The Story of Spacetime - with Fay Dowker

[@lameiraangelo]

The idea of mixing the lecture with Meditation was amazing while explaining Gravity was one of the most creative ways to explain something. She is amazing.

[@leighkite1164]

Yeah, I'd actually unified quantum with relativity during the meditation, but then a KZbin add jarred me out of it and I lost it all. :D

[@ksbalaji1287]

That was a beautiful lecture, thank you Dr. Dowker. Would love to hear more from you about the new theories you are working on. Such a clear presentation of the difference between Newton's view of gravity and that of Einstein ! I am a school level Physics teacher in India and am going to use this. Thank you.

[@samneil8631]

Pls don't teach them about space time curve . Bcos its just a theory . They also cannot able to explain why spacetime is warped towards the center of a heavenly object, and what is the degree of this curvature or graph of warping . Every varification still needs the support of newtons universal gravitation formula .

[@a-square4085]

@@samneil8631 Really, have you wondered why K S Balaji hasn't answered you yet? That's because you're just wrong. Sucks being wrong doesn't it.

[@esisimp123456]

@@samneil8631 Actually that is not true. General Relativity is extremely well tested. Even the GPS in your phone will not work properly if non-Newtonian effects arising from curved space time are not included. The time actually runs faster for a clock in a satellite in orbit compared to a clock on the ground on Earth and you could literally see this difference using a very accurate atomic clock. The only reason GR is not taught in school or (in many places) undergrad is because the maths is very difficult. what you might be confusing this with is things like string theory or quantum gravity etc. Those are currently more speculative/mathematical frameworks without any hard experimental evidence backing them. In that case scepticism is understandable.

[@esisimp123456]

@@samneil8631 Also it is actually not that difficult to calculate the curvature of spacetime around a spherical heavenly object such as the sun. Even a smart undergrad student in physics can do that. The reason people often use Newton's gravitational formula is because the difference in answers from the two theories is very small for such small mass objects such as a star, while the mathematical calculations in Newton's theory is much much easier. So usually people are sacrifice a little accuracy for significant simplification of calculations.

[@samneil8631]

@@esisimp123456 ok . I don't know what is true . I leave it to the scientist.

[@chipkyle5428]

Her careful pace and deliberate selection of words allowed her message to "sink in." Her intention was to see that I understood complex ideas rather than impress me with her brilliance. I did learn and at the same time I learned she is brilliant. I will look for more lessons from Fay Dowker. What an honest teacher. Her ego never got in the way of learning. Bravo! We need more of her.

[@KB-uv7wj]

Finally, someone who understands the subject.

[@sherlockholmeslives.1605]

Leonardo da Vinci ( 1452 - 1519 ) said that objects fall to the centre of the Earth. Not just that objects fall to the Earth but that object fall to the centre of the Earth, and he said this before Galileo ( 1564 - 1642 ) and Newton ( 1642 - 1727 ). It was a ground-breaking piece of insight!

[@sherlockholmeslives.1605]

Leonardo da Vinci ( 1452 - 1519 ) said that objects fall to the centre of the Earth, not just that objects fall to Earth but that they fall to the centre of the Earth, and it was before Galileo ( 1564 - 1642 ) and before Newton ( 1642 - 1727 ). It was a ground-breaking piece of thinking!

[@muthukumaranl]

Obviously the lecture itself was good...but Its the mention & encouragement of the use of meditative/reflective/original thinking techniques by the professor that i found really useful not just here but in general as a tool to think 'out of the box'...thank you!

[@bobpalka2085]

Thank you Ms. Dowker for this enlightening lecture. I'm one step closer to understanding GR and gravity then i was before.

[@terrywbreedlove]

How does mass actually act on space time and warp it ? I understand that is what is happening but I never hear it explained.

[@vickash1072]

nice question terry 🤝

[@david203]

We're still near the beginning of our understanding of physics, thinking we know a lot. But it's really a lot of detail, and many big questions have not been answered.

[@rayjax14]

you really hit quite the spot i would say, despite how much we are able to formulate or explain the gravitational force, our understanding of it is rather incomplete and as far as i have heard here and there in the other youtube videos about gravitation there isn't yet an "complete" explanation or mechanism as to how gravity works.

[@dreianj]

I gather from the picture and lecture that space time is a field. Matter causes that field to distort. Like hanging a towel over a basket and then setting a ball bearing in the center. On the surface, the surface of the towel is indented. Closer inspection shows that the relationship of the fibers themselves has also been distorted and the tension on each fiber has changed in direct relationship to the mass of the object. Those distortions due to an object's mass also cause friction when moved through space-time and maybe the speed of light is the highest amount of distortion that the space-time field will allow like trying to force the water from a fire hydrant through a garden hose. As this gravitic-friction increases with speed, my guess is that when an object is moving closer to the speed of light that the effects of not only distorting but also stretching ST become apparent. The ST field, having its own binding force begins to experience that stretching over a wider area. With enough power and cohesion, the object would be pulling space time into a tube around itself and then eventually dragging reality behind it. That's what I got out of it. If I'm out to lunch, let me know.

[@michaeljones7465]

@@dreianj You cracked it on 3 levels. Just as a planet will warp space around it, like a marble moving inside an inner tube, a black hole totally warping space around it & your towel analogy can now be applied to string theory.

