WSU: Space, Time, and Einstein with Brian Greene

  • Published on: 31 July 2020
  • Join Brian Greene, acclaimed physicist and author, on a wild ride into the mind of Albert Einstein, revealing deep aspects of the world that defy everyday experience. Using a visually rich canvas of animations, Greene leads you through all the startling conclusions of special relativity, from time travel to space warps to E = mc2. In the span of 2+ hours, this short master class will change your conception of reality.

    This is a mostly non-mathematical version of the WSU Master Class “Special Relativity with Brian Greene.” https://youtu.be/XFV2feKDK9E

    #WorldSciU

    0:00 - Start
    The Special Theory of Relativity - 00:05
    Speed - 00:05:50
    The Speed of Light - 00:18:23
    Relativity of Simultaneity - 00:27:42
    Time in Motion - 00:37:42
    How Fast Does Time Slow? - 00:47:49
    Time Dilation: Experimental Evidence - 01:05:31
    The Reality of Past, Present, and Future - 01:14:37
    Time Dilation: Intuitive Explanation - 01:28:38
    Motion's Effect on Space - 01:32:34
    The Pole in the Barn: Quantitative Details - 01:49:48
    The Twin Paradox - 02:10:39
    Implications for Mass - 02:19:17
    Special Relativity - 02:29:06

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  • Runtime : 2:31:27
  • Brian Greene Space Time Einstein Free online courses Physics Albert Einstein special relativity Quantum Mechanics General Relativity black hole speed of light Relativity of Simultaneity How Fast Does Time Slow? Time Dilation The Twin Paradox Implications for Mass laws of physic masterclass World Science U WSU World Science Festival New York City NYC

COMMENTS: 40

  • Neil Libertine
    Neil Libertine   7 hours ago

    There is no pyhtagorean for spherical or cylindrical coordinates. Then how should they use tensor as generalized coordinates, and how should minkowski space is correct. Differential geometry cant replace euclidean geometry which is generalized case and shapes are special. There is no great circle through points on constant latitude. So there is no geodesic for all points on sphere.

  • david zhou
    david zhou   8 hours ago

    Relativity: that speed of light is constant by Michaelson-Morley is not validated. The experiment itself didn’t measure the speed, it shows the light waves interference kept the same. It can only say earth motion doesn’t disturb the interference. Strictly speaking, according to Relativity, light travels in curves in gravity, when the earth is moving, the gravitational field is changing, because it’s positions to sun and other planets are changed. Speeds in x y are changing. But experimental result says not. It contradicts with Relativity, or the instrument doesn’t have enough resolution to prove as such. The speed of light in absolute reference as vacuum is constant doesn’t mean it is constant under any observer’s reference frame. The former is physical speed, the latter is artificial, mathematical, and virtual speed. There is no way it can be constant under any reference frame, or it violates mathematical linear addition principle. But on the other hand, relativity uses such mathematical principle. Relativists are saying atomic in space moves slower than it is on earth because of speed. Let’s assume three atomic clocks ABC. Place A on earth, B on satellite, C on moon. According to them, A faster, B slower, C is slowest from earth. But, from moon observer, C is faster, A and B depends on relative speed with moon. It is paradoxical.

  • Bernard Adesina
    Bernard Adesina   12 hours ago

    "Footballs or hand grenades or any other object in everyday life"~~Brian greene

  • Huckleberry
    Huckleberry   16 hours ago

    very enjoyable although I don’t have much knowledge on math and physics.

