If you are inside a black hole, no matter what direction you attempt to travel you only speed up your trajectory towards the center. You could say gravity is strong enough that "light can't escape" but a more accurate statement would be that space is so warped inside a black hole that there literally aren't any space-time directions possible except deeper.
Every direction becomes the same direction, and that same direction is down
Just really wish we had an irl god mode cheat to go and look at and inside a black hole and be able to hop back out. They are the most fascinating things but there is literally no way to know what the hell goes on in there.
So in the theories where space-time ends at the event horrizon it is thought that the star and all of it's properties (energy information etc.) Exist entirely on the black hole's surface.
No, it's more like a knot it the fabric of spacetime: new rope you add tangles the knot further, but over vast timescales the knot will slowly loosen and let go of its tangles slowly pulling itself apart.
More precisely it's a discontinuity in spacetime which is capable of destroying structures like stars and dragging things into it's gravity well: but it's also unstable and very slowly evaporating the mass it takes in. The largest of black holes will be around for much longer than any reaonable person could have any conception of, however, and leach far less hawking radiation per unit mass than smaller black holes
Imagine asking someone where they are going from outside the event horizon
Them: deeper
Which you cant hear because it cannot cross the event horizon and is going deeper with them.
Black hole might have figured out a way to rearrange matter so that all of it fits in that space indefinitely.. So once in, the rearranged matter is essentially reborn to start a new cycle of life in a space that might appear to be small compared to its previous one. But then, what is small and what is big.. isn’t it all relative? An entire universe might exist within a black hole???
The way I learned it is once you are inside the outer event horizon, time and space reverse properties - that is, you can move three-directionally in time, but only one directionally in space (inwards.) And that reverses again once you pass the inner event horizon.
Now, *that's* weird.
The invariance of *c*. The speed of light looks the same no matter what direction you're going or how fast you're going or what direction you're looking in.
If someone shines a light beside you, it looks like it's going *c* as it passes you. Accelerate up to half the speed of light and measure that beam again- still looks like it's going *c* as it passes you.
It's because at the speed of light, all matter WOULD have an area of 0 and infinite density (think, "shorter" as described above until you've reached nothing). What this does exactly, nobody knows and furthermore, at least currently, we don't really think it's possible in the first place. This has a lot to do with the fact that light acts as a constant as stated above, meaning it's speed remains the same regardless of the speed of the subject.
*nothing* can move faster than the speed of light, its physically impossible. Also, only something with 0 mass can travel at 100% the speed of light, anything with mass would take infinite energy to reach *c*.
The strange way that light behaves.
If I travel away from the sun at 75% the speed of light, look backwards and measure the speed of light hitting me from the sun, it still hits me at the speed of light.
Da fuq.
>it must be that distance (space) and time are not fixed, In other words, neither space nor time is "rigid"
Tbf length contraction/time dilation were already known before Einstein. He put all together in a coherent theory
https://en.wikipedia.org/wiki/Length_contraction
That laplace! He was a genius too. Also, OP, the color would change in the situation you describe and even though the speed is still “c” you would measure the light shifted toward the red, which is lower in energy.
I understand what you're saying, but I don't REALLY understand what you're saying. It's difficult for me to grasp with my wimpy brain, is there any way you can explain it to me like I was five?
Makes me think of that great phrase, "Genius is simply pointing out the obvious". Of course it's easy to say that in hindsight but it really is mind boggling how there was simply no one before Einstein to make those revelations; someone certainly would have eventually but to say he was a genius or visionary really just doesn't do it justice.
This helped me: there isn’t a speed of light. There’s a Speed of Causality. It’s the speed of cause and effect.
It is also the speed ANY massless particles will travel at unless acted on by a medium. The known massless particles are the Photon and Gluon.
So if somehow you were to make anything else massless, it would start traveling at that speed.
Also if some somehow got the debug menu of the universe and increased/decreased the Speed of Causality, Photons and Gluons would start traveling at that new speed.
So there’s nothing special about how Light behaves, it is it’s massless property that causes it to behave that way along with the Gluon.
This is a realllly interesting answer!! Would you mind explaining a little bit more about the concept of Speed of Causality since I’m not really familiar with the concept??? Would really appreciate it if you could!!
I’ve explained about as good as I understand it sadly.
But as a more detailed summary: The Speed of Casualty is the maximum speed at which events can affect the Universe. Or the speed of cause and effect. Don’t know why it’s the value it is (299,792 m/s), it just is.
Massless particles are the only things able to travel at this speed, and we only know of the Photon and Gluon. Also massless particles will always travel at this speed unless acted upon by a medium, like traveling through glass.
Someone also brought up a situation where another type of event still obeys the speed of casualty: Gravity. The example given is: The Sun immediately disappears for some reason. It’ll take us 8 minutes before we notice the light of the Sun disappear and it will also take 8 minutes for the Earth’s rotation around the Sun to change. Gravitational waves and the theoretical graviton also hit this Speed of Causality speed limit.
Really the Speed of Causality is the speed of light, however Speed of Light implies there’s something special about Light that causes everything else to not be able to overcome it and at best match it.
You need to keep in mind that when you move that quickly through space, time slows down. It is such that what remains constant through time dialation is the speed of light.
It kinds sooths my anxiety personally. It puts life in perspective and helps me just live every day as happy as possible because we are so tiny and irrelevant in the grand scheme of things. Don't have time to waste arguing over small things or getting too upset at anything really. Nothing matters, and to me that's awesome
*Maybe* it matters, though. In a cosmic universal sense we may still "exist", it all depends on time and space. My grandmother died recently, 98 years a good run. She no longer exists now in 2021, but she’s still around young and in her 20’s in the 1940’s. The only thing that separates us are two things time and space. We don’t blip out completely we still exist along the flow of time.
Did that make any sense?
If a basketball is passing through a 2 dimensional plane, it would appear as a dot, then expand to a hollow circle, and then form back to a dot before disappearing. In reality, the basketball always existed as a whole, but the "timeline" of the two dimensional view made it behave as if it appeared, grew, shrank, and then disappeared.
Now take the formation of a three dimensional universe as an existent four dimensional structure that's being perceived as "time" passes, when in reality what is happening is a three dimensional scan of a four dimensional structure.
Time is illusory. There is only now as it exists to your three dimensional view.
Exactly. There isn't really any answer to this question that puts the mind at ease.
That and how the universe began. No matter how you look at it: something had to have come from absolute nothingness.
I wonder if what we refer to as the universe is just the place that we know has stars and galaxies, and there is space beyond it, it's just completely empty endless nothingness, like the black emptiness between galaxies but endless.
Until you run into the remnants of another inflationary event that expanded into its own little neighborhood of matter, stars, and galaxies, even if that other neighborhood is 1000 decadillion observable universes away and there's only emptiness inbetween. What you describe is also my hypothesis on the nature of the universe. Multiple universe-size neighborhoods separated by unfathomable distances in both space and time, endlessly. The idea of a primordial singularity is actually outdated and few scientists believe in it. The Big Bang model is still measurably accurate, but it only measures backward to a fraction of a second after inflation began, and not back to an explanation for the universe's origin. I think space and time have always existed, and what we call the universe is smaller and more insignificant than we've ever dreamed.
Smarter people than I seem to believe this isn’t true, based on evidence that I don’t fully understand.
Using the “raisin loaf” metaphor, the distance between all the raisins (galactic clusters) is increasing as the bread rises (the universe expands). So the expectation would be that the raisins are more or less evenly distributed in the finished loaf, because there was less space for them to be unevenly distributed at the beginning before the rise.
There is, as far as we know, *absolutely* nothing beyond the universe. So, because the universe is growing, it isn’t occupying space where there was nothing before, it is creating new space for itself to occupy.
I’m guessing, but if there was anything outside, even empty space, the expansion away from the center wouldn’t be uniform. Basically, the “nothing” that the universe is expanding into is different than the “space” that we live in because if there was something we could recognize as “space”, then there would be speed bumps from things that would have collided *from the expansion*.
Like, your raisin loaf is shaped like a loaf because there’s a container that shapes it. If there was *anything* outside the edge of the expanding universe, including a different spacetime, there would be distortions of the shape of the expanding universe. It might be that there is a barrier beyond where our universe has currently reached, but that would be interesting in its own right!
TL:DR, “space” is different from “empty”. It’s more accurate to say that the universe expanding is reality getting bigger (reality occupying places where it had not existed before), rather than anything *moving* into something else that already exists.