[@MrLeighman]

Great talk. I actually visualised complicated theory's that previously I had struggled with. Basically: there are no forces between objects only the curvature of space time that they make. The changing of space time by an object acts apon other objects instantaneously. The speed of light remains constant and is independent of space time. Thanks

[@Ronilac]

As a freediving instructor, I never ever suspected that teaching the breathing and relaxation techniques for freediving I teach the special relativity theory... nice to know

[@BoatingBiker]

Dr Dowker, Thank you for your fascinating lecture. Absolutely riveting stuff. I didn't get every point you were making so I will be taking several goes at seeing how far my understanding can be expanded. Thanks again.

[@csam8455]

Truly the most concise & inspiring speech, thank you

[@philoso377]

Newton would laugh at Einstein’s light speed limit because earth would eventually swing outside the solar system when gravity takes 8 more minutes to reach earth. That nothing moves faster than speed of light is a declaration but laws of nature. The reason why you are reading this message safely on earth is because gravity is instantaneous that is another reason suggesting that Einstein is a daydreamer far from being a practical physicists.

[@robertglass1698]

I found that the meditation part was helpful. Remember that it isn't meant to confirm the theory, it's meant to support the conjecture that General Relativity is more in line with experience--which isn't exactly an empirical claim anyway. However there is plenty of good evidence which shows that our active or fast thinking mechanisms often make broad generalizations about what we are experience--if a little reflective thinking can get me to focus just on what I'm experiencing and not my interpretation of what I'm experiencing, then great.

[@panosgamer835]

Αςαάάαααάααάάαα

[@panosgamer835]

Άααα

[@bobaldo2339]

My subjective reaction: There is something intuitively correct about the idea of new grains of space time popping into existence. It is a pleasing and somehow liberating idea.

[@owen7185]

Excellent lecture Professor Fowker. Very easy to follow and the material is very relevant and important to the story of spacetime

[@wulphstein]

Can someone explain to me why: over the last 50 years of studying black holes, we learned that the clock slows down as you approach the event horizon (go deeper into the gravity well). But nobody has proposed that there could be higher gravity potential energy "planes" or "dimensions" where the clock runs faster. Like a skyscraper where the event horizon is in the basement, we are in the first floor. The clock runs faster on the second floor, so that spaceships can move faster on the second gravitational floor or dimension. Maybe you have to get to the 50th gravity floor, where the clock runs 50x as fast, before you can think about using the 50th floor for interstellar travel.

[@lepidoptera9337]

The clocks never slow down or speed up. The signals just take longer to get to us. You need to go back to school.

[@stewiesaidthat]

Clocks measure motion in space. Gravity is a Reactionary force. The resistance of the mass to being accelerated by an external force. The ground is accelerating you and you are accelerating the air mass above you. Which is why it requires less force to accelerate you as you go up in altitude. Why water boils at lower temperature. Clocks run slower as the radius increases because they are measuring more distance traveled. The earth is a rotating frame. As the radius increases, so does the circumference. The bigger the circle, the more distance there is between arc seconds. If you want a truly accurate clock, get a sundial. Noon will always be noon no matter the elevation/radius.

[@JianYZhong]

Thank you, Fay, for such an illuminating lecture on General Relativity, presented so carefully. I even learnt something about meditation!

[@tomtomski4454]

Such a calm and clear presentation! I really appreciate it! Great done Prof. Dowker! I wish I had had my physics lectures with this woman... instead extravert blackboard animal mine lecturer was.

[@racarth1]

+Tom Tomski She teaches me GR and I can confirm she's a great lecturer.

[@Gyroglle]

"Try to become aware of the sensations in and on your bottom". Will do miss thanks.

[@a-square4085]

I couldn't handle it. Had to stop. She annoyed me with her constant "tsk" with her tongue, the meditation was the last straw.

[@cmacmenow]

Fascinating and engaging talk;made more accessible by the very talented Ms Dowker. Wait to you hear her thoughts and understanding on "causal set theory!" Incidentally, the graphics and overheads are very well designed.

[@chrisofnottingham]

if some region of spacetime is curved, what is it curved in?ie, what is the reference frame that we consider to be straight?

[@blenderpanzi]

+chrisofnottingham I was told by a physicist: Mathematically it doesn't need to be embedded in a higher dimensional space. But it could be, who knows?

[@chrisofnottingham]

+bloody_albatross Embedded or not, "curved" implies a deviation from a straight line. What is this straight line?

[@blenderpanzi]

+chrisofnottingham In this context I got curved explained like this: Look at the analogy of 2D space. Imagine some cloth or other sheet (this time in 3D space just so you can look at it). If it's simply folded it is not curved. Only if you cannot flatten it to a flat surface without stretching some parts it is curved. So a woollen hat would be curved, but a folded handkerchief would not. I'm just replaying this information as I heard it. I'm not pretending I understand it.

[@chrisofnottingham]

+bloody_albatross The trouble with that explanation is that it requires another dimension, but GR is fine with 4D spacetime and no other dimensions.

[@broadwayat]

+chrisofnottingham we see space via photons or light waves If a portion of space were curved, it would still appear as a straight line to us, because the photons would travel along the curve and we wouldn't be able to distinguish it from normal space. Sometimes, you can observe this during a solar eclipse.

