Articles, Blog

Did Time Start at the Big Bang?

November 29, 2019

Thank you to LastPass for sponsoring PBS Digital Studios Our universe started with the Big Bang. But only for the right definition of our universe and “started” for that matter. In fact, the Big Bang is probably nothing like what you were taught. A hundred years ago, we discovered the beginning of the Universe. Observations of the retreating galaxies by Edwin Hubble and Vesto Slipher, combined with Einstein’s – then – brand-new general theory of relativity, revealed that our universe is expanding and if we reverse that expansion far enough – mathematically – purely according to Einstein’s equations, it seems inevitable that all space and mass and energy should once have been compacted into an infinitesimally small point – a singularity. It’s often said that the universe started with this singularity and the Big Bang is thought of as the explosive expansion that followed. And before the Big Bang singularity, well, they say that there was no ‘before’ because time and space simply didn’t exist. Now, if you think you’ve managed to get your head around this bizarre notion, then I have some bad news: that picture is wrong. And at least according to pretty much every serious physicist who studies the subject. The good news is that the truth is way cooler, at least as far as we understand it Now, before a certain crowd starts with “all the scientists keep changing their minds – they don’t know anything”, or “the Big Bang Theory is just a theory” Let me be very clear, the evidence for a hot dense early universe is practically incontrovertible. The Cosmic Microwave Background is a direct line of sight to the universe as it was Only a few hundred thousand years after the hypothetical beginning of time. We can see pretty much directly that all space and matter in the universe was once crunched at least a thousand times closer together There’s also the relative abundance of simple elements hydrogen and helium in particular Whose ratio is exactly what we expect if the entire universe was a dense billions of degrees nuclear furnace for the first several minutes of its existence In fact, There’s powerful evidence that we should not rewind Einstein’s equations that far, at least without introducing some very new physics For one thing there’s also convincing observational evidence that the time before around 10 to the power of negative 32 seconds Included a period of extremely rapid expansion called cosmic inflation We’ve talked about the reasons we need inflation in previous episodes and I’ll come back to it in a bit adding that initial growth spurt solves a couple of the big problems with the Big Bang Theory, but it doesn’t change the fact that Rewinding the expansion of the universe even at different speeds still leads us towards the T equals zero singularity. I’m going to come back to why we need to forget the idea of this singularity Doing so will change the way we think about cosmic inflation and about the beginning of the universe But before we kill the whole idea of the Big Bang singularity, we need to understand what we’re killing What does it really mean for all of space to be compacted into a single point? This idea is especially weird if the universe is infinite Now the universe may or may not be infinite but if we can understand this for the infinite case Then getting all of this for the finite case is baby stuff at least by comparison It’s tricky to talk about the size of an infinite universe Instead of the overall volume or radius we talk about the size of an expanding infinite universe in terms of the scale factor That’s the distance between any two points in space at some moment in time Relative to their distance at some other reference moments that reference moment is typically taken to be right now So the scale factor of the universe is currently one Several billion years ago, the scale factor was half, all points in the universe were half as far apart as they are today. So when I talk about rewinding the expansion, I mean running the clock backwards to track a shrinking scale factor. One way to do that is to keep halving the scale factor. Do that enough times and any two points, no matter how far apart they were, will end up as close together as you’d like. Do it enough times and the universe could end up as hot and dense as you like But it’ll still be infinite, spatially, the scale factor is incredibly small But an incredibly small number times infinity is still infinity Rewinding the universe this way doesn’t leave us with a singularity The singularity is when all points are not just next to each other but literally in the same spot at which point temperature and density are infinite. That last tiny step is a doozy The scale factor goes from incredibly small to zero. So the infinite universe becomes infinitesimal all points become the same point and three-dimensional space becomes zero dimensional That’s the singularity We say that it didn’t happen in any one place because a point is zero dimensional there weren’t spatial dimensions for it to happen in At the same time we say the Big Bang happened Everywhere at once because even the tiniest fraction of a second later The universe has infinite size and everywhere is expanding equally Even if the universe is not infinite then whatever space there is Comes into being at the same time from that singularity. But what happens to time at the Big Bang singularity? To get that you can’t think about the universe as having one big clock that Rewinds and then winks out of existence of the Big Bang or into existence if you’re going forward No, you have to think about time in the way Einstein Intended there is no universal clock time is relative Clocks are attached to each observer each moving frame of reference to see what time does at the Big Bang We have to trace a path through space and time back