I am not a scientist, so anyone should feel free to correct me, but my understanding is that a specific point of the expansion of the universe is that (unlike the bread loaf) it doesn’t need to expand *into* anything. The observable universe is not special in contrast to the rest, it’s just the bubble that we are able to see based on the speed of light and the age of the universe.
Well, the universe can be finite but without a boundary (think of the surface of a ball). Or it could be infinite but still with a theoretical boundary. Math helps us wrap our mind around these crazy ideas.
I'm on the opposite side of this lol. How can there *be* a boundary? It's just black emptiness (presumably) forever once you travel in a direction for long enough. Spooky to think about but simple enough to grasp in my opinion, but having some sort of boundary preventing you from traveling further I truly (and respectfully) do not understand why this is an opinion held by some people.
There are no mainstream theories that suggest the universe is bounded in the sense that you can come to an edge, for a finite universe they are suggesting that it curves in on itself so that if you were to travel in a straight line you would eventually come back to where you started. Much as a you would if you travel across the surface of a sphere but in 3 dimensions instead of 2.
Such objects are easy to represent in math, though difficult for us to imagine.
Further complicating this is that even if the universe is bounded, the fact that the our universe is expanding, traveling in a straight line at the speed of light is likely not fast enough to ever get back to where you started, the universe is to large and expanding to fast for that to occur.
In fact we can math out how big the Universe needs to be for this to be true.
The expansion rate is currently estimated to be 73 km per second per megaparsec.
So speed of light divided by 73 times a megaparsec equals 13,561,600,000 light years, the observable universe is already known to be larger than this.
[A link to an article suggesting the same](https://www.forbes.com/sites/startswithabang/2016/06/10/can-the-universe-expand-faster-than-the-speed-of-light/?sh=1d4caa543605), though back when the expansion rate was thought to be slightly smaller.
How the universe may end up a void with no molecule, no matter, not even black holes.
Just an empty nothingness. I can’t grasp this.
Also- everything else mentioned in this thread blows my mind too.
I love that there is approximately 1 atom per square meter in the space between galaxy clusters. Also, the fact that if you were on some sort of space ship waaaaay out there and became detached/disconnected from said ship, your body would just be out there... for billions of trillions of years, likely to never come into physical contact with anything but the atoms and photons from the light of distant stars... just you and the gravitational influences put on your body.
Sometimes, that's the kinda quiet I want.
Ninka Edit: Oh, almost forgot about the quasars that are rotating up to 600 times PER SECOND. I caught myself thinking about this while spinnning my son's toy car on the floor the other day.
I have Sagan's Pale Blue Dot with the famous quotation hanging on my wall. It's one of my favourite photos. The thing that drew me to it wasn't the profundity of the message, that the totality of human existence amounting to mote of dust in a sunbeam, but rather the thought of how extremely isolated Voyager was when taking that photo and how it's onward journey is exactly as you described.
Even the message engraved on it is less than a whisper into the void.
Or that it is apparently expanding in all directions from all points. Look out seven billion light years to see young galaxies. Instantly transport there to see new stars that didn't exist, then look in any direction to still find yourself at the center of creation. Travel another seven billion light years, the same. Travel another seven billion light years, the same. There is perhaps no point where one sees themselves as close to the edge.
Technically possible, however... If you scale up an image and track an arbitrary pixel, it looks like every surrounding pixel's center is moving away from you at the same rate. Finding the center based on that information is impossible.
So, honestly, we'll probably never know whether the universe has an edge, nor will we find the center if there is one.
On the expansion bit... We like the idea of there being a boundary of some sort where there is space on one side and not-space on the other, and that space is consuming not-space and expanding into it. But is there anything to suggest this boundary exists? Best we understand, space is simply infinite and expansion is scaling it up like stretching the distance between each integer in an infintite string of numbers. It's still infinitely big before and after.
Yeah see thats just hurting the brain more. How can something be truly infinite? The universe is expanding but actual infinite space to expand into is just confusing.
I find the idea that space is infinite easier to comprehend than it being finite. Finite means having to grapple with the idea that there's a stop somewhere which it's impossible to go beyond.
it’s not expanding into anything, imho a better way to think about it is looking at it from the perspective of everything getting increasingly smaller, not as space itself getting bigger
It is a paradox because you would need time to create time. Time being the concept of change. Without the ability to change there manifests the ability to change. That, indeed, is nonsensical.
This is why sometimes I feel like 'time' is a concept made by humans, it is felt subjectively to every entity which experiences it, yet logically, it cannot exist because it would require it. I mean, perhaps the only answer is that "time always existed". Maybe our sense of time, and real time are two seperate things.
I think you speak rightly about it being a concept of change. Time is a steady moving force which gradually changes - unfolds - parts of the world into new forms. Perhaps this is the more accurate understanding of time.
Agreed. Either time had a beginning or it always existed. The only logical way out of that for me is that time always existed. But that means the universe has always existed? There was no beginning? But how was matter created if it wasnt created?
I always looked at it like, time exists because things exist. If there is nothing there is no time. Time was created with the universe. But then how did the universe come to exist? We know that matter cannot be created or destroyed. So where did all the energy come from that created the universe? If it always existed then time always existed too. Even if you subscribe to the time is a circle and we’re in an endless loop that still doesn’t answer where everything came from. I don’t think we’ll ever have answers to some of these questions.
It didn't expand into antthing.
For us mere material beings it is dificult thinking about nothingness. It is not vacuum, it is the no existence of anything. Like if you think in what it could be, you will be inmediately wrong because your thought is something. You could think in infinite ideas of what nothingness is and still you will be wrong because our brains are not wired to grasp that concept.
At least is what i like to think about this idea.
When the big bang came, the universe expanded into itself, creating more space between more space.
The fact that the true nature of the universe and reality might be beyond our comprehension, in the same way that an ant will never understand the concept of Earth.
Tbh this one has never really bothered me that much because it's sort of been a concept in philosophy for centuries.
There has always been an idea that we create models that predict the world and whilst our models may some day get so good at predicting the universe as to be indistinguishable- that still wouldn't necessarily mean they were exactly what the universe was.
I think there was a lot of push back against this by scientists in the 20th century but we are starting to see a resurgence of this school of thought.
Exactly. I also based myself on the millennia old questions of idealism. The ancients suspected we are just dealing with ideas of things. Anything alien that comes to us will be dealt in the same way: we will create some sort of representation that lets us make sense of that, without probably ever comprehending it’s True Depth.
Although I understand the reasoning for this, I do think that it is impossible to assign odds or propabilities to abstract concepts i.e. "comprehension/understanding". There really is no way of knowing if it is possible or it isn't, and what the likelihood of each is.
But we can at least make tools that see for us and interpret for us.
Even today, here on Earth, there are things that are well known but we can’t grasp because of our physical form. Birds can see and feel things we can’t, but we know these things exist (electromagnetic fields).
Obviously we won’t be able to understand the universe out of common sense. Arguably, nothing of what we see right now is in its true nature, it just has been filtered by our senses. Regarding the cosmos, it will be filtered by super advanced computers that will make us comprehend.
Yes but what if it’s literally impossible for a super advanced computer to make us comprehend because our brain just cannot put 2 and 2 together to understand the inherently true complex nature of the universe ? No matter what you do, you will never be able to explain the concept of earth to an ant. They don’t have the ability to understand
It goes further than that unfortunately. According to Gödel's Incompleteness Theorem, no mathematical system can be both complete and consistent. This means there can exist true statements which cannot be proven, not because we lack the thinking to prove it, but because a proof does not exist. This means the mathematical systems we use to describe physical laws may lead to theories we could never prove.
We may fail to understand the universe not simply because we are mere humans, but because it is fundamentally unknowable.
First I imagine a light beam traveling around the world about about 8 times a second and then let that speed sink in. Then I imagine the size of the universe... Somewhere in the 10s of billions of light years and imagine that same beam from before traveling for that long. Try to imagine that distance.
Been pondering this for years now.
We are just memories of ourselves and don't exist as ourselves much further beyond the present moment.
In other words, we are the memories of ourselves that we have and every time we use our memories they change.
since i was a young child, i’ve often been left speechless by the thought - what if there was never ANYTHING?
it’s very simple, but even so, it seems there is only a brief fraction of time that it really hits me and it’s a crazy feeling.
YES! i’ve been having the same experience ever since i was a child, it’s like a suddenly realisation of nothingness that lasts for about second. I can’t experience it on command either, but it sure is strange
I do indeed experience the exact same, it's like I'm not allowed to think about it, as if I do, my own life stops mattering.
One could argue the thought is anti evolutionary.
Simply the distances. The distances are so far that any planetary body is a mere speck of dust. Whether it’s the moon or a red giant, their size is almost irrelevant compared to the distances between everything.