[@patrickcash2]

this is golden.

[@mateopelufo2555]

Excellent! Thank you very much. Carlo Rovelli explanation says that there is no time at all: it´s all a comparison of movement. I found that notion useful to understand "space time" (taking away time). The movement of anything is affected by the space in where it takes place.

[@mateopelufo2555]

even the watches...

[@tichaonamachiya3204]

I propose that both Newton and Einstein were right. Its just that attraction between 2 large bodies is caused by the sub atomic particles. When they are condensed into one large body the force becomes intense.

[@JJs_playground]

Great talk. One correction I thought Einstein happiest thought was his thought experiment where he managed a man falling in an elevator and deduced he would not know the difference between gravity and deceleration/acceleration.

[@mrnosy1]

Hey! It's my math analysis lecturer...

[@jamesdolan4042]

"It's my math analysis lecturer" does that phrase need to be reworded.

[@Robinson8491]

This was great. Loved her meditation on not feeling gravity but only the normal force to introduce the value of Einstein

[@michaelkreitzer1369]

The amount of armchair experts on the wrong end of the dunning-kruger curve or just complete crackpots that come out in these fascinating video series comments sections can be so depressing.

[@glarynth]

You can't let it get to you. Trust me, you'll go nuts.

[@tomhalloway6674]

Michael Kreitzer bnaturecomplexityreality

[@Hank254]

Is the number of crackpots increasing or are there just more of them finding KZbin?

[@3rdrock]

Michael - lol, it's the arrogance of ignorance, idiots don't know that they are idiots. That's why they are so comfortable spouting bullshit.

[@wesjohnson6833]

Well demonstrated

[@gnorman-ct2lt]

I like her she's holding back a lot in some of her interviews

[@peterpark699]

If an object is in a range of gravitational force, where the force is still in reach of its own arm, then the force act as a magnetic field, in a sense, where the sign of force is already glued to the object. This can be envisioned from the demonstration that the scientist, Ms. Dowker, performed during her lecture. Thus, the sign of change of gravitational force due to change of distance between an astronaut and the earth doesn’t relate to the case where the special relativity may be concerned, because the gravitational force, in another words, can be considered as gravitational field where the signal of the force doesn’t have to travel; the force already and always resides in its own criteria. I’m simply saying that the 'Newtonian gravitational force' doesn’t seem to contradict to the Special Relativity.

[@darkestnile1056]

Brilliantly explained. I learned a lot. Thanks

[@Orlando9161]

if i do have a feather in my right hand and a bowling ball on the other and i let them drop of my hand ,,they wont fall at the same speed....so do not understand the fact that two object fall at the same speed..

[@flopsnail4750]

@@Orlando9161 there's an AIR-or in your experiment.

[@tantiwahopak101]

@@Orlando9161 that experiment will work in a vacuum.

[@Rico-Suave_]

?? not able to fully grasp what she was try to convey? regarding the gravity example, just because you cannot feel gravity pushing down on you does it mean its not there ? so is the chair pushing up on you like acceleration/g-force, that would mean you are flying vertically up through space? and if gravity is not pushing down on you then what about falling, if you remove the chair and their is a 1000 feet drop underneath the chair ? now regarding the 2nd example of time, she said that there is no "global moment of now" or slices of time in GR, there is no way to connect/link time between two her birth-death "world-line" , but that does not mean that there is no time connection between two separate world-lines for example I have my world-line and I am experiencing time with everyone that is living on earth. or anywhere else. just because I don't meet/interact with someone 5 miles away that does not mean we are not experiencing the same time/weather/local-events.....

[@venkateshbabu5623]

Assuming a circular pattern of the cosmos they form what are called circular numbers. The concept of circular numbers arise from right angle triangles. Any triangle can be split into two right angle triangles. So wave nature of particles spread. Calculating the spread gives the numbers 1 +2+3+4+5+.... = -1/12 . Twice is 24. So inverse log is ten power 240 is the micrograins possible.

[@roger_is_red]

wow I love her clarity!!!

[@tibbar1000]

I must have one of Newton's laws stuck in my head...the one about an object at rest remaining at rest, etc...because I cannot believe the dropped object moves without a force acting upon it. I did not stay with her when she answered the question about the dropped microphone. I would enjoy hearing a more detailed explanation of that portion.

[@MrAlRats]

On the surface of a massive body, such as the Earth, the matter content of the body (the electromagnetic interaction between the body and ourselves) prevents us from undergoing an inertial motion (free fall). This means, we are in a non-inertial frame of reference by virtue of the fact that we are not in free fall. Each location on the surface of the Earth is in a different non-inertial frame of reference. Imagine you're in a rocket accelerating in deep space. If you drop an object, it will appear to fall towards the ground. This is because you are in a non-inertial frame of reference while the rocket is accelerating. On the surface of the Earth, dropped objects appear to fall towards the ground because you are in a non-inertial frame of reference.

[@TanerNilluhktaf]

Boom! There was a brain explosion when she said there's no force of gravity on the body. Body just follows the curvature. It's just because space-time is curved. But in Newtonian mechanics we conveniently use force of gravity for that effect.

