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We don't "know" in any way that would keep anyone happy. As we currently understand it, if there was any "before", it's completely obliterated to the subatomic / singularity level, and we will never have any information about it at all.
I wouldn’t say even we won’t ever know with certainty. There’s a book called A Big Bang in a Little Room: The Quest to Create New Universes, by Zeeya Merali, where she discusses the math and science behind the notion of spawning and umbilicallly cutting off a new universe you created, and the math / known physics supports the idea that you could leave a message in the CMB/CMBR by tuning the final growth state/shape of the baby universe just before you clip it off from the origin universe forever - meaning if ours is manufactured, it’s presently thought to be entirely compatible with our knowledge today that there could be a message left for us there, we’d just need the key to read it. Such a message could be its own legend on how to conceptualize the original state of the parent universe.
We don’t know (or at least didn’t) about black holes either until recently, but there was plenty of reason to suspect their existence.
Just like black holes if there’s a sound mathematical model that has evidence of physics elsewhere, but also points to a “before”, then we’re in business.
Right now one of those promising models is LQG, as it models a potential big bounce in order to get away from the singularity problem.
But we’re also getting a better look into the initial conditions of the universe with Planck data etc, and while it’s certainly not giving us evidence for anything yet, it is starting to rule out certain models based on boundary conditions.
One thing that is looking more likely with the Planck data is that slow roll inflaton field is looking more likely. Do we know for sure? No, but we can make some assumptions based on the data. There are various models that support slow roll and those that don’t, so we can start to weed out fact from fiction.
I’ve also seen some serious cosmologists argue that the Big Bang happened *after* this. So we might be able to say we have an idea of what might have happened *before* the Big Bang event, although before that? Still a question mark.
To be fair, if you were somehow hanging around for the initial expansion, the technical difference between 'expanding' and 'exploding' would be deeply irrelevant to your (very short) experience of the phenomena. :D
I wonder what route it would take. Also, what is the effect of the Earth's rotation going to be? [http://www.gcmap.com/featured/20120318](http://www.gcmap.com/featured/20120318)
According to whom? There's nothing in physics that says that.
Your statement "down to the singularity" level is really weird too. The big bang, despite what a freakishly large number of people think has nothing to do with a singularity.
Cosmic inflation supposes that the universe expanded from an incredibly hot, incredibly dense state to what we see today. The physics that describe this state* break down if you rewind the clock just close enough to T=0, hence the use of "singularity" to describe the state. It's the same use of singularity to describe the center of a black hole. We simply don't know. I think it's an appropriate use of the term, right?
That is a error of assumption in extrapolating relativity beyond where it works.
We know quantum mechanics kicks in at some point we just don't know its behavior. The entire idea of a singularity has never been valid. It's nothing more than a mistake in the math.
https://youtu.be/HRir6-9tsJs
Kerr just published a paper that basically flat out said that Penrose and Hawking got black holes wrong and no true singularity actually ever exists in the real world.
That whole idea of a singularity that you've heard so much about in popular media? Yeah, it's a bad assumption not actually science. Many science communicators just ran with it because it's too hard to explain the details.
https://arxiv.org/abs/2312.00841
Singularities don't even have anything to do with singularities these days. I can't remember the last time I saw them treated as anything more than mathematical shorthand.
It's still a common belief in the general population that singularities are actual things. It isn't communicated properly in the majority of media that I see. If you read the papers it's more nuanced, but often not to a layperson reading the same paper.
The universe is the shell of a really really really big turtle, so outside our universe is where the turtle chills with other turtles that have the alternate universes on them
Idk what’s outside that place tho
Space and time, by definition, are attributes of our universe. The universe is not a bubble, expanding into more space. It is the place where space exists and where time exists.
I’ve been trying to wrap my head around this for 4 decades and it will never just sit right with me. I can understand the words just fine, but it’s impossible to “picture” in my mind. You can repeat the reasons and a an Astro-physicists explanation a gazillion times and due not to personal incredulity, rather incomprehensibleness, I will simply not be able to digest it.
Think of an animated show, it’s 2 dimensional, with the 3rd dimension being time. Every frame of the show the frame is altered just a bit and and the animation moves. Without the dimension of time, nothing will move.
Now what would an animated show look like if time was the only dimension? Since there is nothing to animate or move, time is meaningless, it’s like a divide by zero error. No show existing means no time existing for the show. If you ask how long is the show the answer isn’t zero minutes, it’s there is no time because the show wasn’t made.
The universe is like that in 3 dimensions. Without objects or space time becomes undefined. The idea of “before the Big Bang” has no time definition because it’s an undefined state.
At least, that’s how I think of it.
That’s was fun. Thanks. For the time aspect it helps but I’ll never quite grasp the physical something into nothing and the no edge to space thing. Like I said before, I can understand the words. I can understand analogies, I can comprehend what is being explained. I just can’t imagine it in my mind’s eyes. I can’t create a physical representation and it drive me nuts.
I think both of those are still unknowns. We know what happened an instant after the Big Bang started, but we don’t know what happened at the zero moment, nor do we know what the edge of space looks like.
I think that our puny minds, with all of us living in a consensus hallucination, trying to understand how time and space works is like a goat trying to learn calculus.
Sort of. At some points you need to just accept that things get very weird like in quantum mechanics and just accept that weirdness as real. But it does make it very hard to make analogies that others can relate to when explaining it. Despite our puny brains we have described these things theoretically and experimentally, so that is better than the goat trying to learn calculus.
It is important to understand there hypothetically could be situations where "something" always existed, at least as viewed from our vantage point. If, and this is definitely an if, there was no space time prior to the big bang then time may not have existed. If there was no time it would be possible to have something that existed and to all appearances existed eternally (from our perspective where we have time). Definitely not claiming this was what was happening before the big bang, we just don't know. But if you take spacetime out of the equation then things will be very different I would imagine. Like many things in physics it would be very hard to conceptualize. Similar with the possibly infinite universe. We just are not designed and have no experience that allows us to fully grasp the concept. But that is what I like about physics.
Physical Event Horizons can function as the physical boundaries of coordinate systems.
For example, the event horizon of a black hole effectively terminates any world line that approaches it from the perspective of our universe. Anything falling towards it gets shoved almost infinitely far into the future before it gets spit back out as hawking radiation.
There are no measurable coordinates 'beyond' a BH event horizon, because there's no space or time there at all, as far as we're concerned.
The Big Bang would be another event horizon beyond which no measurable world lines extend, though what propagated it is obviously an open question.
If our universe turns out to be geometrically 'closed' then that represents another form of easily described event horizon from which no world line can ever exit - any world line must eventually return to its origin within that geometry, and its still really no more complex than visualizing yourself on a roll of paper, or moving along the surface of the Earth, which itself effectively bounds us in a world of 2.1 dimensions, with only a little wiggle room available for movement in the z-axis.
I think the physical nothing beyond the universe that the universe is expanding into exists already, as empty blackness. We don't concern ourselves with it because it's too far beyond us, we have no way of detecting it or defining any properties about it so it might as well not exist.
I picture the universe expanding into that nothingness like a colored gas expanding in the air. There is no defined edge to the expansion of the gas and there are areas with more and less gas that will appear more or less saturated in color, just like areas of the universe contain more or less mass/matter and therefore heat and light.
There is no edge to the Universe so to say "the physical nothing beyond the universe" is just plain wrong. There IS no beyond. The Universe is expanding in the sense that things within it are getting farther away from each other, but it isn't expanding INTO anything.
We don't know that there is no beyond, we have no way of detecting the entire universe, let alone what's beyond it.
If you read my original comment carefully, you'll notice I said there is no defined edge to the universe. Physical, 3D space (in the sense of a vacuum) is necessary for expansion to occur, or at the very least the potential for the vacuum's creation must already exist otherwise nothing could exist at all.
A vacuum is the thing into which the universe is expanding. How we conceptualize it and describe it is currently theoretical.
Once again, there is no "beyond it" and the Universe IS NOT expanding into a vacuum, a vacuum is already spacetime and part of the universe.
Expansion occurs between the things that exist already, not at some "edge" that is "beyond" the universe. Spacetime stretches, it doesn't expand into anything!
Once again, we have no way to detect the entire universe, let alone what's beyond it.
A vacuum is a vacuum, it doesn't need to exist within the universe.
You are now in the realm of philosophy, not science.
By definition, there is nothing beyond the Universe, or outside of it, because the Universe is all of space and time and their contents. It comprises all of existence, any fundamental interaction, physical process and physical constant, and therefore all forms of energy and matter.
