Does the Past Still Exist?

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Published 2022-07-23
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Albert Einstein taught us that space and time belong together to a common entity: space-time. This means that time becomes a dimension, similar to space, and has profound consequences for the nature of time. Most importantly it leads to what has been called the block universe, a universe in which all moments of time exist the same way together. The future, the present, and the past are the same, it is just our perception that suggests otherwise.

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0:00 Intro
00:58 Space-time
02:09 Space-time diagrams
03:40 Special Relativity
05:05 The Relativity of Simultaneity
10:36 The Block Universe
12:46 The if's and but's
14:50 Sponsor Mess

All Comments (21)
  • I've been patiently waiting for Sabine to make a video on this topic. It's about time.
  • @Gliese380
    The past haunts me every day, whether it still exists or not.
  • @jimihendrix4376
    Not exactly sure about what you said but i did enjoy the way you said it.
  • @richclarke1523
    Also notice that our memories can have differences in this manner. My memories of 50 years ago ( I am 80 ) are in a distant past...but the things I did, that I wish I hadn't, such as being rude as a teenager to someone, and we never forget, is as if it was yesterday.
  • This video made me realize how often we are watching the past. All YouTube videos we watch in the present were made in some recent or distant past and can be played actively as if they are now in the present. All media and entertainment thatā€™s recorded is that way. I think thatā€™s why stories play such an important role in human development - story is time travel.
  • This woman can literally talk about anything and my concentration will never break
  • @mikey1836
    The block universe idea has comforted me for years. All the dead people we know, are still doing things with us "now".
  • @Juice-chan
    Even though I watched a lot of science videos it is the first time I heard about the block universe. Well explained. And now I am mindblown.
  • @kurisutofusan
    This is the first video I see on this channel. This is very refreshing to have explanations without all the usual background music, hyperactive ton of speech, or lots of graphics moving around! The calm tone of the video is very good for learning!
  • @SuperWingram
    I do love the dry humor woven into the ā€˜story tellingā€™ and then referred to again randomlyā€¦a stand up comic schtick that amazingly turns a physics lecture into a conversation between friends. Brilliant.
  • @FCDHVleerstraat
    .. I am puzzled by time too.. having a nice memory is a divine gift and actually works like a time machine.. I am 54 now but one mental step back I am in a moment of time when I was 4 years old...and know how I felt on that moment... that is really really a gift... that is the only time travel we are capable of doing I think, but...let's listen to Sabine !
  • @gdgers
    Germans always speak such perfect English with beautiful accents .
  • This starts to make sense when you think about how we percieve stars. If we observe one star that goes supernova 5 million light years away, and then another star that goes super nova 6 million light years away, each of those events happened a million years apart, and we just happen to be at the oberservable point to witness each at the same time.
  • @Chrisamusic1
    Yes, it does! I'm sitting here in the English countryside, on a dark winter's night, looking high above me, into a sky full of stars; many of which are now dead ā€“ but because of my unfathomably distant vantage point, are still up there shining, still ā€˜aliveā€™. It then follows that an alien being sat on the other side of the galaxy, looking our way through some kind of ā€˜advanced super telescopeā€™, could maybe ā€“ just maybe, see my late mum and dad, meeting for the very first time on that dizzy late summer's evening they used to tell me all about. Believe it; somewhere, everything is still alive.
  • @BokaDeus
    just when I thought I had it Sabine hits me with a "Anything exists now, elsewhere. all obervers viewpoints are equally valid = Everything exists now".
  • @kenmason6135
    Long ago a thought occurred to me about those films my teacher showed our class in grade school that being that the roll of film was all of time past and if you could pick a point or place along that roll is being a point in the past which you could hypothetically look at or even experience. Now it's interesting to see a smart person talking something in those same terms or similar thought exercise. Thank you for your 'films'.
  • @edwardsp1916
    What blew my mind is that when Sabine gave examples of 'now', she knew I was watching the video. Amazing, great video.
  • @hraith
    As a working class layman, thank you for making this topic more accessible to me.
  • The strange things about getting old is that the intimate identification of here and now are slowly lost.One feels transposed into infinity more or less are alone.No longer in hope or fear, only observing.