[@jansvedman3876]

One of the best lectures I have seen on the subject. Fay succeed to explain very complicated issues in a simplistic way - and thats very hard and tricky ! Well done.

[@coreybray9834]

Now, objects responding to a curvature in spacetime would experience a change in direction if they are already in motion, but if you place an object at rest along the curvature of spacetime, and there is no force to motivate said object in one direction or another, this really does not explain why an object at rest along the curvature of space/time should magically be attracted towards or repelled away from the earth either one. If there is no actual gravitational force pulling objects down to the earth, then when Galileo dropped objects from the tower, they should have remained suspended in mid air until acted upon by some force to help identify what direction they should move in. Remember, she went through a whole explanation of why you only feel the force of your chair pushing up, but no force pulling you down. Yet, Galileo clearly showed experimentally that the objects he was dropping did not remain at rest in mid air to comply with this woman’s explanation, but rather the objects Galileo dropped accelerated downwards towards the earth as if motivated by a force with a specific direction to accelerate the objects in that specified direction, and not some other direction. That direction happened to be down towards the earth which suggests that trusting our feeling of pressure on our bottom while meditating, as she had her audience do, is not necessarily an accurate way to identify what is really going on. The first step, as she calls it, depends heavily on our ability to precisely distinguish how much of the pressure we are feeling between our bottom and the chair is due to the normal force pushing up from the chair under us and how much of that pressure is due to the force of gravity pushing down on us. Nothing in this woman’s explanation proved that the pressure we felt was due exclusively to the upward exertion of the normal force while at the same time there being supposedly zero gravitational force pulling down on us.

[@laersonverissimo1715]

Corey Bray . An object at rest (at some referencial) is still moving along the time axis.

[@shahulhameed3625]

Whatever you observe is past What you realise is present What you anticipate is future.

[@michaellbbecker8734]

Has the speed of gravitational attraction ever been measured? Does it propagate at the speed of light? What about gravitational waves - do they propagate at the speed of light?

[@owaisahmad7841]

Brilliant communicator and explained the concepts brilliantly. Just thought that meditation experience in that kind of detail was really not needed.

[@ritemolawbks8012]

"Close you eyes and think about the sensation on your bottom."

[@netajibabusimhadati6745]

"At a distance" shouldn't this be the same problem with magnetic and electric forces? Any force that ever felt or produced doesn't have a continuous matter between force producer and experiencer Eg: I push a ball on a flat surface with my hand. Is there continuous matter between my hand and the ball? How can you accept that force can act over small distance without a medium but not over large distance

[@eyebee-sea4444]

Electromagnetic forces are understood as exchange of virtual photons, according Quantum Mechanics.

[@acezar2644]

I fucking love this channel

[@TheRoyalInstitution]

+Axel Cezar Thanks, the feeling is mutual.

[@cygil1]

+The Royal Institution The royal institution fucking loves Axel Cezar?

[@Mandragara]

+cygil1 That's not what that expression means haha.

[@reecelongden3500]

+Mandragara Yes it is, it means "and I/we feel the same about you"

[@JooJingleTHISISLEGIT]

In this case they are referring to themselves. They feel the same way as Axel Cezar.

[@nachannachle2706]

So, this lecture goes as this: Gravity is not a force => Gravity is similar to the EM field => Gravity is a "gravitational field" => Let's find out if Spacetime is granular. Seriously? How is this any different than looking for the Graviton or the Quantum Field of Gravity? Maybe I should start my own research group to find out if Spacetime is flaky...anyone cares to fund us?

[@ricardoabh3242]

Very clear and relaxing lecture :)

[@inertiaforce7846]

I have been studying gravity on my own out of my own interest and curiosity for 7 years now. 90% of the videos on gravity do not properly explain it. There are some videos that explain it better than others but even those videos do not properly explain it. It amazes me how many of these videos just explain Einstein's view of "curved spacetime" but they do not explain HOW Einstein came to this idea. They just show you a picture of a trampoline with a ball in it and tell you that's what's going on. 7 years of my own study has got me to learn things that aren't mentioned in 90% of the videos on gravity. These videos are meant to simplify gravity for the public. For me, they did not simplify anything, they raised more questions than they answered. It has taken me 7 god damn years of casual study (my most intense study has been since 2015-2017) to sift through all the bs and come to some real answers. These videos are just meant to dumb down gravity and feed it to the public than to explain what's really going on.

[@inertiaforce7846]

Explain how the ground is accelerating up.

[@Celtics-x4w]

inertiaforce Any books you recommend on GR or SR? Or any physics?

[@inertiaforce7846]

Watch this video then get back to me: kzbin.info/www/bejne/fJuaZHV8ZdR-bpY

[@inertiaforce7846]

If you have any questions about the video, let me know.

[@inertiaforce7846]

The whole point of that video is to show that you can't tell that you're accelerating. Any questions lol?

[@rommel23nb]

I very keenly listened to the lecture. Very good lecture. One question which I have been keen to know the answer of , never lucky so far, is this. Why is space-time wrapped near the massive objects? If it is not gravity, what is this that makes the lighter bodies to be trapped in pits of space-time created by massive objects? Why is not the space-time raised up causing to repel the other objects,instead of creating a pit and trap other masses? Dr. Dowker is requested to help. One more question that I have is related to your explanation of letting fall two different masses. You said, they start falling without gravity? What makes them move without force? Should we throw away Newton's second law of motion as well? Thanks. Once again well done with your theories and lecture.