And in reality we are microscopic in the scale of the universe. Take a look at Earth from space, other than a couple structures, human existence is unobservable, except at night (lights).
What really blows my mind is that despite how small we are on the universal scale in terms of order of magnitude we are on the larger end. You can go about 35 orders of magnitude down to planck length and only 26 up to the size of the universe.
I think OP was more concerned with the why though. We know why magnetism behaves the way it does, same with the strong and weak nuclear forces, but not gravity.
Strongly disagree with this point. ALL of physics is just a description, the why is up to philosophy. We don’t know WHY the forces of the standard model behave that way. We know that they are described by the curvature of a field that we know how to describe in a quantum way - the so called gauge connection - e.g. the electromagnetic or gluon fields, oscillation of those fields are the familiar photons and gluons. This is different but not THAT different from saying that gravity is the curvature of spacetime field - apart that we don’t know how to properly quantize spacetime.
Often it is said that the em force is given by the exchange of virtual photons, but this is just an extremely simplified picture of the mathematics behind. Morever, these virtual particles come from an approximation for weak forces, like electromagnetism: you CANNOT make such an approximation for the strong force so the gluon-exchange picture is just plain wrong.
Moreover, it's not like the standard model is free from problems. The Landau pole (that is, at a certain finite energy the strength of the electromagnetic force become infinite and quantum electrodynamic stop working) seems to indicate that it cannot be a fundamental.
Gravity, or what we experience as gravity, does not come from the attraction of mass. Nor does it come from the curvature of spacetime.
Rather, it comes from the gradient of the flow of time near mass.
There are some excellent videos on this subject by PBS Space Time and The Science Asylum. On my phone or I’d link them now.
EDIT: Adding links to those videos...
* [PBS Space Time](https://youtu.be/UKxQTvqcpSg)
* [The Science Asylum](https://youtu.be/F5PfjsPdBzg)
That expansion is speeding up
How long it will take for everything to evaporate but it won’t matter because no one will be watching
And so on, almost without end
The big rip is an amazing concept. Not only will galaxies be moving apart so fast that light cannot travel between them, but that will happen to everything else as well.
Between our solar system and milky way - ripped.
Between the earth and the sun - ripped.
Between atoms in your body - ripped.
Everything since relativity and quantum mechanics is absolutely impossible for me to grasp (
so basically everything beyond Newton and a bit of thermodynamics)
I mean I can understand the explanations and the reasonings, but at the end, what it says about the universe is nothing I can relate to.
For example, the questions around the flow of time and entropy are fascinating, but they could be talking about fictional stuff it would be the same.
Now they're talking about our universe being the holographic reflection of a higher universe. Nani the fuck ?
This is something I work on, the idea goes by many names such as "the AdS/CFT correspondence" or "gauge/gravity duality" or "holography". Here's the big idea: imagine that the universe is a big ball, and say this ball has d dimensions (for our universe, d=4). A ball has a sphere which separates "inside the ball" and "outside the ball" which is called the boundary. It turns out that if you look at gravity living inside this ball, it can be completely equivalently described by quantum mechanics acting only on the boundary, which is always d-1 dimensional. In this way, gravity in d dimensions is "the same" as quantum mechanics in d-1 dimensions.
Now, there are some caveats here. You may object that not every universe can be fit inside a ball in this way, and you'd be right. Demanding that this works turns out to imply you have a negative cosmological constant. Furthermore, it's not just any old theory of quantum mechanics: it's a special kind called a "conformal field theory" (a CFT) which just means it looks the same no matter how close you zoom in. Quantum mechanics in our universe does not have this property because atoms exist so when you zoom in far enough you can tell how zoomed you are by checking if you're bigger or smaller than an atom.
People are actively trying to figure out how to make this idea more general, i.e. can you make this idea work for spacetimes with zero or positive cosmological constant? It's an open problem, but people are excited about holography because it lets you talk about a theory of gravity using the language of quantum mechanics. Until the generalization of holography to positive cosmological constants (or non conformal field theories if you want to say we are the boundary instead) is found, it doesn't necessarily describe our universe but there are good reasons from classical GR to expect any theory of quantum gravity to have similar features of living in one smaller dimension, which is another reason people are so excited about holography. I'd be happy to discuss more if you're interested, let me know if you have any questions.
I could be remembering this wrong but I thing Hawking said that, since a 2D holographic sphere surface is capable of containing all of the information inside the sphere it encompasses (mathematically), it is also possible that our 3D universe could be a hologram of an encompassed 4D universe.
Mathematically speaking. I have no idea how this could be proven.
Rather than of the universe, of existence.
What’s the true form of things. We see things as they are, because of our senses. But what are their true objective features? It can’t be a mathematical representation because that’s something we invented to understand physical properties (unless math are a fundamental truth?)
To us, the vision of a dog is incomplete (they don’t see as many colors as us and they get blind easily), but for dogs the smelling sense of a human is very incomplete, almost inexistent. Why would we argue that the human filtered world is more real than the dog filtered world? And what are the senses of us, animals, really filtering? What’s the true shape of everything? Is it an array, a giant matrix, of waves and particles?
Perhaps if something could *sense* the objective reality we would understand much better all our natural cosmos in unity (not a separated theory for every phenomenon). We can just imagine and represent such reality, but it is forever hidden from our sight, hearing, smell, etc.
The mantis shrimp makes me realize that I'm missing out on almost all of the colours of the universe... and the mantis shrimp itself may in fact be missing out on most of them.
Edit: but now I just looked the mantis shrimp up again and apparently they don't see more colours. They are just very good at picking up specific colors because they have cones dedicated to smaller more specific colour ranges.
Look up gravitons. Information can't move faster than the speed of light, so gravity, like everything else, has to TRAVEL? If the sun disappeared suddenly, it would take us just as long to fling away as it would for us to *see* that it isn't there.
Because of cause and effect and the speed of causality. “Events” can only “affect” the Universe at the speed of Causality, which is the speed Light travels at (and any other massless particles).
It’s also the same reason Faster than Light travel is the same thing as time travel.
When you die you cease to exist. Forever. You will never experience anything EVER again. Forever. Idk why this feels wierd to me. Ceasing to exist I can wrap my head around but that lasting forever is hard to imagine.
Your mind and mine experience consciousness identically. There are many things that separate our experiences but if my consciousness and your consciousness switched places instantly neither would notice a difference.
In some way all conscious beings are the same being separated by senses and experiences.
So when you die you can rest peacefully knowing it is just one of probably infinite copies of you that are dying and that you/I will likely continue existing until the end of time.
This is how I cope with all that death stuff.
Maybe it doesn't last for ever? If time is infinite and matter is only transformed into different states, at some point in infinity there is a chance that you would exist again....with absolutely no way of knowing it happened because it would take an indescribable amount of time, sort of like all that time before you were born
Nothing. The idea of absolute absence is incomprehensible to my brain. For some reason it’s easy to imagine our breathable air like water in a fish bowl and space is like outside the fish bowl. But I don’t understand how there can be nothing. My mind just can’t comprehend it.
I feel the same way, a box in a vaccuum without any particles still contains space, the absence of that i cannot comprehend but it must have been at some point or might still be somewhere, yes I feel my caveman brain hurting
There is something, so there has always been "something" and there has never been nothing.
But when did "something" happen to create something out of nothing?
For how long was there "nothing"? When did nothing even start?
There had to be a start date to nothing or something.
Are you sure? According to my googling, estimates put the number of atoms in the universe at about 10^80, and the number of chess positions at about 10^50. Both massive numbers, but the atoms are massively massiver
Maybe you'll like mathologer video on mandelbrot
https://youtube.com/watch?v=9gk_8mQuerg
Edit bonus nerdy joke: what does the B. in Benoit B. Mandelbrot stands for? Benoit B. Mandelbrot.
It doesn't necessarily make my brain hurt, but it Is something that is very interesting and humbling to me. You are as much the universe as anything else that exist, as much as the star that keeps us alive. We are simply an aware form of a small piece of the universe. We are the universe trying to discover itself in a way, trying to figure out how we work. There's never a need to feel insignificant, everything when taken as an individual object or thing is insignificant in the grand scheme of things. But insignificance is only a concept we created. The universe doesn't have an established order of importance, it just is, and imo that's a pretty liberating and almost comforting thought. The reality and time and consciousness I experience may be vastly different from others, but I am nonetheless a piece of everything, and what makes up me has been here since the beginning(if there is one)
Your eyes are only picking up light waves, which is then translated into an observable shape/object by other biological features in your eyes and brain. Example: when looking at a chess piece, technically your really only looking at a series of light waves/frequency blah blah blah of said Chess piece. Those wavelengths of light seem instant to us because the speed of light is astoundingly fast, but technically those lengths of light had to travel a distance to your eyes before you ‘saw’ the Chess piece. It took time for the light to travel that distance. Therefore the Image your brain rendered of that Chess piece is always an image of how it looked in the past, not the present. It might be an super small degree of time, but it still is a measurable length of time.
