Did Time Start at the Big Bang?

  • Published on Jul 18, 2019
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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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Comments • 4 590

  • arjnsdca
    arjnsdca Hour ago

    We should change the calendar to start from the Big Bang!

  • Fallen Plasma
    Fallen Plasma 5 hours ago

    But how was the big bang formed???

  • Tangent Ovaltine
    Tangent Ovaltine 8 hours ago

    Would shrinking matter explain the accelerating expansion of the universe? To my mind, this would mimic the acceleration, you could maybe measure this by observing trajectory curving not explained by gravitational influence. Would probably have to be synchronous or close to it and also affect light in some way. I kinda wonder if something like that would explain matter and energy deficits. As to why, I have a many-worlds theory on that.

  • U
    U 8 hours ago

    You didn’t really answer the question

  • Igor Tolstov
    Igor Tolstov 10 hours ago

    This guy is so passionate about science fiction he is talking about

  • CJ Payne
    CJ Payne 10 hours ago

    The concept of time has no start

  • gamecoolguy619
    gamecoolguy619 12 hours ago +4

    "Anytime you encounter a singularity in the mathematics of a physical theory...it's probably telling you your theory is incomplete and that you push that theory too far"
    ...finally 😄
    * start talking about black hole singularity *

  • Hav G Reso HGR
    Hav G Reso HGR 15 hours ago

    What if it is light that is 'stretching' to cover space that is constant. Set space and an 'elastic' light that fills the dimension. As our telescopes get more powerful we see more distant places in a set space and the lights coming from distant bodies stretches and seeing the 'stretch' gives the illusion to the person observing that the originating body is receding in order words expanding. The cosmic inflation is an illusion, a fallacy of causality. QED

  • carogame
    carogame 16 hours ago

    Was there a singularity? When and where did all the matter come from? Did it always exist?

  • Lewis T
    Lewis T Day ago

    Does time exist? Sure, in your head. I dare ANYONE to prove that it exists outside of your head. Hint: you can't.

  • chrismas
    chrismas 2 days ago

    Did time start at the Big Bang? No. I never asked myself that question before. Here's a question I've been asking myself recently. What's outside of the universe and what's outside of that?

  • George Jacob
    George Jacob 2 days ago +1

    One day humanity will laugh at our concept of time

  • Brendon-Kayne Albertze

    "certain crowd"?

  • Dichtsau
    Dichtsau 3 days ago

    i believe since a long time that we're inside of a black hole, but i'm curious if any1 else ever thought that this also means we're existing reverse through time, because a big bang fed by an outerdimensional black hole would have to spit out everything the black hole swallows before it did do so - unless my idea which i based on ancient myths is true and the big bang is still ongoing! :)

  • Maulik Bagada
    Maulik Bagada 3 days ago

    Am I on lsd?

  • Marcelo Di Cocco
    Marcelo Di Cocco 4 days ago

    Excellent, very didactic explanation. thanks!

  • Arthur Daily
    Arthur Daily 4 days ago

    You been working out that left arm? 💪. T shirt is hanging off you bro

    RAYEN G'T 4 days ago


  • Dolly Dupee
    Dolly Dupee 4 days ago

    If the Big Bang happened in 1 km in diameter. The only way space can continue to grow is by micro nutritions were there in space to feed and grow. To grow from nothing is not probable.
    Pre Big Bang time exist maybe not for us but for someone. Peri and post Big Bang time exist for us.

  • inox1ck
    inox1ck 4 days ago +3

    If time and the Universe starts at the Big Bang there is no notion of before the Big Bang. There is no universal clock according to relativity, otherwise you could go back anywhere in time in principle and time before BB would make sense. So that way infinities which cannot be explained are not necessary.
    This is not something from nothing because there is no moment in time where there was nothing

  • wood1155
    wood1155 4 days ago

    I can't watch this guy

  • T K
    T K 5 days ago

    Geodesic incompleteness is the most satisfying answer to the logical mindfuck that is the question of time having a beginning. And yet, you take it away from me.

    • inox1ck
      inox1ck 4 days ago

      T K it is the only way you don’t need infinities anymore, which can’t be explained. Relativity is against a master clock. The theory is not a complete theory but it doesn’t mean it gives an answer far from reality.

