Sixty Symbols: The Arrow of Time

Completing an action-packed trilogy that began with quantum mechanics and picked up speed with the Higgs boson, here I am talking with Brady Haran of Sixty Symbols about the arrow of time. If you’d like something more in-depth, I can recommend a good book.

Will there be more? You never know! The Hitchhiker’s Guide to the Galaxy started out as a trilogy, and look what happened to that. (But I promise no prequels.)

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9 Responses to Sixty Symbols: The Arrow of Time

  1. George Veenhuyzen says:

    I’ve always thought that time appears unidirectional to us because we couldn’t possibly perceive time going backwards. We know the present because it is different from the immediate past, and we can tell that because we have a memory of the immediate past (a neural connection pattern that was made coincident with the immediate past). If time were to go backwards, we’d have no way of perceiving that because we have nothing from the future that is analogous to our immediate memory of the past with which to compare our in-the-moment experience. If time were to go run backwards, our memories would be undone (those neural connections would become undone), and there is now way to perceive memories being undone.

    Just imagine the characters in a movie on rewind. We are able to recognize that the film is rewinding because, for us, time is still moving forwards and we are able to recognize the difference between our in-the-moment perception of what is happening in the movie and our past memory of what was happening. But the characters can’t have this privileged vantage point because they are caught up in time itself. As their time runs backwards, their memories are undone. How could they possibly recognize this?

    The way I see it, time could be going forwards, and speeding up, and slowing down, and going backwards “all of the time”, and we’d have no way of recognizing that it was.

    You explain things so clearly. Have you ever done a short video explaining the A and B theories of time, or can you link me to one?

  2. Brenda says:

    I liked this episode. I like Sixty symbols too. Thanks for your contribution.

  3. John says:

    Loving the book Sean. Blowing my mind! (a good thing 🙂

  4. Tony Rz says:

    I got married and entropy increased spectacularly, yah it happens, and there was never enough time period, and as I get older time seems to go faster and faster, always toward, what at this time I’d rather not think about. Talk about the arrow of time!

  5. Simon Morley says:

    Surely events have a dependent succession (which is why they can’t all happen at the same time). Quantum objects have events which can be reversed. But composite objects (objects composed of multiple quantum objects) will have a composite event succession, which will be an aggregate of all its quantum components. But these will not be (necessarily) synchronised. So their reversal won’t create the mirror effect (i.e. ‘time’ is specific to each quantum – it’s not an absolute…see ‘interval’ here

    As the compere says to the bad pianist “You’re playing all the wrong notes!”
    The pianist replies “No. I’m playing all the right notes, though not necessarily in the right order.”

  6. Phil Jackson says:

    That was fascinating. From this point onwards I’m scrambling my eggs using the standard model of particle physics.

  7. Simon Morley says:

    @ Phil Jackson: Then live in the dark. Time is subtle but simple. You just need to let go. The most astonishing thing about time is that physics can’t compute it; and the brittle physician could never contemplate admitting it.

  8. MJA says:

    Physics 101

    Does the Earth turn clock-wise or counter clock-wise and which Way are we going?

    Time is simply a measurement of human construct; and like all other forms of human measure, uncertain or only probable at best. Einstein was right don’t you know, God doesn’t play dice or tell time, and the direction we are going is absolutely immeasurable.
    As Nature is


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