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.
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.*"
Someone had already figured this out - Boltzmann's equipartition of energy idea. There cannot be infinitely small structure to the universe because then there would be infinitely many degrees of freedom to hide energy in ... small spaces would be able to suck up lots of energy ... this same argument applies not only to there being an atomicity to things, but that there probably aren't any other macroscopic physical dimensions (presuming space isn't an emergent quality of quantum entanglement ... Leonard Susskind and other theoretical scientists have suggested that the notion of space might just be a subject sense we have of how closely two things are entangled - where 'entanglement' means the inseparability of the mathematical description of their quantum states).
you do know that time did not start at our universe creation , that imbecilic claim is as good as religion claims for fairy tale genocidal sky freaks. Time is of the cosmos , gravity changes time depending the amount gravitational influence. All stars have multiple time in and around themselves. If you leave the influence of our star time will be a lot faster than sitting beside a sun. and stars including dark stars are not atomic or fusion reactors , photons and all the spectrum of light radiation are produced bye matter changing its state to adapt tot he environment its in. Stars are stable mostly until their mass no longer can produce gravity to keep all the matter in.When they go say for instance into red giant , its not the core that collapse , the gravity is no longer strong enough at surface of the sun and thus all that matter expands from the surface inward . Do the math
@@ossiedunstan4419 Dark stars?? Are you from the 1700’s? If there is no nuclear fusion in the core of stars, what force is keeping the mass of the star from collapsing? Where are elements heavier than H, He, and Li created (besides the heaviest elements created in neutron star mergers/collision)? And if you say the elements were created during “Big Bang” cite the paper and author(s) that make that claim.
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)
Well, when you’re excellent and on top of your game, you have some who feel insecure, threatened & have an insatiable desire to knock you down for no good reason.
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
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.
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.
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 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.
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 RUclips and she is possibly the only match for Hawkins.
I think it's a beautiful theory. and I think if she and her peer scientists can answer the second last question which she described as fantastic, as well as handle the trouble making quantum entanglement which was also mentioned, then the theory will be very close to a Grand Unification.
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.
8 лет назад
I love science , but saying ever we will find a grand theory is just not me. i dont think humans can grasp hole of reality.
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..
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?
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.
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?
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.
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.
I can't believe Fay Dowker is on RUclips! 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
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.
+Oners82 Seriously. The Earth is not a closed system. I will assume that you are aware of the ocean and that the ocean has waves, yes? The waves are, to a large degree, a result of the gravitational influence of the moon. I will also assume that you have looked up and seen the sky, as well. Have you noticed that at night you are able to see the stars and moon and that during the day the sky is illuminated by the sun? Have you ever witnessed shooting stars or viewed the Aurora Borealis / Aurora Australis? Further, are you aware that we have sent astronauts into space and robotic explorers to Mars and the outer planets? None of this would be possible if the Earth were a closed system.
"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.
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.
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 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.
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.
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)).
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.
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
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.
+The Gnostic Truth I think you made a wrong turn, this is a video about science not an opportunity for you to showcase your apocalyptic delusions. You do realise the kind of people who come to watch a video like this just pity you? Apart from people like me that is who would like to see you committed and medicated until you have a) a clean bill of mental health and b) are able to pass high school science.
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.
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!
jeku1987 So the Monty Hall effects only works on doors and not on coins? Well it happens to work on computers as well. I have a SQL script I can share with you that proves that the first choice influences the second choice even though there are no physical forces at work.
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.
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.
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
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.
This is an invitation to see a theory on the nature of time! In this theory we have an emergent uncertain future continuously coming into existence relative to the spontaneous absorption and emission of photon energy. The future is unfolding with each photon electron coupling or dipole moment relative to the atoms of the periodic table and the wavelength of the electromagnetic spectrum. This is part of a universal process of energy exchange that forms the ever changing world of our everyday life.