  • Stéphane Blouin
    Stéphane Blouin 5 days ago

    The problem is that they're assuming T=0 means where time starts. That is not where time starts, but the moment the expansion started. The T variable is not so much a measure of time for say, but of time during the expansion. T=0 being the moment a singularity occurred, the initial moment/time where expansion begins but space/time already existed.

  • Tomas Molina
    Tomas Molina 5 days ago +4

    Am I the only donkey that takes like 40mins to watch each video?

  • kn1102
    kn1102 6 days ago

    Did time start at the big bang..... I will say yes if you see time as AD or BC. Now if we are talking of a universe no.
    By the galactic term I would say it never started or has an end , but is a free flowing recycling event + -

    • kn1102
      kn1102 6 days ago

      Now if you could think of an hour glass at the center there is a small space where every thing is put in one spot it will all go one way in the other way like looking in a mirror. So this would apply bouncing from one verce to one more

  • Philippe durrer
    Philippe durrer 6 days ago

    cool explanation with the geodesics, learned something new :)

  • Topsy Turvy
    Topsy Turvy 6 days ago +1

    [: (0-0=∞) (∞-∞=0 :] it's all an eternal CAUSE-EFFECT cycle."WHY?", Why not, dearSocrates? Let's forget about the OBSOLETE logics of ENDOCTRINATION & ACADEMIZATION.

  • Antonio Carranza
    Antonio Carranza 6 days ago

    4:23 I'm tripping out!!!! This video has put me on an Acid Induced state and I have never taste that stuff.


    Is the expansion in space-time directly linked to the “forward” motion of time?
    Would time “revert” should space-time contract and is that why time runs “slower” near super-dense bodies?

  • The Whiz Kid
    The Whiz Kid 7 days ago

    That would be the Big Bang theory, but it is possible to think of negative time. In the early universe, there was a war of sorts between matter and antimatter.
    Matter won, so we live in an universe which is composed of matter.

  • Nudedragon
    Nudedragon 7 days ago

    I know you get a lot of comments saying people are lost, and for sure I'd have a lot of homework to fully understand, but you do a great job making this stuff accessible imo. It's really complex and it's still understandable enough for me to take some information out of each episode that makes sense

  • SomeGuy
    SomeGuy 7 days ago

    His uneven shirt ruined this video for me.

  • Adrian Flatley
    Adrian Flatley 7 days ago

    When did you start these ads??

  • Blue
    Blue 7 days ago

    Great channel and stuff, great topics... but your voice gets a little boring after some time watching you. IMO there can be a little improvement on that. I dont expect you talk like a twitch streamer, but some tricks and techniques can help you out with your view count (I think).

  • Ian Foote
    Ian Foote 7 days ago

    But, the universe ISN'T infinite. It has an edge. So, why do you keep talking about the "infinite universe" over and over when it's not?

  • Vindignatio
    Vindignatio 7 days ago

    what dat music at the end, i like

  • Man Jay
    Man Jay 7 days ago

    Q: Did Time Start at the Big Bang? A: No. Why? Because obviously, there was a "time" before Time. When was that? Well, it was the time before Time started.

  • Robert McMurry
    Robert McMurry 7 days ago

    What is the music playing at the end of this episode during the Last-pass sponsor announcement?

  • tabaks
    tabaks 8 days ago

    Question like this implies we know the nature of time, it even implies time exists. I don't think we're there yet!

    • tabaks
      tabaks 7 days ago

      Hmmm, that's just old thinking. Maybe time is just a theoretical derived measure of energy and wave propagation. "This wave took 20 oscillations of this other wave to propagate from here to there..."

    • Tony Mangaka
      Tony Mangaka 7 days ago

      Time clearly does exist, it takes X time to get from point A to B, that's why we refer to this dimension as 'SpaceTime'. You'd be teleporting everywhere at will otherwise, but implications are way worse, age, your existence, current state of everything as we know it just wouldn't be.

  • john hanrahan
    john hanrahan 8 days ago +1

    How can any action take place without time?
    Was the lack of time the constraint which kept the singularity intact?

  • Apaulo Thegreat
    Apaulo Thegreat 9 days ago +2

    Time began the time God created read my lips

  • patriotgregory
    patriotgregory 9 days ago +1

    Is it possible that math and the laws of physics that govern our known Universe become obsolete at both the Macro and the Micro levels?