to the singularity We trace a path called a geodesic which in general relativity is the shortest path between two space-time coordinates These are the grids we use to map space-time Remember that in our rewind all points in the universe get arbitrarily close together before merging at T equals zero Well, that’s the same as saying that all geodesics in the universe converge at the Big Bang singularity In the same way all lines of longitude converge at the North Pole so each Geodesic tracks earlier and earlier times as it approaches the Big Bang infinite clocks rewinding toward zero and then they all converge and Then what? well, then nothing. All geodesics end at the Big Bang singularity and their timelines end with them Or they start depending on how you want to think about it The point is that in the pure Einsteinian picture There is no before the Big Bang because no time line in this universe can be traced there. This is called geodesic in completeness and it also happens at the singularity in the center of a black hole all timelines end this time in the forward direction The analogy with the North Pole is a good one and Einstein himself used it. Lines of longitude end at the North Pole and it’s meaningless to ask what is north of the North Pole? from the pure Einsteinian point of view It’s meaningless to ask what happened before the Big Bang or after reaching the black hole Center? Okay, so I’m taking my time to explain something I already told you is wrong But it’s important because the extreme weirdness of the Big Bang singularity is part of what tells us. It’s wrong Any time you encounter a singularity in the mathematics of a physical theory you have good reason for skepticism It’s probably telling you that your physical theory is incomplete and that you push that theory too far That’s what’s happening here We used general relativity to rewind the universe, but we already know that despite its incredible successes GR Is an incomplete theory? At the crazy densities and temperatures of the Big Bang singularity, and just after, GR comes into terrible conflict with quantum mechanics We’ve talked about that conflict and its possible resolutions before But the upshot is that we just don’t know how the universe behaves in those conditions But we do know that pure general relativity is not a good description and so he probably shouldn’t believe its prediction that all space was compacted into a single point and that this is where Time started. Ok. So what are the alternatives? Can we really track Geodesics? and the timelines they embody through the Big Bang and out the other side If so, what do we find there? There are several possibilities and they deserve their own episodes and we’ll actually get to those soon But to whet your appetite, first up, cosmic inflation can offer a temporary reprieve from the singularity. eternal inflation suggests that our universe appeared as a regularly expanding bubble in an unimaginably larger continuously inflating space-time in that case before the Big Bang was a period of exponential expansion that could have lasted indefinitely We’ll get to the nitty-gritty of that with its inflow tongs and bubble universes real soon There are also various cyclic universe options the first cyclic universe idea was the Big Bounce in which the Gravitational attraction of all matter in the universe was enough to cause it to re-collapse and then presumably bounce outwards again We now know that there isn’t anywhere near enough matter to do that unless we bring in string theory the Steinhardt-Turok model suggests that our universe floats in a higher dimensional space living on geometric objects called brains collisions between those brains initiate cycles of expansion of contraction Then there’s Roger Penrose Conformal cyclic cosmology it’s even weirder because it postulates the infinite future boundary of an eternally expanding universe Looks like the Big Bang of a new universe Mathematically so our heat death is someone else’s Big Bang? There are some less abstract ways to get a new universe out of an old one for example an extreme quantum fluctuation could initiate a new Big Bang given infinite time or The same amount of time could lead to all particles randomly converging back to the same spot Or maybe black holes birth new universes as in Lee Smolin’s “Fecund Universe” hypothesis. There’s a poetry to that last one. The geodesics approaching the black hole singularity Become the geodesics emerging from the new Big Bang singularity people love cyclic and regenerating universes They appeal to our sense of narrative which might be a reason to be wary of these hypotheses Now they also appeal to our intuition for causality Things happen because prior events caused them many of our ideas Just push back the uncomfortable something from nothing moments physicists have a thing or two to say about that from quantum fluctuations from nothing – Stephen Hawking’s timeless interpretation of internal inflation that draws on the holographic principle all things we’ll discuss in the future as we travel beyond the beginning of Space-Time. A big thank you to LastPass for sponsoring previous digital studios LastPass remembers your passwords for you by Auto filling your usernames and passwords LastPass is designed to store the count walkouts, which means you won’t need to answer security questions like ‘What is your favorite childhood pet’s name?’ or, ‘what street did your paternal grandmother live on growing up?’ they protect your data and give you the power to make your passwords impenetrable You could also easily and safely share passwords through LastPass if others need to access your accounts the service works on mobile sites and on apps for iOS and Android The service provides unlimited password storage. There are additional service options available. Click on the link in description below to start today

