandscience5791]

Your explanation is awesome. Love you from India.

[@TimondeNood]

Wow, I think you really did a great job at explaining this matter. I finally get a bit of a grip on it! Thank you so much

[@Iterr]

Omg finally someone explains and SHOWS it in a way that makes sense! Love you!

[@narenrai4884]

Question: If the universe is expanding in 3D, then how come we still locate the stars who seems to be in tact since the days of pyramids? Just curious..

[@ششششش-ز4ح]

based on my understanding, the reason is because these stars are in our galaxy. What travels away from each other are the galaxies. So, every galaxy has its own located stars. The shape of a galaxy is the total lights of its own stars.

[@ششششش-ز4ح]

I might be wrong, but this what I understood 😃

[@pennymac16]

tl;dr - Expansion of space is not fast enough for the stars in our galaxy to become unobservable by us. What @شش ششش wrote is half of the answer: The stars we observe are the ones in our galaxy. As was explained in the video, something must be sufficiently far away for it to "move" away from us "faster than the speed of light" due to all the space between it and us expanding. The closer something is to us the less space there is to expand, meaning it "moves" away slower than something farther away. And since the stars in our galaxy are so close to us (compared to galaxies far, far away), meaning there is relatively little space between them and us, the expansion of space has little effect on whether we can see them or not. The light emitted by them doesn't have to travel much farther due to the expanding space between us and them because the expansion of space is not really that fast. (The Milkyway Galaxy is about 100.000lys across. Then, from one end to the other, space expands at the rate of about 2,17km/s, much slower than the speed of light at about 300.000km/s.) In fact: If something is close enough to something else, their mutual gravitational attraction may cancel out the expansion of the space between them or even beating it, meaning they will move closer to each other over time due to gravity bringing them closer rather than further away from each other due to the expansion of space.

[@davidamoritz]

Also a few thousand years is not even a blink in cosmic historical scales.

[@nadeemahmad-xn4ov]

..expansion is in relative motion to the galactic movement of our solar system...which is cancelling it's effect ..so constillations are still there where they were 2400 yr back. My theory is ..time is slower beyond our galaxy..

[@vasilisvita]

I do not know if you will ever read this but this video has told me stuff that I never knew . It is mind blowing that I thought I knew but this is all new information . I think many people are like me . they think that they understand but are in the dark . thank you

[@hughjasse4047]

I can't get my head around, "Space isn't expanding into anything (like the oven). it IS everything". I mean, there has to SOMETHING outside for it to expand into, right?

[@o1-preview]

No one knows. This could also be all a simulation or something we can't even imagine.

[@grantandrew9308]

there was nothing once, why can it not expand forever further into nothing ?

[@pneumaniac14]

I will never understand this notion that there has to be more than what we know. There doesnt have to be something before the big bang, or anything outside the universe.

[@autohmae]

@@pneumaniac14 if it's all past our observable universe than we just don't know. Just lots of and lots of unknown.

[@johntate6537]