It's all based on Hawkin when he write his phd he anecdotally highlighted how finly tuned the universe is. And as a atheist this strongly upset him and he spent the rest of his life trying to find an alternative explanation. In that work he come across Hawkins radiation. The theory is that empty space isnt empty and that particles pop in and out if existence as universes could this multi verse. Given enough time and chances anything possible. The problem us also when you say anything's possible that means even the theory your fighting against .lol Mathematically it troublesome anytime infinity shows up as it most oftenly means your wrong. And if bh can feed off empty space with one entangled particle escaping with information you have a bh that can feed infinitely on nothing but fabric of space. We've all been told if bh don't feed they die. So its got problems like any theory. Hawkins taught many people like her so of course they lecture and debate the theory with the most following wins. I just have an issue with Hawkins motivation.
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.
As a jazz musician who has a passionate but amateur interest in natural philosophy, Professor Dowker came much closer to explaining the complexities of her research - in plain language - to a non-scientist such as myself than ever I would be able to explain to a non-musician the sonority of a B flat minor seventh chord + flat 9 and sharp 11. I have a suspicion the mind of Hawking, Feynman, 't Hooft, et al, may not be that far removed from the musical genius of Charlie Parker. A question I would have like to have asked Professor Dowker is whether her research is uncovering objective reality or "creating" something that is subjectively "real". 2+2 = 4. That is objective reality and not the subjective creation of homo sapiens. In other words, is Professor Dowker and her researchers just peeling an onion? With all due respect to Professor Dowker, Archimedes, Newton, Galileo, Einstein, et al, I suspect they are all Grand Chefs - waiting to create the Theory of All Meals!!!
***** The reason I did not include the Bible is because it was written by a bunch of Iron Age peasants on hearsay - long after the supposed events took place. The Bible may be a good book of mythological literature. But as a source of historical value, it ranks alongside the myth of King Arthur and his Knights of the Round Table. Think about this: in today's world, an event is videoed with smart phones by numerous bystanders, eye witness accounts are gathered by the police - and all "hearsay" accounts differ as to what took place. To top it all off, the Judge in the case has to spend numerous days trying to make sense of it all. I suspect if I told you the Earth was flat and populated by Unicorns, you would believe it. Zeus be praised!
TOM NEEDHAM I see the analogy you are trying to make, and understand where the thought comes from (having had similar thoughts myself in the past), but I assure you, as a musician who has written many a song and also as someone who is currently studying math and physics at a University level, it does not quite fit. The difference between when I write down a song and when I write down some physical theory is that the song does not have to predict anything about the future. The song just is what is it. Listen to it, dance to it, enjoy it, or dislike it altogether... It does not attempt to explain the structure of anything but itself, in the moment the song is playing. A song is a whimsical sort of thing in many ways.... sure, one can painstakingly agonize over every note, but just as many, if not more, songs have been written off the cuff, in the heat of the moment, a torrent of chords, notes, and lyrics just sort of tumbling out in a creative burst. Afterwards, you do not have to question the validity of the song's existence. It just exists. It just is what it is. Another difference is that, while musicianship requires cumulative skill building (like physics), but it does not require that the product (i.e, a composition/song) fit cumulatively with what has come before. The song does not have to "make sense" when compared to the other songs that have come before it (i.e., compare to how a theory has to "make sense" or "explain" results from the past). That is, OK Computer by Radiohead may be influenced by the Beatles, but it does not have to "stand on top of" or "fit together with" music of the past in the same way that physics of the future has to fit with physics of the past. Sure, sometimes new physics refutes the accuracy of older models, but the line of reasoning that leads up to the newer model is based upon careful and detailed "piggy-backing" upon what has come before. It all builds up cumulatively. If you come out with a theory of unified physics that maybe borrows concepts form one place, but does not fit with anything else historically, physicists will raise their eyebrows in a serious manner, and your career could be over. In contrast, in music, you will have people who dislike large breaks in style from what the past has already given us, but you do not stand to be called a charlatan or a crank because you learned some jazz standards and then broke off to create some crazy kind of "dub step jazz psychedelic indie shoe gaze pop." It might not be popular, but it is still valid musically to those who enjoy it. But someone's pet theory of physics that breaks at random from the past, with no concern for the cumulative nature of human knowledge, is not innovation or paradigm shift, but crackpottery.
