Fay Dowker: Past, Present and Future: The Science of Time
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- Опубліковано 1 чер 2024
- English version of video
Geneva, 17 May 2018
Talk by Fay Dowker, Professor of Theoretical Physics, Imperial College London
Dedicated to the memory of Professor Stephen Hawking
“The question of the nature of time has been part of human intellectual exploration of our world throughout recorded history. Time both attracts and repels investigation: attracts because there is nothing more fundamental to our subjective experience than its temporality and repels because time is a notoriously difficult concept to pin down.
I will explain what our current best scientific theory about time, General Relativity, Einstein’s theory of gravity, tells us about its nature. I will explain how it does justice, beautifully, to one aspect of our experience of time, its subjectivity. I will argue that General Relativity accords better with our experience than the Newtonian concept of time. I will also describe why there is no place in General Relativity for another aspect of time - our experience that it passes! There are indications, however, that future advances in physics, a theory of quantum gravity, may achieve some coordination with our experience of the passage of time.” Fay Dowker
Fay Dowker is a British Professor of Theoretical Physics at Imperial College London. She conducts research in a number of areas of theoretical physics including quantum gravity and causal set theory. As a student, she was interested in wormholes and quantum cosmology. She was awarded the Tyson Medal in 1987 for her work in Mathematical Tripos at the University of Cambridge. She completed her PhD on space-time wormholes in 1990 with Stephen Hawking.
Welcome by Professor Marcel Weber, Director of the Department of Philosophy, University of Geneva
Introduction by Professor Christian Wüthrich, Geneva Symmetry Group, Department of Philosophy, University of Geneva
With a simultaneous translation into English of the welcoming words by Professor Weber
Starts at 11:11
Events of causal set theory are scattering events of quasiparticles/collective excitations. They are emergent from a more fundamental causal set and so on.
The whole thing is a mystery. Good presentation.
Great presentation!
Fay at 48:00 i think she means she sides with think A not think B.
“We often discussed his notions on objective reality. I recall that during one walk Einstein suddenly stopped, turned to me and asked whether I really believed that the moon exists only when I look at it.” Rev. Mod. Phys. 51, 863-914 (1979), p. 907
This passage inspired the title of David Mermin's well known article "Is the moon there when nobody looks? Reality and the quantum theory." Physics Today, April 1985, pp. 38-47. This can also be applied to two separate non causal events in causal set theory.
Hey its fascinating. Can you explain further?
How so? Application to two non causal events, I mean. Anyway Causal Set Theory is a misnomer, there is no causality only correlation since no event causes any other, they're all there all the time -- what nonsense!
Excellent presentation. I agree with the B argument, time is "process" (birth events). Simply put, I say, "time is a measure of change, no change = no time." Imagine an unchanging, one particle universe. There is no 'time' in an unchanging, one particle universe. There is no process happening. Therefore, no birth events = no time.
Aristotle.
I agree with you, Paul. Time is a "process." This is one of a collection of things, along we "we're not conscious" and "we don't have free will," where I think scientists forget that what they have is a MODEL of reality - they make the map the territory. Some things (we do have free will, we are conscious, and time does flow) are just plainly and self-evidently obvious. I think some folks think it makes them sound brainy to take these audacious positions - it's a way of getting attention.
@@KipIngram "plainly and self-evidently obvious" as geocentric models.
@@LateButGreat :-) Not so much. In the case of the geocentric model, we have ample evidence that shows us that was an incorrect model. It's only plainly and self-evidently obvious if you restrict your attention to your locale. Once you look out at the universe, and for that matter travel out into the universe and look BACK, the geocentric model is "plainly and self-evidently WRONG." There is no such contravening evidence in the case under discussion here. What there actually is is an almost complete lack of understanding, but that's an entirely different thing.
At last I find the person that understands time!!!
Now Here (Nowhere ...)
We can't make the concept of time pure-- we alway need motion.
The expansion of time toward the future is contingent upon its passage. Of course _something_ is moving.