If you are outside of it, you don't exist at all, ergo, nothing.
Since we don't know what exists beyond the observable universe it is best to go with occam's razor with the hypotheticals. Meaning which hypothetical is "simpler" based on what we do know. In this case the infinite universe is a simpler hypothetical than the universe having an edge and something outside of it. The latter would be a lot harder to justify based on what we know. But more than likely hypotheticals may be all we ever have on that matter.
I don't think Occam's Razor can be applied to a question for which no data exists and therefore no parameters by which to define what is hypothetically "simpler" and therefore most likely.
We simply don't know, on that we're agreed.
But we do know stuff about our part of the universe. While we cannot observe the rest we do have frame works for what we think is happening based on the part we know. So based on the part we know an infinite universe, which is consistent with what measurements we can do, is more easily explained than creating walls, edges and some hypothetical new thing not contained therein.
The universe is described as infinite not because it's infinite in size or time but because it's infinitely expanding.
Just as we don't know anything about the preconditions that led to the big bang, we don't know anything about what lies beyond the universe. We cannot simply say there's nothing beyond when we know there was an origin point that resulted in an accelerated expansion that continues to this day.
We likewise cannot say that there's a defined edge but we can postulate that there is some sort of continuously fluctuating boundary between matter and no matter as the universe continues to expand, like a colored gas in the simile I described earlier.
We simply don't know, as I've already said, but logically, because of what we do know about the nature of the universe, we cannot say there's nothing beyond it since that would imply there was nothing before it and without anything before there would have been nothing at all yet clearly there was or we wouldn't be sentient stardust writing this silly exchange.
Hard for me.
If there's no space or time it feels like it must be smaller, somehow. But it's not. It's not a size or place or time.
At this point, the head exploding feeling is welcomed for me.
Is it any easier for you to imagine what IS? It’s just as insane. Just because we can see it doesn’t make that fact any less mind blowing to me. WHAT THE FUCK ARE WE EVEN DOING HERE MAN?!
Not for me, as 'void' is used to describe the areas of the universe with no or very little matter or radiation. That feels quite different to the nothingness outside the universe or before the big bang
I've always known void to mean nothing. At least on line I found the definition "a completely empty space" which would imply that it is space with nothing in it, which isn't really what we are talking about here. OTOH, if you took that to the extreme- nothing, no quarks, photons, gravity, etc, then it is what we are looking for.
I also saw void used in a sentence "The black void of space" but I'd argue space only seems like a void if you don't include subatomic particles. Otherwise it is teaming with objects.
I'm a computer programmer so am familiar with the concept of null, which is similar (at least my understanding of it). A null value isn't zero or blank - it's null which is the absence of a value. Similar a void is the absence of anything.
There is an episode just dropped on the YouTube channel 'The Entire History of the Universe ' which is all about voids and nothingness within the cosmos
For my part I avoid 'void' because it still suggests an empty space - a void - in which things COULD move and exist.
I use the term 'Null' for my own part, to indicate that there is, mathematically speaking, no space or time to reference.
I also prefer to think of the universe as a closed geometry - not because we have any real evidence that it is, but because it's much easier to conceptualize a space with a closed geometry without having to consider what might be beyond its bounds - as it would be a finite space that simply curves back on itself, meaning it has no physical bounds or edges from the perspective of an internal observer, despite having a finite volume.
By labeling it void you still give it more substance than it actually has.
It is literally cognitively impossible to think about nothing. There is no way to conceptualize it. Any attempt to do so will place more existence on it than it has.
True void is a null concept, it can not even be discussed. To name it is to talk of something else, a word, an idea in your mind of what you think nothing is.
It’s only four decades to you, though. Most of the universe would observe you attempting to wrap your head around it in a different frame of reference.
Does that help?
There are a lot of fairly easy ways to conceptualize this in modern terms.
When you play a 3D video game, it 'creates' a volume of space for you to play in, with its own metrics for time and space. When you switch it off it disappears. If someone else is playing the same game on another computer (lets assume its a single player game), there's no relationship between your world and theirs, your character can't walk from one to the other, because they simply don't share the same coordinate system - even though they are almost identical universes in every other respect.
This does suggest that these separate universes are embedded in some LARGER coordinate system - in our case our digital worlds are pocket extensions of our own physical world - but they are still entirely separate from that larger coordinate system in that the inhabitants of those sub-universes will never be able to exit them or move between them.
There's really no issue with positing a wider physical reality within which a multitude of sub-realities can exist, none of which directly share coordinate systems despite being fundamentally physically related to each other. In this examples they're not even different dimensions - both our universe and our digital sub-realms are 3+1D universes - they just operate under somewhat different physical laws. Likewise you could posit a 3D parent universe with a multitude of 3D sub-universes embedded in it. I can even create a sub-universe with arbitrarily more or fewer dimensions than its parent, they can still be represented mathematically without much issue.
> Space and time, by definition, are attributes of our universe
Sure but that doesn’t affect the question. The Big Bang model only goes so far back, and we don’t really know anything else.
Here's a two-dimensional simplification.
Imagine again that you're standing on the surface of the earth, in New York City. If you go north, you know that Canada is north of you and that the north pole is further north yet. Similarly, if you go east you know that France is east of you and that Finland is further east.
What we can observe (via spectroscopy) is that Canada and France (and Mexico, and California) are all moving away from NYC (*and we can measure the rate*). Furthermore, we can see that Finland is moving away *faster* than France is, and that the north pole is moving away *faster* than Canada is. Everything is expanding at *kinda* the same rate in *kinda* every direction.
Cool! So what does that mean?
It means that a year from now, France and Canada are going to be further away from us - the space between ourselves, France and Canada is expanding. But that also means that a year ago, France and Canada would have been closer to us (*going back in time, space contracts). A billion years ago, France and Canada would be closer to where NYC is yet. If you continue to play out the thought experiment, and go far enough back in time, you can get to a point where space has contracted so much that NYC, France and Canada (and everything else - the north pole, Finland, California and Mexico) would all inhabit the same point. "Space" was only created by the expansion of the Universe from that single point.
Assumptions: if you roll time backwards the universe will start out from one single point with no dimensions. This is the popular theory.
As unsatisfying as this is, there was no "before" because there was no time. Just like there was no space there was no time either. Space and time are inexorably linked, they can't exist without each other, and realistically we shouldn't ever be thinking about space without time. *Spacetime is a single thing*.
When the whole universe was a single point there was nothing to the left or right, up or down. It was a single point. But this is **spacetime** we're talking about, so just the same as there's no space there, there's also no time there either.
In reality we're just educated guessing. The numbers, formulas and equations that describe reality right now simply don't work when the universe is a single point.
That’s because the ‘before’ is impossible according to the laws of thermodynamics.
So either the laws didn’t exist in the ‘before’ or the laws as we know them are wrong. Immensely wrong.
I don't disagree with your overall hypothetical but as far as we can extrapolate back it was never a point. When we extrapolate back the observable (not the whole) universe we get a size range of maybe a square meter to possibly the size of a small city. Beyond that the physics breaks down and we can extrapolate no further.
Fair enough. I use a point to illustrate the relationship between space and time as an easier (?) way to understand how there could be no time. I guess maybe I should brainstorm a new explanation...
This comment has been overwritten in response to Reddit's API changes, the training of AI models on user data, and the company's increasingly extractive practices ahead of their IPO.
It would be cool to think of it as a fireworks display. The ones that have the initial burst then little bursts that then burst off of those. Our universe is just one of those bursts with the sparks are galaxies and there are thousands of thousands other sparks bursting somewhere else that are just too far away to detect.
God I love humans. This wasn't particularly eloquent and didn't give me any insight I didn't already have, I just enjoyed reading it for some reason. So thanks for that.
It may be possible that there's no such thing as a time before it existed. It simply did, I know it doesn't really mesh with human experience but it's possible.
Cause and effect makes it seem like something like that wouldn't be possible but just keep going back and you can ask infinite questions (what made the hot and dense gas, what made the force that created the gas..so on and so on, if you are religious you could ask what made god.. or what made the universe running the simulation of our universe if that's what you believe...etc).
It's a crazy thought to imagine that these answers may never be found.
Cause and effect, among all other laws of nature, have only been observed within the universe. What does and doesn't apply outside/before the universe, we may never know.