  • Neil Libertine
    Neil Libertine   1 days ago

    So how would length of an object is measure. By placing it against standard scale, its one end is marked on scale then other end. The difference in value of two ends is length. One thing is assumed here that an object is at rest with scale which is also called as coordinate or frame. Now if an object have some speed against the scale or frame then does its length could be measured accurately. No, because it's not possible to mark both ends at same time and if object and scale have relative speed then one of end either contract or expand the measured length of object. This is relative measurement and when object is at rest with scale is proper or absolute measurement.Now relativists says that both measurement are correct and more than that if either object or scale is moving then relative measurement is giving actual description of object's physical quantity. So whether length contract or expand that relative measurement define physical state of object as by relativists.Further than that, in most conditions there is no frame moving with light speed and some events happening in it. Observation of planet is not relative because observer with scale like clock and angular scale is on earth. In case of far objects it's not possible to directly measure object so light is used. But relativists says that speed of light is constant whether source or observer have relative speed or not. First thing, general science laws doesnt allow it, second it require that light should have special quality which it has not so. In classical relativity that replaced by theory of relativity which we know now, has no problem with measurement of distant objects because its absolute and relative measurements are same so no problem. All problems start with insistence of relativists that speed of light is constant so they change fundamental quantities like length, time, mass.Suppose some children are playing in ground which is stationary. Now if an observer moving with quarter of light speed measure length of ground as per theory of relativity, found that length of ground is small as compared to what is told. Another observer with half light speed measure length of ground and found that length is contracted and also differ from first observer, then who is right, observer at rest with ground or moving observers. Does measurement of moving observers that differ from rest one, in any way affect or give actual representation, no. Same thing is with time, moving observers says children are slow. Does clock of moving observer change the movement of children on ground, no.Question is why they are doing so inspite of evidences against their theories. Reason is that constancy of speed of light is required for their model of universe, if that is changed then their model collapse.

  • Justin Newton
    Justin Newton   1 days ago

    Great... I've always wanted to go to college... and I've always been interested in courses like this one... thank you great lecture... thanks for putting this on YouTube.

  • Neil Libertine
    Neil Libertine   2 days ago

    Serpents have fork shape tongue, metaphorically they are human who double talk. Similarly relativists, who profess theory of relativity, have logic of double talk.They says that time moves slower in presence of high gravity or force and speed is slow in high gravity due to curvature of space. At high speed which is far from gravity or force, time should moves fast as gravity is low. But their other part of theory says time goes slower due to high speed. But speed of body is due to curvature of spacetime and which is due to gravity or force. So what is movement of time farther from gravity, is it slow due to high speed or fast due to low gravity.Example is their explaination of time in satellites or they say that GPS and International Space Station. According to them time moves slower in them than earth because they are moving but at same time they are floating in less gravity than Earth so time should be fast. This is the condition of their theory and they keep bragging about it via various documentaries, channels, articles about their understanding and exploration of mysteries of universe.

  • Neil Libertine
    Neil Libertine   2 days ago

    Clock at rest measure proper time, so if your clock is moving then relative. But moving objects like planets and stars dont carry clock, clock is on earth. So why dont they give up their false ideas and come out of day dreaming. They are against Mach's idea of relativity, inertial frames are absolute, geocentric model is handy and practical.Okay time measured in S is t, observed by S' is t'. S' is moving relative to S with speed v'. Now another observer S" moving relative to S with speed v" observe time t" as per theory of relativity. S' and S" both measured time differently relative to S. So relativists claim that time dilation is real then which time is more correct t, t', t". Does measurement from S' and S" affect measurement of S, no. Therefore relative measurement is not real or actual and it has no physical significance.

  • Neil Libertine
    Neil Libertine   2 days ago

    Frame S is at rest relative to frame S' moving with speed v relative to frame S. Speed of projectile to frame S' is c then speed of projectile to S is c+v. These are absolute measurement, means measurement within frame. So relative speed of projectile to S' measured by S is (c+v)-v=c. This is relative measurement between two objects, here S' and projectile from S. Similarly speed of projectile to S from S' is c-(-v)=c+v.Thus in any good transformation system, measurement by relative frames should agree on absolute and relative measurement. Relative frames are those having constant speed between them so anyone could treated as rest.Compare it with transformation by theory of relativity. That says or interpreted as that speed of projectile remain same for both frames having relative speed. Absolute speed is sum if source of projectile is moving and relative speed is difference of speeds. So how could relative speed means anything if absolute speed is constant while speed of projectile is relative. Therefore constancy of speed of light is invalid because term rekativity means relative motion and speed is only measure of motion. So there is no length contraction and time dilation as these are relative measurement and not absolute. In relativity they used proper kength and time to differentiate between absolute and relative measurement.

