There was a man named bright, who traveled faster than light, he left one day in a relative way, and returned the previous night. My version.

Interesting lecture, and PI shows once again that in fact it is possible to record a human voice in the 21st century century in a proper way. Some other institutes seem not convinced about that yet.

Dear Perimeter Institute for Theoretical Physics =) I would like to say, thank you, to you for taking the time and effort to both upload and share this video with the youtube family =). I hope you have a lovely day, Perimeter Institute for Theoretical Physics! =) Kind Regards Raymond Lai (Member of the Physics Family)

This is my first time seeing Professor Dowker on YT! I was so shocked! In my opinion, she is one of the best lecturers of the "golden triangle".

I am actually very impressed. prof Dowker explained it very well, she touched on subjects I wondered for a while, and it is useful to have it in one space

So much packed into one lecture. Well done Fay!

OMG, what a beautiful talk. 37:52 Most important conclusion: "The value of the entropy, that it is the number of Planck-sized pixels on the [black hole event] horizon, suggests that there is something 'atomic' going on, that the black hole horizon is comprised of individual microscopic 'somethings' on the scale of the Planck length. ... *But the horizon is just a surface in empty space-time, so that suggests that space-time itself ... is made of microscopic grains, that space-time itself is atomic at Planckian scales.*"

Whenever great scientists refer to other great scientists lectures from the past I feel like I just found a rare gem

I love watching her and amazingly I've actually learnt something thanks, Fay.

What are these commenters below talking about? She has a clear and understandable speaking voice, the sentences are well-formed. A good presentation.

I really like the idea that time is local,discrete and causal. And,the conceptualisation that spacetime is granular by its very nature,is both breath taking and a "quantum leap" in our understanding of our universal lives.

Brilliant and elusive lecture on blacholes and entropy.

Yes and she also has the best way of explaining entropy I've seen yet.

Extremely well done lecture. Dr. Dowker did a superb job.

Fay is a real inspiration to me. Just like the elegant articulation of her theories in this lecture; her actual theories have an elegance to them. Her Causal Set Phenomenology article is concise; to the point but also beautifully demonstrates that you don’t need to add unnecessary flamboyance to get your point across. Show evidence, explain the evidence and leave it to your reader to imagine analogies and situations that it may be appropriate to.

awesome talk!

very impressive lecture

Really well done, made complicated things easier to understand, impressed by the clarity of her mind.Thanks

Fantastic lecture. Much appreciated.

A fascinating, thought-provoking talk.

Brilliant lecture, many thanks for upload!

absolutely brilliant! Thank you

Wow, what a brilliant lecture, such an inspiring idea, it has such a simplicity about it that is begs to be true, will look forward to following this hypothesis develop

Having recently read Susskind's "The Black Hole Wars" I certainly had a lot of questions about the relationships between thermodynamics and black holes, which the book did not clarify for me. Dr. Dowker's talk here was very much enlightening on many of those questions. Great talk, very comprehensible.

She's giving a popular lecture on a particular theory (causal sets) for quantum gravity. The simple stuff at the beginning is just prep work for the more interesting stuff that comes later.

cool presentation and totally interesting

this is way beyond what I can digest.

She explains all these concepts a lot better than most of the people I have heard before! Hopefully in 50 years they teach the Law of Black Hole Mechanics and other theories in grade school along with the Laws of the Motions and Thermodynamics.

She's brilliant. Wonderful talk.!

Wonderful lecture

awesome content

I thought she did a great job - a very enjoyable lecture. She managed to be perfectly clear throughout her presentation, and her manner very pleasing as well.

so excellent.

