Did Time Start at the Big Bang?

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Our universe started with the big bang. But only for the right definition of “our universe”. And of “started” for that matter. In fact, probably the Big Bang is 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 there was no “before”, because time and space simply didn’t exist. If you think you’ve managed to get your head around that bizarre notion then I have bad news. That picture is wrong. 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.

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Hosted by Matt O'Dowd
Written by Matt O'Dowd
Graphics by Leonardo Scholzer
Directed by Andrew Kornhaber
Produced By: Kornhaber Brown
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سلطان الخليفي




  • My crazy guess; when black holes have eaten a few hundred billion galaxies they will a some point through yet unknown physics collapse into a hot rapidly expanding gas (big bang) of hydrogen and helium. This happens all the time around us, but at distances and time scales we can not see yet. The bubbles of big bangs surrounding our big bang pulls on eachother causing our "universe" to expand faster. The extremely violent explotions of black holes vipes out everything in a very huge radius thus making life "short" lived and extremely rare.

    Aleksander StensenAleksander Stensenชั่วโมงที่ผ่านมา
  • Singularity is hard to believe. First is time, so the first star to come into existence burst light photons into space let's say not long after the singularity this photon traverses the universe all the way to our planet which could be billions of light years away but the photon is only a couple seconds old when it arrives,ok makes perfect sense. Matt was saying there was no space and time before the singularity so he essentially is saying that the singularity existed before it had anywhere to be or go before space and time. Also plenty of other issues that would take toolong to explain

    kaiden8701kaiden870121 ชั่วโมงที่ผ่านมา
  • Time is a human concept. There’s no such thing. Only a long and unending chain of events.

    Brian SpanglerBrian Spanglerวันที่ผ่านมา
  • i understand english, but i dont understand what he's talking about

    Resty Moreno LisingResty Moreno Lising2 วันที่ผ่านมา
  • Explanation of the Universe. The space of three dimensions arose from the space with zero number of dimensions. Three dimensions are cracks in zero space that can change their length. They are connected in the center between themselves and rotate around the center of the connection. If you look at them from three-dimensional space. The rotation of such a cell of space is time! The size of such a quantum or atom of space is 1/c2. In the universe of such quanta of space about 10-130 degree units. Time at the beginning of the birth of the universe at first went slowly, and time then began to accelerate. This acceleration determines the acceleration of the expansion of the universe. See here for more details. ru.calameo.com/read/0033783564a96e15b646e

    Андрей ПолевиковАндрей Полевиков2 วันที่ผ่านมา
  • This cool

    Kyle ZappiKyle Zappi2 วันที่ผ่านมา
  • So did it or not tho. Tldr??

    John ConstantineJohn Constantine2 วันที่ผ่านมา
  • At every point in time, there's a past, present, and future. To say there was no time before the big bang would also suggest that there was no past. Also, basing present-day ideas solely on Einstein's theories cuts short our potential for growth. It's like saying, "We don't have to figure anything out, because Einstein did 75 years ago."

    David KellyDavid Kelly2 วันที่ผ่านมา
  • You finally explained space-time in a way I understand.

    Ghost NoodleGhost Noodle3 วันที่ผ่านมา
    • There's a 3-dimensional version of this talk if you're tired of watching it in the old 2 dimensions that we're all familiar with.

  • your mum started at the big bang

    Jesse GallowayJesse Galloway3 วันที่ผ่านมา
  • No, In order for the big bang to have happened time would have needed to begin existence. There had to be real estate for the big bang to occur. Otherwise, it would have been impossible for the big bang to come into existence according to the theory of the big bang.

    Ronald GideonRonald Gideon3 วันที่ผ่านมา
  • What if it started when a program on a high tech computer started up and we are living in a simulation.

    Drew BerryDrew Berry4 วันที่ผ่านมา
  • To some up.. we don’t know much but we have some theories based on some bad ass mathematical equations, that are based on theories, that come to prove or disprove other, theories... man I’m in the wrong line of work!