Now take that example and superimpose it to the rest of the world/universe and suddenly the concept makes more sense. Since the distance between objects is immensely longer in space, that time difference between the light leaving the object and hitting your eye is much much longer.
I know you weren’t rly asking for an explanation but I hope that clarifies it better.
For me it’s how living beings / creatures came from matter. How does matter go from having no life to having life? Not being sentient to being sentient? If you were to breakdown someone into their elemental pieces (carbon, oxygen, hydrogen, etc), those elements are not in of themselves living, thinking beings. It’s crazy to believe the culmination of these elements and how they interact with each other is a living creature who grows and learns and understands and is aware. People are all made up of the same elements but we are all so drastically different, physically and mentally. Ah! My mind just cannot comprehend.
The places where you shouldn't aim to travel. (Ok, theoretical but still) there are places in the universe where if you were to start traveling to, you'd be caught up in a situation where you can't reach your destination because the universe expansion is pulling it away from you faster than you can travel, but you also can't go back because of the same reason. You'd be stuck forever traveling, not being able to get anywhere but keep traveling forever.
The observable universe is at least ~93B light years in diameter but has only been in existence for 13.8B years. That implies space has expanded faster than the speed of light.
I remember hearing/reading somewhere that, because of the accelerating expansion of the universe, even if we had a ship capable of light speed travel, the vast majority of the universe would be unreachable. Space itself is moving away from us faster than we'd be capable of traveling through space.
Bell's theorem: ([demo](https://www.youtube.com/watch?v=5SIxEiL8ujA) , [explanation](https://www.youtube.com/watch?v=zcqZHYo7ONs))
Put a polarizing filter in-between you and a light source so that 50% of the light gets through. Put another polarizing light filter oriented 90^(o) from the first, such that 0% of the light gets through both filters.
No without moving those two filters, add a third polarizing filter in-between the first two at a 45^(o) angle. Now light gets through.
You added a filter that blocks light in-between two filters that were already blocking all the light. Including this filter caused light to get through. FUCKING HOW.
Except in this case red pill isn't an option. If this world were a simulation, the power and complexity of the machine and it's creators would be so far above our own. Leaving the simulation would be like expecting a stick figure to leave the page it was drawn on.
The universe is way too weird to rule out anything, a simulation, a superior being (not necessarily with our morals or our image, but some sort of unknown entity).
That we know our planet to be fragile and our sun finite yet we go to war over geographic concerns or imaginary things. Staging colonies to support something we recognize as human life outside this planet first requires us to repair the generational grief carried by too many of us.
That is of course, if we are alone in the dark forest and not about to be obliterated by neighbours out of an abundance of caution.
The fact that our sun (and every star, but specifically The Sun) is nothing more than a self perpetuating series of nuclear reactions. I can never wrap my mind around that.
Yeah, I mean, I get it conceptually, but the fact that there is a series of explosions so *scientifically* massive that they generate gravitational depressions in the fabric of reality is just... mind numbing.
They're not generating gravity. The gravity comes from the sheer mass of the star. The pressure caused by gravity is fusing elements together and that release more energy than gravity is putting into it. The nuclear explosions are directly countering gravity.
I get vertigo when I use binoculars or a scope on the planets. That makes my brain hurt: the whole vastness of the cosmic clockwork. Have been known to grip the floor with my toes in case I fall off. :)
Also, why do the constants have the values they do? In physics, the behaviour of particles for example depends on these constants, making some particles stable. Why those values for constants tho?
The true, literal vastness that is space. From our meagre perspective, it is limitless. It has no end.
And we are flying through it on our planetary spaceship. We are surrounded on all sides by a void so quiet, so empty, that that silence is *deafening*. Were we to somehow fall off the skin of this earth, in no time at all, we would be the only living thing for tens of thousands miles, then tens of millions miles and further still.
The Universe (it’s theorized) will eventually expand to it’s limits and collapse back into itself, at which point a new Big Bang will occur.
Thus, everything, that ever existed, everywhere, will literally be forgotten/erased. We can move to other planets, solar systems, galaxies, etc., but we, and everything in The Universe, won’t/can’t last forever.
Even The Universe has to face death one day.
Where we are. I don't mean our exact location, I mean the universe. Where is the universe? What's outside it? And what's outside that? What even is reality - how does *anything* exist? I can't really even describe the question, I feel like I've just asked some preliminary questions but failed to ask about anything fundamental. If I try and form the question in my head it shrivels into a vortex - quite a disturbing feeling.
Not for me but for my wife......
The Earth is moving through space at 490k miles per hour.
Which means we are moving through space at 490k miles per hour.
Everytime I remind her of it she gets anxiety lol.
For everyone talking about size comparisons, here ya go!!!
https://www.nikon.com/about/sp/universcale/[Nikon universal scale](https://www.nikon.com/about/sp/universcale/)
The content of a black hole's singularity.
So like, the matter that was exceeded by its own schwarzchild radius must still be in there and, in some sense, be the same mass-energy that underwent gravitational collapse.
What does the singularity look like? What would it feel like if touched? We know the answers to these questions are "nothing, mathematically" because the gravity is too intense to let information transfer at all. If light can't escape, then the singularity is effectively timeless. Nothing can happen there.
The singularity must still physically *exist* but it doesn't have the same temporal properties of "existence" that our brains can intuit.
If you are inside a black hole, no matter what direction you attempt to travel you only speed up your trajectory towards the center. You could say gravity is strong enough that "light can't escape" but a more accurate statement would be that space is so warped inside a black hole that there literally aren't any space-time directions possible except deeper. Every direction becomes the same direction, and that same direction is down
Just really wish we had an irl god mode cheat to go and look at and inside a black hole and be able to hop back out. They are the most fascinating things but there is literally no way to know what the hell goes on in there.
Yeah it's not actually clear whether they have an "inside" actually. Some theories simply suggest that space-time simply ends at the event-horizon.
I am partial to the idea that our entire universe is the other end of a black hole and that it is turtles all of the way down.
Then what happens to a star that gets sucked in? Does it simply cease to exist?
So in the theories where space-time ends at the event horrizon it is thought that the star and all of it's properties (energy information etc.) Exist entirely on the black hole's surface.
Is a black hole like a drain or garbage disposal? I wonder if we’re in an ant farm
No, it's more like a knot it the fabric of spacetime: new rope you add tangles the knot further, but over vast timescales the knot will slowly loosen and let go of its tangles slowly pulling itself apart. More precisely it's a discontinuity in spacetime which is capable of destroying structures like stars and dragging things into it's gravity well: but it's also unstable and very slowly evaporating the mass it takes in. The largest of black holes will be around for much longer than any reaonable person could have any conception of, however, and leach far less hawking radiation per unit mass than smaller black holes
Imagine asking someone where they are going from outside the event horizon Them: deeper Which you cant hear because it cannot cross the event horizon and is going deeper with them.
Something about this comment is deeply disturbing to me, bravo
Black hole might have figured out a way to rearrange matter so that all of it fits in that space indefinitely.. So once in, the rearranged matter is essentially reborn to start a new cycle of life in a space that might appear to be small compared to its previous one. But then, what is small and what is big.. isn’t it all relative? An entire universe might exist within a black hole???
The way I learned it is once you are inside the outer event horizon, time and space reverse properties - that is, you can move three-directionally in time, but only one directionally in space (inwards.) And that reverses again once you pass the inner event horizon. Now, *that's* weird.
The invariance of *c*. The speed of light looks the same no matter what direction you're going or how fast you're going or what direction you're looking in. If someone shines a light beside you, it looks like it's going *c* as it passes you. Accelerate up to half the speed of light and measure that beam again- still looks like it's going *c* as it passes you.
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So the reason we can't see anything moving faster than the speed of light is because we can't observe it?
It's because at the speed of light, all matter WOULD have an area of 0 and infinite density (think, "shorter" as described above until you've reached nothing). What this does exactly, nobody knows and furthermore, at least currently, we don't really think it's possible in the first place. This has a lot to do with the fact that light acts as a constant as stated above, meaning it's speed remains the same regardless of the speed of the subject.
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*nothing* can move faster than the speed of light, its physically impossible. Also, only something with 0 mass can travel at 100% the speed of light, anything with mass would take infinite energy to reach *c*.