Great discussion that got me to thinking about causality and quantum mechanics. At the Planck temperature, any additional energy added would not cause the temperature to increase. A temperature increase would cause the wavelength frequency to reduce below the Planck constant. This reminds me of what happens during a phase change. Thermodynamics has us use enthalpy to measure the increase in energy instead of temperature during a phase change. With that thought in mind, causality at the quantum level must change "shape" to avoid exceeding the speed of light or reduction below the Planck constant. An example of information flattening at the space-time surface of a black hole. On a side note, if a black hole has "no hair" can all properties of matter be derived from just angular momentum, electric charge, and spin using curvature of space-time?

so informative and complete...i try to understand physics. "causality limitation" make calculating action and reaction across a vast scale simpler. thanks

I can't believe Fay Dowker is on KZfaq! She was our lecturer at Imperial College London for the first year undergrad Mathematical Anaysis course in 2010. Just find it a little weird that a world expert in Quantum Foundations and Quantum Gravity could be teaching an elementary undergrad course! lol

Wow she's an excellent teacher of known and accepted physics

Very interesting. Thanks

Interesting, thought provoking talk. BTW the expansion via number of space/time granules would mean that in order to go back in time you would have to decrease the number of space/time granules. So it seems the arrow of time goes with the increase.

Thank you for a very informative and well spoken explanation. Thank you for making the effort to explain it in terms that a troglodyte like me can understand, a bit. And my thanks to the sound engineer, it was a pleasure to hear. I also listen to Leonard Susskind, his material is excellent but the audio quality on his lectures is abysmal.

Thank you for a great talk! So, I guess the universe *_really does_* contain an 'aether' - and it's made of Planck-scale space-time itself! It's like a 'fluid' that moves, curves, & flows. ℝ𝕚𝕜𝕜𝕚 𝕋𝕚𝕜𝕜𝕚.

I've noticed that inserting the proper fraction can make any equation work as long as you already have the answer you want.A the light from a galaxy beyond a causal horizon could reach us, if only indirectly. If stars (or galaxies) have photoelectric properties, the light could be transmitted to others. If I step on a pin, my brain will know it, regardless of the equally vast (relative) distance.

I'm listening to this to put me to sleep at night (I figure I'll make out what she's saying after about 20 listens). I just picked it up in the middle again and she's talking about black hole horizons - the threshold that, when crossed, "you can't get out" she said. Now a thought occurred to me, that the horizon is really relative to the object in question - based on several factors - the thrust you have available, your speed, your trajectory, and your mass (at least those). For a given mass, speed, and trajectory, for example, if you were in free-fall, the horizon (for you) would be much farther out than if you had thrust available. An extreme example would be between you and a star - the star bringing a lot more warped space-time to the equation. So it seems, to common sense at least (which, it appears, doesn't always apply in cosmology or particle physics), that the horizon is relative to the characteristics of the object, and is not a fixed point in space for all objects, as she implied. (something tells me they know this, but they never point it out - scientists not being trained verbal communicators) (and, to give critique - she was terrible in that category here! - I do pity her, however - tongue-wagging and thinking do not go together - tongue-wagging being so primitive and geared toward the physical world (meaning sex), which is nothing but a distraction)).

24:20 - I can't help noticing that if we choose units where c=1, then delta E = delta M, so the left hand side of those equations are the same quantity.

A brilliant lecture, and I don't often say that.

ENERGY: In discussions with others here on the internet, I have come across 3 different views concerning 'energy' so far. 1. Energy cannot be created nor destroyed. (One of the foundations of physics). 2. Energy can be created and possibly destroyed. ('Dark energy' coming into this universe by some means). 3. Energy does not actually even exist. ('Energy' is just a name given to a concept of two or more interacting forces. It does not actually exist in and of itself). So, which definition(s) is/are really true? An inquiring mind would like to know.

@ Kai Tale: She's a physicist, not a radio/TV personality.

Super brain Prof Fay Dowker. My money is on her discovering a Grand Unification theory in her lifetime. I watched all her lectures posted on KZfaq and she is possibly the only match for Hawkins.

To say that spacetime itself is granular (could one say "particulate"?) is a significant departure from most current accounts of the Standard Model.

excellent

Exceptions to the 2nd law of thermodynamics: 1. Salad dressing: (Vinegar, Oil, Water): Mix the heck out of it and let it sit. Over time, the fluids become orderly due to the forces acting upon them and their own internal interactions. 2. The hexagon on Saturn: Swirling mixed up winds form a hexagon in certain circumstances, also the forces acting upon them as well as their own internal interactions. 3. The structure of the atom itself hasn't changed, why not? 4. The forces of nature haven't changed, why not? 5. Knowledge increases from within this universe itself, how can that be? 6. And I could go on, but I won't right now, so where is the entropy there even?