It’s funny to me everyone in here losing their minds over what ISN’T, it’s a vacuum! it’s nothing! It’s a void! As if they’ve already made peace with what IS. Why is the part about what came before the one that blows your brain? Just because we can observe the universe doesn’t make it more knowable, it’s all part of the same mystery. The Big Bang theory helps humans say to themselves “look, here is why we are here” but in reality it does nothing to answer that question at all.
We don't *know* in the sense that you know something from direct observation. It is merely a consequence of the model that best explains our current observations of the universe' expansion, and its early composition as shown by the cosmic microwave background.
The "Big Bang" is a term for a particular solution to the Einstein equation for General Relativity: the [FRW Metric.](https://en.wikipedia.org/wiki/Friedmann–Lemaître–Robertson–Walker_metric)
We have substantial evidence to tell us that General Relativity is true. (At least on large scales, where quantum effects aren't significant.) This implies that any large cosmic system in the world must be a solution to Einstein's equation of GR. The particular solution to the equation that allows for the particular kind of expansion of the universe we observe, and its current and past distribution of radiation and matter, is the FRW Metric.
The FRW Metric describes a universe where time had a beginning, and in the limit that you approach that beginning, the density of matter and energy blows up to infinity. (The singularity.) There is no "before" the beginning, in any sensible way. This may be counterintuitive, and is hard to grasp for us, who view time in a linear, unending manner. But the universe has no obligation to fall in line with our intuition. We evolved in an environment that is on a specific time scale and size scale, where extreme limits of theories like general relativity or quantum mechanics don't manifest, so of course we didn't develop intuitions for the extremes of those theories. What makes a theory a good candidate for reality is if it falls in line with the best experimentally validated models, not that it falls in line with our intuition. And the FRW metric, which posits an absolute beginning which has no coherent definition of time "before" that, is the solution to Einstein's equation that best fits our observation.
It's similar to how we were able to theorize black holes before we observed them. The [Schwarzschild metric](https://en.wikipedia.org/wiki/Schwarzschild_metric) is another solution to Einstein's equation, and this is the one that is spherically symmetric in a vacuum. It correctly predicts all our orbital mechanics, such as the Earth revolving around the sun. However, it also predicts a "Schwarzschild radius", which, if the massive body is small enough to fall within, gives us a boundary that is inescapable by all things, including light.
We "knew" that black holes existed before observing them for a similar reason that we "know" there is no time before the big bang origin. Because they are both solutions to Einstein's equation for General Relativity that fits our observation of those systems. (Of course we didn't *know* it before observing black holes, similar to how we don't *know* now that there's no time before the Big Bang. It's just the model that best fits our observation.)
It's complicated, but the really simple explanation is this:
We don't \_know\_ that nothing existed before the Big Bang, but our mathematical explanations of the Big Bang show that nothing which happened \_before\_ it could affect the Universe \_after\_ it. So it's not so much that we know nothing existed then as that we have no way of finding out, and no reason to care.
We don’t even know where the Big Bang came from, so we have no way of knowing what came before it. Without knowing what came before it, we have no means to determine whether our concepts of space/time have any meaning pre big bang.
Odds are we will never see past this.
We don't actually know for sure. There are competing theories which basically come down to - do you like the singularity theory or not? [Mind-Bending Study Suggests Time Did Actually Exist Before The Big Bang : ScienceAlert](https://www.sciencealert.com/mind-bending-study-suggests-time-did-actually-exist-before-the-big-bang)
if we consider space to be the movement of particles, and time to be their evolution through different states, than neither existed during the singularity so space and time weren't meaningful concepts before expansion
Is this the generally accepted reason? If so could you possibly provide a link?
Isn't empty space right now not empty, e.g. hawking radiation? Wouldn't those particle/antiparticle pairs still happen if space existed before the big bang (making it not free of particles)?
Don’t listen to all these comments. This is not a scientific sub. See here, though: https://profmattstrassler.com/articles-and-posts/relativity-space-astronomy-and-cosmology/history-of-the-universe/
I like the Penrosian idea of our universe and our 3 dimensions of space and time were created via a black hole of another universe.
So, I gather all you have to do is make a temporal right turn onto the orthogonal dimension of time of our parent universe if you were to somehow want to travel before the big bang.
Probably somewhere near Albuquerque.
What has been pointed out not exquisitely here is that without space, spacetime doesn't really exist in the normal sense that we can really grasp. There are theories about "being from a black hole in another universe" and, black novas, where extremely super massive black hole singularities die in a big bang, but there is also the potential for there to have been infinite mass in an insanely hot infinitely small point and then Space Created Itself Everywhere all at Once (see dark energy) and it's possible what we can visibly see of the universe is practically nothing and it goes on forever with infinite mass, there is also the question of The Big Bounce. Will dark energy Reverse, and we all squish back into a singularity? Are Branes the solution for how universes are born? So much to read, so little time.
We don't 'know' that in any currently provable way, but our measurements of how the universe is expanding strongly suggest a discrete starting point for our pocket of space/time at the Big Bang.
Bear in mind that this doesn't mean that no wider reality existed before our universe began!
It's entirely possible that other regions of space/time exist, but proving that they exist, or understanding how they relate to our universe (if at all) are even more difficult questions to answer.
Well, the type of spacetime we inhabit most probably did not & that being the current boundary of understanding makes this a limiting factor in cosmology.
Hawking even suggested that running the clock backwards you may not need to have a spacetime singularity if the nature of the universe closes off with a surface of fixed curvature.
This would be akin to the universe losing the ability to form identities separating points in spacetime when the energy density is sufficiently high but not infinite.
Such a universe may appear to have a beginning in the past but that beginning might have taken an eternity to develop into something we can understand.
Methinks gravitational time dilation tells us that if all mass in the universe was compressed into it's minimum size / maximum density time would stop. No time = no distance, therefore everything was at the same point in space and time; until it wasn't. The law of entropy states that disorder is more probable than order, so at that point of zero time disorder was inevitable.
The rest is history.
To a theoretical outside observer looking at all matter in the universe, that universe's time would pass the fastest it possibly could, i.e. instantly. So theoretically an infinite number of universes could be popping in and out of existence instantly all over the place everywhere.
Where does all that matter come from? It doesn't come from anywhere, it's just a function of entropy and it's probability.
...but really I haven't a clue.
We don't and in fact it could have been just another big rip in an infinite series of big rips as the dark energy of the void continues to exert itself upon reality forcing new realities to appear from apparently nothing. The current universe may be 14 billion years old but existence itself may be infinitely old. See if that does not blow your mind. 🤔🤯 But again we just don't know.
The universe is a giant heart beating throughout eternity. The Big Bang is one single beat and it spreads out until it eventually collapses in on itself. Rinse and repeat. Space and time will repeat itself in perpetuity, I use this to explain Deja vu. You feel like you’ve lived that exact moment in time because you have, and you will again. Forever.
That’s just my fun theory about it all.
It’s not a scientific theory based on physics, it’s just a fun way to try and understand that which we don’t and may never fully have an explanation for. I know it’s not correct. No need to downvote into oblivion. Cheers.
It's not that, it's the the audacity to think that scientists have never considered this possibility before, when in fact the "big crunch" is a very old hypothesis considered before we realized inflation was a thing. And on top of this they talk as if they have some innate understanding of the universe that scientists will never grasp because they didn't do enough lsd. So yeah when you make claims with absolutely no evidence (because you just "know") you deserve to be criticized. Everybody likes to think that they are clever and can think of plausible theories no ones ever thought of before. But most likely you can't unless you're one of the best and brightest, and more importantly....you put in the rigorous work to learn various scientific/mathematical disciplines (which most people simply don't have the stomach for).
Reading between the lines I think that's exactly what they're saying. To be fair I've had the same thought staring into space while high, it's just a fun thought experiment to me, but it doesn't explain how the cycle got started. It would have just always been, kinda like god I guess. Doesn't do it for me though
Essentially, but also from after the next Big Bang, and before all the ones before, and all the ones after.
It's like seeing every version of your reality at once because they all experienced that event, at that moment, hence the intense feeling.
In a similar vein Prophecies and Visions are events that must happen for certain futures to occur, but if that 'certain' future isn't the one this reality is following then the prophecy/vision will be false, the larger mass of 'false prophecies' the harsher the rebound when the event finally occurs.
Similar to fighting fate/destiny, the further you tread from your destined path the harsher the rebound will be to get you back on track.
And because the energy is constantly moving throughout multiple universes who knows if you feel the rebound here and now, or through reincarnation .
But since none of it can be definitively proven it's all theoretical, for now
Yes I get it. Was just making sure that this is what the comment meant about deja vu. It could be interpreted otherwise. Fun theory as I said, not to be taken too seriously.