  • Sc1 Sc1
    Sc1 Sc1   2 days ago

    If you have the exact time and location you were born, can a cosmologist calculate how many miles of space you have traveled through, in your life? Would that calculated number be equivalent, to the speed of light? if not, could it be measured against the speed of light? It might give great data on any living creatures perception of time.

  • Neil Libertine
    Neil Libertine   3 days ago

    We are not going into how frquency of wave changes without change in its speed. As i know that doppler shift in light according to relativity is toward red spectrum for receeding source and blue for approaching source.But observation says another story like in general relarivity more curvature of space causing close slower orbits than farther faster orbits, so time period remain same but this is not as observed. Also orbits of planets are in same plane which is inexpalinable by curvature of space. Now comes to point that sun at zenith is farther than sun at horizon and light from noon sun is white and from morning-evening is red. Sun is nearer at horizon than at zenith could be explained by apparent size of sun measured in angular distance.Relativity is useless beacuse there are no frame that moves close to speed of light so relative measurement of events happening can produce any significant relativistic effect as per theory. While motion of source of light can change the speed of light which discarded by relativists but useful in calculating actual distance of body if possible.

  • Joseph Cafariello
    Joseph Cafariello   3 days ago

    Cosmologists fail to understand one very simple concept of space... its density is not uniform all throughout; rather, its density varies. For consider this... We agree that space "bends" under the force of gravity, which explains the movement of bodies through their orbits, and the movement of light around bodies. In order for space to bend, it must contract on the one side and expand on the other side of any curvature of space. Take that thought one step further and we can see that in order for space to be more contracted in some places and more expanded in other places, it must have density (to a degree much higher than is currently accepted). When measuring the luminosity of bodies and their distances, we need to factor-in any "pockets" of more dense or less dense space between us and them. Red shifts are suddenly much less reliable than we thought, since the redness of the shift could be caused not by distance alone, but also by any pockets of more dense space between us and its body. This is similar to the red sunsets we have on Earth, where the redness is caused by the sun's light passing through a thicker cross-section of the Earth's atmosphere at lower angles. A star's red shift, then, could be much more illusionary than we realize, much like a sunset's redness is. Just because one sunset is redder than another, does not mean the sun is farther away, but simply means there is more dust in the air. So we need to find a way of accounting for pockets of varying space density here and there and wherever they may be. To do so, we need to note that the density of space is affected by matter. There is a body at the center of every pocket of dense space, and the greater the mass of that body, the greater the size and warpage of the "bubble" of warped space around it. For example, we know that the Earth bends the sun's light such that we see the ball of the sun at sunrise just a little sooner, and we see it at sunset just a little later than it actually is. If the Earth's mass were greater, we would see the ball of the sun even sooner at sunrise, and even later at sunset. So the greater the mass of a body is, the greater the size and power of the warpage of the space around it. This is why black holes trap light and any matter close to it, as the body at the center of the black hole contains so much mass that it warps the space around it to an extreme degree. Pockets of varying space density force us to change our mapping of the whole universe. Bodies may not actually be where we currently believe they are, just like the sun isn't exactly where we see it as being due to the Earth's "bubble" of space warpage.

  • Neil Libertine
    Neil Libertine   4 days ago

    Origin of relativity lies in no instantaneous action at distance as result of reaction from force or say flux. Most of equations formulated as law are result of reaction. It's like centrifugal force is measurable and not centripetal. Similarly relativity's orgin is against the newtonian concept of fundamental force in which there is no time of interaction, action and reaction are instantaneous. Both relativity and quantum mechanics are similar in concepts, like concept of field and one find that one could arrive at same conclusion from any one of them.So relativists claim that in reality action and reaction are not instantaneous if interacting bodies are far. This doesnt affect the relation of physical quantities as such but put a question on nature of mechanism. So relativists came with old concept with new twist, that there must be communication for interaction and speed of information is speed of light. They thought that contemporary mechanics not give explanation about time and speed of information to acknowledged field by bodies. But they forgot that most of mechanical laws are about steady state and not about transition state.Now look at their claim that time taken by information varies with distance or they are instantaneous from their own calculation. Take an example of light coming from distant star or take sun. Time taken by light to reach us information about sun's position in space of visible sky is about some minutes as per their calculations. But according to relativity, at speed of light distance is contracted to point or no distance. Similarly time taken measured by observer is also zero or instantaneous. If relativity is not used then there maybe some value of time but not with their own calculation. So according to relativity, action from reaction is instantaneous.