Well no, there doesn't have to be anything to expand into. This is to do with a concept called intrinsic curvature. If you draw a triangle on a piece of paper, the three angles at the corners will always add up to 180 degrees. This is consisten with a set of axioms written down by Euclid about 2,000 years ago. However, one of those axioms - the parallel line axiom - was always considered suspect. For most of that 2,000 years, mathematicians debated whether the fifth axiom couldn't in fact simply be derived from the others. In the 19th century, it was finally realised that geometries could be constructed that defied Euclid's Fifth Axiom - non-Euclidean geometries. The simplest of these to imagine is the surface of a sphere, like (approximately) Earth. The breaking of the Fifth Axiom leads to triangles that, in the case of the sphere, have internal angles that always add up to more than 180 degrees. For example, the angles between two points 90 degrees apart on the equator and one of the poles will all be 90 degrees giving a total of 270 degrees. The point here is that you can redefine the concept of curvature now by simply looking at how angles behave and not looking at the 3-dimentional shape the surface forms part of. This is intrinsic curvature. What intrinsic curvature is saying is that when you measure your way around a space the results diverge in some way - are greater than or less than - the results you would expect if the space were Euclidean. Intrinsic curvature is therefore about how you measure things within a certain space, not about the description of the embedding of that space into another, higher-diminsional space. If you add to this the concept of spacetime, you get the possibility that, again, the measurements of the differences in space and time of various events will not necessarily behave as you would expect if you made the normal Newtonian assumptions of Euclidean space and a universal measure of time. This is precisely what happens when we shift from Newtonian physics to Relativity. The ways that we describe distances and times changes because the Newtonian model does not accurately describe what we actually observe in the universe around us. It might be best to think of intrisic 'curvature' as a metaphor. What it says is that the relationships between distances and times in our universe behave AS IF they were part of a higher-dimensional object. However, nothing that might be happening off this surface has ever been shown to have any influence on what happens around us. The extra dimensions only exist in our imagination. The curvature is just a description. When distances and times behave in a way that is non-Newtonian we describe them as being 'curved' but all we are really doing is using a metaphor to create a mathematical language that allows us to describe what is going on. All that's really happening with an expanding universe is that the distance between two points is not fixed but increases with time. That's it. Space is just getting bigger. If you left two objects deep out in space outside of the effective influence of the gravitational attraction of any massive objects and you just left them there, they would slowly drift apart due to the expansion of the universe. No force would be involved. They would just get further apart because that's what our space is doing. Yeah, that's long. Not sure it makes anything clearer, but I hope it does.

[@thomas.02]

spoiler for solution! % of universe not travelling FTL = (c*D/H)^3 x 100%, where c = speed of light, D = radius of observable universe and H = hubble constant (calculate everything in compatible units) assuming the Hubble constant is true for all distances of course. by nature of the cube in the equation, our sphere of accessibility is sensitive to 2 things, one physics and one sci-fi: if the Hubble constant turn out to be lower, our sphere of accessibility increases; if we turn out of make FTL travel workable, we can greatly increase our sphere of accessibility too - 2x speed of light, 8x the percentage.

[@richardjanowski7219]

So if it's outside of the observable Universe we'll never be able to see it as it is NOW, but might eventually see it as it was?

[@grantandrew9308]

outside the observable universe means .....So, no., they do not come back once gone, they're gone forever

[@timplote6533]

My solution to your question: I computed first the distance after which an object would fly away from us faster than the speed of light. The velocity of inflation H0 is 70 km/s per Mpc v = s*v/s c = n*H0 (n is number of Mpc and therefore the distance) => n= 4285 Mps S(n)= 4285 * 3,26*10^6 lightyears After 1,3*10^10 lightyears, there is no possibility for us to reach an object because after this distance the object will travel faster away than the speed of light. This is 28% of our Universe. (1,3*10^10 lightyears / 45*10^9 lightyears (magnitude of the universe)) I was thinking of a straight line in one direction to the end of the observable universe. As the universe appears to be spherical it is a valid abstraction. And therefore roughly 72% of the universe is never to be reached. (1-28%) The difference to the real answer is due to approximations e.g. I used 3*10^8 m/s for c. I beg you to excuse my bad English and my ugly math. For the first, I am not a Native Speaker; for the second, I wrote this in a hurry on my phone. The size of the universe and H0 was googled by me after watching the video because you got me quite curious and so I was tempted to solve it myself although I didn't want to do it at first.

[@danielolivenca388]

And what this sphere of inaccessibility does to Fermi's paradox?

[@TheZenytram]

Nothing

[@al1383]

This expansion of space, and the existence of matter, is what creates gravity. If space is expanding everywhere, what happens when there's matter in space? When matter takes up the area where the universe once existed. Black holes for instance. BHs are so dense they displace the same area as the universe, as their size. (Like a bowling ball in a pool of water. The ball is now taking up the space water once did). This area of space, that is being displaced by the BH, is now in multiples around the BH. Because we have multiples of the fabric of space, the expansion of the universe around the BH is also multiplied. THIS causes gravity. It's not that "matter attracts matter". The strength of gravity depends on the amount of matter and the density of that matter.