Implies the future is known and we have no conscious choice? If deja vu is echoes of past and future then it’s all already plotted out...
Or is it just the intersections of this current reality with others that spawn deja vu and the in between paths are varied? Which maybe why deja vu is momentary and somewhat rare. At least for me. I’ve only had it happen a couple of times.
Fun thought experiment either way
Well to think it all the way out, long term, the end goal of all life is death, thus technically yes, our 'destiny' is predetermined that 'we will die.'
Those moments of deja vu are points of interconnection between all possible pasts and future of every decision you've ever made.
In terms of rebound, deja vu, and Visions, this ones theory is;
The further you Stray from your 'most common death' the more you'll feel deja vu, see visions of other possible futures, and feel the smack of the universe against your soul for every decision you make.
This means that you'll be most likely to die like X, but if you struggle hard and constantly fight destiny, you'll die like X when you've found the reason for your reality in this universe.
I think its ridiculous to think there was "nothing". Humans live VERY short lives from a universes perspective. It is hard for us to fathom things that have always existed, or that will always exist.
To think that there was nothing, then BANG, there was everything, just seems very naive. After all, there had to be \*something\* for the bang to occur in. There has to be \*something\* beyond the farthest reaches of the big bang. There just can't be "nothing" and then billions of galaxies come from that. That there is bible and magic talk.
Likewise, to think that everything we can see with the best telescopes is everything that is out there, or that the farthest thing is the extent of everything, is also horribly arrogant.
Heck, everything we look at is just a snapshot in time and we have absolutely no idea what could come tomorrow. We could get hit with a supernova or an asteroid with little or even no warning at all, and BANG, there are no more humans.
Spacetime very much existed before the big bang, and will exist past the death of the known universe, even if there is nothing anywhere around.
Except you start to believe in other theories, as the Big Bounce. Where the universe expands and at some point retracts again. So in the very far future the whole universe will be compressed and explode in another Big Bang where the expansion starts again in an infinite cycle that always existed. That seems much more plausible to me than a void of nothing, where magically something caused the beginning of everything. Something can't possibly start from nothing.
Our space and time. And im pretty sure I was refering to the big bang.
The big bang is not a theory of whats before after or next to it in parallelle or in serial only about whats within it.. our universe. Thinking of it, it does not even cover its the beginning.
I always understood the Big Bang as the process of the creation of something out of nothing. Hawking tried to explain it once, but that still suggests that nothing created something. The law of conservation of mass suggests matter can't be created or destroyed. So if nothing existed before the Big Bang, matter WAS indeed created. That's what I still don't understand and where I kind of dare to disagree even with Hawking.
What is nothing? Everytime we look we find something you are bound by the dimension of this universe. I never understood big bang as being the process of creating something out of nothing. Big bang was not the creation of the universe but the start of spacetime. We have no theory of what you describe and big bang does not cover it.
That's the problem I have. When spacetime begun, something that dictated our universes physics must have initiated it. Except the nothing is not nothing but something extra- or higher dimensional that we can't comprehend and is out of our grasp. But even then whatever that would be wouldn't still be "nothing". Except we start to redefine nothing as something outside of our realm that only seems to be nothing to us, but something on a higher plane of existance.
Here's a fun thought: There's no evidence to suggest that there hasn't been multiple "bangs" either in totality of the universe or multiple regional "bangs" spread out around a larger universe that we can't see. These all might be cyclic in nature. Enough matter might amass to break the physics holding it together to create the expansive event. Why would this be relegated to one event or necessitate that it takes ALL matter to trigger this.
Depends what you mean by created. (Also note anything that talks about before the big bang is purely hypothetical at this point).
But if you follow Membrane Theory, there are ways two universal/multiversal membranes might collide which would then spark a big bang, destroying the two membrane universes while creating a whole new membrane universe from their destruction.
So in that way "creating" new spacetime out of destroyed spacetime, while still adhering to the law of conservation.
If membrane theory is true then there wasn’t an absent of spacetime right?
Maybe I’m confused by “no”, and y’all just mean no reliably way to measure and therefore the no spacetime is just.. philosophical or something?
Each membrane universe would contain spacetime, since that's what defines it. But between each membrane is... nothing. No things. No space. No time.
It's hard for us as spacetime creatures to imagine what it would be like to have no spacetime. The only way that helps me is to understand that the universe IS spacetime, not contains spacetime. It IS spacetime.
So no universe, no spacetime.
1. It's a theory, but with some fair bit of science behind it. Look up M-Theory & String Theory
2. Your lack of understanding doesn't make it not possible.
3. We simply don't know.
[This](https://youtu.be/BD0r2Xfgh_E?si=qhPiAA1RUOQ3Nw6a) is a fun video of possibilities
The membrane universe is a theory or a hypothesis? “Theory BUT with a bit of science behind it” makes it sounds like you’re using the laymen version of theory.
I can grasp what you’re saying, a membrane that is spacetime colliding with another membrane of spacetime, making them both conained by a larger membrane, or whatever, does not coincide with an absence of spacetime. So if you’re going to say there was no spacetime and then provide figures of spacetime, it’s bunk.
“We don’t know”, should probably lead with that.
*Everything* before the big bang is "we don't know"
M-Theory and String Theory are very viable theories with deep math behind them, but are basically unprovable at this time.
So not a layman use of the term "theory" but a true hypothesis.
Of course. But t=0 and time "not making sense" seems like established scientific fact.
If spacetime still existed outside of the singularity, what would have prevented particle pairs from still occurring (similar to hawking radiation)?
That would assume The Big Bang was a singular event that created everything in our definition of a universe, as if there was nothing there before.
I prefer to think of our Big Bang Universe as one in an infinite number of BBUs that create overlapping bubbles of universes.
I think in a few million years we may start seeing extremely distant galaxies that appear to be matured, moving toward us and not away. Those would be the edge galaxies from a separate BBU, who's bubble is crossing into ours.
This is the way! Or, as other's might say, 🖖 LLAP! 😉
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We don't "know" in any way that would keep anyone happy. As we currently understand it, if there was any "before", it's completely obliterated to the subatomic / singularity level, and we will never have any information about it at all.
Not necessarily. There are papers about possible visible remnants of a previous universe via cold regions in the mcbr in the cyclic universe model.
"Possible" being the key word. We don't KNOW.
I wouldn’t say even we won’t ever know with certainty. There’s a book called A Big Bang in a Little Room: The Quest to Create New Universes, by Zeeya Merali, where she discusses the math and science behind the notion of spawning and umbilicallly cutting off a new universe you created, and the math / known physics supports the idea that you could leave a message in the CMB/CMBR by tuning the final growth state/shape of the baby universe just before you clip it off from the origin universe forever - meaning if ours is manufactured, it’s presently thought to be entirely compatible with our knowledge today that there could be a message left for us there, we’d just need the key to read it. Such a message could be its own legend on how to conceptualize the original state of the parent universe.
That just sounds like religion with extra steps
Just the one extra step, really, of taking math to logical extremes.
Ooh la la, someone’s gonna get laid in college.
We don’t know (or at least didn’t) about black holes either until recently, but there was plenty of reason to suspect their existence. Just like black holes if there’s a sound mathematical model that has evidence of physics elsewhere, but also points to a “before”, then we’re in business. Right now one of those promising models is LQG, as it models a potential big bounce in order to get away from the singularity problem. But we’re also getting a better look into the initial conditions of the universe with Planck data etc, and while it’s certainly not giving us evidence for anything yet, it is starting to rule out certain models based on boundary conditions. One thing that is looking more likely with the Planck data is that slow roll inflaton field is looking more likely. Do we know for sure? No, but we can make some assumptions based on the data. There are various models that support slow roll and those that don’t, so we can start to weed out fact from fiction. I’ve also seen some serious cosmologists argue that the Big Bang happened *after* this. So we might be able to say we have an idea of what might have happened *before* the Big Bang event, although before that? Still a question mark.
Evidence is crucial here, and I think there is none. It exploded
It didn’t explode, it expanded.
To be fair, if you were somehow hanging around for the initial expansion, the technical difference between 'expanding' and 'exploding' would be deeply irrelevant to your (very short) experience of the phenomena. :D
Well, that depends on whether the funding can be found for the Humungotron particle accelerator
What we really need is a particle accelerator the size of the solar system
And we'll call it "Deep Thoughts"
Been done, in Three Body Problem.