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  • Reply Tori Rosewood November 6, 2019 at 6:51 am

    Umm.. wot

  • Reply Enize CA November 6, 2019 at 1:14 pm

    I find these videos cheap and boring, clickbait and pointless words. I love the subject but he Just keeps talking and talking about fried air. I prefered the old videos where they talked about how things actually work with as much amazement as me watching..

  • Reply MegaDarktor November 6, 2019 at 3:32 pm

    The universe is perhaps just a projection of what was already inside the singularity which was in fact another universe that contracted itself into a singularity and burst on the other side to create our universe. Imagine it like that infinity symbol where an inflate universe reaching it limits of expansion contract itself back into a singularity which passes through a tiny space to finally explode on the other side, which starts another expansion that reaches it's limit and reverse back to do the same previous thing on an infinite inflation deflation that causes the empty powerful gravity it lefts behind to make it work like a motor piston or a beating heart. LOL , Einstein was right, Imagination is more important than" real science".

  • Reply Richard Shane November 6, 2019 at 9:50 pm

    I'll challenge any mathematician here on this youtube channel

    o' show me where I'm wrong about your mathematics

    mathematics the boogie man of the universe of godless fuks created in the minds of humans for selfish greedy purposes

    now they think they have mastered a belief that create sub sets of reality!

    using it in an erroneous reality called mathematical computation

    There is no such thing as time

    Time is a biological construct of A mammalian species who became aware several million years ago using mathematics as a crux of their greediness

    A measurement that cannot be measured it's all theoretical you tell me one person here that says this is real and true and I'll call you a bullshiting bullshitter

  • Reply Richard Shane November 6, 2019 at 10:01 pm

    Singularities is a common occurrence in well defined spiral galaxys emitted at the Spiral Galactic cores As leading and trailing singularities which created our reality

    That is our big Bang observation

    The original big Bang will never ever be able to be formulated or understood its several rankings if not infinity -1 rankings of realities away from our little existence as human biological species

    which think now we're the ship and they use a moniker called scientist

    You scientists are an alternate reality if you lived in the civilian workforce then you would be ported in reality

    you live in the alternate reality created by big governments for their ultimate reality

    get a fucken civilian job that are lifers in academia and government and see if your GOD called SCIENCE will support your asses in academia and government without taxpayers funds called fuking TAXATION!

    The big Bang of our observation the original big Bang the original creation is so far in different rankings of levels of reality that we will never be able to explain it or prove it

    it's a waste of fucken your time my time

    time that's created by a biological species for their innate understanding that they have a finite time

  • Reply jo will November 7, 2019 at 3:12 am


  • Reply HighlyMediocre November 7, 2019 at 1:15 pm

    The way his shirt is off center on his neck and on his arm……………………

  • Reply Al Garnier November 7, 2019 at 3:03 pm

    Simple answer….YES!
    It's a collision of electrons that create photons, quarks, glueons, protons and matter withing a spiral, thermodynamic galaxy.