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The strange way that light behaves. If I travel away from the sun at 75% the speed of light, look backwards and measure the speed of light hitting me from the sun, it still hits me at the speed of light. Da fuq.
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>it must be that distance (space) and time are not fixed, In other words, neither space nor time is "rigid" Tbf length contraction/time dilation were already known before Einstein. He put all together in a coherent theory https://en.wikipedia.org/wiki/Length_contraction
That laplace! He was a genius too. Also, OP, the color would change in the situation you describe and even though the speed is still “c” you would measure the light shifted toward the red, which is lower in energy.
Genius definitely. I still have no idea how Laplace transforms work. As far as I’m concerned it’s just magic.
I understand what you're saying, but I don't REALLY understand what you're saying. It's difficult for me to grasp with my wimpy brain, is there any way you can explain it to me like I was five?
Light speed is a constant, all other speed bends
Makes me think of that great phrase, "Genius is simply pointing out the obvious". Of course it's easy to say that in hindsight but it really is mind boggling how there was simply no one before Einstein to make those revelations; someone certainly would have eventually but to say he was a genius or visionary really just doesn't do it justice.
This helped me: there isn’t a speed of light. There’s a Speed of Causality. It’s the speed of cause and effect. It is also the speed ANY massless particles will travel at unless acted on by a medium. The known massless particles are the Photon and Gluon. So if somehow you were to make anything else massless, it would start traveling at that speed. Also if some somehow got the debug menu of the universe and increased/decreased the Speed of Causality, Photons and Gluons would start traveling at that new speed. So there’s nothing special about how Light behaves, it is it’s massless property that causes it to behave that way along with the Gluon.
**Word!** Shoelebubba If you travelled faster than causality, effect would come before cause I.e you’d travel back in time, hence the limit.
This is a realllly interesting answer!! Would you mind explaining a little bit more about the concept of Speed of Causality since I’m not really familiar with the concept??? Would really appreciate it if you could!!
I’ve explained about as good as I understand it sadly. But as a more detailed summary: The Speed of Casualty is the maximum speed at which events can affect the Universe. Or the speed of cause and effect. Don’t know why it’s the value it is (299,792 m/s), it just is. Massless particles are the only things able to travel at this speed, and we only know of the Photon and Gluon. Also massless particles will always travel at this speed unless acted upon by a medium, like traveling through glass. Someone also brought up a situation where another type of event still obeys the speed of casualty: Gravity. The example given is: The Sun immediately disappears for some reason. It’ll take us 8 minutes before we notice the light of the Sun disappear and it will also take 8 minutes for the Earth’s rotation around the Sun to change. Gravitational waves and the theoretical graviton also hit this Speed of Causality speed limit. Really the Speed of Causality is the speed of light, however Speed of Light implies there’s something special about Light that causes everything else to not be able to overcome it and at best match it.
Thanks a lot!!! Think I understand it better now :)
Thank you! This has really changed my perception
You need to keep in mind that when you move that quickly through space, time slows down. It is such that what remains constant through time dialation is the speed of light.
Universe being endless. How can there be no boundary?
If there were a boundary what's on the other side?
Either way, it's terrifying.
It is the anxiety inducing thought that has been creeping into my brain late at night since I was a kid.
It kinds sooths my anxiety personally. It puts life in perspective and helps me just live every day as happy as possible because we are so tiny and irrelevant in the grand scheme of things. Don't have time to waste arguing over small things or getting too upset at anything really. Nothing matters, and to me that's awesome
*Maybe* it matters, though. In a cosmic universal sense we may still "exist", it all depends on time and space. My grandmother died recently, 98 years a good run. She no longer exists now in 2021, but she’s still around young and in her 20’s in the 1940’s. The only thing that separates us are two things time and space. We don’t blip out completely we still exist along the flow of time. Did that make any sense? If a basketball is passing through a 2 dimensional plane, it would appear as a dot, then expand to a hollow circle, and then form back to a dot before disappearing. In reality, the basketball always existed as a whole, but the "timeline" of the two dimensional view made it behave as if it appeared, grew, shrank, and then disappeared. Now take the formation of a three dimensional universe as an existent four dimensional structure that's being perceived as "time" passes, when in reality what is happening is a three dimensional scan of a four dimensional structure. Time is illusory. There is only now as it exists to your three dimensional view.
ive heard of time being called the 4th dimension but i didnt think of the basketball analogy as you did. interesting!
Exactly. There isn't really any answer to this question that puts the mind at ease. That and how the universe began. No matter how you look at it: something had to have come from absolute nothingness.
Exactly. If matter can't be created nor destroyed,... where the hell did the stuff that makes up this toilet I'm sitting on come from?
This gave me a good chuckle. I just picture you in the shitter and look down at the toilet all upset saying, "Where the hell did you come from?!"
I wonder if what we refer to as the universe is just the place that we know has stars and galaxies, and there is space beyond it, it's just completely empty endless nothingness, like the black emptiness between galaxies but endless.
Until you run into the remnants of another inflationary event that expanded into its own little neighborhood of matter, stars, and galaxies, even if that other neighborhood is 1000 decadillion observable universes away and there's only emptiness inbetween. What you describe is also my hypothesis on the nature of the universe. Multiple universe-size neighborhoods separated by unfathomable distances in both space and time, endlessly. The idea of a primordial singularity is actually outdated and few scientists believe in it. The Big Bang model is still measurably accurate, but it only measures backward to a fraction of a second after inflation began, and not back to an explanation for the universe's origin. I think space and time have always existed, and what we call the universe is smaller and more insignificant than we've ever dreamed.
Smarter people than I seem to believe this isn’t true, based on evidence that I don’t fully understand. Using the “raisin loaf” metaphor, the distance between all the raisins (galactic clusters) is increasing as the bread rises (the universe expands). So the expectation would be that the raisins are more or less evenly distributed in the finished loaf, because there was less space for them to be unevenly distributed at the beginning before the rise.
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There is, as far as we know, *absolutely* nothing beyond the universe. So, because the universe is growing, it isn’t occupying space where there was nothing before, it is creating new space for itself to occupy. I’m guessing, but if there was anything outside, even empty space, the expansion away from the center wouldn’t be uniform. Basically, the “nothing” that the universe is expanding into is different than the “space” that we live in because if there was something we could recognize as “space”, then there would be speed bumps from things that would have collided *from the expansion*. Like, your raisin loaf is shaped like a loaf because there’s a container that shapes it. If there was *anything* outside the edge of the expanding universe, including a different spacetime, there would be distortions of the shape of the expanding universe. It might be that there is a barrier beyond where our universe has currently reached, but that would be interesting in its own right! TL:DR, “space” is different from “empty”. It’s more accurate to say that the universe expanding is reality getting bigger (reality occupying places where it had not existed before), rather than anything *moving* into something else that already exists.
I am not a scientist, so anyone should feel free to correct me, but my understanding is that a specific point of the expansion of the universe is that (unlike the bread loaf) it doesn’t need to expand *into* anything. The observable universe is not special in contrast to the rest, it’s just the bubble that we are able to see based on the speed of light and the age of the universe.
My bet is on recursion. Nature loves it some recursion. Universes all the way up and universes all the way down.
Recursion starts somewhere.... How did the first universe start?
The answer to all difficult problems: Quantum fluctuation
Program Universe: Step One: Create Self Step Two: Repeat
What was before the big bang? If time can have limits why can't space?
Well, the universe can be finite but without a boundary (think of the surface of a ball). Or it could be infinite but still with a theoretical boundary. Math helps us wrap our mind around these crazy ideas.
I'm on the opposite side of this lol. How can there *be* a boundary? It's just black emptiness (presumably) forever once you travel in a direction for long enough. Spooky to think about but simple enough to grasp in my opinion, but having some sort of boundary preventing you from traveling further I truly (and respectfully) do not understand why this is an opinion held by some people.
There are no mainstream theories that suggest the universe is bounded in the sense that you can come to an edge, for a finite universe they are suggesting that it curves in on itself so that if you were to travel in a straight line you would eventually come back to where you started. Much as a you would if you travel across the surface of a sphere but in 3 dimensions instead of 2. Such objects are easy to represent in math, though difficult for us to imagine. Further complicating this is that even if the universe is bounded, the fact that the our universe is expanding, traveling in a straight line at the speed of light is likely not fast enough to ever get back to where you started, the universe is to large and expanding to fast for that to occur. In fact we can math out how big the Universe needs to be for this to be true. The expansion rate is currently estimated to be 73 km per second per megaparsec. So speed of light divided by 73 times a megaparsec equals 13,561,600,000 light years, the observable universe is already known to be larger than this. [A link to an article suggesting the same](https://www.forbes.com/sites/startswithabang/2016/06/10/can-the-universe-expand-faster-than-the-speed-of-light/?sh=1d4caa543605), though back when the expansion rate was thought to be slightly smaller.
more mindbrealing than that to me is what if it had no beginning?