Fay says nothing about the frequency ratios formed by causal sets, and she may not know they exist. The frequency ratios serve to define energy ratios in accord with E=hf. The causal link is identified as the quantum of energy, and the common particles, including the hydrogen atom-- proton with its electron cloud-- have been graphed using the directed graphs of causal set theory. This is something you would want to include in a talk about the importance of atoms. Since she ignored it, you can see the particle graphs online as "Causal Set Theory and the Origin of Mass-ratio."
I'm sorry, I did not mean that YOU were complaining. It was a general statement to all of us, including myself : "Stop complaining, You are NOT the one having the hardest time". It was just an attempt to describe the actual value that 'un-normals' have in general. Sadly, it can be divided in 2 portions : societies that respect them (yours and mine) and societies that do not : North Korea, China, Russia, White Russia, Rumania, etc.. - A society can only be evaluated upon how it treats minorities
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).
Funny thing is, the main idea of causal set theory and other discrete spacetime theories is not new - it's like the atomic theory of the Greeks. There is a philosophical "thought experiment": draw a line and place a marker on it, then move the marker one end to another. How many points on the line has the marker crossed ? - can't be infinite, therefore space is discrete and finite. Discrete spacetime theories do make sense
Actually it could be infinite, we don't know if space-time is quantized or not in any actual, physical sense. We can say that nothing is smaller than the Planck length, but really we just would not be able to ever determine if anything is smaller. In a sense, you are using a form of Zeno's paradox, which, to my mind, and most others who have looked at it, has been resolved in several way..
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!?
I have to strongly disagree with the opinion that she is a terrible lecturer or that she "needs to work on her stage presence." Jesus, I believe she needs to work on her theories to bring us some new interesting ideas and discoveries. This is no show or political oration. She presents her ideas very clearly and apprehensibly and I need nothing more. But maybe I am wrong and she should sing or rap her lecture and do some twerking... Then she would become a perfect physicist, dont you think?
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?
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.
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?
58:00 ...palaeontologists don't use equivalence relations as the fundamental descriptions of dinosaurs. If they claimed the bones were invisible, then we might question them too.
So dinosaurs were destroyed and humans with 6th scene were created to maintain the entropy of earth..?? A stable entropy results in long life of earth.
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.
I don’t understand the entropy being order moving towards disorder part. As energy in an area decreases isn’t it becoming in equilibrium with the area around it. Doesn’t that create order? Wouldn’t stored energy be moving potential energy away from perfect equilibrium? Putting energy into something lets us move it away from natural order so that we can exploit inequalibrium, but given time it will move towards natural equilibrium. For example we can do a reduction reaction with rust in a high heat, low oxygen artificial environment to create iron and steel. But let it sit outside and it will start turning to rust again as the iron forms bonds with oxygen. Isn’t that creating order as it goes through entropy? But maybe creating the artificial environment drove it towards equilibrium as it became iron? Maybe entropy is relative to localized equilibrium ?! I don’t know
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..)
so informative and complete...i try to understand physics. "causality limitation" make calculating action and reaction across a vast scale simpler. thanks
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
--> 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.
Black hole doesn’t absorb everything it gives something back. Stephen hawking particle is true. Not a temperature, it is outside effect. Also there is no big or small black hole, the difference is the amount mass they absorb. Absorbed mass is not the black hole reality. Its explanation is in the “What Zero is: The Quantum Moment vs. Speed Reality” presentation.