  • Reply Nic Hole November 7, 2019 at 3:09 pm

    I'm not a skeptic here but I think this conversation is using different definitions. Time is a human concept of matter interacting with matter. So if all the matter in the universe is "together" singularity. There is no motion, meaning no way to tell time. If you have a magical way to tell time without motion or matter I would completely agree with your premise. But by definition time could only begin at human creation of the concept.

  • Reply Patrick See November 7, 2019 at 8:56 pm

    Maybe, perhaps , maybe. Total speculation without any basis and not testable sport

  • Reply Ezekiel Jarek November 8, 2019 at 1:17 am

    Why is it that no "scientist" can answer my simple question!
    What created singularity?

  • Reply Ezekiel Jarek November 8, 2019 at 1:25 am

    This is fairy-tales made for kids?
    Based on "cosmic rays" scientists can determine what, when, where, and how singularity was created?
    Most people fail to realize one thing. This whole video was "A THEORY" no factual recreation can be made in any lab. This is the same speculation as in religion, do God/gods exist? Except if you question "the science" you become silly, right? How accurate is the big bang theory? What will happen in 50 years when a new theory will emerge, like "The multiverse"? Science can't explain what created the universe. They can't even say where did singularity come from.

  • Reply Ezekiel Jarek November 8, 2019 at 1:31 am

    It's meaningless to ask what happened before the big bang?
    We can determine precisely the north of the north pole! Can we say what happened before the big bang? Come on, now…

  • Reply Albert Barnett November 8, 2019 at 2:04 am

    I find it interesting that all videos that attempt to explain the big bang show the big bang as a speck of light in a void of blackness! This is of course is crap, we as human time travelers can only exist in 3d space and Could never envision the big bang. Prior to the big bang there was no space and no time, no light, nothing! Asking if anything exists out side of the universe is impossible to answer any way but no, thus the universe is infinite since there is no outside, you can't get to the edge if there is no outside!

  • Reply lil jack russell November 8, 2019 at 6:58 am

    I AM!

  • Reply PotatoAim November 8, 2019 at 6:31 pm

    LogMeIn – ahh the wc3 LAN days using Hamachi

  • Reply Mike Walls November 9, 2019 at 6:53 am

    I'm drunk AND stoned, now it all makes sense ?

  • Reply C Haz November 9, 2019 at 1:49 pm

    Woo-woo killer

  • Reply John Flemings November 9, 2019 at 4:13 pm

    This broke my brain.

  • Reply OvalWingNut November 9, 2019 at 7:28 pm

    ⭐⭐⭐⭐⭐ ?? You just blew my mind and I'm lovin it.

  • Reply Stu Mas November 10, 2019 at 12:31 am

    Would it ever be possible for A.I. characters in a computer game, to find out the truth about their creation and the origin of their universe? Perhaps, like us humans, they may be able to figure out the rules of their physics, but I doubt they’ll ever be able to know much else. One thing they might realise, is that no universe can spontaneously create itself. Everything that can possibly exist, requires a pre-existing and continuing host-environment. Put simply, I believe our universe was created, and exists within a greater host-universe

  • Reply Bob November 10, 2019 at 1:08 am

    Space was never crushed into a singularity. The matter in the space was. Matter is not infinite, space is.

  • Reply chris daffron November 10, 2019 at 1:29 am

    So that's a NO?

  • Reply Conrad Pohlman November 10, 2019 at 3:23 am

    Couldn't watch, sleeves kept taking my attention.

  • Reply Sitting On Ceilings November 10, 2019 at 5:58 am

    I'm drunjki realy shouldnt be warching tbisa

  • Reply Keith Smith November 10, 2019 at 1:35 pm

    I just find it very difficult to believe there was nothing, and all of sudden there is an explosion and the whole universe now exists. But hey, what do I know. I’m just a plumber.

  • Reply Rick M November 10, 2019 at 11:12 pm


  • Reply The Spectosphere November 11, 2019 at 7:31 am

    Officially tired of seeing people trying to answer the unanswerable.