The usual progression of events, and time itself may be two quite separate things. That is, although events seem to follow one after the other (moving toward the future - "the arrow of time"), the "time" for them to take place in is unfolding (flowing) from the future through the present and into the past. Picture a reel to reel tape recorder. The unrecorded tape (future) passes through the record head (present) and onto the take-up reel (the past - history). Time in itself may well "move" in such a manner. [Am I arguing against the "block" of 4 dimensional space-time? No, I just enjoy thinking of it the way I suggested.]
i like your analogy, there are many similar, , , i like your unrecorded tape, and that it represents the future, even un recorded it still exists, like the block universe and the spacetime continuum, , ,
The DVD movie one is more realistic, , ,all of the movie exists in the same way all of time exists, its all in there, you can watch the movie that represents the present moving into the future and the rest of the film, the past has gone but still there, the past present and future all exist, , ,
Thankyou.
19:30 - Davies is completely wrong. Of course time flows. It's obvious to all of us that it does. That's getting on up to Daniel "We're Not Conscious" Dennett level idiocy. People forget that our theories are models that we made up; they start to think the map is the territory.
Great talk but the very end of the talk when he said we are the universe. Not so fast were observers. Did the universe exist before humans observed it. Some intelligent points of view we are the proof that something exists and maybe it made us so we can tell it what it is. We could all be sells in a brain trying to figure out what we are? Just a thought
Do world lines only go forward or can they go backward in space time. What makes them appear to all go forward.
Mathematically it’s due to the the structure of Minkowski space where “distance^2” is measured by t^2 - x^2 -y^2 -z^2 a kind of weird version of Pythagorus’s rule. Except it measures time along a world line . It’s another way of saying that every object moves through space-time at the speed of light.
If we are at rest in space, it’s purely through time. If we are moving we go through both on an angle. The weirdness is the minus signs which say the faster we move through space the slower we move through time. The extreme limit is a 45 degree line, where we move at the speed of light through space which cancels out the time motion through time and time will have stopped.
Now for the simpler explanation, since Increasing time is up, and we always go forwards in time, the fact that worlds lines go up is just the way we have drawn the diagram. All the mathematical stuff is just calculation according to special relativity.
this was a great talk, well done Fay Dowker
That was brilliant. I would have a question: Does time really stop at the event horizon if there are still some events happening like Hawking radiation? Looks like a paradox to me.
Time does not stop there. Why and how should it stop?
The event horizon is just the boundary (a "sphere" around the black hole), from which information (i.e. photons) cannot reach us due to the immense gravitation. Spacetime is bent so much (and thus the gravitational "pull/force" so high), photons cannot escape the inside if this sphere.
Time is local. Space atoms are not causally related across horizon, but on each side time can be measured between space atoms. More, time can be measured only between causally related atoms
time doesn't stop there from all perspecives. remember in relativity there can be more than one valid perspective aka "frame of reference"
Higgs creates particle world line cloud. Flow of time is trail of events?
Einstein said - If you are moving with respect to me, we shall not agree upon the rate of flow of time, your clock runs slower than mine when you move and all processes that change with time change at a slower rate when observed in motion, one clock does not beat out time for the whole universe, a separate clock is needed for each state of motion. , , , , , , , , , , Hmmmmm speed is a process that can change with time, so if an object travelling at an actual 86.6% C has a 2x dilation, would a stationary observer see an apparent speed of 43.3%, , , ?
astronomers keep saying "the edge of the observable universe" and "looking back in time to the big bang" - saying "galaxies are receding faster than the speed of light outside this 'bubble'" kind of means that time, in some places or under some conditions, really would have no meaning, or at least a very different meaning, or action. and since we are now including gravitational waves, bending space/time, then surely we need to start to think of time as waves too.
the movie "arrival" fascinated me as it used interpreting alien language as it's central theme, that the language we use is the barrier to understanding time, and that once we learned the alien language the thought process enabled us to not only remember the past, but remember the future too, far fetched as it may be it is true that we ONLY experience *this instant* in time, any other instant is future or past.
just for the record, in case i AM right, i think at some point another einstein, or another hawking will come along with another light bulb and change everything again, all this string theory and quantum universes stuff is too messy, someone, hopefully in the next 25 years, will have their personal bulb switched on - somehow we need to be traveling outside of time or we won't even explore our own solar system, let alone explore other stars or galaxies. i refuse to believe we are to be tied by the current laws, someone will break them i'm sure.
In spirit form we will travel the stars
Perhaps people experience a state '"outside of time", routinely but in the world of empiricist fundamentalism are told to discount any such experiences?
The way to think about the delayed choice quantum experiment in the context of the Spacetime Wave theory is to realise that the wave quantum passing through the apparatus is taking all possible paths through the apparatus. It is only when a detection is made that the spread out wave is absorbed by the detector.
ua-cam.com/video/zEu-_0ACl3I/v-deo.html
In the Spacetime Wave theory, nature is non-local at the point of measurement.