    Aaron FullerAaron Fuller4 วันที่ผ่านมา
  • In the same way time does not end at the black holes I seriously doubt time started at the big bang. As the singularity suggests we obviously have the math wrong and should start over. What if instead of beggining time we end up outside of an event Horizon of an other black hole? We seriously might be living inside one. Is that not what GR suggests?

    Dougie FuocoDougie Fuoco4 วันที่ผ่านมา
  • Amazing!!!!

    Ms MonirMs Monir4 วันที่ผ่านมา
  • Idk when time started but I know when it stopped ZA WARUDO

    Miguel SilveiroMiguel Silveiro4 วันที่ผ่านมา
  • Practily; that seems to be the key word here everything is hype. but not any proof, science wow, we always need more info and there is never enough!

    gradpa davegradpa dave4 วันที่ผ่านมา
  • I think my brain just underwent a bid bang.

    Imran ShishirImran Shishir4 วันที่ผ่านมา
  • Did time start at the bing bang? Science: Well maybe but actually maybe

    SlotzoffunSlotzoffun4 วันที่ผ่านมา
  • Why would the big bang be. When. We can't hear it why.Why It.s gravity waves. To be

    Richard buntRichard bunt5 วันที่ผ่านมา
  • At the big bang singularity I believe that were no space,there was nothinngness.

    Kevin HoneshKevin Honesh5 วันที่ผ่านมา
  • I am disappointed that you went like your listeners are creationists

    OmnissiahZelosOmnissiahZelos5 วันที่ผ่านมา
  • Hi. Thick Newtonian person here. I cant get my head around expansion. If the universe is expanding then is the space between particles also expanding? Or do the forces within resist the expansion?

    WillWill6 วันที่ผ่านมา
    • I think gravity holds em together

      Supreme Taco84Supreme Taco843 วันที่ผ่านมา
  • Its my third time a watch it... still lost ...going for 4

    Ernesto Carlos Rodríguez ArgüelloErnesto Carlos Rodríguez Argüello6 วันที่ผ่านมา
  • A hundred years ago we discovered that using a false metaphysics to understand math produces a pseudo-scientific restatement of the ancient religious claim that that God created the universe. Pythagoras said that justice is seven. He also warned against beans because they cause farting. One out of two is not bad.

    TeaParty1776TeaParty17767 วันที่ผ่านมา
  • Space and time, as Aristotle discovered w/philosophy, are relationships among things in the universe.

    TeaParty1776TeaParty17767 วันที่ผ่านมา
  • With philosophy, Aristotle identified the eternity of the universe. Some facts are too big for mere science.

    TeaParty1776TeaParty17767 วันที่ผ่านมา
  • What if particles are just shrinking because they're losing energy?