[@edeneden97]

Expansion rate = 70km/s per MegaParsec Speed of light = 300,000 km/s Distance to reach light speed = 300k/70 = 4285.7 MegaParsec In light years = 4285*3,260,000 = 13.97 billion LY radius of universe = 45 billion LY Ratio of spheres = 13.97^3/45^3 = 2.99% So 97% is faster than light!

[@rahmath3305]

That means we can never ever imagine how vast the universe is!!😮😮😮

[@haroos]

The more i see these videos, the more i think physicists don't realy know what they are talking about.

[@smokey04200420]

The one thing Einstein said about relativity (how to add relativistic speeds) he failed to do. Had he added the velocities correctly, he would find that NOTHING not even space itself TRAVELS FASTER THAN LIGHT!

[@Jaeger_MK3]

Oh my gosh this message was 4 years ago. Funny how much we found out now huh? Black holes More light dark matter that could still go on but get the ironic part is we're still not sure what lies up ahead when it comes to space

[@lewistimson4617]

I like your videos man. This is the first i’ve ever watched from your channel. I like how you put the puzzle in so I subscribed. Good job man.

[@Staroy]

Loved this video even though I'm familiar with the concepts. Have you read the three-body problem, if so how did you like the science and speculative sci-fi in it? Btw you should get on a zoom podcast with Lex Fridman!

[@-andrea-9006]

hey i dont know if you will see this, but i just wanted to say your channel is amazing and my interest in science has re opened because of your videos :) im only 15 but i really hope to expand my knowledge so thank you for inspiring me

[@CaptainBohnenbrot]

So here's the deal: things we can access is earth itself, the moon, and mars. These are 3 things. 3 is 3% of 100. And 100-3% is 97%, which is the amount of inaccessible galaxies. qed

[@ThijquintNL]

7:21 some times, i hear: future humans won't be able to see the expanding universe. They will only see there galaxy: milkdromeda. But if, over time, humans can see more and more of the universe. Won't they be able to figure out that the universe is expanding???

[@kaiwan66]

[Quran 51.47] And the heaven, We built it with craftsmanship and We are still expanding.

[@cia9288]

1) we will not see more galaxies as the time passes because intensity of light emitted from those galaxies will be greatly reduced by interstellar gasses and dust. Thus we will see less and less galaxies as the time goes on. 2) you did not take 'relative velocity of the objects' relativistic formula into consideration. All the electromagnetic radiation that will be emitted in some point of time from source A will reach its destination B, no matter how far or how fast A and B are moving from one another.

[@philoso377]

Edwin Hubble mental flaw. Principle and practice : (true) Higher the muzzle recede velocity (causes) the projectile to reach further out (effect) Principle and practice : (false) Farther reached projectile (causes) will recede at a higher velocity from a present location (effect) Edwin Hubble published that (1) Higher red shift, higher recession (causes) the galaxy to reach further out (effect). While making a 2D chart Edwin, mistakenly placed the (cause) on y-axis while the (effect) on x-axis. How could a man like him made such a mistake, yes he is that kind of man. Such mistake soon be taken as a basis for his next theory months later. Months later : after his paper published, Edwin review the same chart again, only this time he pick x-axis as the (cause) and y-axis as an (effect) for his new theory (2) below. (2) further reached galaxies (causes) a higher receding velocity at current location (effect) Edwin continues ... at a higher receding velocity, the galaxy will be relocated further, once there it gain a new higher recession velocity to a new further location continuously accumulating speed and distance ... until receding velocity exceed “c” therefore it suddenly the galaxy disappear from an earth base observer ...... If you can understand his thought process above you may agree that Edwin has a minor mental problem or willfully ignorance, fail to recognize that (cause) and (effect) is a one way process that can not go in reverse order. And yet 99.999% scholars today take it for granted - as if that is real. If we can’t think correctly or given up thinking, all we can do is either, to keep learning or keep composing, junk science.