Regarding the arrow of time: we know that the speed of light can only be positive. We know that the magnitude of a distance can only be positive, so time must always move in the positive direction.
Richard
Wow i will never look at time the same.I guess this how they get the zodiac & its effecta on us
Is it possible that we use 'time' as a measure of change and it varies throughout our universe, the particles change slower or faster in different areas of space dependant on the environment that differs in that particular space. The present is the only constant, the past is a record that helps us shape the present and henceforth the future is un-predictable because we have free-will. If you want to predict the future, surely you cannot interact with the universe you wish to predict as you need to reach it's end point before you can predict it, if you interact with it then you cannot predict it's future as you got involved, but if you wish to exist then you need to manipulate it from the point you can exist. But to be able to reach that point you need to sit back and watch. To be able to sit back and watch don't you need to create a situation where you exist so you can do that and sit back and watch? OMG I'm so confused!!!
How then free will is possible may I ask you
Time & Space are illusions!
This is a teriffic explanation of the development of the understanding of time. I come back to it to refresh my memory occasionally. Edit. I note that entanglement seems to violate the rules of causality so there is more to this than is being discussed at the end.
it doesn't violate causality though it seems like it should
21:33 two hundred and fifty thousand years ago ( 250,000 years )?
Causal set theory should include another of saying by eastern mystics (Tao) with a modern version given by Capra/Chew and others in The Tao of Physics, that seems related to the topic discussed here. Trying to find the fundamental building blocks, the universe is made of, the mystics arrived at the following conclusion: None of the properties of part of the web is fundamental; They all follow from the properties of the other parts, and the overall consistency of their inter-relations determines the structure of the entire web. This view sounds similar to Wheeler who held " time is what stops everything from happening at once"[simultaneity].
I think time is not one dimensional, it is infinite dimensional. Being part of the same web, yet time flows differently for different objects and it manifests as one dimensional.
indra's net?
21:25
Parmenidies 500BC lived 250 thousand years ago? Did she mean to say 250 decades ago? Is this like using ergs instead of joules? Even then this is 2 orders off, not 7 if CGS was on her brain.
lol, pedant. it is disappointing when scientists cock up, it's bad enough when a priest does it.
Yeah I noticed that, I think she was gonna say 2500 years ago but read “500 BBC” and said the number that was in her head. I’ve done that at lectures before where you read a number and remember a number at the same time. It’s an obvious mistake but doesn’t detract from the incredible content in this lecture.
Nearest to accurately defined observation of Actuality, but the "more you know" the less you can believe in alternatives, and the less you can communicate with an alternative POV unless you start from First Principle.
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Babies are natural Physicists and Engineers by accumulated intuitions collected from the surrounding culture.
The Calculus, pure Dynamic Mathematics of relative sync-duration, comes to perceptions as Statics: ie hidden synchronisation @.dt zero-infinity singular, sizeless vanishing point/Singularity), and Dynamics of mass-energy-momentum continuous creation connection cause-effect logarithmic condensation modulation/interference. (It's not what you think, it's everything it's possible to imagine merging into Infinity, like the Hilbert Hotel concept, ie "modular" coherence-cohesion math-quant concepts)
Impossible not to agree with the Professor.
By the way, I can't spell and I just work in a pub, my bad
A tenure harnessed accadamianammazoid -
All world lines start and end in the present since the past is gone and you don’t know when you’ll die. The future doesn’t exist yet.
Time is evil`s defeat because love is endless ! Every quantum movement in Energy wave and particle is recorded by time itself .
"Time" is all-ways the resonance imaging combination information that is omnidirectional-dimensional Conception-Origin, ..here-now eternally, the cause-effect of Clocked synchronous "Spin" alignment->positioning at zero-infinity, ..and the "Conformal Fields" original spacing equivalent to the conception that is simultaneous difference-displacement, (ie Space Time),
..and "Timing" is the Universe of infinitely relatively excluded, be-coming.., measurable degree of non-sync, Math-Phys-Chem specific change/navigation.
The future is mapped for navigation by the probabilities in potential possibilities of the observable past, always at/by the "video recording of memory modulated relative rates of change", cause-effect here-now. The Universe is a Hologram of pure relative motion structured as a "photonic-projection" simultaneous event.