  • Neil Libertine
    Neil Libertine   5 days ago

    Is relativity against own foundation from its inception. Relativity is based on realistic view of Mach that there is no absolute motion, all motion are relative. They misinterpret it as inability to find absolute motion outside, thus relative measurement are real or actual measurement. While this is incorrect, because what Mach's principle means is, there is no need for looking absolute motion. Measurement in a frame is absolute and measurement of other frame is relative. So relative measurement is not actual or real even using Lorentz's transformation. We are not discussing here that how incorrect are Lorentz's transformation in relative measurement because they alter result of measurement of fundamental physical quantities. There is no agreement on these quantities if measured in one frame.Relativists are using self-defeating arguments. Suppose length of moving object is measured in inertial frame. An inertial frame is equivalent to rest frame if observing with in frame. Speed of ball measured in moving coach is same as on ground, one can play with ball in both frames without any difference. Relative measurement is observation of ball in coach by observer on ground or vice-versa. Question is, does observation from ground affect event in moving frame, no. Thus relative measurement is not actual if they differ from absolute measurement.Implication of this is that there is no time dilation or length contraction. Observation in an inertial frame is absolute. So there is no advantage of heliocentric model over geocentric, later is more practical. Also Lorentz transformation are useless because they have disagreement in absolute and relative measurement and thus producing difference of frame for observation, while they says that all inertial frames are equal, no preference. This shows that relativists preaching is different from practicing.

  • Ivan Leon
    Ivan Leon   6 days ago

    2:14:20 , why does Gracie has a bear? is that a relativistic effect? LOL.

  • Book Worm
    Book Worm   6 days ago

    One concept everyone misses is the size variant. Everyone tends to agree that the universe is expanding, I for one believe that some regions are also contracting. But that's another conversation. But what if I told you the same thing is happening on the atomic scale. This is exactly in fact what keeps instances of time from overlapping. The problem is that you can't currently observe this because any instruments you might use to study it are undergoing the same changes. However the nearest example is atomic decay. Really we are talking about temporal resonance and phase variance. But without it reality experienced as a passing of time could not exist.

  • Ivan Leon
    Ivan Leon   6 days ago

    I cant respect a physicist that uses Imperial system.

  • SHAUN CAMPBELL9
    SHAUN CAMPBELL9   6 days ago

    Hello, I would make a great time traveler, as I have no family; No friends or acquaintancea, no one would miss me. Where others would think, time travel as dangerous, I would not, because I have no fear of death.All the best Shaun of NYC

  • Neil Libertine
    Neil Libertine   1 weeks ago

    What people generally think of pressure as force per unit area, where area is 2 dimensional having no thickness. This is given by tyre pressure in unit of pounds per square inch, psi. The force exerted on inside surface of tyre by air contained in it.But this is half truth, in reality there can be no pressure on surface without having some thickness. What it means, that unit of pressure is given in 2d but it not applies on surface or area having no thickness. Imagine one having thin sheet of metal, now pressure is applied against thickness of sheet in form of hammering or weight. The metal sheet spreads out and become more thin. But if sheet have no thickness then no deformation.So how space-time given in 2d deformed by anything. It is other thing that mass is not equivalent to force unless it have some speed so having energy or under influence of some pull due to force or density. Similarly energy cant exert force unless it is contained in form of kinetic energy.If mass exert force then it is similar to Newton's law of gravitation, so what difference theory of relativity made. According to which black holes dont exists, they are against nature of force which is evident in big-bang model. Big-bang is expansion of matter and black hole is contraction of matter under same law.Differential geometry doesnt account for general model as they are for shapes and shapes are specific. Thus differential geometry of tensor not make equations independent of coordinates but opposite of it. It is also evident from model of universe as expansion. Universe expansion is transformation into planar space or euclidean space. While their model is flawed because expansion of a singularity is in first place having euclidean space.So their relation of mass-energy tensor to curvature of space-time is invalid because first tensor is operator and without specifying function it means nothing but numbers. Second thing mass and energy in itself no force so there could be no deformation. Third 2d surface cant have deformation whatever. Fourth there is assumption of surface prior to observation, it is assumed the shape of universe.This model of universe came is biblic in nature, everything comes from nothing. If one look at big-bang, it is culmination of their theory about universe, then how spreading of matter consitutes closed surface as spherical geometry required. Spherical geometry means closed body, having two opposite poles or sources, so no net source. This implies origin of universe from nothing. But two opposite source cancel each other to make region source free and if separated by distance cause directional movement result of gradient. Thus make work done possible. But their model ultimately ended in single point source of one kind when tracing backward in time.