It's said that 'space' is expanding, why can't it be that 'time' is slowing down? Or maybe both are true, 'space' expanding AND 'time' slowing down? What exactly is 'space' that it can expand? What exactly is 'time' that it can vary? Surely 'space' and 'time' must actually have some sort of existent reality for 'speed' to actually exist, 'speed' being distance divided by time, and distance being two points in space with space between those two points. If 'space' and/or 'time' does not have any sort of actual existent reality (besides just being a concept), then 'speed' cannot actually exist in existent reality (except as a concept alone). How else can it be otherwise? An inquiring mind would like to know.
The big problem I have with Hawkins radiation theory is that it states that particles not only escape entanglement but that bh can feed infintly always being fed by the very fabric of space-time particles popping into existence. You know every time infinity shows up in math it most often it means a theory Is wrong . Hawkins accidentally opened up a can a works when he wrote his Ph.D. paper that highlighted how finely tuned the universe is. And as you can imagine for an atheist this is troublesome. And indeed it was to Hawkins because he spent the rest of his life searching an alternative explanation and in that this Hawkins radiation and that empty space isnt empty. That universe could pop in and out of existence or multiverse.
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)?
This is a late reply but the answer is that entropy will always increase overall so with regards to the oceans cooling for example the heat will divísate into the atmosphere which itself increases the entropy overall.
Black holes are the most elegant MICROSCOPIC object in the universe. Smallness Dark energy is the most elegant TELESCOPIC object in the universe. Bigness They both have event horizons and they are opposite 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?
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.
I don't think it's strictly true that we can't distinguish an event horizon from empty spacetime. For one, astronomical objects are somewhat uniformly distributed across the celestial sphere, and any very large black hole we were near would instantly betray its presence by a lack of starlight from that direction.
The edge of our observable universe itself is an event horizon. I think it would be like how we are now in our universe when you fall into a black hole. Inside of a giant black ball, except the horizon wouldn't shrink on you like it does with our universe.
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 ?
I'd like to see her write long equations with a magical wand while wearing a long black gown. Anyway good definition of entropy and heat. She doesn't define energy but she uses the word a lot. What is energy?
If as Ms Dowker says these "space-time atoms " are the size of the Plank length, perhaps we should call them Planktons after all we have protons, neutrons, electron and a whole array of fundamental particles that are --------ons.
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.
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.*"
Someone had already figured this out - Boltzmann's equipartition of energy idea. There cannot be infinitely small structure to the universe because then there would be infinitely many degrees of freedom to hide energy in ... small spaces would be able to suck up lots of energy ... this same argument applies not only to there being an atomicity to things, but that there probably aren't any other macroscopic physical dimensions (presuming space isn't an emergent quality of quantum entanglement ... Leonard Susskind and other theoretical scientists have suggested that the notion of space might just be a subject sense we have of how closely two things are entangled - where 'entanglement' means the inseparability of the mathematical description of their quantum states).
how would Lorentz invariance be handled in an atomised spacetime?
you do know that time did not start at our universe creation , that imbecilic claim is as good as religion claims for fairy tale genocidal sky freaks.
Time is of the cosmos , gravity changes time depending the amount gravitational influence. All stars have multiple time in and around themselves.
If you leave the influence of our star time will be a lot faster than sitting beside a sun.
and stars including dark stars are not atomic or fusion reactors , photons and all the spectrum of light radiation are produced bye matter changing its state to adapt tot he environment its in.
Stars are stable mostly until their mass no longer can produce gravity to keep all the matter in.When they go say for instance into red giant , its not the core that collapse , the gravity is no longer strong enough at surface of the sun and thus all that matter expands from the surface inward .
Do the math
@@ossiedunstan4419 Dark stars?? Are you from the 1700’s? If there is no nuclear fusion in the core of stars, what force is keeping the mass of the star from collapsing? Where are elements heavier than H, He, and Li created (besides the heaviest elements created in neutron star mergers/collision)? And if you say the elements were created during “Big Bang” cite the paper and author(s) that make that claim.
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)
shut up man
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".
What are these commenters below talking about? She has a clear and understandable speaking voice, the sentences are well-formed. A good presentation.