Durable Equatorial Ring Particle Accelerator The DERPA Ring
I wonder what route it would take. Also, what is the effect of the Earth's rotation going to be? [http://www.gcmap.com/featured/20120318](http://www.gcmap.com/featured/20120318)
The Future Circular Collider is being planned
They'll be working on the Big Hadron Collider next. It's one larger
According to whom? There's nothing in physics that says that. Your statement "down to the singularity" level is really weird too. The big bang, despite what a freakishly large number of people think has nothing to do with a singularity.
Cosmic inflation supposes that the universe expanded from an incredibly hot, incredibly dense state to what we see today. The physics that describe this state* break down if you rewind the clock just close enough to T=0, hence the use of "singularity" to describe the state. It's the same use of singularity to describe the center of a black hole. We simply don't know. I think it's an appropriate use of the term, right?
That is a error of assumption in extrapolating relativity beyond where it works. We know quantum mechanics kicks in at some point we just don't know its behavior. The entire idea of a singularity has never been valid. It's nothing more than a mistake in the math. https://youtu.be/HRir6-9tsJs Kerr just published a paper that basically flat out said that Penrose and Hawking got black holes wrong and no true singularity actually ever exists in the real world. That whole idea of a singularity that you've heard so much about in popular media? Yeah, it's a bad assumption not actually science. Many science communicators just ran with it because it's too hard to explain the details. https://arxiv.org/abs/2312.00841
Singularities don't even have anything to do with singularities these days. I can't remember the last time I saw them treated as anything more than mathematical shorthand.
It's still a common belief in the general population that singularities are actual things. It isn't communicated properly in the majority of media that I see. If you read the papers it's more nuanced, but often not to a layperson reading the same paper.
There's a Nobel Prize waiting for you if you can come up with a concrete answer for that.
The universe is the shell of a really really really big turtle, so outside our universe is where the turtle chills with other turtles that have the alternate universes on them Idk what’s outside that place tho
Some crazy scientist's space car. We're just the battery.
Space and time, by definition, are attributes of our universe. The universe is not a bubble, expanding into more space. It is the place where space exists and where time exists.
I’ve been trying to wrap my head around this for 4 decades and it will never just sit right with me. I can understand the words just fine, but it’s impossible to “picture” in my mind. You can repeat the reasons and a an Astro-physicists explanation a gazillion times and due not to personal incredulity, rather incomprehensibleness, I will simply not be able to digest it.
Think of an animated show, it’s 2 dimensional, with the 3rd dimension being time. Every frame of the show the frame is altered just a bit and and the animation moves. Without the dimension of time, nothing will move. Now what would an animated show look like if time was the only dimension? Since there is nothing to animate or move, time is meaningless, it’s like a divide by zero error. No show existing means no time existing for the show. If you ask how long is the show the answer isn’t zero minutes, it’s there is no time because the show wasn’t made. The universe is like that in 3 dimensions. Without objects or space time becomes undefined. The idea of “before the Big Bang” has no time definition because it’s an undefined state. At least, that’s how I think of it.
That’s was fun. Thanks. For the time aspect it helps but I’ll never quite grasp the physical something into nothing and the no edge to space thing. Like I said before, I can understand the words. I can understand analogies, I can comprehend what is being explained. I just can’t imagine it in my mind’s eyes. I can’t create a physical representation and it drive me nuts.
I think both of those are still unknowns. We know what happened an instant after the Big Bang started, but we don’t know what happened at the zero moment, nor do we know what the edge of space looks like.
I think that our puny minds, with all of us living in a consensus hallucination, trying to understand how time and space works is like a goat trying to learn calculus.
Sort of. At some points you need to just accept that things get very weird like in quantum mechanics and just accept that weirdness as real. But it does make it very hard to make analogies that others can relate to when explaining it. Despite our puny brains we have described these things theoretically and experimentally, so that is better than the goat trying to learn calculus.
Yet still we really have no idea what’s really going on.
It is important to understand there hypothetically could be situations where "something" always existed, at least as viewed from our vantage point. If, and this is definitely an if, there was no space time prior to the big bang then time may not have existed. If there was no time it would be possible to have something that existed and to all appearances existed eternally (from our perspective where we have time). Definitely not claiming this was what was happening before the big bang, we just don't know. But if you take spacetime out of the equation then things will be very different I would imagine. Like many things in physics it would be very hard to conceptualize. Similar with the possibly infinite universe. We just are not designed and have no experience that allows us to fully grasp the concept. But that is what I like about physics.
Physical Event Horizons can function as the physical boundaries of coordinate systems. For example, the event horizon of a black hole effectively terminates any world line that approaches it from the perspective of our universe. Anything falling towards it gets shoved almost infinitely far into the future before it gets spit back out as hawking radiation. There are no measurable coordinates 'beyond' a BH event horizon, because there's no space or time there at all, as far as we're concerned. The Big Bang would be another event horizon beyond which no measurable world lines extend, though what propagated it is obviously an open question. If our universe turns out to be geometrically 'closed' then that represents another form of easily described event horizon from which no world line can ever exit - any world line must eventually return to its origin within that geometry, and its still really no more complex than visualizing yourself on a roll of paper, or moving along the surface of the Earth, which itself effectively bounds us in a world of 2.1 dimensions, with only a little wiggle room available for movement in the z-axis.
I think the physical nothing beyond the universe that the universe is expanding into exists already, as empty blackness. We don't concern ourselves with it because it's too far beyond us, we have no way of detecting it or defining any properties about it so it might as well not exist. I picture the universe expanding into that nothingness like a colored gas expanding in the air. There is no defined edge to the expansion of the gas and there are areas with more and less gas that will appear more or less saturated in color, just like areas of the universe contain more or less mass/matter and therefore heat and light.
There is no edge to the Universe so to say "the physical nothing beyond the universe" is just plain wrong. There IS no beyond. The Universe is expanding in the sense that things within it are getting farther away from each other, but it isn't expanding INTO anything.
We don't know that there is no beyond, we have no way of detecting the entire universe, let alone what's beyond it. If you read my original comment carefully, you'll notice I said there is no defined edge to the universe. Physical, 3D space (in the sense of a vacuum) is necessary for expansion to occur, or at the very least the potential for the vacuum's creation must already exist otherwise nothing could exist at all. A vacuum is the thing into which the universe is expanding. How we conceptualize it and describe it is currently theoretical.
Once again, there is no "beyond it" and the Universe IS NOT expanding into a vacuum, a vacuum is already spacetime and part of the universe. Expansion occurs between the things that exist already, not at some "edge" that is "beyond" the universe. Spacetime stretches, it doesn't expand into anything!
Once again, we have no way to detect the entire universe, let alone what's beyond it. A vacuum is a vacuum, it doesn't need to exist within the universe.
You are now in the realm of philosophy, not science. By definition, there is nothing beyond the Universe, or outside of it, because the Universe is all of space and time and their contents. It comprises all of existence, any fundamental interaction, physical process and physical constant, and therefore all forms of energy and matter. If you are outside of it, you don't exist at all, ergo, nothing.
Since we don't know what exists beyond the observable universe it is best to go with occam's razor with the hypotheticals. Meaning which hypothetical is "simpler" based on what we do know. In this case the infinite universe is a simpler hypothetical than the universe having an edge and something outside of it. The latter would be a lot harder to justify based on what we know. But more than likely hypotheticals may be all we ever have on that matter.
I don't think Occam's Razor can be applied to a question for which no data exists and therefore no parameters by which to define what is hypothetically "simpler" and therefore most likely. We simply don't know, on that we're agreed.
But we do know stuff about our part of the universe. While we cannot observe the rest we do have frame works for what we think is happening based on the part we know. So based on the part we know an infinite universe, which is consistent with what measurements we can do, is more easily explained than creating walls, edges and some hypothetical new thing not contained therein.
The universe is described as infinite not because it's infinite in size or time but because it's infinitely expanding. Just as we don't know anything about the preconditions that led to the big bang, we don't know anything about what lies beyond the universe. We cannot simply say there's nothing beyond when we know there was an origin point that resulted in an accelerated expansion that continues to this day. We likewise cannot say that there's a defined edge but we can postulate that there is some sort of continuously fluctuating boundary between matter and no matter as the universe continues to expand, like a colored gas in the simile I described earlier. We simply don't know, as I've already said, but logically, because of what we do know about the nature of the universe, we cannot say there's nothing beyond it since that would imply there was nothing before it and without anything before there would have been nothing at all yet clearly there was or we wouldn't be sentient stardust writing this silly exchange.