ISTM that The Law of Probability should be considered as expanding any concept of causality. For example, the hundredth time I flip a coin is in some sense influenced by the previous ninety nine flips and it is not limited by the speed of light. Entanglement then could be explained as a 1:1 probability. Excellent lecture!

"...Watch this space..." LMAO!!! That was funny!

Super bowo!

In 56:06 prof. Fay Dowker says: "The volume of Universe is 10 to 240 in Plank units". But how it can be when Radius of observable Universe in Plank lenght is 10 to 60. Then what is with formula for lambda fluctuations!?

At 39:56 we have the most British definition of causality: "if someone makes a loud noise over there I drop my cup of tea". I love it! :)

What a great word;" Atomicity".--@2;56

What happens to individual particles of atoms when they enter a black hole? It would seem that each particle would be made to take on some new quality when becoming a part of a black hole.

Dear Prof Dowker, how can I get a poster of the entropy diagram? It resonated with me. Very clear, enlightening lecture. Thanks!

Can a black hole , have such a high charge it could change the distance of the event horizon for differently charged particles ? can the charge be so strong a particle could hover , at the event horizon ?

1:08:59 'we don't know what causality means in a quantum context'. That sounds kind of important -

When an object approaches the speed of light moving away from us, does its light shift to the infrared. If there are objects that have already reached the speed of light moving away from us, is that light just locked in space? The object is obviously not actually traveling the speed of light, only in relationship to the distance it is from us.

Great lecture, although I am lacking some prerequisites for following the causal set theory. Note, however, that an American professor would not be confused about whether the cup contained coffee or tea.

Is time and entropy is same thing, both are moving in only forward direction

Great talk. I would like to see an elaboration of the answer to the question the guy asked about why we can't tell if we're passing through an event horizon, or why you can't tell if you're inside an event horizon. Can two observers inside an event horizon send information to each other?

Having read - without really understanding big chunks of - Penrose's 'The road to reallity', I believe I can rememer a picture in the loop quantum gravity section of his book being quite similar to her introductory picture of causal sets; is there a relation between this causal set theory and loop quantum gravity?

What part does the Atmosphere play and the magnetosphere?

I understand the idea that one event can not effect another if the two events are separated by the limit imposed by the speed of light but what about quantum entanglement. If particle a on earth were entangled with particle b on alpha centauri there would be a connection

I think i got it....in singularity particle stops moving but in event horizon there is entropy. Curvature of space can also be seen as energy.

To repeat: The earth is not a closed system. The smallest closed system that can be imagined, relevant to life on earth, is the sun earth-system. The entropy of the sun-earth system does increase with time. Therefor life on earth does not violate the second law of thermodynamics.

This talk suggests a possible and somewhat frightening potential explanation of the universe - that it is actually arrayed on the surface (at the event horizon) of a very large black hole.

Understanding that the "grains" she spoke of are of space-time, and not space, as a non-scientist, I still wonder how the expansion of space is realized in terms of units. Does space expand in numbers of Planck unit cubes? If so, does it expand evenly in all directions? Also (hey, why not?) if space-time were truly continuous (not "granular"), would that not imply that both space and time would be infinitely divisible? And would that not inevitably introduce an infinity that would scream "singularity" (or, in pinball machine language, "tilt!") ? Is there not a sense in which math is inherently discontinuous? It seems true that human language concepts are necessarily discontinuous (in the business of creating distinctions between this and that), and that IF math is a subset of human concepts, it would be no exception - hence naturally applicable to a granular universe..

14:30 I guess it depends on what you consider order. Over time, without adding energy, things will cool and tend to settle. Oceans are where water pools up, oil pools, things that are similar in structure tend to glom together just from gravity. Is that because of a dissipation of energy (loss of heat)?

Isn't the surface gravity, the gravity at the event horizon of a black hole, always the same? The surface area of the event horizon depends on the mass, but the surface gravity is the same. Am I missing something?