  • Reply doxen king November 11, 2019 at 7:38 am

    Video starts at 8:14

    But I would highly recommend watching the whe thing

  • Reply zac galoviz November 11, 2019 at 8:47 am

    420 at 4:32

  • Reply Zes November 11, 2019 at 9:04 am


  • Reply Mark Scott Staggs November 11, 2019 at 9:41 am

    Prior to the big bang there was no time no space and consequently no matter. So what was the first cause?

  • Reply J XV November 11, 2019 at 10:24 am

    I need to know so I can set my clock so I'm not late for work.

  • Reply Dreaming Music November 11, 2019 at 8:23 pm

    Host: "The universe began as a singularity"
    Colliding galaxies: "Are we a joke to you?"

  • Reply Wichard Nieuwenhuis November 11, 2019 at 9:38 pm

    Multi cyclic on a bicycle in beijing, so…. the beginning of time is at the end of the observable… so… is the end of time is at the beginning of observation?. Damn!!! That's why every time I begin to think about this, I'm starting at the end of my thinking… so.. time starts now or in the future and end in the beginning.. ahaaa.!! I get it.. the 'Big Bang' it's my head exploding at the beginning..

  • Reply Leo Yohansen November 12, 2019 at 1:00 pm

    A quantum field excitation is not a singularity.
    The universe is not infinite.
    The unified quantum/spacetime field from which the universe emerged is infinite, not the excitation that resulted in the universe.

    The Schwarzschild radius, a feature of general relativity that is prohibited from ever being reached by the Lorentz factor/zero point energy, prohibits the existence of singularities as well as black holes.

    False Messiah @LeoYohann

  • Reply Derek Frost November 12, 2019 at 2:37 pm

    Unobservable science is basically philosophy. Of course you have as much right to philosophize as anyone, but you do a great disservice when you say it's science..

  • Reply Si Wilson November 12, 2019 at 7:26 pm

    That awesome tune at the end made me want to dance!

  • Reply skuncl8 November 12, 2019 at 9:09 pm

    This is a lot of dancing around the fact that there has to be a beginning. And that there was something that is eternal before the universe existed.

  • Reply Common Sense Criticism November 12, 2019 at 10:03 pm

    I love the jab at the flat earthers. Best part of the video.

  • Reply dom crocitto November 12, 2019 at 10:10 pm

    Time started when God started

  • Reply dom crocitto November 12, 2019 at 10:24 pm

    I propose that the Big Bang never happened. We are still a singularity.
    As you approach the speed of light time slows down relative to where you are because the distance between objects shortens as you approach light speed. At light speed time stops because there is no distance between objects. At light speed everything is in one spot. A singularity. therefore our perception of expansion is an illusion from our point of observation

  • Reply Nick King Televised November 13, 2019 at 2:46 am

    Since time is Relative, isn't possible Time always existed but was traveling faster than the Speed of Light? We know that Space in our own Universe can travel faster than light. It's doing right now at our causal horizon, which is the regions of space we'll never interact with because they're expanding away faster than light. More specifically the Space between them and us is expanding faster than Light, an object can't go faster but Space can do whatever it pleases. Yes, I've been watching Rogan. Anyways since time is relative to Speed, and we know about SpaceTime, and we know that SpaceTime can travel faster than Light isn't it possible time has always existed? Or never existed and is only a function of Speed after the BB?

  • Reply iggy082 November 13, 2019 at 3:07 am

    Of course time started with the BB. You cannot have motion without time.

  • Reply John Zechmeister November 13, 2019 at 7:13 am

    Watching this channel is like putting brain under benchpress, niceeeee :)))

  • Reply Andreas Papadakis November 13, 2019 at 8:59 am

    what is zero?

  • Reply Dave P. November 13, 2019 at 10:07 am

    I've got it! The infinite number of clocks which, of course, have non-zero mass and non-zero speed converging in a single point must have caused the big bang! Everything is made out of clock matter!

  • Reply Cory Ayers November 13, 2019 at 10:44 am

    Isn't in incredible that there is something rather than nothing?