[@niro56]

I see your logic but his explanation works, yes? I mean even if Andromeda disappeared today we wouldn't find out till millions of years, would still see it in the sky..

[@papdiana]

What if the universe is stationary and the only one moving is you , moving through the events? Every spice time you are in has its own perspective. You call them past and future like memories and projections. It’s like you can observe what makes for you logical comparing with your beliefs and technological possibilities from an infinite possibilities of the universe.

[@XoPlanetI]

As per Hindu mythology Universe is 311 Trillion years old

[@jelt110]

Given that _fully formed_ galaxies with 99.99% empty space exist 13 billion years ago, I'll wager the (our) 'Universe' is _way_ older than 13.8 billion years old. Maybe not 311,000 billion years, but way older than 13.8 billion. How would _you_ form a galaxy in so little time, and more importantly, how would you clear the space _between_ the galaxies?

[@buzz200066]

Envision an object (A) accelerating to 51% c, and a second object (B) accelerates to the same velocity in the opposite direction. Point A can now be said to be traveling 2% faster than light relative to point B, and vice-versa. Now, envision a singularity containing all matter in the universe. It need only explode with enough force to propel the resultant shrapnel outwards in all directions at a rate higher than 1/2c. This is what would account for SOME chunks of the universe to be moving faster than light relative to our chunk of universe... and it would also save you from having to explain how exactly the empty space between galaxies can expand, but the empty space, say, between your ears, has a harder time of it.

[@jorgepeterbarton]

The point of Special Relativity is that; no your first example wouldn't happen due to time dilation and length contraction. Only happens with space, not objects within space. But isee some point- how fast can you stretch an elastic band? Presume 1mph, but then imagine elastic bands end to end across the entire universe doing the same. Locally nothing is violating c, and only gradual distance eventially adds to faster than C. When it does, its not /information/being sent (which is the real limit) but information being made unreachable with the observable universes event horizon shrinking

[@encinobalboa]

If one beam of light is traveling in opposite direction of another, relative to each other, the speed is double.

[@raney150]

Despite the counterintuitiveness of it, from each beam of light's perspective, the other is still only going the speed of light, not twice the speed of light like you might assume.

[@encinobalboa]

@@raney150 If two light sources are traveling at light speed in opposite directions, they will not have any perspective of each other.

[@jorgepeterbarton]

Nope. You need to know Special Relativity. Its whole point is to preserve the speed of light. From a stationary reference frame there is no perception of 'double speed', its just two objects moving at c. From a moving reference frame (oh, assume 9.99999% or whatever) then that is where we classically sum relative velocities. E.g. a car driving away from another moving car- the stationary observer perceives actual velocities unsummed only. The cars perceive sum. So from the moving near-c frames time dilation and length contraction deal with it... that's all. Contrast to universe expanding we ARE in such a moving frame and yet it is space expanding so relativistic effects do not occur

[@encinobalboa]

@@jorgepeterbarton Perhaps my initial thought needs better framing. An observer traveling at the speed of light cannot see a light source traveling in the opposite direction at the speed of light because the light emitted can never reach the observer. So, anytime two objects traveling in opposite directions with each object not exceeding the speed of light but with relative speed exceeding the speed of light cannot be observed by each other. This scenario preserves the speed of light.

[@50secs]

I asked this question to one of the astrophycisit who does PBS videos. "We are certain that everypoint is a center of universe, but we don't know for a fact that where it all start expanding from and where it all is expanding into?" They responded Si Senor.

[@altayardicoglu5741]

I guess you may want to change the title into The Galaxies Moving Away Faster Than Light or sth.

[@TheJuthika]

This video is really simple but elegant with its content. I am looking forward to see more videos like this. I would love to see u explaining Planck constant for instance.

[@alexborr84]

QUESTION: The sphere of inaccessibility should be the same size of the observable universe to my intuition. Why it's not? My reasoning: if we receive light from something outside OUR sphere of inaccessibility, the sender must have sent this light outside of HIS own sphere of inaccessibility which violates the definition of said sphere; therefore sphere of inaccessibility an observable universe must have the same size. Where am I wrong?