  • Apple F69
    Apple F69   1 weeks ago

    No offense.. i really cant take him srsly after the diss by sheldon and amy in tbbt 😂😂

  • Neil Libertine
    Neil Libertine   1 weeks ago

    Vantage point is, time measured of event happened in moving frame S' that was round trip of light in transverse direction of motion is t', c' = 2L/t' ---- (1),where L is length, and c' is speed of light in S'Relative time measured from rest frame S is t, c = 2L/t ---- (2)where c is speed of light in SFrom relativity, time is slow in S' measured from S so, t = t'# ---- (3), # is Lorentz factorFrom (2) and (3), c = 2L/(t'#) ---- (4),From (1) and (4), c = c'/# ---- (5)From (5), it is clear that speed of light, c in S is not equal to c' in S' and slower.Thus speed of light not remain invariant in relative motion. There is no constancy of light or either time is not different in relative frames. Time is no more local if speed of light to be remain same in relative motion.Similarly in longitudanal direction of light, relation between c and c' is given by, c = c'/(#^2) --- (6)Using above relations in case of Michelson-Morley's experiment's calculation, time measured in frame of interferometer for transverse direction is,t'=2L/c' similarly, t=2L/c=2L#/c'for longitudnal direction,t'=2L/c' and, t=2L×#^2/c'

  • Neil Libertine
    Neil Libertine   1 weeks ago

    Why Euclidean geometry is general case and differential geometry is special case, which they say otherwise.Take an example of surface of sphere so radius become constant. Now line element is given by, ds² = g(ij)dx(i)dx(j) = r²d□² + r²sin²□d○²,where □ is azimuthal angle or angle with one fixed axis of Euclidean space from 0 to pi, and ○ is polar angle or angle around centre of circle whose radius is projected by □.In sphere line element is given by fixed radius and fixed azimuthal angle, □. That is given by, ds = r×sin□d○But it is good for fixed □, like arc of great circle at equator or small circle having fixed latitude. If there is arc part of great circle other than equator, the above relation can't calculate length. That is its azimuthal axis is tilted by some angle. Even if one previously transformed rectangular coordinates into spherical, it didn't calculate.To calculate above arclength, one has to use rotation matrix or change coordinates in Euclidean space or rectangular coordinates of plane having azimuthal axis. This shows that what they publicise that metric tensor free from coordinates is untrue. Problems are specific and they can't be generalized when speaking of geometrical measurements.Euclidean geometry is basis of space because it is not closed like other, so Euclidean geometry is generalized form and differential geometry is specific depends upon problem or surface encountered.

  • J
    J   1 weeks ago

    the more I watch these videos the more of the same mumbo jumbo gets said in different ways. I want some exciting ideas not grade level suppositions on spacetime.