    Phillip OteyPhillip Otey8 วันที่ผ่านมา
    • Particles decay

      Kevin HoneshKevin Honesh5 วันที่ผ่านมา
  • Is there exigent a theory for something akin to a black hole or singularity nova? To explain this we need to make the following assumptions. One, the 'center' of a black hole is not a mathematical singularity but rather something very similar to a neutron star. Indeed, under this model the smallest of black holes that form naturally would be simply a normal neutron star that has grown to a point where light can no longer escape it's gravitational pull. As this object continues to grow, though some mechanism that will not be addressed here, this object would then transition into a smaller object where in the neutrons consist not of up and down quarks, but of charm and strange quarks. Similarly at some much larger mass a transition would occur converting our object into one comprised of top/bottom neutrons. So why would there be a transition? At minimum/maximum curvature of spacetime the higher energy level quarks would become manifest due to overtaking their lower energy counterparts in terms of stability. During such a transition, volume would be greatly reduced while maintaining mass. Eventually however the mass of our object would reach a critical level. A point where top/bottom quarks begin to again destabilize but lack a higher energy counterpart into which to transition. At this point the amount of spacetime curvature would be so extreme that gravity would be approximately equal to the forces produced at the point of impact in a particle accelerator. As we approach this point small variations in the outward pressure exerted by it's constituent quarks would allow some neutrons to naturally superimpose. Thus triggering premature matter degeneration. To put this another way all mass in this twinned particle overlap would then be expressed as energy. And due to the nature of the local environment the type of energy expressed most I think would be heat. These transitions would slow our objects progression toward it's ultimate critical mass. But inflict an escalating level heat at and around the core. Allow this process to continue long enough and another type of critical level might be reached. The core may reach a temperature so hot that matter can no longer exist. At this point all bets are off as our tragically doom object collapses at an incredible rate carrying everything down to the smallest of possible measurements. A sphere with a one plank diameter. A true singularity comprised of only energy with no mass. Well what would happen then? First given the volume of this all temperature would be equalized. Space would suddenly no longer feel the pull of mass that had so severely warped its shape into so small a point. Space would be carried outward pulled by the adjoining space as it attempts to equalize its own internal pressures. The heat and other types of manifest energy is carried outward with this sudden expansion. And so we have the event we call the big bang. This is an interesting idea that I've been thinking on for many years now. It offers us not only a possible mechanism for how the big bang might have formed. But also an answer to what dark energy is comprised. Imagine if you will, that spacetime is expanding far faster than the effects we measure from the motion of galaxies moving away from one another. As spacetime washes over each galaxy it's is compressed and then decompresses as it moves through. This then giving rise to a kind of drag on spacetime that we can observe via the acceleration in the universal expansion. The inflationary period via this model is also very easily explained. Unhindered by the presence of mass, spacetime seems to explode outwards at far greater than the speed of light, carrying all that energy with it. Not in a kind of soap bubble but rather more akin to a sponge that is no longer compressed. Inflation stops once matter begins to form at the point where space is cool enough to allow it's coagulation. Thus a renewed compression/spacetime curvature became exigent. This would bring us to the natural question of, well why didn't everything just recollapse right then? And I think the most likely candidate to answer this would be spatial inertia. Additionally since matter/antimatter is being formed and systematically destroyed in it's creation cycle the amount of mass in any such system would necessarily be lower than the amount a mass in the original object. After all you have to account for all the heat and light that exists during this time. We can see the end result of this in what we call the universal microwave background radiation map. Lastly we come to the only scientific point of which I am aware that would counteract this model which is Stephen Hawking's calculations that point to time beginning at the big bang. What if, all the calculations are correct, but it means something that is subtly different than what we think it means? What if instead of the big bang being the beginning of time itself, the big bang was instead the beginning of the arrow of time. This leads into another idea of mine. What if the arrow of time acts in a way very similarly to that of the electromagnetic force. Move a conductive wire inside a magnetic field and you produce an electric field. Similarly what if the flow of spacetime past celestial bodies above, at, or near to the speed of light produces an effect akin to electricity flow. That being the monodirectional expression of time. Could someone either explain why this model is wrong, or point me to literature that can show the same. If that is not possible then I ask why don't we think that this is what happend?

    Empathy is only humanEmpathy is only human8 วันที่ผ่านมา
    • > exigent Wow! You must read a lot of books.

      TeaParty1776TeaParty17767 วันที่ผ่านมา
  • I'm still not clear why it is assumed that BOTH matter and SPACE were concentrated in this infinitesimal space. Why could it not simply be that all matter expanded into a pre-existing void?

    EASYTIGER10EASYTIGER108 วันที่ผ่านมา
  • I hit play that's when time started.