A playback speed of 1.25x sounds good.
They're men who can't believe a woman is smarter than they could ever be!
@@TravelGamerKpopper Her presentation skills are poor. That's not sexist, that's a fact.
Well, when you’re excellent and on top of your game, you have some who feel insecure, threatened & have an insatiable desire to knock you down for no good reason.
Agreed, Faye is a _physicist,_ not a _talk show host,_ and as such she does a perfectly good job of presenting her fields work.
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
Lies again? Samsung Ugly People
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.
Me like food
Whenever great scientists refer to other great scientists lectures from the past I feel like I just found a rare gem
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.
I love watching her and amazingly I've actually learnt something thanks, Fay.
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.
So much packed into one lecture. Well done Fay!
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.
Ask miss brite, she could travel much faster than lite, she went off one day in her usual way and returned the previous nite.
Brilliant and elusive lecture on blacholes and entropy.
Yes and she also has the best way of explaining entropy I've seen yet.
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.
Really well done, made complicated things easier to understand, impressed by the clarity of her mind.Thanks
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 RUclips and she is possibly the only match for Hawkins.
Sounds like you have fallen i love with her :)
I think it's a beautiful theory. and I think if she and her peer scientists can answer the second last question which she described as fantastic, as well as handle the trouble making quantum entanglement which was also mentioned, then the theory will be very close to a Grand Unification.
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.
I love science , but saying ever we will find a grand theory is just not me. i dont think humans can grasp hole of reality.
René Plougsgaard I think human mind can grasp anything it's just a matter of time I guess
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..
Extremely well done lecture. Dr. Dowker did a superb job.
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?
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.
this is way beyond what I can digest.
@ Kai Tale: She's a physicist, not a radio/TV personality.
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?
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.
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.
To say that spacetime itself is granular (could one say "particulate"?) is a significant departure from most current accounts of the Standard Model.
I can't believe Fay Dowker is on RUclips! 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
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.
+Oners82 Go to school.
+Oners82 Seriously. The Earth is not a closed system. I will assume that you are aware of the ocean and that the ocean has waves, yes? The waves are, to a large degree, a result of the gravitational influence of the moon. I will also assume that you have looked up and seen the sky, as well. Have you noticed that at night you are able to see the stars and moon and that during the day the sky is illuminated by the sun? Have you ever witnessed shooting stars or viewed the Aurora Borealis / Aurora Australis? Further, are you aware that we have sent astronauts into space and robotic explorers to Mars and the outer planets? None of this would be possible if the Earth were a closed system.
"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.
Wow she's an excellent teacher of known and accepted physics
Somehow that sounds insulting...
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.
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.
Fantastic lecture. Much appreciated.
Are you kidding? This is pretty dumbed down.
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.
very impressive lecture
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.
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)).
She's brilliant. Wonderful talk.!
P.I. won't have anyone but the best ❤
awesome talk!
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.
Could not agree more... science, like most things, goes in cycles...
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
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.
+The Gnostic Truth I think you made a wrong turn, this is a video about science not an opportunity for you to showcase your apocalyptic delusions. You do realise the kind of people who come to watch a video like this just pity you? Apart from people like me that is who would like to see you committed and medicated until you have a) a clean bill of mental health and b) are able to pass high school science.
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.
A fascinating, thought-provoking talk.
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! :)
Cup "O" Tea
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!
jeku1987 Are you familiar with the Monty Hall effect?
jeku1987 So the Monty Hall effects only works on doors and not on coins? Well it happens to work on computers as well. I have a SQL script I can share with you that proves that the first choice influences the second choice even though there are no physical forces at work.
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.
black holes are weird
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.
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.
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
I get tired when I get hot are my atoms miss behaving?
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.