[@smitakhamkar4487]

Love your content and the way of presentation

[@samuelmcsinz9279]

So basically, even if we move at the speed of light, we can never travel from one galaxy to another, we simply could never catch up

[@Acke1974]

One of the best videos thank you! I never seen it from this point of view. Thank you!

[@BW-xz6ol]

Thanks. Another video I’ll have to watch 50 times before I get it

[@Rady610]

Hi! I am no mathematician, but I think that the answer is 13 961 763 044 light years. So in order to have an expansion, faster that the speed of light you need roughly 14 billion light years of distance. I divided the speed of light by the expansion and multyplied it by a megaparsec. So everything that is 14 billion years from us is moving away from us faster than light. I did not take into account the 13.5 billion year life of the universe, as I think it is irrelevant, since it is about objects that are currently 14 billion years away from us. So all that is left is to count the objects that are 13 961 763 044 light years and more from us. In relation to the total volume of the observable universe the objects that are not moving away from us faster than light are (13.97^3/45^3) * 100. That would mean that 2.991...% of objects are not moving faster than the speed of light, relative to us, so 97.118%... are. Correct me If I am wrong. This is not my field of expertise.

[@thesunexpress]

Another reason why sci-fi movie inspired "warp drive" is such a non-starter: Wherever you "warp" to will *not* be in the same arrangement as once observed; so you quite literally haven't the slightest idea if your destination is a bit of empty space or the core of some massive star.

[@mircea5013]

I don't really see how we are not able to ever reach certain points of the universe. As long as the universe isn't expanding faster than the speed of light (between two points), we can reach any destination, theoretically. And if we can travel between two points, we can travel anywhere. I'm not entirely sure I've explained properly, but i do feel like the statement in the video doesn't make sense.

[@meghanshu7424]

Then how light is getting to us. Like if the universe is expanding faster than light then it should cancel the speed or light will not beat that speed. -- Please Help prof.

[@shawnharrison7596]

If the galaxies are moving faster than light due to the expansion of the universe and if the subatomic space is still shrinking then there must be a correlation or scale invariance that makes certain undiscovered massless quanta move faster than photons too.

[@johnleosatur2076]

I just had this dream last night, i was on one of my class, then my instructor asked me, "what if other galaxies didn't moved away? What if it was just matters moves slower and slower as it travels the vast space?" and as i woke up, it keeps on ringing on my mind. What if? What if it is true? Could it be?

[@hughb5092]

Thank you for making this understandable to us common folk.

[@MAZA_ZatiKhayal]

I won't be able to join any courses over the said website but I would keep watching videos you upload here on KZbin, thank you very much for this kind of free and lovely material. Keep uploading. Love 💞 from Pakistan.

[@TheScienceBiome]

Wonderful video!

[@domainofscience]

Thanks! :)

[@AquarianSoulTimeTraveler]

@@domainofscience watch my videos about accelerating expansion of the universe and how it is dark matter creating an illusion of accelerating expansion by absorbing energy that pass through the dark matter and increasing its matter exponentially causing the illusion of accelerating expansion!

[@artherladett442]

Totally floored by this. Thanks 👍

[@anexoticidiot2548]

I loved this video. keep up the good work

[@lopatitefoa8997]

For them to go faster than light, may well be that, before the lump of very high energy was transformed into ordinary matter - galaxy, (C power 4 to C power 2); it was a thrown out lump of energy that had a very low density therefore spinned faster than others, resulting in rolling faster through the negative dark energy that made up the fabric of space (dimensional medium or space-time continuum) In other words, depends on speed of universe expansion, density of both the dimensional medium and the energy ingredient and its high rotating speed. We must also account for the excessive negatives contained in the ingredient that could be more friendlier with the fabric of space negative dark energy.

[@grantandrew9308]

in other words, you like to dribble

[@corinnaauxtero6920]

The bitter-sweet symphony of space - beautiful, mind-bending and oh so melancholic!