    HowdeeTMMHowdeeTMM8 วันที่ผ่านมา
  • But it is a theory and a fucking good one

    Paulkeith CharlesworthPaulkeith Charlesworth9 วันที่ผ่านมา
  • Time started with God

    dom crocittodom crocitto9 วันที่ผ่านมา
  • No no; the universe was always hear. This world was once a piece of the sun. The big bang was a solar flare. An explosion in the sun ejected this rock, we call home. And way back a billion years ago. When this rock was ejected, it was still molten lava. As it cooled, as it traveled triugh space. It cooled off. And eventually water waper was formed. In a few million years after this rock was ejected from the sun it slowly turned and water waper formed. Water waper cooled the cracks, and eventually water became lakes. In time water became oceans as this world slowly stopped. That's how you hot this world. Eventually life was creating around. In the water. And the word was extremely hot still . Water wapor cooled things down.

    Gerard MillerGerard Miller9 วันที่ผ่านมา
  • This shit is so deep I can already see the 14 year olds in the comments.

    LumpagLumpag9 วันที่ผ่านมา
  • I’m gonna have a panic attack.

    SandBoy NullSandBoy Null9 วันที่ผ่านมา
  • What is the music playing at the end of the episode and where can I get it?

    Paul SwensenPaul Swensen9 วันที่ผ่านมา
  • th-vision.net/detail/%E0%B8%A7%E0%B8%B5%E0%B8%94%E0%B8%B5%E0%B9%82%E0%B8%AD-JiMqzN_YSXU.html there was no big bang

    Wilfred TorresWilfred Torres11 วันที่ผ่านมา

    Marlo HMarlo H11 วันที่ผ่านมา
  • I was just given to know this. The Universe is not infinite because of the true nature of reality. Still it's potential is Infinite.

    Life's truthsLife's truths11 วันที่ผ่านมา
  • This is purely in the realm of hypothesis, but I imagine our universe is the result of the long death of another one. The inexplicable physics of that universe formed an unimaginably large black hole, and the beginning of ours started from the end of its gravity well (that infinitesimally small point). It had a gravity so intense it not only ate light, it ate a lot of its spacetime as well (since as we know, mass warps spacetime). Then, the Big Bang is kind of a cosmic "appendix bursting" of that black hole, again via inexplicable physics.

    Steve MagruderSteve Magruder11 วันที่ผ่านมา
  • Nah time is always constant you can not control time or fast foward it

    Chris ZigaChris Ziga11 วันที่ผ่านมา
  • The year O = 0 "No matter" who ? th-vision.net/detail/%E0%B8%A7%E0%B8%B5%E0%B8%94%E0%B8%B5%E0%B9%82%E0%B8%AD-0d5eP0wWLQY.html

    James OconnorJames Oconnor12 วันที่ผ่านมา
  • Something came from nothing. Which means that nothing is actually something. Now what is it? Humans don’t know, can’t know ,and won’t ever know. With that being said the Big Bang just doesn’t haven’t without something already being present therefor time already existed obviously

    Rell-JRell-J12 วันที่ผ่านมา
  • I'm still not able to conclude whether time started with big bang or not.

    necromancernecromancer14 วันที่ผ่านมา
  • Speed of light We have a measured speed of light of approximately 186 thousand miles per second We also have two other speeds of light you are not aware of. They are beyond measure yet they have value zero and the speed of now All that exists at the moment of the big bang is light+space and the absolute void the singularity exists within. The singularity at the big bang is light at speed zero, light does not move beyond the point of A The point of B does not exist as a point the ether is also a creation of the big bang. An ether expanding within an absolute void At the singularity were both light and space existing both within a single point and neither having any speed of movement the energy of the light was contained by the impedance of space otherwise light would have moved at instantaneous speed across the void and nothing would exist... All things being created from the interaction between space and light The speed of light through space from point A to point B is 186k miles per second The ultimate speed of light is now, it moves from point a to point b instantly With three speeds for light 2 intuited and 1 observed, you can calculate the impedance of space on light. knowing the impedance of space on light you can create new matter, consume matter for energy or extract energy from space itself. You could even move between 2 points faster than the speed of light. Unfortunately you cannot time travel because time does not actually exist

    lostbuffalolostbuffalo14 วันที่ผ่านมา
  • Infinity is a word that means not measurable, or beyond measure. it is also used to say something is without value or beyond having a value to measure something you need to correlate it with something you know, like how you hold a ruler to line to measure the line. singularity is infinite in there not being a way to measure it But it is not infinite in the sense of having value Singularity is a value in itself just as zero has value on a number line.