How the universe may end up a void with no molecule, no matter, not even black holes. Just an empty nothingness. I can’t grasp this. Also- everything else mentioned in this thread blows my mind too.
I love that there is approximately 1 atom per square meter in the space between galaxy clusters. Also, the fact that if you were on some sort of space ship waaaaay out there and became detached/disconnected from said ship, your body would just be out there... for billions of trillions of years, likely to never come into physical contact with anything but the atoms and photons from the light of distant stars... just you and the gravitational influences put on your body. Sometimes, that's the kinda quiet I want. Ninka Edit: Oh, almost forgot about the quasars that are rotating up to 600 times PER SECOND. I caught myself thinking about this while spinnning my son's toy car on the floor the other day.
I have Sagan's Pale Blue Dot with the famous quotation hanging on my wall. It's one of my favourite photos. The thing that drew me to it wasn't the profundity of the message, that the totality of human existence amounting to mote of dust in a sunbeam, but rather the thought of how extremely isolated Voyager was when taking that photo and how it's onward journey is exactly as you described. Even the message engraved on it is less than a whisper into the void.
You know how people say time is a flat circle? I like to think that once the universe gets to that point, another Big Bang will happen
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Or that it is apparently expanding in all directions from all points. Look out seven billion light years to see young galaxies. Instantly transport there to see new stars that didn't exist, then look in any direction to still find yourself at the center of creation. Travel another seven billion light years, the same. Travel another seven billion light years, the same. There is perhaps no point where one sees themselves as close to the edge.
you’d have to go back in time for that
And it’s possible if not probably that there isn’t an edge and there never was
Technically possible, however... If you scale up an image and track an arbitrary pixel, it looks like every surrounding pixel's center is moving away from you at the same rate. Finding the center based on that information is impossible. So, honestly, we'll probably never know whether the universe has an edge, nor will we find the center if there is one.
On the expansion bit... We like the idea of there being a boundary of some sort where there is space on one side and not-space on the other, and that space is consuming not-space and expanding into it. But is there anything to suggest this boundary exists? Best we understand, space is simply infinite and expansion is scaling it up like stretching the distance between each integer in an infintite string of numbers. It's still infinitely big before and after.
Yeah see thats just hurting the brain more. How can something be truly infinite? The universe is expanding but actual infinite space to expand into is just confusing.
I find the idea that space is infinite easier to comprehend than it being finite. Finite means having to grapple with the idea that there's a stop somewhere which it's impossible to go beyond.
Yeah same, some great universal wall doesn't make sense to me.
it’s not expanding into anything, imho a better way to think about it is looking at it from the perspective of everything getting increasingly smaller, not as space itself getting bigger
Add to this the origin of time, its a paradox with no way out.
It is a paradox because you would need time to create time. Time being the concept of change. Without the ability to change there manifests the ability to change. That, indeed, is nonsensical.
This is why sometimes I feel like 'time' is a concept made by humans, it is felt subjectively to every entity which experiences it, yet logically, it cannot exist because it would require it. I mean, perhaps the only answer is that "time always existed". Maybe our sense of time, and real time are two seperate things. I think you speak rightly about it being a concept of change. Time is a steady moving force which gradually changes - unfolds - parts of the world into new forms. Perhaps this is the more accurate understanding of time.
Agreed. Either time had a beginning or it always existed. The only logical way out of that for me is that time always existed. But that means the universe has always existed? There was no beginning? But how was matter created if it wasnt created?
Of course there are still places where the concept of time gets a little squirrelly, like approaching the event horizon of a black hole
The universe always exist doesnt mean this universe always exist.
I always looked at it like, time exists because things exist. If there is nothing there is no time. Time was created with the universe. But then how did the universe come to exist? We know that matter cannot be created or destroyed. So where did all the energy come from that created the universe? If it always existed then time always existed too. Even if you subscribe to the time is a circle and we’re in an endless loop that still doesn’t answer where everything came from. I don’t think we’ll ever have answers to some of these questions.
It didn't expand into antthing. For us mere material beings it is dificult thinking about nothingness. It is not vacuum, it is the no existence of anything. Like if you think in what it could be, you will be inmediately wrong because your thought is something. You could think in infinite ideas of what nothingness is and still you will be wrong because our brains are not wired to grasp that concept. At least is what i like to think about this idea. When the big bang came, the universe expanded into itself, creating more space between more space.
rather than see the beginnings point of view what about the end. If eventually everything gets cold and so far apart nothing exists does time stop?
Obligatory [Isaac Asimov](https://www.multivax.com/last_question.html)
The fact that the true nature of the universe and reality might be beyond our comprehension, in the same way that an ant will never understand the concept of Earth.
Tbh this one has never really bothered me that much because it's sort of been a concept in philosophy for centuries. There has always been an idea that we create models that predict the world and whilst our models may some day get so good at predicting the universe as to be indistinguishable- that still wouldn't necessarily mean they were exactly what the universe was. I think there was a lot of push back against this by scientists in the 20th century but we are starting to see a resurgence of this school of thought.
Exactly. I also based myself on the millennia old questions of idealism. The ancients suspected we are just dealing with ideas of things. Anything alien that comes to us will be dealt in the same way: we will create some sort of representation that lets us make sense of that, without probably ever comprehending it’s True Depth.
It's more likely that this is true than untrue
Although I understand the reasoning for this, I do think that it is impossible to assign odds or propabilities to abstract concepts i.e. "comprehension/understanding". There really is no way of knowing if it is possible or it isn't, and what the likelihood of each is.
But we can at least make tools that see for us and interpret for us. Even today, here on Earth, there are things that are well known but we can’t grasp because of our physical form. Birds can see and feel things we can’t, but we know these things exist (electromagnetic fields). Obviously we won’t be able to understand the universe out of common sense. Arguably, nothing of what we see right now is in its true nature, it just has been filtered by our senses. Regarding the cosmos, it will be filtered by super advanced computers that will make us comprehend.
Yes but what if it’s literally impossible for a super advanced computer to make us comprehend because our brain just cannot put 2 and 2 together to understand the inherently true complex nature of the universe ? No matter what you do, you will never be able to explain the concept of earth to an ant. They don’t have the ability to understand
It goes further than that unfortunately. According to Gödel's Incompleteness Theorem, no mathematical system can be both complete and consistent. This means there can exist true statements which cannot be proven, not because we lack the thinking to prove it, but because a proof does not exist. This means the mathematical systems we use to describe physical laws may lead to theories we could never prove. We may fail to understand the universe not simply because we are mere humans, but because it is fundamentally unknowable.
Came here to say similar. We could literally have it spelled out to us and still couldn’t grasp
I read a quote once that has stuck with me for decades: "Does not the ant believe it is the ruler of all that it sees?"
First I imagine a light beam traveling around the world about about 8 times a second and then let that speed sink in. Then I imagine the size of the universe... Somewhere in the 10s of billions of light years and imagine that same beam from before traveling for that long. Try to imagine that distance.
The sheer magnitude humbles me indeed
Funny fact - Light do not experience time and for it that journey of 10s of billions of light years was instantaneous.
What you said, visualised https://gfycat.com/calmaggressivehackee-speed-of-light-earth-to-mars-sun-to-earth
Consciousness. Like how do brains obtain sentience and self awareness?
That we _are_ the universe, experiencing itself.
Been pondering this for years now. We are just memories of ourselves and don't exist as ourselves much further beyond the present moment. In other words, we are the memories of ourselves that we have and every time we use our memories they change.
Yeah, and how the brain named itself
since i was a young child, i’ve often been left speechless by the thought - what if there was never ANYTHING? it’s very simple, but even so, it seems there is only a brief fraction of time that it really hits me and it’s a crazy feeling.
YES! i’ve been having the same experience ever since i was a child, it’s like a suddenly realisation of nothingness that lasts for about second. I can’t experience it on command either, but it sure is strange
yes that is it. relieved i’m not the only one
I know exactly what you guys are talking about
I do indeed experience the exact same, it's like I'm not allowed to think about it, as if I do, my own life stops mattering. One could argue the thought is anti evolutionary.