[@ryanshaw7716]

Expanding into what tho?! What’s there before empty space and how does one tell the difference/defining line

[@acecatman]

I think the universe still expands even though it is everything because there is an infinite amount of infinities, since some infinities can be bigger than others.

[@iDoComputers]

thats what i asked when i was 8, idk, at 12 still have no answer

[@kenpinbasar6455]

Expansion of universe is just a beautiful theory....

[@GLPentAxel]

If I understand it correctly, isn't it a little misleading saying the sphere of inaccessibility is shrinking? The density of objects inside of it will decrease over time, with more matter "escaping" from our perspective, yet the distance we could possibly reach if travelling just below the speed of light remains the same. Have I misunderstood anything here?

[@GLPentAxel]

@Boris R. Cuduco Yeah, I get the implications of the expansion of space, I just feel like it's maybe a bit misleading saying the sphere of inaccessibility is "shrinking". There's less _stuff_ inside of it, but the sphere size itself remains the same I think.

[@Missle636]

@@GLPentAxel The size of this sphere actually increases because Hubble's constant decreases.

[@GLPentAxel]

@@Missle636 Right, I totally forgot about that! That's neat

[@johnbennett1465]

When it comes to the sizes, I think you are close but not quite right. Reachable Universe - The rate of expansion is constant so the actual size should stay the same. You are correct that stuff is leaving it. So the number of stars/galaxies that are reachable is shrinking. Observable Universe - This is current limited by the way cosmic background radiation. As such you are correct that it is expanding at the current time. There will come a time when that is not true. At this point a fixed expansion rate will also lead to a fixed size Observable Universe. At this point the stuff that has been coming into view will start going back out of view. I believe that the current expectation is that everything except the local cluster will eventually leave the Observable Universe. Of course if the rate of expansion changes with time, then the results will be different.

[@ringocash6143]

Hello need a help "TO CALCULATE REDSHIFT OF LIGHT DUE TO EXPANSION OF SPACE ONLY" For eg If A gamma ray having wavelength 100 picometers (pm) is moving in a space considering only redshift due to expansion of space, what will be redshift if it travels for 1000 years

[@thechosenone9628]

How about warp-drives or wormholes? They don't violate any laws, if we somehow achieved them, could we reach other galaxies?

[@callejondorado]

I wouldn’t say the inner sphere is shrinking but that the galaxies in it are getting out of that inner sphere. I mean the inner sphere remains the same, but galaxies are escaping from it, after all the size of the inner sphere is based on what the light can rich.

[@zealandia5668]

Just like the girl dancing on the table, you can look, but cannot touch. 😁

[@gaurdiantome8352]

The possibility also lies in how the galaxies got there. I reckon, as nothing can travel faster than light, through e=mc² nothing is converted into energy and matter by limits on energy principles.

[@GorbonM]

Always an interesting topic, does this mean that space obeys Galilean relativity, even though SR/GR is a better explanation for things within space?

[@daviddredge1178]

This is an excellent video!

[@mlfilion]

My thoughts are that we are in a whirlpool. The galaxies are going faster and faster because they are being sucked down the vortex and stretching. Take a bathtub and pull the plug. The water furthest away from the drain is going slower than the water being sucked down the drain. As we approach the vortex everything speeds up faster and faster until it is sucked down the drain. The big bang was a wormhole on the other side of the vortex in another dimension. Therefore in our universe everything came from nothing or everything came out of a wormhole, or everything came on the other side of the drain or vortex into another dimension. We are headed towards a super ultra massive black hole and being stretched and sucked into it. Everything is going faster and faster. When we hit the bottom everything will be over, until we go through another wormhole where everything will come out the other side. Again everything coming from nothing. Another wormhole where all energy and matter come through a singularity. Where everything comes from nothing in another universe or dimension.. My opinion haha

[@daliborbartos1396]

if something moves away from us faster than the speed of light THEN we cannot see it...we might be able to see those galaxies only in that time when they were slower than the speed of light.....

[@user-fx7pj3sk1r]

Very simple explanation and easy to understand ....this how you teach science to love science

[@sungibatman1996]

It makes me sad that there will be worlds that we won’t ever reach until we can use teleportation which we are not even sure is possible.