[@stevefaure415]

What a wonderful, thoughtful, and entertaining lecture. You don't often come across a teacher both so smart and engaging.

[@whirledpeas3477]

On the internet, really?

[@kokomanation]

I think spacetime doesn’t physically exist but it is a great mathematical model for physics possibly massive objects create a gravitational field that may resemble spacetime pretty well

[@oilinki3]

I don't understand why there wouldn't be an universal 'now'. I would think that it's possible to take a snapshot of the universe, which requires that universal now moment. For us, observers on Earth, the now on Alpha Centauri is not what we observe happening there at the moment, but what we observe after 4 years, once the information from the same now moment has reached us. The talk was wonderful. I have to rethink the whole concept of spacetime. According to this talk, spacetime cancels the concept of gravity, in the traditional way. That would make a whole lot of physics calculations way different in the gravity dip, like Earth, compared to the open space, away from the gravity centres?

[@ahappyaxolotl1210]

+oilinki3 Even "now" is quite relative, according to the fact that eventhough light from terrestric distances reaches us almost instantaneously, there is always a certain delay until the path to our eye is been travelles by a ray of light. Eventhough these timescales are irrelevant for us, on smaller scales we are basically constantly experiencing a reflection of the past that we live in and move through, on that basis there is no exact "now", just an arbitarily decreasing notion of the past.

[@jasonboyd782]

Something I don't get is if the moon's orbit around the Earth is caused by the curvature of spacetime caused by the mass of the Earth, and the moon is actually moving in a constant "straight line" through this curved space... ok, but why then does light, say starlight, pass through an actual straight line through the same region of space?

[@erikziak1249]

Interesting hypothesis by Rafael Sorkin. Could this explain entropy?

[@michaelhull1813]

Erik Žiak The Second Law of Thermodynamics explains entropy sufficiently, don't you think?

[@avidmisreader]

Really engaging. Though a bit weird that she continually refers to space-time granularity as being a worked on (but as yet untested, speculative) theory rather than a (very legitimate) hypothesis. Hope it's just confused terminology.

[@reecelongden3500]

+B.E. Henriksen (jiku) Yeah, because by definition, a theory is supported by evidence, whereas a hypothesis is untested and unsupported by evidence.

[@KorAllRBare]

Let me repeat.. Wouldn't it be bothersome if all Mass were repulsive including the mass of Near-Vacuum, "That's right no such thing as a magical attraction" and what's more the more energetic the mass the more repulsive it would be, Which would mean the Near-Vacuum would actually be the most repulsive as its ratio of Energy to Mass would have it as the most energetic, it's the only "constituent" or "Matter" supporting Maximum Velocity, which BTW is faster than the local speed of light Eg: "Our location within a Galaxy" And yes I treat Near-vacuum as matter, a highly energetic mass with near to zero density as it hasn't experienced fusion, a media that makes up all atoms. The fact is, Near-Vacuums repulsion is responsible for Fusion, and for that matter the accumulation of all less energetic matter, but that becomes only apparent if one understands how Energy is stored or converted to Mass via "opposing velocities being cancelled out", Which basically means the Near-Vacuums accelerating expansion must expand into all the newly created spaces left over after the fusion of atoms. So yeah.. Does that accelerating expansion sound suspiciously like anything else you may have heard about? Could it be that simple? Mind you this would mean the Entire Universe is actually a wave Function rather than some crazy Big-Bang Theory, thus no need to refer to contradictory terms such as a zero point in time etc. And what about that accelerating inward momentum as fusion occurs? What would that force be? Repulsive or Attractive? The ignorant see it as some magical attraction, Whilst those of us who clearly understand Force, General Relativity and Mass/Energy must also clearly understand the mechanics, in fact we have no need to rely on Dark Matter and Dark Energy to explain a Galaxies physics, as those terms are only for morons who simply don't understand the basic physics, and more than likely are just bleeping like sheep lost in a wash of theoretical Mathematics. Here's another thought, what if the Universe were Finite? It would make perfect sense, because once EVERYTHING is quantified we have nothing left, Only then can we treat Everything as a single closed system (The Universe=1), Everything sums up to a single closed Universe, ergo all quanta/s would then have to be a percentage or fraction of 1 and thus if we are to mathematically prove expansion, Some quanta would need to accrue whilst another quanta or set of quanta's reciprocate, Put simply it just needs us to work with Mass/Energy or if you wish Space-Time right down to the Quantum level. But only if we treat all space as matter, a ratio of Mass/Energy, only then will it make so much more sense, and this would be right down to the quantum level, Granted working with this simplistic model, we don't have the luxury of the current disparity at the Quantum level like main stream has, So unfortunately, we may need to fudge some figures into this model so it too may have the current disparity, but until someone knows what those figures need to be, Then this is how I understand the universe to be..

[@dreamdiction]

Yes.