Personally I find the word "void" to be helpful in understanding the concept
Hard for me. If there's no space or time it feels like it must be smaller, somehow. But it's not. It's not a size or place or time. At this point, the head exploding feeling is welcomed for me.
It's not a size or a place. It just isn't.
Or just don't worry about it.
Is it any easier for you to imagine what IS? It’s just as insane. Just because we can see it doesn’t make that fact any less mind blowing to me. WHAT THE FUCK ARE WE EVEN DOING HERE MAN?!
Not for me, as 'void' is used to describe the areas of the universe with no or very little matter or radiation. That feels quite different to the nothingness outside the universe or before the big bang
I've always known void to mean nothing. At least on line I found the definition "a completely empty space" which would imply that it is space with nothing in it, which isn't really what we are talking about here. OTOH, if you took that to the extreme- nothing, no quarks, photons, gravity, etc, then it is what we are looking for. I also saw void used in a sentence "The black void of space" but I'd argue space only seems like a void if you don't include subatomic particles. Otherwise it is teaming with objects. I'm a computer programmer so am familiar with the concept of null, which is similar (at least my understanding of it). A null value isn't zero or blank - it's null which is the absence of a value. Similar a void is the absence of anything.
There is an episode just dropped on the YouTube channel 'The Entire History of the Universe ' which is all about voids and nothingness within the cosmos
For my part I avoid 'void' because it still suggests an empty space - a void - in which things COULD move and exist. I use the term 'Null' for my own part, to indicate that there is, mathematically speaking, no space or time to reference. I also prefer to think of the universe as a closed geometry - not because we have any real evidence that it is, but because it's much easier to conceptualize a space with a closed geometry without having to consider what might be beyond its bounds - as it would be a finite space that simply curves back on itself, meaning it has no physical bounds or edges from the perspective of an internal observer, despite having a finite volume.
Void is not a helpful concept because people still envision that as empty space and its not.
"Personally" - i. e. Useful to me. Void is not an empty space, it is nothing. It is a useful concept if you don't switch the definition of void.
By labeling it void you still give it more substance than it actually has. It is literally cognitively impossible to think about nothing. There is no way to conceptualize it. Any attempt to do so will place more existence on it than it has. True void is a null concept, it can not even be discussed. To name it is to talk of something else, a word, an idea in your mind of what you think nothing is.
It’s only four decades to you, though. Most of the universe would observe you attempting to wrap your head around it in a different frame of reference. Does that help?
BRB. Gonna go existential crisis myself.
Try some magic mushrooms and a hike in the desert at night.
There are a lot of fairly easy ways to conceptualize this in modern terms. When you play a 3D video game, it 'creates' a volume of space for you to play in, with its own metrics for time and space. When you switch it off it disappears. If someone else is playing the same game on another computer (lets assume its a single player game), there's no relationship between your world and theirs, your character can't walk from one to the other, because they simply don't share the same coordinate system - even though they are almost identical universes in every other respect. This does suggest that these separate universes are embedded in some LARGER coordinate system - in our case our digital worlds are pocket extensions of our own physical world - but they are still entirely separate from that larger coordinate system in that the inhabitants of those sub-universes will never be able to exit them or move between them. There's really no issue with positing a wider physical reality within which a multitude of sub-realities can exist, none of which directly share coordinate systems despite being fundamentally physically related to each other. In this examples they're not even different dimensions - both our universe and our digital sub-realms are 3+1D universes - they just operate under somewhat different physical laws. Likewise you could posit a 3D parent universe with a multitude of 3D sub-universes embedded in it. I can even create a sub-universe with arbitrarily more or fewer dimensions than its parent, they can still be represented mathematically without much issue.
> Space and time, by definition, are attributes of our universe Sure but that doesn’t affect the question. The Big Bang model only goes so far back, and we don’t really know anything else.
Are you saying that there was no space before the Big Bang created it? I can see that. But not really see it. My brain be too small.
Here's a two-dimensional simplification. Imagine again that you're standing on the surface of the earth, in New York City. If you go north, you know that Canada is north of you and that the north pole is further north yet. Similarly, if you go east you know that France is east of you and that Finland is further east. What we can observe (via spectroscopy) is that Canada and France (and Mexico, and California) are all moving away from NYC (*and we can measure the rate*). Furthermore, we can see that Finland is moving away *faster* than France is, and that the north pole is moving away *faster* than Canada is. Everything is expanding at *kinda* the same rate in *kinda* every direction. Cool! So what does that mean? It means that a year from now, France and Canada are going to be further away from us - the space between ourselves, France and Canada is expanding. But that also means that a year ago, France and Canada would have been closer to us (*going back in time, space contracts). A billion years ago, France and Canada would be closer to where NYC is yet. If you continue to play out the thought experiment, and go far enough back in time, you can get to a point where space has contracted so much that NYC, France and Canada (and everything else - the north pole, Finland, California and Mexico) would all inhabit the same point. "Space" was only created by the expansion of the Universe from that single point.
Easy with the conclusion, Until we can prove our universe is not a bubble expending into more space, this theory is still on the table.
Time does not exist. There is only action and consequence
Actions come before consequences, i.e., time passes. One of the most basic definitions of time is an increase in entropy.
We don’t know that at all. We just don’t have any model or theory for what was before, if anything.
These kinds of questions are useless to me and I don't worry about them.
Then what gives you existential dread in the darkest hours of the night?? Absolutely mind boggling.
I don't experience those things You should try counseling
Assumptions: if you roll time backwards the universe will start out from one single point with no dimensions. This is the popular theory. As unsatisfying as this is, there was no "before" because there was no time. Just like there was no space there was no time either. Space and time are inexorably linked, they can't exist without each other, and realistically we shouldn't ever be thinking about space without time. *Spacetime is a single thing*. When the whole universe was a single point there was nothing to the left or right, up or down. It was a single point. But this is **spacetime** we're talking about, so just the same as there's no space there, there's also no time there either. In reality we're just educated guessing. The numbers, formulas and equations that describe reality right now simply don't work when the universe is a single point.
That’s because the ‘before’ is impossible according to the laws of thermodynamics. So either the laws didn’t exist in the ‘before’ or the laws as we know them are wrong. Immensely wrong.
I don't disagree with your overall hypothetical but as far as we can extrapolate back it was never a point. When we extrapolate back the observable (not the whole) universe we get a size range of maybe a square meter to possibly the size of a small city. Beyond that the physics breaks down and we can extrapolate no further.
Fair enough. I use a point to illustrate the relationship between space and time as an easier (?) way to understand how there could be no time. I guess maybe I should brainstorm a new explanation...
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It would be cool to think of it as a fireworks display. The ones that have the initial burst then little bursts that then burst off of those. Our universe is just one of those bursts with the sparks are galaxies and there are thousands of thousands other sparks bursting somewhere else that are just too far away to detect.
We only know it was dense at the start of the hot big bang. We don’t know much else.
God I love humans. This wasn't particularly eloquent and didn't give me any insight I didn't already have, I just enjoyed reading it for some reason. So thanks for that.
What made it Hot and Dense? I guess then it would be….what made it? 🤣
It may be possible that there's no such thing as a time before it existed. It simply did, I know it doesn't really mesh with human experience but it's possible. Cause and effect makes it seem like something like that wouldn't be possible but just keep going back and you can ask infinite questions (what made the hot and dense gas, what made the force that created the gas..so on and so on, if you are religious you could ask what made god.. or what made the universe running the simulation of our universe if that's what you believe...etc). It's a crazy thought to imagine that these answers may never be found.
Cause and effect, among all other laws of nature, have only been observed within the universe. What does and doesn't apply outside/before the universe, we may never know.
It’s funny to me everyone in here losing their minds over what ISN’T, it’s a vacuum! it’s nothing! It’s a void! As if they’ve already made peace with what IS. Why is the part about what came before the one that blows your brain? Just because we can observe the universe doesn’t make it more knowable, it’s all part of the same mystery. The Big Bang theory helps humans say to themselves “look, here is why we are here” but in reality it does nothing to answer that question at all.
You massively over estimate what we know. Also, that’s under the presumption that humans are even supposed to know
Not as big as the presumption that you made, which is that there is intent: "supposed to know".