This is an invitation to see a theory on the nature of time! In this theory we have an emergent uncertain future continuously coming into existence relative to the spontaneous absorption and emission of photon energy. The future is unfolding with each photon electron coupling or dipole moment relative to the atoms of the periodic table and the wavelength of the electromagnetic spectrum. This is part of a universal process of energy exchange that forms the ever changing world of our everyday life.
It's all based on Hawkin when he write his phd he anecdotally highlighted how finly tuned the universe is. And as a atheist this strongly upset him and he spent the rest of his life trying to find an alternative explanation. In that work he come across Hawkins radiation. The theory is that empty space isnt empty and that particles pop in and out if existence as universes could this multi verse. Given enough time and chances anything possible.
The problem us also when you say anything's possible that means even the theory your fighting against .lol
Mathematically it troublesome anytime infinity shows up as it most oftenly means your wrong.
And if bh can feed off empty space with one entangled particle escaping with information you have a bh that can feed infinitely on nothing but fabric of space.
We've all been told if bh don't feed they die.
So its got problems like any theory.
Hawkins taught many people like her so of course they lecture and debate the theory with the most following wins.
I just have an issue with Hawkins motivation.
This lady does not have a ring on, unbelievable there’s gonna be a lucky guy out there to have such a smart lady.
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.
As a jazz musician who has a passionate but amateur interest in natural philosophy, Professor Dowker came much closer to explaining the complexities of her research - in plain language - to a non-scientist such as myself than ever I would be able to explain to a non-musician the sonority of a B flat minor seventh chord + flat 9 and sharp 11. I have a suspicion the mind of Hawking, Feynman, 't Hooft, et al, may not be that far removed from the musical genius of Charlie Parker. A question I would have like to have asked Professor Dowker is whether her research is uncovering objective reality or "creating" something that is subjectively "real". 2+2 = 4. That is objective reality and not the subjective creation of homo sapiens. In other words, is Professor Dowker and her researchers just peeling an onion? With all due respect to Professor Dowker, Archimedes, Newton, Galileo, Einstein, et al, I suspect they are all Grand Chefs - waiting to create the Theory of All Meals!!!
***** The reason I did not include the Bible is because it was written by a bunch of Iron Age peasants on hearsay - long after the supposed events took place. The Bible may be a good book of mythological literature. But as a source of historical value, it ranks alongside the myth of King Arthur and his Knights of the Round Table. Think about this: in today's world, an event is videoed with smart phones by numerous bystanders, eye witness accounts are gathered by the police - and all "hearsay" accounts differ as to what took place. To top it all off, the Judge in the case has to spend numerous days trying to make sense of it all. I suspect if I told you the Earth was flat and populated by Unicorns, you would believe it. Zeus be praised!
TOM NEEDHAM
I see the analogy you are trying to make, and understand where the thought comes from (having had similar thoughts myself in the past), but I assure you, as a musician who has written many a song and also as someone who is currently studying math and physics at a University level, it does not quite fit.
The difference between when I write down a song and when I write down some physical theory is that the song does not have to predict anything about the future. The song just is what is it. Listen to it, dance to it, enjoy it, or dislike it altogether... It does not attempt to explain the structure of anything but itself, in the moment the song is playing. A song is a whimsical sort of thing in many ways.... sure, one can painstakingly agonize over every note, but just as many, if not more, songs have been written off the cuff, in the heat of the moment, a torrent of chords, notes, and lyrics just sort of tumbling out in a creative burst. Afterwards, you do not have to question the validity of the song's existence. It just exists. It just is what it is.
Another difference is that, while musicianship requires cumulative skill building (like physics), but it does not require that the product (i.e, a composition/song) fit cumulatively with what has come before. The song does not have to "make sense" when compared to the other songs that have come before it (i.e., compare to how a theory has to "make sense" or "explain" results from the past). That is, OK Computer by Radiohead may be influenced by the Beatles, but it does not have to "stand on top of" or "fit together with" music of the past in the same way that physics of the future has to fit with physics of the past.