Thank You Dr. Dowker and PIOutreach for another fantastic lecture. As with a few other viewers, I'd enjoy finding out if and how Causal Set Theory may be expanded into an Acausal Set Theory via Entanglement. Do you believe that this is a necessary attribute for a plankian/atomistic construction of spacetime? Is Entanglement a necessary ingredient in any theory of quantum gravity? I'd enjoy hearing any pros and cons.

infrared radiation is a form of electromagnetic radiation (i.e. light). Thermal energy is the movement of particles. Infrared radiation can carry heat energy through space by being emitted by hot objects (thus taking energy out away from them/slowing them down), then zoom (at the speed of light) across the room, planet, solar system, universe, be reabsorbed by another particle, thus giving it more energy, and causing it to move around faster. Heat is particles moving, IR is a way to transfer it

This lady does not have a ring on, unbelievable there’s gonna be a lucky guy out there to have such a smart lady.

It is how modern physics seems to evolve. If phenomenon (mathematically) look the same with another, it is actually guessed to be it. In other words, an analogy in the fundamental physics is no longer deemed just an analogy. Duck Typing was adopted by programmers as a practical approach to reduce duplication of the same code. You can think of Universe as a huge computer computing according to the laws of physics. Then, if analogy is found, it is probably computed by the same "function" (law).

welcome

Yes, the famous Hawking Radiation. That is a perfect analogy for what will take place concerning the dimensional quarantine of this realm. That quarantine will be the metaphysical "black hole" that will absorb into it all "particles" and yet release all of the anti-particles where these are polarized toward and away from the essential energy of that being. This "unity" will be a duality of what the quarantine absorbs and rejects. When that is completed then the separation of all such entities as are polarized in this way will be complete. There will be nothing left in the universe except two classes completely separate and immiscible, and there will be no cause for their being reintroduced to one another. THAT will be similar to the end this world can expect when its beings are completely separated by their moral qualities, which are antivalently distinguished with terms analogous to "Good" and "evil". But it is not symmetrical, and the "evil particles" will be unified into what is metaphysically understood as "oblivion". That will be completely separated from reality "as such". A TRUE black hole in existence, but then dispersed for lacking mass, because it will be transmuted into nothingness. Thoroughly dissipated.