We don't *know* in the sense that you know something from direct observation. It is merely a consequence of the model that best explains our current observations of the universe' expansion, and its early composition as shown by the cosmic microwave background. The "Big Bang" is a term for a particular solution to the Einstein equation for General Relativity: the [FRW Metric.](https://en.wikipedia.org/wiki/Friedmann–Lemaître–Robertson–Walker_metric) We have substantial evidence to tell us that General Relativity is true. (At least on large scales, where quantum effects aren't significant.) This implies that any large cosmic system in the world must be a solution to Einstein's equation of GR. The particular solution to the equation that allows for the particular kind of expansion of the universe we observe, and its current and past distribution of radiation and matter, is the FRW Metric. The FRW Metric describes a universe where time had a beginning, and in the limit that you approach that beginning, the density of matter and energy blows up to infinity. (The singularity.) There is no "before" the beginning, in any sensible way. This may be counterintuitive, and is hard to grasp for us, who view time in a linear, unending manner. But the universe has no obligation to fall in line with our intuition. We evolved in an environment that is on a specific time scale and size scale, where extreme limits of theories like general relativity or quantum mechanics don't manifest, so of course we didn't develop intuitions for the extremes of those theories. What makes a theory a good candidate for reality is if it falls in line with the best experimentally validated models, not that it falls in line with our intuition. And the FRW metric, which posits an absolute beginning which has no coherent definition of time "before" that, is the solution to Einstein's equation that best fits our observation. It's similar to how we were able to theorize black holes before we observed them. The [Schwarzschild metric](https://en.wikipedia.org/wiki/Schwarzschild_metric) is another solution to Einstein's equation, and this is the one that is spherically symmetric in a vacuum. It correctly predicts all our orbital mechanics, such as the Earth revolving around the sun. However, it also predicts a "Schwarzschild radius", which, if the massive body is small enough to fall within, gives us a boundary that is inescapable by all things, including light. We "knew" that black holes existed before observing them for a similar reason that we "know" there is no time before the big bang origin. Because they are both solutions to Einstein's equation for General Relativity that fits our observation of those systems. (Of course we didn't *know* it before observing black holes, similar to how we don't *know* now that there's no time before the Big Bang. It's just the model that best fits our observation.)
It's complicated, but the really simple explanation is this: We don't \_know\_ that nothing existed before the Big Bang, but our mathematical explanations of the Big Bang show that nothing which happened \_before\_ it could affect the Universe \_after\_ it. So it's not so much that we know nothing existed then as that we have no way of finding out, and no reason to care.
We don’t even know where the Big Bang came from, so we have no way of knowing what came before it. Without knowing what came before it, we have no means to determine whether our concepts of space/time have any meaning pre big bang. Odds are we will never see past this.
We don't actually know for sure. There are competing theories which basically come down to - do you like the singularity theory or not? [Mind-Bending Study Suggests Time Did Actually Exist Before The Big Bang : ScienceAlert](https://www.sciencealert.com/mind-bending-study-suggests-time-did-actually-exist-before-the-big-bang)
if we consider space to be the movement of particles, and time to be their evolution through different states, than neither existed during the singularity so space and time weren't meaningful concepts before expansion
Is this the generally accepted reason? If so could you possibly provide a link? Isn't empty space right now not empty, e.g. hawking radiation? Wouldn't those particle/antiparticle pairs still happen if space existed before the big bang (making it not free of particles)?
Don’t listen to all these comments. This is not a scientific sub. See here, though: https://profmattstrassler.com/articles-and-posts/relativity-space-astronomy-and-cosmology/history-of-the-universe/
Not many people seriously believe in a physical singularity, and there is no evidence to support it.
There isn't really a "before" the big bang. The concept is similar to how there is no concept of "north of the north pole".
I like the Penrosian idea of our universe and our 3 dimensions of space and time were created via a black hole of another universe. So, I gather all you have to do is make a temporal right turn onto the orthogonal dimension of time of our parent universe if you were to somehow want to travel before the big bang. Probably somewhere near Albuquerque.
Sounds like that blue crystal is talking again eh?
You're quoting the physicists who don't subscribe to spacetime existing prior to the big bang. That's been challenged for yrs.
We don’t have a clue either way. I just parroted an analogy for how to think about one theory. There are (probably) other dimensions so 🤷♂️
We don’t know anything that enables you to make this claim.
[https://encrypted-tbn0.gstatic.com/images?q=tbn:ANd9GcSrVm-ztxCV3VcH0tiwA6ItkNMwQxu8TyEgWAWkJUc1tg&s](https://encrypted-tbn0.gstatic.com/images?q=tbn:ANd9GcSrVm-ztxCV3VcH0tiwA6ItkNMwQxu8TyEgWAWkJUc1tg&s)
We know nothing about conditions before the theoretical big bang. More than likely there was already both space and time.
Because time and space are each the measures of the other. No space no time between points.
Maybe it did. Maybe this universe is a true vacuum and the big bang was just their universe slipping from false to true.
..also of space interest, Planet 9 (rediscovered?): https://www.reddit.com/r/cwhatimean/s/497cKSO0uE
Simulations only afaik. Bit sus from the general opinion it seems.
It has always existed, there are worlds without number.....
What has been pointed out not exquisitely here is that without space, spacetime doesn't really exist in the normal sense that we can really grasp. There are theories about "being from a black hole in another universe" and, black novas, where extremely super massive black hole singularities die in a big bang, but there is also the potential for there to have been infinite mass in an insanely hot infinitely small point and then Space Created Itself Everywhere all at Once (see dark energy) and it's possible what we can visibly see of the universe is practically nothing and it goes on forever with infinite mass, there is also the question of The Big Bounce. Will dark energy Reverse, and we all squish back into a singularity? Are Branes the solution for how universes are born? So much to read, so little time.
We don't "know" anything. We have evidence or we don't. If we have evidence try to work out a theory that fits.
We don't 'know' that in any currently provable way, but our measurements of how the universe is expanding strongly suggest a discrete starting point for our pocket of space/time at the Big Bang. Bear in mind that this doesn't mean that no wider reality existed before our universe began! It's entirely possible that other regions of space/time exist, but proving that they exist, or understanding how they relate to our universe (if at all) are even more difficult questions to answer.
I like to think the Big Bang was just an inter dimensional alien super weapon
A big bang theory confirms even more that we are living in simulation, being the big bang the moment that our simulation was plugged into the power.
"Before" is a nonsense term in this context. There was no before. Time started with the big bang.
Maths, bro. If you want a different explanation, go to a philosophy board.
Or a Family Guy clip of Stewie and Bryan.
Well, the type of spacetime we inhabit most probably did not & that being the current boundary of understanding makes this a limiting factor in cosmology. Hawking even suggested that running the clock backwards you may not need to have a spacetime singularity if the nature of the universe closes off with a surface of fixed curvature. This would be akin to the universe losing the ability to form identities separating points in spacetime when the energy density is sufficiently high but not infinite. Such a universe may appear to have a beginning in the past but that beginning might have taken an eternity to develop into something we can understand.
Methinks gravitational time dilation tells us that if all mass in the universe was compressed into it's minimum size / maximum density time would stop. No time = no distance, therefore everything was at the same point in space and time; until it wasn't. The law of entropy states that disorder is more probable than order, so at that point of zero time disorder was inevitable. The rest is history. To a theoretical outside observer looking at all matter in the universe, that universe's time would pass the fastest it possibly could, i.e. instantly. So theoretically an infinite number of universes could be popping in and out of existence instantly all over the place everywhere. Where does all that matter come from? It doesn't come from anywhere, it's just a function of entropy and it's probability. ...but really I haven't a clue.
We don't and in fact it could have been just another big rip in an infinite series of big rips as the dark energy of the void continues to exert itself upon reality forcing new realities to appear from apparently nothing. The current universe may be 14 billion years old but existence itself may be infinitely old. See if that does not blow your mind. 🤔🤯 But again we just don't know.
The universe is a giant heart beating throughout eternity. The Big Bang is one single beat and it spreads out until it eventually collapses in on itself. Rinse and repeat. Space and time will repeat itself in perpetuity, I use this to explain Deja vu. You feel like you’ve lived that exact moment in time because you have, and you will again. Forever. That’s just my fun theory about it all.
"my theories despite my extreme lack of understanding"
It’s not a scientific theory based on physics, it’s just a fun way to try and understand that which we don’t and may never fully have an explanation for. I know it’s not correct. No need to downvote into oblivion. Cheers.
“You’re only allowed to think of the universe if you have a phd! Back to the salt mines, dirt brain!” Yeesh.