Sure, sometimes new physics refutes the accuracy of older models, but the line of reasoning that leads up to the newer model is based upon careful and detailed "piggy-backing" upon what has come before. It all builds up cumulatively. If you come out with a theory of unified physics that maybe borrows concepts form one place, but does not fit with anything else historically, physicists will raise their eyebrows in a serious manner, and your career could be over. In contrast, in music, you will have people who dislike large breaks in style from what the past has already given us, but you do not stand to be called a charlatan or a crank because you learned some jazz standards and then broke off to create some crazy kind of "dub step jazz psychedelic indie shoe gaze pop." It might not be popular, but it is still valid musically to those who enjoy it. But someone's pet theory of physics that breaks at random from the past, with no concern for the cumulative nature of human knowledge, is not innovation or paradigm shift, but crackpottery.
Einstein said something along the notion that a smart person could explain things simply
Fay says nothing about the frequency ratios formed by causal sets, and she may not know they exist. The frequency ratios serve to define energy ratios in accord with E=hf. The causal link is identified as the quantum of energy, and the common particles, including the hydrogen atom-- proton with its electron cloud-- have been graphed using the directed graphs of causal set theory. This is something you would want to include in a talk about the importance of atoms. Since she ignored it, you can see the particle graphs online as "Causal Set Theory and the Origin of Mass-ratio."
I'm sorry, I did not mean that YOU were complaining. It was a general statement to all of us, including myself : "Stop complaining, You are NOT the one having the hardest time". It was just an attempt to describe the actual value that 'un-normals' have in general. Sadly, it can be divided in 2 portions : societies that respect them (yours and mine) and societies that do not : North Korea, China, Russia, White Russia, Rumania, etc.. - A society can only be evaluated upon how it treats minorities
1:08:59 'we don't know what causality means in a quantum context'. That sounds kind of important -
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).
Funny thing is, the main idea of causal set theory and other discrete spacetime theories is not new - it's like the atomic theory of the Greeks. There is a philosophical "thought experiment": draw a line and place a marker on it, then move the marker one end to another. How many points on the line has the marker crossed ? - can't be infinite, therefore space is discrete and finite. Discrete spacetime theories do make sense
Actually it could be infinite, we don't know if space-time is quantized or not in any actual, physical sense. We can say that nothing is smaller than the Planck length, but really we just would not be able to ever determine if anything is smaller. In a sense, you are using a form of Zeno's paradox, which, to my mind, and most others who have looked at it, has been resolved in several way..
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!?
I have to strongly disagree with the opinion that she is a terrible lecturer or that she "needs to work on her stage presence." Jesus, I believe she needs to work on her theories to bring us some new interesting ideas and discoveries. This is no show or political oration. She presents her ideas very clearly and apprehensibly and I need nothing more. But maybe I am wrong and she should sing or rap her lecture and do some twerking... Then she would become a perfect physicist, dont you
think?
Why are you attacking / undermining her? Feeling some competition?
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?
Dear Prof Dowker, how can I get a poster of the entropy diagram? It resonated with me. Very clear, enlightening lecture. Thanks!
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.
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?
58:00 ...palaeontologists don't use equivalence relations as the fundamental descriptions of dinosaurs. If they claimed the bones were invisible, then we might question them too.
So dinosaurs were destroyed and humans with 6th scene were created to maintain the entropy of earth..?? A stable entropy results in long life of earth.
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.
I don’t understand the entropy being order moving towards disorder part. As energy in an area decreases isn’t it becoming in equilibrium with the area around it. Doesn’t that create order? Wouldn’t stored energy be moving potential energy away from perfect equilibrium? Putting energy into something lets us move it away from natural order so that we can exploit inequalibrium, but given time it will move towards natural equilibrium. For example we can do a reduction reaction with rust in a high heat, low oxygen artificial environment to create iron and steel. But let it sit outside and it will start turning to rust again as the iron forms bonds with oxygen. Isn’t that creating order as it goes through entropy? But maybe creating the artificial environment drove it towards equilibrium as it became iron? Maybe entropy is relative to localized equilibrium ?! I don’t know
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..)
so informative and complete...i try to understand physics. "causality limitation" make calculating action and reaction across a vast scale simpler. thanks
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
cool presentation and totally interesting
--> 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.