[@MrWinotu]

imagine teleporting 15k kilometers from the planet that is the size of Earth and instead of landing in the teleporting capsule finding yourself in the void of space... that could be scary, no one will know where You are etc...

[@resistyranny_0992]

How does the expansion of the universe affect how time is experienced on earth compared to a distant galaxy. They are moving away from us faster than the speed of light so their clock is moving into the past according to our time?

[@muhammadharis9996]

no one is moving with speed of light no galaxy is moving with speed of light It is the space ✨ that is expanding They galaxies are still there And special relativity says if any object planet galaxy etc moves > light speed then there will be a past for them

[@alexbublea]

Beautiful thank you for this!

[@uril.6814]

Since space travels faster than light. Then pause a object in space so it will move faster in than the speed of light, we don’t need a mega spaceship but a object that is not effected by its surroundings so it can stay in a point of space and at some point the sphere of inaccessibility will reach it. The point is that if this object is not affected by gravity, temp or other factors.. etc it can travel with out moving. I hope I am making my self clear. But this video made me think a lot about space and time.

[@uril.6814]

One more thing, the object is not moving; everything is moving around the machine. I am thinking of an anti-gravitational spherical shape

[@itzgranny8618]

For those who think, this doesn't make sense because of special relativity, like i thought in the beginning, here is a short explanation. Special relativity only applies to things moving in space. The galaxies which apparently move faster than the speed of light are actually not moving relatively to space itself. Space can actually expand faster than light and therefore the galaxies appear to move faster than light. Space expands due to dark energy, which we can't quite explain with todays understanding of the universe.

[@kagannasuhbeyoglu]

Thanks a lot DoS. Good subject.

[@fast_harmonic_psychedelic]

they are not moving away from anything. Misinterpretation of Red-Preference over vast distances. Light loses higher frequencies the longer it travels, more and more high frequency photons are stripped out by dust and gas in between the source and the telescope. By the time it reaches us, only the lower frequency redder light has survived the journey. It has nothing to do with the doppler effect.

[@Olivia-ik2rj]

I have been trying to understand how all of this works for like 4 h now. I think that Im starting to understand most of it now. However, there's one thing I do not understand. How can it be that everything moves away from us to the extent that it will eventually be out of sight for us? If the whole universe expand, dont that mean we that do too? When we talked about this in school (im just in the lasy year of the Swedish high school, so its not super complicated stuff) I could not stop thinking about the fact that we also must move?But if in several million years everything will have passed us by and is too far away to see, what will happen to everything that is "behind us"? It can not move faster than us because you move faster the more you have expanded? Feeling a little stupid I dont understands this.

[@DMSJagXK]

Some people think that light can travel faster than c (300,000,000m/s). If light travelled faster than c, then it would violate one of Einstein's postulates within his Theory of Special Relativity. In free space, wherever you are, the velocity of light is c. 2 stationary objects can have a velocity of 0m/s and yet move further apart if the space between those 2 objects is expanding. The expansion of space has no effect on their velocity since velocity is displacement from its original point divided by time. Since it has not moved from its original point, even though its position has changed relative to things around it, its velocity is zero since relative to its own position it has not moved. Now if we had an observer looking at those 2 stationary objects, they would have a relative velocity to the observer because they are moving relative to them, even though both objects still have a velocity of 0m/s. This is the exact same for light, the expansion of space has no effect on the velocity of light. The reason why some people think that it is possible for light to travel faster than c is to do with their confusion with the apparent velocity of light to an observer, rather than the actual velocity of light. If we consider objects that were actually moving within an expanding space, or just relatively moving to each other as a result of the expansion of space, then we would also have to take into account Special Relativity, since such objects will experience time dilation compared to time on Earth. The velocity of light would still be c. Time travels more slowly on moving objects, but in 1 second of wherever you are in the Universe, light will travel 300,000,000 metres. Did you know that there isn't enough energy in the Universe to get even a single electron to reach the velocity, c, of light?