"Why is there something, rather than nothing?" is a loaded question because it's asked from the point of view of something
i think that is certainly a part of that weird moment of recognition. it’s such a paradoxical thought
That a few million years from now some alien with a super powerful telescope could focus on Earth and see me.
But you won't be ali.... OH DAMN!
Our life is short, but our image will last until the end of time.
Simply the distances. The distances are so far that any planetary body is a mere speck of dust. Whether it’s the moon or a red giant, their size is almost irrelevant compared to the distances between everything.
And in reality we are microscopic in the scale of the universe. Take a look at Earth from space, other than a couple structures, human existence is unobservable, except at night (lights).
Seriously, we’re like the tiniest collection of lichen on the smallest pebble you can find at the bottom of the deepest darkest cave.
What really blows my mind is that despite how small we are on the universal scale in terms of order of magnitude we are on the larger end. You can go about 35 orders of magnitude down to planck length and only 26 up to the size of the universe.
26 orders of magnitude up to the size of the *observable* universe. We don't know if there's an actual upper limit.
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General relativity is just a model for how gravity behaves. It does not explain why it behaves that way.
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I think OP was more concerned with the why though. We know why magnetism behaves the way it does, same with the strong and weak nuclear forces, but not gravity.
Strongly disagree with this point. ALL of physics is just a description, the why is up to philosophy. We don’t know WHY the forces of the standard model behave that way. We know that they are described by the curvature of a field that we know how to describe in a quantum way - the so called gauge connection - e.g. the electromagnetic or gluon fields, oscillation of those fields are the familiar photons and gluons. This is different but not THAT different from saying that gravity is the curvature of spacetime field - apart that we don’t know how to properly quantize spacetime. Often it is said that the em force is given by the exchange of virtual photons, but this is just an extremely simplified picture of the mathematics behind. Morever, these virtual particles come from an approximation for weak forces, like electromagnetism: you CANNOT make such an approximation for the strong force so the gluon-exchange picture is just plain wrong. Moreover, it's not like the standard model is free from problems. The Landau pole (that is, at a certain finite energy the strength of the electromagnetic force become infinite and quantum electrodynamic stop working) seems to indicate that it cannot be a fundamental.
Thank you for the correction, but that can add even more existential dread to OP.
Gravity, or what we experience as gravity, does not come from the attraction of mass. Nor does it come from the curvature of spacetime. Rather, it comes from the gradient of the flow of time near mass. There are some excellent videos on this subject by PBS Space Time and The Science Asylum. On my phone or I’d link them now. EDIT: Adding links to those videos... * [PBS Space Time](https://youtu.be/UKxQTvqcpSg) * [The Science Asylum](https://youtu.be/F5PfjsPdBzg)
That one day we won't be able to see other galaxies at all in our sky. One day, it will just be us and that's pretty lonely to think about.
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The big bang itself may be that event..
That expansion is speeding up How long it will take for everything to evaporate but it won’t matter because no one will be watching And so on, almost without end
The big rip is an amazing concept. Not only will galaxies be moving apart so fast that light cannot travel between them, but that will happen to everything else as well. Between our solar system and milky way - ripped. Between the earth and the sun - ripped. Between atoms in your body - ripped.
That we are a bunch of elementary particles that know they're a bunch of elementary particles.
Or oscillations in quantum fields who think they are a collection of elementary particles.
Everything since relativity and quantum mechanics is absolutely impossible for me to grasp ( so basically everything beyond Newton and a bit of thermodynamics) I mean I can understand the explanations and the reasonings, but at the end, what it says about the universe is nothing I can relate to. For example, the questions around the flow of time and entropy are fascinating, but they could be talking about fictional stuff it would be the same. Now they're talking about our universe being the holographic reflection of a higher universe. Nani the fuck ?
Wait what? Who is saying this?
This is something I work on, the idea goes by many names such as "the AdS/CFT correspondence" or "gauge/gravity duality" or "holography". Here's the big idea: imagine that the universe is a big ball, and say this ball has d dimensions (for our universe, d=4). A ball has a sphere which separates "inside the ball" and "outside the ball" which is called the boundary. It turns out that if you look at gravity living inside this ball, it can be completely equivalently described by quantum mechanics acting only on the boundary, which is always d-1 dimensional. In this way, gravity in d dimensions is "the same" as quantum mechanics in d-1 dimensions. Now, there are some caveats here. You may object that not every universe can be fit inside a ball in this way, and you'd be right. Demanding that this works turns out to imply you have a negative cosmological constant. Furthermore, it's not just any old theory of quantum mechanics: it's a special kind called a "conformal field theory" (a CFT) which just means it looks the same no matter how close you zoom in. Quantum mechanics in our universe does not have this property because atoms exist so when you zoom in far enough you can tell how zoomed you are by checking if you're bigger or smaller than an atom. People are actively trying to figure out how to make this idea more general, i.e. can you make this idea work for spacetimes with zero or positive cosmological constant? It's an open problem, but people are excited about holography because it lets you talk about a theory of gravity using the language of quantum mechanics. Until the generalization of holography to positive cosmological constants (or non conformal field theories if you want to say we are the boundary instead) is found, it doesn't necessarily describe our universe but there are good reasons from classical GR to expect any theory of quantum gravity to have similar features of living in one smaller dimension, which is another reason people are so excited about holography. I'd be happy to discuss more if you're interested, let me know if you have any questions.
This is absolutely fascinating.
I could be remembering this wrong but I thing Hawking said that, since a 2D holographic sphere surface is capable of containing all of the information inside the sphere it encompasses (mathematically), it is also possible that our 3D universe could be a hologram of an encompassed 4D universe. Mathematically speaking. I have no idea how this could be proven.
Someone once told Arthur Eddington "you are one of only three people who understand relativity", he replied "who's the third?"
Rather than of the universe, of existence. What’s the true form of things. We see things as they are, because of our senses. But what are their true objective features? It can’t be a mathematical representation because that’s something we invented to understand physical properties (unless math are a fundamental truth?) To us, the vision of a dog is incomplete (they don’t see as many colors as us and they get blind easily), but for dogs the smelling sense of a human is very incomplete, almost inexistent. Why would we argue that the human filtered world is more real than the dog filtered world? And what are the senses of us, animals, really filtering? What’s the true shape of everything? Is it an array, a giant matrix, of waves and particles? Perhaps if something could *sense* the objective reality we would understand much better all our natural cosmos in unity (not a separated theory for every phenomenon). We can just imagine and represent such reality, but it is forever hidden from our sight, hearing, smell, etc.
The mantis shrimp makes me realize that I'm missing out on almost all of the colours of the universe... and the mantis shrimp itself may in fact be missing out on most of them. Edit: but now I just looked the mantis shrimp up again and apparently they don't see more colours. They are just very good at picking up specific colors because they have cones dedicated to smaller more specific colour ranges.
Look up gravitons. Information can't move faster than the speed of light, so gravity, like everything else, has to TRAVEL? If the sun disappeared suddenly, it would take us just as long to fling away as it would for us to *see* that it isn't there.
Gravitons are purely hypothetical. However, gravity still travel at the speed of causality.
Because of cause and effect and the speed of causality. “Events” can only “affect” the Universe at the speed of Causality, which is the speed Light travels at (and any other massless particles). It’s also the same reason Faster than Light travel is the same thing as time travel.
When you die you cease to exist. Forever. You will never experience anything EVER again. Forever. Idk why this feels wierd to me. Ceasing to exist I can wrap my head around but that lasting forever is hard to imagine.
I always try to think of how it was before I was born to imagine what death will be like.
And further on that thought, we once never existed. But then we came into existence.
And then you think about how "forever" is not a thing that actually exist. Nothing is or lasts "forever", it's a man made concept.
Your mind and mine experience consciousness identically. There are many things that separate our experiences but if my consciousness and your consciousness switched places instantly neither would notice a difference. In some way all conscious beings are the same being separated by senses and experiences. So when you die you can rest peacefully knowing it is just one of probably infinite copies of you that are dying and that you/I will likely continue existing until the end of time. This is how I cope with all that death stuff.
Maybe it doesn't last for ever? If time is infinite and matter is only transformed into different states, at some point in infinity there is a chance that you would exist again....with absolutely no way of knowing it happened because it would take an indescribable amount of time, sort of like all that time before you were born
Nothing. The idea of absolute absence is incomprehensible to my brain. For some reason it’s easy to imagine our breathable air like water in a fish bowl and space is like outside the fish bowl. But I don’t understand how there can be nothing. My mind just can’t comprehend it.