The optimal application of the Physics of Time is in Medical Imaging studies.., leading to a Universal Health state of mind.
The cause-effect modulation of Time Timing is the Universe/Hologram projected by the Quantum Operator Fields Modulation Mechanism of QM-Time Principle In-form-ation.., which turns and tunes e-Pi-i resonance imaging insideout in the manner demonstrated by Veritasium for a Black Hole on the macro scales, but it's the same principle/process for every potential possibility level of orbital in resonance bonding -> Math-Phys-Chem, WYSIWYG in continuous creation connection-completeness of Conception-Origin Superspin-coordination.
It's fun to imagine if you've enough understanding of the Observable Universe to put some elemental compositions of abstract information in this unified context.
It's not easy to visualize because it's equivalent to looking around the Universe at the back of your head ..that i-reflects timed/clocked resonance probability, but not asynchronous "empty" spacing modes of inflation and condensation, "flipside" conformal complexity positioning properties associated with entanglement.
AdS/CFT makes a statement of mathematical conception/assertion. I support the concept without understanding the derivation..
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But all information is temporal, so it's equally a naturally occurring arrangement of component event modulation in an eternal-infinity, and "available" for recognition by resonance "in the prepared mind". (ie I don't know if it should be identified as "Gnosis")
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Practiced sciencing is as reiterative a methodology as the continuously created resonance in Superspin QM-TIMESPACE Principle In-form-ation formulae of relative proportions of time duration timing modulation is the natural occurring Conformal Cyclical Cosmological existence of Eternity-now, the infinity of e-Pi-i resonance imaging of multi-phase superimposed frequency interference that "floats on no-thing", perceived as the Universal Hologram.
Anu Observer sees coherent cohesion objectives in pulsed resonances, of e-Pi-i interference positioning multi-phase state resonance superimposed in perspective, which is "Everything in nothing", on the background of the Universal Black Hole Singularity distributed vanishing point of zero difference in timing connection rates = sync.
The re-definition of Physics terminology in temporal-navigational terminology is first, the forms studied by physicists and proposed to be representative, must be mathematically recalculated and reconstructed to fit the information into the algorithmic objective form, in sync with natural instantaneous differntiation-integration, past-future cause-effect of superimposed frequency interference positioning, the QM-TIMESPACE Principle.
And start all over again, again, again, ..that's the Quantum Operator, Fields Modulation Mechanism in continuity.
O yeah!
@@michaellangan4450 Lol
Does anyone seriously believe that past, present and future events have already happened? Life would not be worth living. Einstein himself was seriously worried by the implications of his theory. It is good to see a physicist has read Stcherbatsky's great book (Buddhist Logic). But the Hinayana Buddhist monks in question would have been horrified by Dowker's use of their ideas. The doctrine of Dependent Origination implies successive slices of time similar to Newton's time and the moral notion of karma, central to Buddhism, means that we are fully responsible for our good or bad actions and that these actions will have repercussions in this or a future life. The block universe world-view is both silly and terrifying and the clever mathematics doesn't change this. I can only hope it will be proved wrong like Calvin's perversion of Christianity that it resembles.
Yes. Go to 26 minutes in. You can actually prove that past present and future exist simultaneously. Time is not linear.
However you cannot actually prove the opposite (the general linear perception of time) - all you can do is experience it, but you can’t prove that your future isn’t happening at that moment. You can prove that it is.
@@oldskoolozzy how is that posible ?
@@filipvasilevski8115 don’t ask me. I wrote that comment a year ago when I was high as fuck.
@@filipvasilevski8115 don’t ask me. I wrote that a year ago when I was high as f*ck. I just read it back and it makes no sense at all.
Complete and utter fantasy. Time is a man made concept.
Space-time is the invention of a mad man.
metaphysical nonsense
What a BORING long drawn out lecture, there was nothing new on aspects of understanding time, , , i believe time travels at the speed of light, so when i see you move relative to me faster and faster, i see you catch up with time making your clock run slower than mine
TIME!! for a DVD movie analogy, , , ,Time is like a DVD movie, , ,all of the movie exists in the same way all of time exists, its all in there, you can watch the movie that represents the present moving into the future and the rest of the film, the past has gone but still there, the past present and future all exist, , , the block universe or space\time continuum, , , if you have seen the movie for the first time, the future is unknown like in real life
Wow. You really do not understand time. Also, please stop misusing commas.
been in business says alot