  • Reply Liam Warburton November 13, 2019 at 6:22 pm

    Given that God is infinite, and that the Universe is also infinite…would you like a toasted teacake?

  • Reply Mike G. November 13, 2019 at 11:13 pm

    Time started when you were born. ????????

  • Reply Spkr4TRUTH November 14, 2019 at 12:49 am

    Love the content, but that shirt collar bro, I can’t watch

  • Reply Chisuz November 14, 2019 at 7:58 pm

    im completely not sober and i wonder what did matt mean with the heat death?

  • Reply mattmacd2009 November 14, 2019 at 10:33 pm

    I can't help thinking I've heard all of this before & many many years ago…..

    Douglas Adams & The hitchhikers guide to the Galaxy.

  • Reply Jorge Augusto Guberte November 15, 2019 at 3:54 am

    Lately I've been wondering that the hot dense particle was the primal state of all matter, unaffected by time. When time penetrated the third dimension, that particle was exposed to the possibility of a sequence of events, and then it took the chance. At the precise moment where time penetrated the third dimension, that primal state of matter experienced change for the first time ever. And here we are.

    PS: how or why it, the primal particle, took the chance? I haven't wandered that far yet. But my first guess is "time made it realize it was bored".

  • Reply sharon bestley November 15, 2019 at 11:11 am

    I never understood how the Universe began from nothing or one point. I find your alternative interesting and more logical.

  • Reply Billy Mcnomates November 15, 2019 at 3:48 pm

    So we need to adjust present physical constants and equations to explain the big bang. So all bets are off . If there was a singularity with the mass of the universe it would never expand. Trying to work out what happened then is like getting some caveman to explain the footage from the ISS on a Iphone 10. Dont you dare talk about infinities when the only way quantum theory works is by adding them to equations to stop them exploding because otherwise the divisor is 0! GOOD VIDEO THOUGH 🙂

  • Reply Billy Mcnomates November 15, 2019 at 3:51 pm

    The scale factor never becomes 0. Quantum and string theory wont allow.

  • Reply Holly boop November 15, 2019 at 3:52 pm

    The Big Bang event is simply the only moment in life of the universe on which time was absolute and equal to every observer. From then on, time became a relative dimension. That accounts for why GR can not explain what happens at the very beginning.

  • Reply RedBeardNP November 15, 2019 at 5:50 pm

    No nod to Georges Lemaître for theorizing the Big Bang before Hubble's paper?

  • Reply San Diego Rideshare Driver November 16, 2019 at 3:50 am

    My or… Or a very large portion of hot universe rapidly, atoms shrank going the illusion of expanding space.
    The Big Collapse

  • Reply David Sinclair November 16, 2019 at 4:45 am

    The issue I have the big bang, is the same issue I have with believing earth is the only planet with life, if it happened once, it likely happens alot, its very possible that beyond our known universe there is other expanding universes, but due to the massive distance, nothing from them has became visible yet.

  • Reply Adrian chapman November 16, 2019 at 6:32 am

    so after listening to this how he says everything started at one point and expanded from there , in my head i view it as something was drawing everything ( all masses in the universe to one spot ) than subsequently igniting and blasting everything out at that point , this would destroy the evidence of all matter being dragged into it . so time didn't start at the big bang it simply just another moment in time , this is only my view

  • Reply Michael November 16, 2019 at 11:17 pm

    Your shirt is on crooked

  • Reply TheIceThorn November 17, 2019 at 1:59 am

    Since nothing is made, nothing is loss and everything changes, knowing that e==Mc² we know that energy can't be made or destroyed. That means universe is eternal and eternally changeing.
    What we know is that big bang happened but for sure is not the start because…it can't start nor end. Stealing something S.Hawkings said about "before" the big bang: it's like searching or the corners of the Earth: it's a geoid, it has no corners. Searching for them is pointless.

  • Reply Fernando Alcocer Vera November 17, 2019 at 4:23 am

    this guy is hot!!