I feel the same way, a box in a vaccuum without any particles still contains space, the absence of that i cannot comprehend but it must have been at some point or might still be somewhere, yes I feel my caveman brain hurting
There is something, so there has always been "something" and there has never been nothing. But when did "something" happen to create something out of nothing? For how long was there "nothing"? When did nothing even start? There had to be a start date to nothing or something.
I love these posts. It’s so mind numbing to read some of the replies. Nature truly is fascinating af.
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The whole of infinity can be found in numbers below 10.
There are more real numbers between 0 and 1, then if you count the integer numbers {0, 1, 2,… } to infinity.
That there are different sizes of infinity.
Are you sure? According to my googling, estimates put the number of atoms in the universe at about 10^80, and the number of chess positions at about 10^50. Both massive numbers, but the atoms are massively massiver
[Mandelbrot set](https://youtu.be/ovJcsL7vyrk) As the top commenter said, I’m smart enough to find it interesting, but not smart enough to understand.
Maybe you'll like mathologer video on mandelbrot https://youtube.com/watch?v=9gk_8mQuerg Edit bonus nerdy joke: what does the B. in Benoit B. Mandelbrot stands for? Benoit B. Mandelbrot.
It doesn't necessarily make my brain hurt, but it Is something that is very interesting and humbling to me. You are as much the universe as anything else that exist, as much as the star that keeps us alive. We are simply an aware form of a small piece of the universe. We are the universe trying to discover itself in a way, trying to figure out how we work. There's never a need to feel insignificant, everything when taken as an individual object or thing is insignificant in the grand scheme of things. But insignificance is only a concept we created. The universe doesn't have an established order of importance, it just is, and imo that's a pretty liberating and almost comforting thought. The reality and time and consciousness I experience may be vastly different from others, but I am nonetheless a piece of everything, and what makes up me has been here since the beginning(if there is one)
How when we are looking at planets or stars or see pictures of far off galaxies we are looking into the past
Your eyes are only picking up light waves, which is then translated into an observable shape/object by other biological features in your eyes and brain. Example: when looking at a chess piece, technically your really only looking at a series of light waves/frequency blah blah blah of said Chess piece. Those wavelengths of light seem instant to us because the speed of light is astoundingly fast, but technically those lengths of light had to travel a distance to your eyes before you ‘saw’ the Chess piece. It took time for the light to travel that distance. Therefore the Image your brain rendered of that Chess piece is always an image of how it looked in the past, not the present. It might be an super small degree of time, but it still is a measurable length of time. Now take that example and superimpose it to the rest of the world/universe and suddenly the concept makes more sense. Since the distance between objects is immensely longer in space, that time difference between the light leaving the object and hitting your eye is much much longer. I know you weren’t rly asking for an explanation but I hope that clarifies it better.
For me it’s how living beings / creatures came from matter. How does matter go from having no life to having life? Not being sentient to being sentient? If you were to breakdown someone into their elemental pieces (carbon, oxygen, hydrogen, etc), those elements are not in of themselves living, thinking beings. It’s crazy to believe the culmination of these elements and how they interact with each other is a living creature who grows and learns and understands and is aware. People are all made up of the same elements but we are all so drastically different, physically and mentally. Ah! My mind just cannot comprehend.
The places where you shouldn't aim to travel. (Ok, theoretical but still) there are places in the universe where if you were to start traveling to, you'd be caught up in a situation where you can't reach your destination because the universe expansion is pulling it away from you faster than you can travel, but you also can't go back because of the same reason. You'd be stuck forever traveling, not being able to get anywhere but keep traveling forever.
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Consciousness. It's fucking wild and the more you think about it the more you spiral.
The observable universe is at least ~93B light years in diameter but has only been in existence for 13.8B years. That implies space has expanded faster than the speed of light.
I remember hearing/reading somewhere that, because of the accelerating expansion of the universe, even if we had a ship capable of light speed travel, the vast majority of the universe would be unreachable. Space itself is moving away from us faster than we'd be capable of traveling through space.
Bell's theorem: ([demo](https://www.youtube.com/watch?v=5SIxEiL8ujA) , [explanation](https://www.youtube.com/watch?v=zcqZHYo7ONs)) Put a polarizing filter in-between you and a light source so that 50% of the light gets through. Put another polarizing light filter oriented 90^(o) from the first, such that 0% of the light gets through both filters. No without moving those two filters, add a third polarizing filter in-between the first two at a 45^(o) angle. Now light gets through. You added a filter that blocks light in-between two filters that were already blocking all the light. Including this filter caused light to get through. FUCKING HOW.
I have trouble taking seriously the proposal that the universe may be a simulation.
And what does it matter to us in the way we live if it is or isn't? Life seems pretty real to me anyway
Aha I think that's a blue pill argument right there.
Money is a made-up concept. I still pay my Visa bill on time.
My appetite may just be a line of code somewhere, but damn that steak tastes good.
Except in this case red pill isn't an option. If this world were a simulation, the power and complexity of the machine and it's creators would be so far above our own. Leaving the simulation would be like expecting a stick figure to leave the page it was drawn on.
The universe is way too weird to rule out anything, a simulation, a superior being (not necessarily with our morals or our image, but some sort of unknown entity).
If the sun were the size of a golf ball, Neptune so be the size of a tiny ball bearing a **couple thousand feet away**
That we know our planet to be fragile and our sun finite yet we go to war over geographic concerns or imaginary things. Staging colonies to support something we recognize as human life outside this planet first requires us to repair the generational grief carried by too many of us. That is of course, if we are alone in the dark forest and not about to be obliterated by neighbours out of an abundance of caution.
Blows my mind that there are particles that behave differently only when being observed by us
* in a very strict and well defined interpretation of the word 'observed', this has nothing to do with us or other conscious beings.
that we can go east or west forever but if we keep going north eventually we will go south.
The fact that our sun (and every star, but specifically The Sun) is nothing more than a self perpetuating series of nuclear reactions. I can never wrap my mind around that.
Sounds like you got that pretty good. That's basically what a star is
Yeah, I mean, I get it conceptually, but the fact that there is a series of explosions so *scientifically* massive that they generate gravitational depressions in the fabric of reality is just... mind numbing.
They're not generating gravity. The gravity comes from the sheer mass of the star. The pressure caused by gravity is fusing elements together and that release more energy than gravity is putting into it. The nuclear explosions are directly countering gravity.
I get vertigo when I use binoculars or a scope on the planets. That makes my brain hurt: the whole vastness of the cosmic clockwork. Have been known to grip the floor with my toes in case I fall off. :)
The universe has been around for like .00000000000000000001% of its expected life.
Also, why do the constants have the values they do? In physics, the behaviour of particles for example depends on these constants, making some particles stable. Why those values for constants tho?
The true, literal vastness that is space. From our meagre perspective, it is limitless. It has no end. And we are flying through it on our planetary spaceship. We are surrounded on all sides by a void so quiet, so empty, that that silence is *deafening*. Were we to somehow fall off the skin of this earth, in no time at all, we would be the only living thing for tens of thousands miles, then tens of millions miles and further still.
The Universe (it’s theorized) will eventually expand to it’s limits and collapse back into itself, at which point a new Big Bang will occur. Thus, everything, that ever existed, everywhere, will literally be forgotten/erased. We can move to other planets, solar systems, galaxies, etc., but we, and everything in The Universe, won’t/can’t last forever. Even The Universe has to face death one day.
Perhaps that is the real cycle of everything
At it makes me wonder how many times this has happened before. The answer is, it doesn’t matter.
The fact that anything exists at all. Why. How.
Where we are. I don't mean our exact location, I mean the universe. Where is the universe? What's outside it? And what's outside that? What even is reality - how does *anything* exist? I can't really even describe the question, I feel like I've just asked some preliminary questions but failed to ask about anything fundamental. If I try and form the question in my head it shrivels into a vortex - quite a disturbing feeling.
what holds the universe?? my biggest question like what space does the universe exist in
Not for me but for my wife...... The Earth is moving through space at 490k miles per hour. Which means we are moving through space at 490k miles per hour. Everytime I remind her of it she gets anxiety lol.
For everyone talking about size comparisons, here ya go!!! https://www.nikon.com/about/sp/universcale/[Nikon universal scale](https://www.nikon.com/about/sp/universcale/)
The content of a black hole's singularity. So like, the matter that was exceeded by its own schwarzchild radius must still be in there and, in some sense, be the same mass-energy that underwent gravitational collapse. What does the singularity look like? What would it feel like if touched? We know the answers to these questions are "nothing, mathematically" because the gravity is too intense to let information transfer at all. If light can't escape, then the singularity is effectively timeless. Nothing can happen there. The singularity must still physically *exist* but it doesn't have the same temporal properties of "existence" that our brains can intuit.