[@En-of5oh]

Time is real, it's not an illusion, unless we want to think other than that. Every event need time and space to take place, so we always notice the strong relation between time and space. We need to describe when and where an event took place or taking place or will take place, so the wonderful idea of the genius Albert Einstein to make from space and time one fabric called spacetime was an amazing idea, then phenomena like mass wrap to spacetime in form of gravity, and according to mass of an object how big or small that curvature become, all those phenomena and more happen according to GR of the genius Albert Einstein.

[@UmmCarl]

Time is the GUT. We measure everything as a measurement of time. Time is not linear, it's omni-directional.

[@imaam6]

Me having difficulty in understanding how a curved surface forces an object to go inward particularly in the absence of a pushing or pulling force. And when we come on the earth How this is related to an event when an object fells down from a bed to the floor. Why??

[@brainstormingsharing1309]

Absolutely well done and definitely keep it up!!! 👍👍👍👍👍

[@MrFuchsiamagic]

If gravity does not pull us down into our chair but only pushes us up as Fay suggests, then why don't we fly up into the air?

[@jameso1447]

23:50 Force without force. Infinite gravity from nothing - a gravitational field composed of nothing made of 'space time itself' which is made of nothing with infinite force but it's not force because if gravity was a force than the gravitational field of nothing has infinite potential. Circular and paradoxical. General Relativity.

[@ronintennispro7708]

Ms. Fay Dowker... what a Beautiful Woman with a Beautiful Mind! I love her voice, she should be the new Voice of Siri and I would switch to Apple's iOS immediately :)... BUT I Digress... I have been obsessed with Quantum Physics since my 10th grade Science Project on Light as a Particle versus a Wave using a Medical Electron Accelerator my father had access to as Chief of Vascular & Interventional Radiology... CHEERS RI :) !

[@ronintennispro7708]

CHEERS Ri* :)

[@noahway13]

You must like robots.

[@algonte]

Two balls of the same size, one made of wood and the other made of iron, released together, fall together and hit the ground at the same time, this appears natural if there is no gravitational force, BUT, which is then the cause that make them to accelerate?

[@jagathmithya719]

I didn't know Kundalini awakening at the Mooladhara chakra is a way to disprove Newtonian gravity! Amazing! According to Eastern thought, space is not nothing; and it is from space that matter is projected. Maybe she can research these ideas and take forward her granular theory of spacetime!

[@Valdagast]

I needed this after watching Flat Earth videos.

[@suddndestruction6199]

the problem with sun is .. energy falloff . its..drastic.. over distance it loses energy really fast.. so.. little bit after earth would be freezing.. and source would be tremendous.... and how can we see star light if its faaaaar away? basically what im saying is also about sun angle.. more angle less energy thus we have antartica? this is really extreme drop of value over space.. its just not possible to have source of energy faaarfar away

[@waikikiman007]

Whar we precive as time is really a perception of change. We experience xhange not time.

[@davidwilkie9551]

Timespace positioning here-now synchronicity forever, "makes sense" because it's emulated in the projection of our (meditative) thinking.

[@ritemolawbks8012]

[ 19:56 ] This would be a terrible time to have gas.

[@mrwideboy]

I love listening to her,

[@cygil1]

I've watched this twice now and I still don't get it. I think i'd have a better chance if she'd just break out the tensor calculus. All these bottom metaphors aren't helping.

[@ghromm]

Light is the propagation of information about change at distant point of space. It cannot move faster than itself. Light is change of space.

[@samirrimas]

Thee fact the universe is the bicth of lightspeed and has to bend and curl to keep it constant is a bunch of horse shit. Light has a constant speed because the universe requires it to do so not beacuse light likes to travel at a constant speed.

[@collinbarker]

Albert Torres A black hole is black because light cannot get out of it. the escape velocity of a black hole is greater than that of light, therefore it is black. Falling in, nothing exceeds the speed of light, but nothing is ejected. those plumes that come off perpendicular to the accretion disk are stuff that missed the black hole but ewas shredded and flung from it at extreme speeds , but not at lightspeed

[@josesaldivar655]

cygil1 you could ask if she has been out of school

[@jimlaguardia8185]

cygil1 Spacetime is a single thing, and it’s density varies. I.e., it is nonlinear.

[@Rawmon94]

i find it very hard to understand the concept of the curviture of spacetime in a 2 dimensional space like in the picture around 25:00 . Im wondering what the spacetime curviture would look like in 3D drawing. Lets say you could draw that dip in spacetime by earth from every imaginable angle, wouldnt they eventually cancel eachother out?

[@lameiraangelo]

This new theory of spacetime that she is investigating is revolutionary, if it can be proved... it will be an astronomical discovery.

[@albertjackson9236]

Oppenheimer once told his brother, "I need physics more than friends".

[@santanukumaracharya3467]

Really enchanting.

[@LinuxLuddite]

between 17:15 and 17:25 there is too many 'tch' sounds, is that an audio anomaly or she was doing it ?

[@tomb8078]

I came here from a bbc podcast she was on where she kept smacking her lips like this - it was driving me crazy

[@williamwong1544]

I am here because of the Discovery of the Gravity wave...>.

[@josephmeredith7436]

Yeah those gravity waves LOL what a crock.

[@bobaldo2339]

I am here because I cannot afford to live on the west coast.

[@collinng670]

Moments are felt as continous experience due to our conciousness and memory, present when we are alive...when we died, we then understand atoms & such, keep appear & disappear in discontinous pixelated world (?)