  • Aadhitya Sriram
    Aadhitya Sriram 10 days ago +1

    Hey I have a doubt if there was only a infinitely small point what was around it

    • Abe Kane
      Abe Kane 5 days ago

      @Aadhitya Sriram No problem. It's a question I've thought about a lot and it always good to find people curious about the same things

    • Aadhitya Sriram
      Aadhitya Sriram 5 days ago +1

      @Abe Kane dude thanks for taking the time to explain, that I really appreciate. Thank you.

    • Abe Kane
      Abe Kane 5 days ago

      That's a question what can't (yet) know the answer to. Some people speculate there is other universes, but I like to imagine it is a anti-temperospatial negative energy void and our universe is it's opposite, a bubble of positive energy/mass with existing time-space, that the vacuum outside is trying to tear apart, causing our bubble to expand until it pops and returns to the void

  • mert gökgöz
    mert gökgöz 10 days ago +1

    5:28 mentioned singularity is different then what is inside a black hole? Or are they literally the same thing? I assume not but just curious

  • Keshava Reddy
    Keshava Reddy 10 days ago

    I was lost at 3:53

  • Kory Toombs
    Kory Toombs 10 days ago +1

    If time is relevant to the mass of an abject then time was irrelevant before the big bang.
    This means that time acted chaotically or didn't exist.
    Chaos Time is the best.

  • Sawyer West
    Sawyer West 13 days ago

    If time slows down when gravity increases, shouldn’t it be the case that no clock from any observer in the universe could be rewinded far enough to reach T = 0?

    • Sawyer West
      Sawyer West 13 days ago

      A follow up question: how would this adjusting ‘speed of time’ scale the time geodesic @7:24 as the graph shows earlier and earlier time periods?

  • Physics Ghost.
    Physics Ghost. 13 days ago

    Einstein's theory of Relativity says that time flows at different rates everywhere. Therefore the big bang theory where time is traced back to a single point in the past is a misconception.

  • JINXtheGamer
    JINXtheGamer 15 days ago

    It wouldn't surprise me if TBB didn't create time-space but instead expanded in preexisting time-space.

  • Worldwar2 Lucky
    Worldwar2 Lucky 16 days ago

    And did you know all electrons have the same and energy, all exactly identical, all the way up to the Google number

  • ajit thakali
    ajit thakali 16 days ago

    to big bang to happen time is required...time was there before nothingness as well

  • BumOn TheCorner
    BumOn TheCorner 17 days ago

    Living beings with an understanding of impermanence created time. Time is not a natural force there is no such thing as time. It is directly dictated by our sun. However there is timing and yes time and timing are different.

  • God Zilla
    God Zilla 17 days ago

    This deserves multiple viewings. I like the analogy of shrinking longitude lines!

  • Isaac Douglas
    Isaac Douglas 18 days ago

    No one: what if Feynman and hit German techno artist, Kraftwerk, made a collab?
    The creators of PBS Space Time: Say no more...

  • 5pecular
    5pecular 19 days ago +2

    What if there was no big bang. How do we know galaxies are not continually forming?

  • Jonathan Hall
    Jonathan Hall 19 days ago

    Yes. Matter, Space, and Time came into existence at the same time.

  • JJ Dwayne
    JJ Dwayne 19 days ago

    Parabola = observer ?

  • JJ Dwayne
    JJ Dwayne 19 days ago

    Time starts at 1st move. Something from nothing abstract / pre nature/pre- matter.
    Did God/creator take time to think about cubic space? dot Perpetual A to A x y + ?????????
    blueprint for Bang!????? Mind of Creator ??? im out.... my head hurts

  • Uday Kumar
    Uday Kumar 19 days ago

    If time depends on gravity. Then what is the time at the place where non-gravitational space?

  • Kyrlics
    Kyrlics 19 days ago

    Didn't watch the video but i don't believe time exist just because the big bang did. The universe was a singularity. It already existed. The big bang was simply the multi-dimensional expansion of it.
    There were things going on in that universe already. Quantum fluctuations and many other bizzare things that must be pretty hard to imagine, thats if we could even potentially imagine a small part of it.
    Time didn't exist because you, the egg and sperm popped into existence. Things were already happening way before you came in. Just like the big bang.