  • uzijn
    uzijn   1 weeks ago

    52:48 is my favourite part. Didn't even get to KUH

  • david zhou
    david zhou   1 weeks ago

    In Galileo system, x=vt, if only if dx/dt is constant. Lorentz transformation goal is distances (x, x’) x=f(v,t)and x’=g(c, t’) are mathematically equal in both systems with symmetry. So c is not Galileo or classic velocity, and t’ is not classic time. In Galileo, v varies, t is uniform at any point in space; whilst in Lorentz, t’ varies, c is constant in space. c =eu , is really the property of the space, or medium, or Ether. It is not velocity in Galileo.( v, C),(t,t’), they are (Apple, Orange), (Peach,Grape) in two math systems. People are still thinking they are same things. That causes confusion. Saying 1) if an object moves at speed of light, time stops. Moving object slows clock, etc. That’s wrong. It should be said t’ in Lorentz stops, or equal to 0. In Galileo, t is uniform, it never stops or slows. 2). Speed of light C is constant from any observer at different speeds. That is wrong. c as speed in Galileo changes from observers, C in Lorentz as the property of space is constant. Then there is no ambiguity, confusing, both accurate in their own system for/from measurements. Time dilation, space-time curvature, etc. are all bogus by mixing concepts in two systems. If you use Fourier series to express a signal S, it is not the signal in time domain, it’s amplitude A in frequency domain. Nobody treats A-S as “signal dancing”. But sigma of all these series by frequency goes back to the value of signal in time domain. They are just mathematically equivalent, not necessarily physically same. There are many ways to do it mathematically, too. Relativity is just another way of measuring of the nature using electric magnetic wave in Lorentz system. It has advantages over Galileo system in Astronomy, because Maxwells equations describe electromagnetic wave in vacuum with eu as constant, which is the space property and its value equals to speed of light in Galileo.In Algol events (visit Algol website) can prove the speed of light wave in Galileo system changes with observer’s or earth’s motion

  • Martin Mitchell
    Martin Mitchell   1 weeks ago

    I find these lectures better to follow than when they gather together a number of experts on the stage and they start discussing various theories. For me that becomes quite confusing, even with a layperson interviewer, or a host like Brian Greene, trying to drag the discussion back to what the average person might be able to follow. Brian is so clear and such a good speaker. The one disappointment here was a clear disjunction at 1:50 when it jumped into the pole in the barn issue which clearly he had already set up earlier. There was quite a lot of maths in that part which made me wonder if it was an import from the parallel maths version of these presentations? But overall - excellent.

  • Mang Yana
    Mang Yana   1 weeks ago

    Jadikan aku murid-mu guru 🙏😭

  • Neil Libertine
    Neil Libertine   1 weeks ago

    A ship moves with relative speed of lorentz factor 2. An object of length 3 nanosecond in ship measured from ground. Relative length (why relativists make fuss that relative observation are actual while they are apparent) of an object is calculated as 12 nanosecond. How it comes, first if relativity is correct then there is time dilation for relative time, so relative time is 6 nanosecond. So length comes out as 6 nanosecond but as it is supposed that relative length is contracted so boost it with lorentz factor to calculate actual length of an object.As seen above length is expanded and not contracted in relative motion as per theory of relativity. Question is then why they used contraction. Answer for that beguile one, historically special theory of relativity known to world first than general. But they had knew the general relativity first. In 19th century there was came spherical geometry and they modeled universe as some sphere. In sphere, orthogonal unit vectors in angles for surface is not constant but varying in direction which is okay but also vary in magnitude. Means one unit of length near equator is contracted at pole. From this they got idea of length contraction. As speed is slower at pole due to curvature if part of sphere, so that become region of high gravitation causing slower clocks. Now in differential geometry, length of curve is given by scalar multiple of speed with parameter. So they need some constant speed so they can relate it with surfacial model of universe, and light became their ideal choice. To have constant speed of light near poles, they need change in unit of time, so time is dilated in high gravity. But these concepts of change in relative length and time is introduced through special relativity. Why, because they want to show that these changes are not due to gravity or accelaration but intrinsic property of motion or say relative motion. But for special part they need some exponential multiple to produce effect of curved surface equivalent to spherical surface, so they introduced concept of ultimate speed of light and that became essential constant of speed for spherical surfaces and lorentz factor for logarithmic multiple effect of curved surface in inertial relative motion.

  • efte hassan
    efte hassan   1 weeks ago

    What if i put the light clock in a deferent orientation where path of the light will be parallel to the path of the clocks motion ? then what will happen?