  • Reply Canon Wright November 17, 2019 at 6:24 am

    Ok, so inside an infinitesimal is an infinity. Well duh, but if you're saying that in side an infinity small thing, there's an infinity big thing then… You're nuts.

  • Reply Josh Bomar November 17, 2019 at 8:10 am

    Please tell me you had a reason for your shirt being pulled to one side. It's throwing me off man. you arm and neck lines don't allow me to concentrate. I'm sorry

  • Reply Jim Thomas November 17, 2019 at 8:48 am

    Yes , time started after everything was created , but mankind was too stupid to start telling time until 2020 years ago

  • Reply Sandy Manor November 17, 2019 at 4:15 pm

    When GOD put all in motion.. is when it all began.. I tend to grasp onto idea that TIME on the other hand had no significance or relevance until mankind came into play. GOD is outside of time as we humans know it, tho surely is REAL. How can we know HE exists? By seeking to learn HIS real truths. When one humbly seeks with full humility & real concern for self in finding truth, one will meet HIM. Science is facinating, GOD even more so… bec ause HE will reveal HIMSELF by 'lifting a veil' that we cant see thru, until we humbly choose to meet HIM. When its lifted, it's the most amazing astounding thing we can experience inside, and for the remainder of our lives on earth. The cross…. fully truth as well. A NEW knowledge is gifted to all, who truly & humbly seek to understand HIM, & the meaning behind HIS cross. It's something supranatural that takes place when we find & meet GOD- and really cannot be described…because it's something that comes to the 'seeker' outside of mankinds realm. It remains hidden until one chooses to find. It's one of HIS promises: J es us stated: "Seek & you WILL find". There is no 'maybe' that HE added into the words. And there is not a single thing in our human existence more important than HIS truth. This is why one of the greatest songs ever written, was written. Its title: Amazing Grace. .

  • Reply Metaldetection tube world wide November 17, 2019 at 9:36 pm

    Compare the universe like a CO2 bubble being created in coca cola .
    It also seemly begins in a singularity .
    But isn't so …its due to thr pressure drop when bottle is opend , the CO2 molucalair dissolved , comes out of solution .
    Thats my vision …or 'theory' so much simelarity's
    Greets Johny Geerts

  • Reply 1234 November 18, 2019 at 10:34 am

    Before I start this video imma say idk….

    From how I understand time, time and movement of matter is intertwined. If no particles move or change states, then technically they are frozen in time, time is not passing.

    But I know too little about before the big bang to know.

    If particles were moving then surely there was time. Time from how I understand it is simply the movement of particles. If all particles froze in space then no time would pass.

    So if particles were superheated and condensed as they say it was before the big bang then probably time was passing?

    So I will say time was passing. Though to be honest who the fuck really knows?

  • Reply Ruben Raviv November 18, 2019 at 10:09 pm

    Hey I might be saying something stupid, but if the universe is finite in one direction in time, IF that turns out to be true, as in, it has a beginning, doesnt that fact make it more likely it is also finite in the other direction, as in, it has an end? and if it is finite in time, wouldnt that make it very likely that it is also finite in spatial dimensions?

    And to my understanding the universe is pretty symmetrical. Forces tend to work in all directions evenly, right? Then why does time flow the way it does, in one direction? Isnt it reasonable to think there might be something that satisfies this weird asymmetry?
    I am NOT a physicist, and I am NOT being rethorical. I'm really curious, and seriously asking.

  • Reply Billy Mcnomates November 19, 2019 at 5:06 am

    Why are Redshifts quantized?

  • Reply Karl Will November 19, 2019 at 11:51 am


  • Reply Nathan Sharp November 19, 2019 at 5:30 pm

    The geodesic point could just be a node that converges with an inverse geodesic. Time might look more like an hourglass than a single sided plume. Maybe its repeating like a double helix. Maybe the universe is a big guitar, and when one chord rings out, God just strums out another one.

  • Reply Dean Meadows November 19, 2019 at 5:54 pm

    The universe is definitely not infinite.