[@williambeck5678]

The constant speed of light and gravity, it self, can be explained if one assumes that all matter is composed of tiny quantum fields(qf) that are flat discrete and flipping at a constant speed between 3 dimensions. Each (qf) is fixed in place at 3 coordinates and entangled with several adjacent (qf) in our dimension as with other separate (qf) in other matter in each separate dimension. Thus matter attracts mater. We can only see 1/3 of matter from our dimension, the rest being dark matter. Light waves cause each (qf) to vibrate and pass on the vibration only while in our dimension, thus limiting the speed in the same way it limits the ultimate temperature matter can be heated and the reason our universe has not burned up. As the fields flip there is a brief instant when it can not be seen by any of the 3 dimensions, Time would not exist at that short period seen from each of the 3 dimensions, whereas time would be linked being the same in all dimensions. Thus causing time distortion around black holes.

[@philoso377]

Contradiction between Newtonian and Special/General Relativity : because Newton study laws of nature and summarized it into three laws representing nature precisely - while Einstein study in his mind experiment to summarize it into laws can only represents his imagination but nature. Don’t just learn but think Don’t just think but thinking outside the box - imposed on us by academia.

[@douglaswilliams8336]

The British.... personally I'd like to see more explanation by way of hard math. I understand it I just enjoy hearing different lecturers wax eloquent about their thingys along with a bit of understated British wit. Kai to the Uploader!! My deepest accord's

[@ArminGips]

whats up with the esoterics in the middle?

[@VibratoIbanez]

I need a book on Tensor theory with exercises. Can anyone please suggest me the best pdf available online which is free ? (It must have exercises)

[@mnizam84]

Beautiful lecture

[@LeoMadrid]

All objects with mass, curve spacetime, not just massive ones.

[@NikolaosSkordilis]

5:12 I do not understand if by "No matter what they are made off" she meant "...as long as they are made of the same material" or that "each can be made of a different material". The latter is almost always wrong (unless the density of the two materials is the same, and high enough) and even the former can be wrong if they are made of a low density material. Regarding the latter a small ball made of cork will certainly fall faster than a large ball made of cork. Cork is a very low density material and the large ball will be slowed due to air resistance. The same should apply to wood, but maybe from a higher tower than Pisa's, since the difference will be much less pronounced. If you made a small and a large ball from crumbled paper you could even test this from your balcony, provided you live at least on the second floor. The same applies to the former. A ball of iron will fall faster than a ball of wood and much faster than a ball of cork, no matter which one is larger. Mass is irrelevant (unlike what Aristotle thought, without testing it) but density is not, because it makes the ball more sensitive to air resistance. The effect of air resistance cannot be observed with small and large balls made of rock or metal, because Pisa Tower is not high enough for it to have any impact on the balls. But if you threw them from an airplane or maybe even Burj Khalifa the air resistance would register on the balls.

[@michaelkreitzer1369]

Well sure, if you add in air resistance.. which this talk was not about. Considering the talk was about gravity and that the first experimental evidence of the claim that objects affected by gravity fall at the same rate was established over 400 years ago, it's a fairly bold claim to try to argue otherwise.

[@marktime9235]

She should have mentioned that the effect only works in a vacuum.

[@michaelkreitzer1369]

Overbearing pedantry just makes these sorts of talks boring, and when discussing gravity it's a fair assumption that you're not including other non-gravity influences.

[@collinng670]

Time or Moments is continous only if i am alive... Eg.if i died now, next moment, things just move on, but i dun experience it... Things can just pixelated.... And if i came back from death next moment (or born again) i experience continous moments again...

[@attilabpc542]

How did you do/get that experience?

[@mkelkar1]

"The inverse Lorentz transformation used in relativity is false, it does not define a division operation and using it produces incorrect results, which are called paradoxes, because they contradict common sense. There is a mathematically correct inverse Lorentz transform that can be derived by assuming a linear algebra with a multiplicative group structure in which a mathematical division operation is defined, and in this mathematical structure the traditional inverse Lorentz transformation is known as the adjoint or dual Lorentz transformation" Harry Ricker III Special Relativity Is Irksome www.naturalphilosophy.org/site/harryricker/2015/07/09/special-relativity-is-irksome/

[@kenmarriott5772]

Man is constantly seeking to understand how the universe works. After working out a mathematical model that works and explains a lot a paradox arises which causes us to develop the next model. Did you notice that you have to use gravity on the trampoline to understand the bowling ball explanation of gravity between objects? Can there be a better illustration of gravity?

[@jenniferfardaei3388]

Please check the Universal Time, which Abert Einstein missed it. The real Time and his Time two different thing.

[@michaeljones7465]

Duration, time & space-time. Humans by now should know what the difference is.

[@nisshantvernekar6245]

Great one. THANKS FOR THIS.

[@rationalsceptic7634]

She was born in the same City as Prof Brian Cox,Manchester,holds 2 Degrees from Cambridge,trained by the late Stephen Hawking

[@paulfletcher4213]

Colin Dowson Prof Brian Cox was born in Oldham, not Manchester.