  • 3dgar 7eandro
    3dgar 7eandro   1 weeks ago

    25:25 the speed of light is probably (until this day, maybe tomorrow we'll discover something faster) the fastest way information (electromagnetic wave) travels, but the speed of a photon could be indeed lower: while traveling through a denser medium like water or a cristal. The speed of light isn't always 300.000km/s, that would be only true on the emptiness of space.33:33 this mental experiment is useless: in reality no train can travel close to the speed of light.And of course any object or particule would take longer to travel on a diagonal trajectory than on a perpendicular one... That is just simple mathematics... Nothing special about light there. I truly believe we would never be available of traveling (at least in a conventional way) even at 10% of speed of light so would could never measure if moving towards or away of beam of light would truly affect the Total speed of the measurement.... I have the feeling that the day we actually do that experiment it would be the day we change our perception on the constant speed of light: "c".45:00 Again you have to move those clocks at really high speeds to notice those diagonal trajectories.

  • Neil Libertine
    Neil Libertine   1 weeks ago

    In general relativity, basis for space is expressed in two oblique base units, like euclidean space is expressed in spherical coordinates and considering surface as sphere having constant radius, thus two base unit is azimuthal angle and planar angle. But thing is that, first there is assumption of sphere like surface and having fixed radial distance. How this is free from coordinate choice when its itself bounded by shape.Second thing as 3d is represented by 2d surface, and area of surface depends upon angle between base units, thus unit vector is not constant which is changing angle. So measurement of space is different for different location in length. For example 1km near pole of earth is different from 1km at equator in terms of longitude and latitude.Third thing, as unit surface area is cross product of two base unit, which is multiple of sine of angle to area of orthogonal base unit. Thus resultant of sum of base is different.Fourth thing, pythogoreous theorem to find resultant is invalid for inside angle. Why, because that gives negative of sine and represent difference of two vectors, not sum.

  • AJ 🥊
    AJ 🥊   1 weeks ago

    Can anyone explain the time dilation that occurs in the Carl Sagan film “Contact” becomes it made no sense to me

  • Martin Mitchell
    Martin Mitchell   1 weeks ago

    Excellent presentation - cannot imagine how it could have done any better. Having said that it seems on this particular uploading that at 1:50 we jump into the mathematical presentation with the pole in the barn?

  • eferodo
    eferodo   1 weeks ago

    Thanks Dr. Green for your beautiful lecture. I would like to find the advanced course with math that Dr. Green tells us in his video.

  • Neil Libertine
    Neil Libertine   2 weeks ago

    This is going to be endgame for theory of relativity which is mere words salad or juggling of words, overall gibberish. The final equation of general relativity as interpreted by scientists is that mass and energy cause curvature in space-time. We are not discussing that how illogical and ridiculous these assumptions are, and these are taken as fact without priori proved.Thing is that other than interpretation, the equation states that metric tensor is equal to some constant multiplied to mass-energy tensor. Those who not know what tensor is, it is matrix or array of number which changes magnitude of quantity with it multiplied. So equation is, nothing cause change in nothing, or say numbers produces effect in numbers which govern motion of objects. Tensors are number and not represent any physical quantity and when equation have on one side tensor or matrix and on other side some constant with another matrix.To understand it better, suppose one wants to measure height of tall object but unable to measure it directly. Then one takes help of trignometry and first measure distance between object and point of observation from where one can measure angle between top of tall object to bottom of it. Now from trignometric relation, tangent of angle is ratio of height of object and distance from it. Now point is that neither angle nor tangent of angle represent any physical quantity measurable, like distance or height as length, mass, time and other things. It is just number similar to matrix or tensor. Now if one give equation in which sine of angle is product of tangent and cosine of angle, does this is physical law representing any cause and effect law of nature or purely mathematical equation.Conclusion is that Einstein and his team was fraud and they had agenda to do this. If one reduces their equations, one find inconsistencies and unproved or unprovable or illogical assumptions.

  • yahya fattah
    yahya fattah   2 weeks ago

    Stop shalowing him guys he didn't respect your brain even enough to give a proof that the speed of light is contants just cartoons i don't take information that way no proof no interest