  • Reply stewart quark November 19, 2019 at 10:08 pm

    I still don't understand why so many feel that time exists as an entity unto itself, or, as a "thing" as opposed to what it actually is

  • Reply Rotor Blade November 19, 2019 at 11:26 pm

    When we compress the space into a single point we imagine that point as a point in space, but remember that point is what is left of space itself

  • Reply Strumptavian Roboclick November 20, 2019 at 1:11 am

    man I've been watching pBs spacetime for a while, I've come to a conclusion.. they just use different words to say the same thing over and over…
    also I'd like to point out that's it's not a humans innate ability to see causality, it's the universe's own need for causation that we've picked up..

  • Reply cosmos and physical laws November 20, 2019 at 10:41 am

  • Reply Mangekyo3000 November 20, 2019 at 2:45 pm

    The song at the end activated my fight or flight

  • Reply Stephen Hill November 20, 2019 at 3:16 pm

    Ah. Another video from PBS that I hoped I would understand but didn't.
    If the universe wasn't created out of a singularity then how was it created? He said he would explain but I didn't noticeunderstand the explanation. I'll have a beer and forget about it until the next time.

  • Reply karolina ktoś November 20, 2019 at 5:31 pm

    If the universe is expanding are there galaxies that we used to see but we can't anymore?

  • Reply Zeyad Hany November 20, 2019 at 9:08 pm

    I do believe that time only exists when there is mass identify it's existence.

  • Reply PushandillPushback November 21, 2019 at 1:56 pm

    Hard for time to start at an event that never happened.

  • Reply neil u November 21, 2019 at 3:04 pm

    Very cool episode. M-Theory, 2 branes clapping together seems sensible. No?

  • Reply waterborne November 21, 2019 at 10:53 pm

    Spacetime is just an emergent construct from quantum fields. As such time as we know it is not fundamental and is just an emergent property from the energy and information that forms the quantum fields.

  • Reply A Tothetop November 22, 2019 at 9:14 pm

    Gawd didit

  • Reply ONNIE TALONE November 22, 2019 at 9:28 pm

    wow a PBS video one can comment on, about time? time is so hard to understand, as did not begin, so has no end but has no middle, so what time is it, simple question, cannot be answered when asked about something that does not exist, Bend time, ripple time, but how can time have no real value in the Universe!

  • Reply LaTerry Dorsey November 23, 2019 at 11:10 am

    Would the Big Bang be equivalent to the first time a sentient mind forms a thought? Could the " Speed" of said thought be somewhat equivalent to the speed of light? Quantum mechanics says Thought creates matter, correct?

  • Reply NoShaleGastly November 24, 2019 at 5:43 am

    The background noise in this was annoying as fuuck

  • Reply ccall48 November 25, 2019 at 8:55 pm

    Does time really exist if you're not mortal?

  • Reply Kevin Castillo November 26, 2019 at 12:12 am


  • Reply Kevin Castillo November 26, 2019 at 12:15 am


  • Reply Kevin Castillo November 26, 2019 at 12:18 am


  • Reply Timothy Truitt November 26, 2019 at 3:30 am

    "In the beginning…. God".

  • Reply Mark R November 26, 2019 at 5:29 am

    how do you measure and track a point in space in time? like, how can you compare the distance of two points in this moment and then the next moment? what even is a point? a quark? or the 'fabric' that the quark exists on? if comparison requires delineation, what is being compared?

  • Reply Buttmaster Flex 69 November 28, 2019 at 8:40 am

    gourd mad duh univarse n duh urf iz flatt, stoopid afiests

  • Reply Jack251190 November 28, 2019 at 3:31 pm

    Time started when matter or rather energy came into existence. Why? Think about how we measure time. It is the change of state or location of matter. Without matter, time means nothing.

  • Reply vince pie November 29, 2019 at 1:38 am

    No, there were surely causal sequences of events before hand that resulted in the big bang, we just have no idea for sure what any of it was or could be.

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