"Space" is energy itself, the pulsating, swirling 'gem' photon being the energy unit of this universe that makes up everything in this universe. "Time" is the flow of energy. "Temperature" is the interaction of energy. Revised TOE: 3/25/2017. My Current TOE: THE SETUP: 1. Modern science currently recognizes four forces of nature: The strong nuclear force, the weak nuclear force, gravity, and electromagnetism. 2. In school we are taught that with magnetism, opposite polarities attract and like polarities repel. But inside the arc of a large horseshoe magnet it's the other way around, like polarities attract and opposite polarities repel. (I have proved this to myself with magnets and anybody with a large horseshoe magnet and two smaller bar magnets can easily prove this to yourself too). 3. Charged particles have an associated magnetic field with them. 4. Protons and electrons are charged particles and have their associated magnetic fields with them. 5. Photons also have both an electric and a magnetic component to them. FOUR FORCES OF NATURE DOWN INTO TWO: 6. When an electron is in close proximity to the nucleus, it would basically generate a 360 degree spherical magnetic field. 7. Like charged protons would stick together inside of this magnetic field, while simultaneously repelling opposite charged electrons inside this magnetic field, while simultaneously attracting the opposite charged electrons across the inner portion of the electron's moving magnetic field. 8. There are probably no such thing as "gluons" in actual reality. 9. The strong nuclear force and the weak nuclear force are probably derivatives of the electro-magnetic field interactions between electrons and protons. 10. The nucleus is probably an electro-magnetic field boundary. 11. Quarks also supposedly have a charge to them and then would also most likely have electro-magnetic fields associated with them, possibly a different arrangement for each of the six different type of quarks. 12. The interactions between the quarks EM forces are how and why protons and neutrons formulate as well as how and why protons and neutrons stay inside of the nucleus and do not just pass through as neutrinos do. THE GEM FORCE INTERACTIONS AND QUANTA: 13. Personally, I currently believe that the directional force in photons is "gravity". It's the force that makes the sine wave of EM energy go from a wide (maximum extension) to a point (minimum extension) of a moving photon. When the EM gets to maximum extension, "gravity" flips and EM goes to minimum, then "gravity" flips and goes back to maximum, etc, etc. A stationary photon would pulse from it's maximum extension to a point possibly even too small to detect, then back to maximum, etc, etc. 14. I also believe that a pulsating singularity (which is basically a pulsating photon) is the energy unit in this universe. 15. When these pulsating energy units interact with other energy units, they tangle together. Various shapes (strings, spheres, whatever) might be formed, which then create sub-atomic material, atoms, molecules, and everything in existence in this universe. 16. When the energy units unite together they would tend to stabilize and vibrate. 17. I believe there is probably a Photonic Theory Of The Atomic Structure. 18. Everything is basically "light" (photons) in a universe entirely filled with "light" (photons). THE MAGNETIC FORCE SPECIFICALLY: 19. When the electron with it's associated magnetic field goes around the proton with it's associated magnetic field, internal and external energy oscillations are set up. 20. When more than one atom is involved, and these energy frequencies align, they add together, specifically the magnetic field frequency. 21. I currently believe that this is where a line of flux originates from, aligned magnetic field frequencies. NOTES: 22. The Earth can be looked at as being a massive singular interacting photon with it's magnetic field, electrical surface field, and gravity, all three photonic forces all being 90 degrees from each other. 23. The flat spiral galaxy can be looked at as being a massive singular interacting photon with it's magnetic fields on each side of the plane of matter, the electrical field along the plane of matter, and gravity being directed towards the galactic center's black hole where the gravitational forces would meet, all three photonic forces all being 90 degrees from each other. 24. As below in the singularity, as above in the galaxy and probably universe as well. 25. I believe there are only two forces of nature, Gravity and EM, (GEM). Due to the stability of the GEM with the energy unit, this is also why the forces of nature haven't evolved by now. Of which with the current theory of understanding, how come the forces of nature haven't evolved by now since the original conditions acting upon the singularity aren't acting upon them like they originally were, billions of years have supposedly elapsed, in a universe that continues to expand and cool, with energy that could not be created nor destroyed would be getting less and less dense? My theory would seem to make more sense if in fact it is really true. I really wonder if it is in fact really true. 26. And the universe would be expanding due to these pulsating and interacting energy units and would also allow galaxies to collide, of which, how could galaxies ever collide if they are all speeding away from each other like is currently taught? DISCLAIMER: 27. As I as well as all of humanity truly do not know what we do not know, the above certainly could be wrong. It would have to be proved or disproved to know for more certainty. _________________________________________________________________________________________________________________________ A test for the gravity portion of the above TOE is as follows: Here is the test for the 'gravity' portion of my TOE idea. I do not have the necessary resources to do the test but maybe you or someone else reading this does, will do the test, then tell the world what is found out either way. a. Imagine a 12 hour clock. b. Put a magnetic field across from the 3 to 9 o'clock positions. c. Put an electric field across from the 6 to 12 o'clock positions. (The magnetic field and electric field would be 90 degrees to each other and should be polarized so as to complement each other.) d. Shoot a high powered laser through the center of the clock at 90 degrees to the em fields. e. Do this with the em fields on and off. (The em fields could be varied in size, strength, density and depth. The intent would be to energy frequency match the laser and em fields for optimal results.) f. Look for any gravitational / anti-gravitational effects. (Including the utilization of ferro cells so as to be able to actually see the energy field movements.) (An alternative to the above would be to shoot 3 high powered lasers, or a single high powered laser split into 3 beams, each adjustable to achieve the above set up, all focused upon a single point in space.) 'If' effects are noted, 'then' further research could be done. 'If' effects are not noted, 'then' my latest TOE idea is wrong. But still, we would know what 'gravity' was not, which is still something in the scientific world. Science still wins either way and moves forward.

is it possible that an atom can "go back in time" ----AND change it's polarity? this to me represents a Möbius curve?

A well-paced chat at the lay level. But I began to feel uneasy around the time that "standing on the threshold of unity" came around. The justification for the planxellation [sic] of spacetime just isn't there. Area is a continuous classical concept/thing, and the fact that it can be chopped up in no way implies that spacetime itself is similarly chopped up. Anyone can perform arithmetic division without believing that it has hard physical consequences.