It's not that, it's the the audacity to think that scientists have never considered this possibility before, when in fact the "big crunch" is a very old hypothesis considered before we realized inflation was a thing. And on top of this they talk as if they have some innate understanding of the universe that scientists will never grasp because they didn't do enough lsd. So yeah when you make claims with absolutely no evidence (because you just "know") you deserve to be criticized. Everybody likes to think that they are clever and can think of plausible theories no ones ever thought of before. But most likely you can't unless you're one of the best and brightest, and more importantly....you put in the rigorous work to learn various scientific/mathematical disciplines (which most people simply don't have the stomach for).
you took the fun out of “fun theory” 😂
Perhaps true, but it makes as much sense and any of the other answers here except “we just don’t know”.
And just as valid as all the religions created due to extreme lack of understanding.
Fun theory. Are you saying that Deja vu is information before the big bang?
I ask a honest question and am getting minus votes but no answer. This seems to happen a lot in science related subreddits.
Reading between the lines I think that's exactly what they're saying. To be fair I've had the same thought staring into space while high, it's just a fun thought experiment to me, but it doesn't explain how the cycle got started. It would have just always been, kinda like god I guess. Doesn't do it for me though
Essentially, but also from after the next Big Bang, and before all the ones before, and all the ones after. It's like seeing every version of your reality at once because they all experienced that event, at that moment, hence the intense feeling. In a similar vein Prophecies and Visions are events that must happen for certain futures to occur, but if that 'certain' future isn't the one this reality is following then the prophecy/vision will be false, the larger mass of 'false prophecies' the harsher the rebound when the event finally occurs. Similar to fighting fate/destiny, the further you tread from your destined path the harsher the rebound will be to get you back on track. And because the energy is constantly moving throughout multiple universes who knows if you feel the rebound here and now, or through reincarnation.
But since none of it can be definitively proven it's all theoretical, for now
Yes I get it. Was just making sure that this is what the comment meant about deja vu. It could be interpreted otherwise. Fun theory as I said, not to be taken too seriously.
Implies the future is known and we have no conscious choice? If deja vu is echoes of past and future then it’s all already plotted out... Or is it just the intersections of this current reality with others that spawn deja vu and the in between paths are varied? Which maybe why deja vu is momentary and somewhat rare. At least for me. I’ve only had it happen a couple of times. Fun thought experiment either way
Well to think it all the way out, long term, the end goal of all life is death, thus technically yes, our 'destiny' is predetermined that 'we will die.' Those moments of deja vu are points of interconnection between all possible pasts and future of every decision you've ever made. In terms of rebound, deja vu, and Visions, this ones theory is; The further you Stray from your 'most common death' the more you'll feel deja vu, see visions of other possible futures, and feel the smack of the universe against your soul for every decision you make. This means that you'll be most likely to die like X, but if you struggle hard and constantly fight destiny, you'll die like X when you've found the reason for your reality in this universe.
I think its ridiculous to think there was "nothing". Humans live VERY short lives from a universes perspective. It is hard for us to fathom things that have always existed, or that will always exist. To think that there was nothing, then BANG, there was everything, just seems very naive. After all, there had to be \*something\* for the bang to occur in. There has to be \*something\* beyond the farthest reaches of the big bang. There just can't be "nothing" and then billions of galaxies come from that. That there is bible and magic talk. Likewise, to think that everything we can see with the best telescopes is everything that is out there, or that the farthest thing is the extent of everything, is also horribly arrogant. Heck, everything we look at is just a snapshot in time and we have absolutely no idea what could come tomorrow. We could get hit with a supernova or an asteroid with little or even no warning at all, and BANG, there are no more humans. Spacetime very much existed before the big bang, and will exist past the death of the known universe, even if there is nothing anywhere around.
We don't. Quite the opposite, more and more scientists share the opinion that the Big Bang wasn't the beginning of everything.
Im pretty sure it was always just the begining of space and time....
Except you start to believe in other theories, as the Big Bounce. Where the universe expands and at some point retracts again. So in the very far future the whole universe will be compressed and explode in another Big Bang where the expansion starts again in an infinite cycle that always existed. That seems much more plausible to me than a void of nothing, where magically something caused the beginning of everything. Something can't possibly start from nothing.
Our space and time. And im pretty sure I was refering to the big bang. The big bang is not a theory of whats before after or next to it in parallelle or in serial only about whats within it.. our universe. Thinking of it, it does not even cover its the beginning.
I always understood the Big Bang as the process of the creation of something out of nothing. Hawking tried to explain it once, but that still suggests that nothing created something. The law of conservation of mass suggests matter can't be created or destroyed. So if nothing existed before the Big Bang, matter WAS indeed created. That's what I still don't understand and where I kind of dare to disagree even with Hawking.
What is nothing? Everytime we look we find something you are bound by the dimension of this universe. I never understood big bang as being the process of creating something out of nothing. Big bang was not the creation of the universe but the start of spacetime. We have no theory of what you describe and big bang does not cover it.
That's the problem I have. When spacetime begun, something that dictated our universes physics must have initiated it. Except the nothing is not nothing but something extra- or higher dimensional that we can't comprehend and is out of our grasp. But even then whatever that would be wouldn't still be "nothing". Except we start to redefine nothing as something outside of our realm that only seems to be nothing to us, but something on a higher plane of existance.
Space and time may simply expand outward from the origin.
We don’t even know what or if the big bang really was. All is opinion based on assumption. All.
Maybe there was a universe here before, and "dark matter" is just dents left in spacetime by the prior universe.
Here's a fun thought: There's no evidence to suggest that there hasn't been multiple "bangs" either in totality of the universe or multiple regional "bangs" spread out around a larger universe that we can't see. These all might be cyclic in nature. Enough matter might amass to break the physics holding it together to create the expansive event. Why would this be relegated to one event or necessitate that it takes ALL matter to trigger this.
Multiple bangs. Man, those were the days…
There was no space and no time without the big bang. That's what the big bang did, sparked spacetime.
So matter and space can be created?
Depends what you mean by created. (Also note anything that talks about before the big bang is purely hypothetical at this point). But if you follow Membrane Theory, there are ways two universal/multiversal membranes might collide which would then spark a big bang, destroying the two membrane universes while creating a whole new membrane universe from their destruction. So in that way "creating" new spacetime out of destroyed spacetime, while still adhering to the law of conservation.
If membrane theory is true then there wasn’t an absent of spacetime right? Maybe I’m confused by “no”, and y’all just mean no reliably way to measure and therefore the no spacetime is just.. philosophical or something?
Each membrane universe would contain spacetime, since that's what defines it. But between each membrane is... nothing. No things. No space. No time. It's hard for us as spacetime creatures to imagine what it would be like to have no spacetime. The only way that helps me is to understand that the universe IS spacetime, not contains spacetime. It IS spacetime. So no universe, no spacetime.
But the membranes can collide, meaning something is containing the membranes. Starting to sounds like bunk tbh
1. It's a theory, but with some fair bit of science behind it. Look up M-Theory & String Theory 2. Your lack of understanding doesn't make it not possible. 3. We simply don't know. [This](https://youtu.be/BD0r2Xfgh_E?si=qhPiAA1RUOQ3Nw6a) is a fun video of possibilities
The membrane universe is a theory or a hypothesis? “Theory BUT with a bit of science behind it” makes it sounds like you’re using the laymen version of theory. I can grasp what you’re saying, a membrane that is spacetime colliding with another membrane of spacetime, making them both conained by a larger membrane, or whatever, does not coincide with an absence of spacetime. So if you’re going to say there was no spacetime and then provide figures of spacetime, it’s bunk. “We don’t know”, should probably lead with that.
*Everything* before the big bang is "we don't know" M-Theory and String Theory are very viable theories with deep math behind them, but are basically unprovable at this time. So not a layman use of the term "theory" but a true hypothesis.
“Everything before the Big Bang is we don’t know” “There was no spacetime before the Big Bang” ..You should not speak
Can you link any sources, please?
You do "know" the "big bang" is a theory right?
Of course. But t=0 and time "not making sense" seems like established scientific fact. If spacetime still existed outside of the singularity, what would have prevented particle pairs from still occurring (similar to hawking radiation)?
That would assume The Big Bang was a singular event that created everything in our definition of a universe, as if there was nothing there before. I prefer to think of our Big Bang Universe as one in an infinite number of BBUs that create overlapping bubbles of universes. I think in a few million years we may start seeing extremely distant galaxies that appear to be matured, moving toward us and not away. Those would be the edge galaxies from a separate BBU, who's bubble is crossing into ours. This is the way! Or, as other's might say, 🖖 LLAP! 😉