    lostbuffalolostbuffalo14 วันที่ผ่านมา
  • Time is merely a mental construct the mind employs to differentiate between memory (past) experience (present) and intuition (future) There is no evidence that time exists as a force of nature Your mental construct is correlated with the world outside your mind creating the illusion of time. Modelling change, or cause and effect moving through time is a useful way of organizing your observations but it is an illusory mental crutch. cause and effect or change do not actually move through time your perception of change moves through your concept of time within your mind Time does not actually exist. The scientific error here is a rational inability to discern between reality and concept.

    lostbuffalolostbuffalo14 วันที่ผ่านมา
  • 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.

    vince pievince pie15 วันที่ผ่านมา
  • 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.

    Jack251190Jack25119016 วันที่ผ่านมา
  • gourd mad duh univarse n duh urf iz flatt, stoopid afiests

    AssmasterFlex69AssmasterFlex6916 วันที่ผ่านมา
  • 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?

    Mark RMark R18 วันที่ผ่านมา
  • "In the beginning.... God".

    Timothy TruittTimothy Truitt18 วันที่ผ่านมา

    Kevin CastilloKevin Castillo18 วันที่ผ่านมา

    Kevin CastilloKevin Castillo18 วันที่ผ่านมา

    Kevin CastilloKevin Castillo18 วันที่ผ่านมา
  • Does time really exist if you're not mortal?

    ccall48ccall4819 วันที่ผ่านมา
  • The background noise in this was annoying as fuuck

    NoShaleGastlyNoShaleGastly20 วันที่ผ่านมา
  • 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?

    LaTerry DorseyLaTerry Dorsey21 วันที่ผ่านมา
  • 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!

  • Gawd didit

    A TothetopA Tothetop22 วันที่ผ่านมา
  • 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.

    waterbornewaterborne22 วันที่ผ่านมา
  • Very cool episode. M-Theory, 2 branes clapping together seems sensible. No?

    neil uneil u23 วันที่ผ่านมา
  • Hard for time to start at an event that never happened.

    PushandillPushbackPushandillPushback23 วันที่ผ่านมา
  • I do believe that time only exists when there is mass identify it's existence.

    Zeyad HanyZeyad Hany24 วันที่ผ่านมา
  • If the universe is expanding are there galaxies that we used to see but we can't anymore?

    karolina ktośkarolina ktoś24 วันที่ผ่านมา
  • 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 notice\understand the explanation. I'll have a beer and forget about it until the next time.

    Stephen HillStephen Hill24 วันที่ผ่านมา
  • The song at the end activated my fight or flight

    Mangekyo3000Mangekyo300024 วันที่ผ่านมา
    • what is the title of this song?

      Patryk BudzyńskiPatryk Budzyński22 วันที่ผ่านมา
  • engineering-and-science.com/general-theory-of-relativity.html

    cosmos and physical lawscosmos and physical laws24 วันที่ผ่านมา
  • 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..

    Strumptavian RoboclickStrumptavian Roboclick24 วันที่ผ่านมา
    • Well, we are children of the universe, so we're caught up in how it works. We are a part of which we describe.

      Steve MagruderSteve Magruder11 วันที่ผ่านมา
    • @Read Marx do you actually believe that? or are you joking around.. there are good arguments for both sides of the debate.. myself I do think it is a lie..

      Strumptavian RoboclickStrumptavian Roboclick17 วันที่ผ่านมา
    • Free will is a lie

      Read MarxRead Marx17 วันที่ผ่านมา
Did Time Start at the Big Bang?