Black hole doesn’t absorb everything it gives something back. Stephen hawking particle is true. Not a temperature, it is outside effect. Also there is no big or small black hole, the difference is the amount mass they absorb. Absorbed mass is not the black hole reality. Its explanation is in the “What Zero is: The Quantum Moment vs. Speed Reality” presentation.
It's said that 'space' is expanding, why can't it be that 'time' is slowing down? Or maybe both are true, 'space' expanding AND 'time' slowing down? What exactly is 'space' that it can expand? What exactly is 'time' that it can vary? Surely 'space' and 'time' must actually have some sort of existent reality for 'speed' to actually exist, 'speed' being distance divided by time, and distance being two points in space with space between those two points. If 'space' and/or 'time' does not have any sort of actual existent reality (besides just being a concept), then 'speed' cannot actually exist in existent reality (except as a concept alone). How else can it be otherwise? An inquiring mind would like to know.
absolutely brilliant!
Thank you
The big problem I have with Hawkins radiation theory is that it states that particles not only escape entanglement but that bh can feed infintly always being fed by the very fabric of space-time particles popping into existence.
You know every time infinity shows up in math it most often it means a theory
Is wrong .
Hawkins accidentally opened up a can a works when he wrote his Ph.D. paper that highlighted how finely tuned the universe is. And as you can imagine for an atheist this is troublesome.
And indeed it was to Hawkins because he spent the rest of his life searching an alternative explanation and in that this Hawkins radiation and that empty space isnt empty. That universe could pop in and out of existence or multiverse.
is it possible that an atom can "go back in time" ----AND change it's polarity? this to me represents a Möbius curve?
Are black holes densest at the center? What is this substance? Neutrons? Or something completely new to us?
pure space no matter a black hole is just that, a hole in spacetime.
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)?
This is a late reply but the answer is that entropy will always increase overall so with regards to the oceans cooling for example the heat will divísate into the atmosphere which itself increases the entropy overall.
Black holes are the most elegant MICROSCOPIC object in the universe. Smallness
Dark energy is the most elegant TELESCOPIC object in the universe. Bigness
They both have event horizons and they are opposite 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?
A brilliant lecture, and I don't often say that.
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.
If quantum entanglements were resolvable with simultaneous equations, would it help?
Is time and entropy is same thing, both are moving in only forward direction
I don't think it's strictly true that we can't distinguish an event horizon from empty spacetime. For one, astronomical objects are somewhat uniformly distributed across the celestial sphere, and any very large black hole we were near would instantly betray its presence by a lack of starlight from that direction.
What about the black hole of size of the universe? You wouldn't see anything different from what you see now.
The edge of our observable universe itself is an event horizon. I think it would be like how we are now in our universe when you fall into a black hole. Inside of a giant black ball, except the horizon wouldn't shrink on you like it does with our universe.
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 ?
I'd like to see her write long equations with a magical wand while wearing a long black gown. Anyway good definition of entropy and heat. She doesn't define energy but she uses the word a lot. What is energy?
If as Ms Dowker says these "space-time atoms " are the size of the Plank length, perhaps we should call them Planktons after all we have protons, neutrons, electron and a whole array of fundamental particles that are --------ons.
Howabout "timeton".
What exactly is "space"? What exactly is "time"? An inquiring mind would like to know.
If someone complain about style being difficult to get past, then they can't be very interested in the content...
That's the motto of bad communicators.
Do causal sets conflict with string theory?
Enlightened-Progressive Nothing conflicts with string "theory," which makes no predictions.
Just add another few dimensions to string theory to fix any possible conflicts.
String theory is made for that.
The number of times scientists used the expression "timespace itself"
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.