[@reecelongden3500]

Am I the only one who has noticed her incorrect description of c (the speed of light), through her omission of tachyons? She states that nothing can travel faster than c, but that is incorrect. Firstly, the rule is that INFORMATION cannot travel faster than c. Secondly, the rule is that nothing with mass can travel AT the speed of light, as it takes infinite energy to accelerate an object with mass TO the speed of light. However, it is possible for objects with mass to travel FASTER than the speed of light: they're called tachyons, and they always travel faster than c. It takes infinite energy to decelerate them TO the speed of light. The reason this works is due to time dilation: the closer you get to c, the less you experience time, and so the faster time outside your frame of reference goes compared to time within your frame of reference. At c, time ceases to exist within your frame of reference: everything happens at once, as observed by you, but from the outside time travels as normal. This is called Perfect Time Dilation. However, tachyons travel faster than c, and from their frame of reference, time travels backward, so they arrive before they set off.

[@rstevewarmorycom]

That's a theory, not something discovered.

[@jomen112]

_"Am I the only one who has noticed her incorrect description of c"_ The only thing I notice is your cherry picking of what she said. She said _"nothing can travel faster than the speed of light. NO physical influence can travel faster than light"_. _"Firstly, the rule is that INFORMATION cannot travel faster than c"_ Which is exactly what is meant with _"NO physical influence can travel faster than light"_. Therefore we can safely ignore the rest of your rant. _"Secondly, the rule is that nothing with mass can travel AT the speed of light_ Irrelevant. She was talking about instant signaling. Instant signaling demands FTL communication, therefor what and what not can travel at the speed of light is irrelevant. _"However, it is possible for objects with mass to travel FASTER"_ Really, possible? And your observational evidence, beside a formula on a paper, for this is? (I would say you confuse the map with the terrain here).

[@dazzassti]

I think she was trying to make easy to digest, if you believe you can bump heads with Fay Dowker then you'll find she knows exactly what she's talking about and you don't lol

[@owen7185]

but space time is a mathematical model yes? Minkowski came up with it to display events from Einstein's special relativity

[@umkumar]

Brian Greene says so...(Fabric of Space)

[@gforce9854]

OMG. So much to think about.

[@Thrax005]

At 8:51 prof Dowker points out that Newtonian gravity law states that acceleration is inversely proportional to mass, so that when to objects are falling from the same height at the same time should arrive at the same time, and that's cuz the more massive object accelerates at a lower rate than the less massive object.Now to my knowledge the acceleration actually is the constant quantity 9.8 meters per second per second, so when the 2 bodies fall together -one of 'em say twice as massive as the other- they reach the ground at the same time and both were accelerating at a rate of 9.8 m/s^2 (which is a fact), so the force here is the quantity that varied for the 2 bodies, in other words: the earth exerts a greater force on the more massive body to pull it than it does on the less massive one....... Isn't that so??????????????????????

[@jomen112]

Newton had to invent the fictive (counter)force of inertia to explain uniform acceleration in gravitational fields. However, Einstein taught us there is no force acting on a free falling object. As a consequence bodies with different masses will fall (accelerate) at the same rate.

[@craigfordyce4645]

'Spacetime' is not a physical reality. Matter attracts matter.

[@whirledpeas3477]

Thanks. I have been saying that for half my life. Also, I am 6 years old

[@TeraByteify]

Can somebody please explain to me the difference between a gravitational field/magnetic fields, and an 'ether' that was previously believed to be the material thing things sit on?

[@ralfwk163]

+Kevin Gallagher get 'a brief history of time', it's not expensive. You'll find most of your answers in there and it's not a hard read.

[@TeraByteify]

+Ralf WK One of the first science texts I read, don't remember the difference being explained, but I'll have a look.

[@laersonverissimo1715]

A field (on this context) is a space that each point can be assigned a value. For example, you can assign a depth to each point of the seafloor, and call that a seafloor depth field, where each point has a scalar value. The magnetic field is where we assign to each point of space a value of how strong is a force the a specific magnet will experience on that point, and the direction of that force (vector). The gravitational field is a tensor assigned to each point of space time. About the ether: Before special relativity, we used Galilean relativity to change inertial frames on Newtonian mechanics calculations (for example, if you are walking on a moving train, we could basically add the speed of the train to your speed relative to the train to know your speed relative to the ground). However, there’s a inconsistency with Maxwell’s equations, Newtonian Mechanics, and Galilean relativity, if you do the calculations for two different inertial frames that aren’t in rest relative to each other, a charged particle in movement creates different electromagnetic fields depending of the frame of reference (there’s on Wikipedia the whole story about it, and this calculation if you are curious). A solution to this problem was a hypothetical material called ether, that was the medium for eletromagnetical waves. As long as you use this ether as a frame of reference (that was basically an absolute frame) there were no inconsistencies. However, the Mikonwski experiment proved that there was no ether. Following that, some physicists and mathematicians proposed some solutions like time and space dilation as a way to make the Maxwell’s equations consistent, and that leaded to Einstein’s special relativity.

[@realitycheck3363]

Newton can not explain Mercury's observed orbit exactly. GR can. This is because gravity is not really a force. The Earth is not being "pulled" by the sun by some "force". The Earth follows a straight path through space. It's path however is "bent" by the sun, which causes its orbit.

[@kingtriplebbb5347]

Great Professor, 🎓