If quantum entanglements were resolvable with simultaneous equations, would it help?

Few people can talk about this stuff as well as Fay Dowker.

This is interesting. Where do we have proof of plancks length/constant? And I want to theorize that the "grid" or "granularity" of spacetime has an uncertainty. That is to say that it doesn't all fit into a rigid lattice.. but all things actually fall into some kind of planck uncertainty that is a superposition between one grain and another or the neighboring grains.. in the form of an amount of being in one or the next.. Not to mention lambda and the uncertainty that has to do with expansion when there are supposedly these "grains" of planck volumes.. I think that means that it may be possible that the planck boundary (grain boundary of the universe at the smallest scale) is able to be located with an uncertainty of 1. (And then what is 1 - 1/lambda, and how might you look at that for the de brogle wavelength of a unit of spacetime 1 of the plancks constant.. with an energy (mass) lambda) and what would that mean in relation to lambda and how might that affect things to arise with formulas and calculations that lead us then to working formulas that would explain things like Surface plasmon polaritons interacting with light and basically.. across the surface of an interface which is however smooth, atomically bumpy.. There really isn't any point in this other than to say well there is kinetic energy and space time and the granularity has an uncertanty that has to come to some outcome.. even with single photons.. but might have to do with quantum theory. but also is related to the fact that you can shine a laser across the moon or space and that could travel faster than light in the form of information.. (Which is interesting causally as well but has to work out in our observable universe with the granular theory and the idea of plancks constant..)

I get tired when I get hot are my atoms miss behaving?

Space Time The String , Time And Space The Vibration Or Frequency , Gravity And Black Holes Stretching The Strings Causing Them To Vibrate With A Beginning And End In Perfect Harmony And Discourse . Creation The Guitar Pick In The Song Writers Hand , Thank You Fay Dowker For Helping Me See The Universe .

I think we really need to understand time and in doing that we need to conquer (exceed) the speed of light. Once we manipulate time (at least in some basic way) we can get on the highway out of this town called stagnation. I also believe we need to inhabit other worlds but we are so busy fighting and financing wars the odds are stacked heavily against us. We may go the way of the dinosaurs before any of this happens. We can only hope for mankinds survival but the universe could care less it simply goes on.

Gravity is a tension of the fabric of space/time that matter causes due to density. Energy is simply movement of particles, or an oscillation. The tension of gravity causes matter to oscillate even more then the c of light, depending on the factors of the amount of density. And what if particles simply become sized to being as small as particles that happen to be in the past. Time/Space and Matter is always relative but never changed. Time is not replaceable but more like an echo.

so what is sience 4?

1:12:00 - Gee, it seems to me like Sorkin should have shared that Nobel prize, or gotten it outright. He PREDICTED what the winners measured.

new information for me.

She has some sort of inherent elegance... (besides, of course, being wonderfully competent)

What's happening event horizons when black hole radiation

If someone complain about style being difficult to get past, then they can't be very interested in the content...

Are black holes densest at the center? What is this substance? Neutrons? Or something completely new to us?

it would be easier to explain "space-time" atoms( I would refer to as voxels) as a rank 5 tensor. where each "space-time" atom is affected by each adjacent causal set both in space as well as time.

--> 34:11 "... Standing on the threshold of unity, ... So I believe that we stand at the same juncture as people who were studying #thermodynamics without having an atomic picture of nature -- they were studying the laws at the level of a macroscopic temperature... / of macrospcopic phenomena and heat, but they didn't know (yet) what the atomic/ microscopic physics was, that explained thermodynamics... " Like Eric Verlinde proposed, #Gravity might be understood as an emergent effect or property of some _other_ underlying structure or phenomenon... --> Peter Freund: arXiv.org > hep-th > arXiv:1008.4147 >> Emergent Gauge Fields Peter G.O. Freund (Submitted on 24 Aug 2010) Erik Verlinde's proposal of the emergence of the gravitational force as an entropic force is extended to abelian and non-abelian gauge fields and to matter fields. This suggests a picture with no fundamental forces or forms of matter whatsoever.

I like Krauss, but have you sampled Renate Loll or Sean Carroll?