How Our Universe Violates a Fundamental Law of Physics! Energy Conservation

Claim your SPECIAL OFFER for MagellanTV here: try.magellantv.com/arvinash . Start your free trial TODAY so you can watch "Is the Universe Infinite?" to learn how far stars stretch out into space? And what's beyond them? www.magellantv.com/video/is-t...
REFERENCES
General Relativity: • General Relativity Exp...
Dark Energy: • What is Dark Energy ma...
History of the universe: • A Brief History of the...
All Physics Explained: • All physics explained ...
PATREON:
For Early Access, Input on New Videos, Personal answers to Questions, Join My Patreon:
/ arvinash
CHAPTERS
0:00 Energy only changes form
1:19 Open vs Closed vs Isolated system
2:39 Is the universe an Isolated system?
3:50 What General Relativity says about energy conservation
6:00 Evidence for Violation of Energy conservation
7:40 Could lost energy be transforming into Dark Energy?
8:50 If the Universe is infinite, then all bets are off
9:47 Even if not infinite, we are almost certainly losing energy
10:28 Opposing view on why Energy could still be conserved
SUMMARY
The law of energy conservation may be the most fundamental law in physics. It says that overall energy is always conserved. It can never be created nor destroyed - it can only change form. But this law is probably violated by our universe as a whole.
Specifically, the Energy Conservation law states that in an isolated system, that is a system in which no matter or energy enters or leaves, overall energy remains the same. Energy only changes form.
But isn't the entire universe a well-defined isolated system? Since the universe if everything, shouldn’t it be the ultimate isolated system? It turns out that the answer not straightforward. If we want to include the whole universe, we have to include everything from the very small to the very large. Let’s start with the very small. The behavior at the micro-scale is described by quantum mechanics.
At the quantum level, the concept of energy conservation is explicitly defined. This is shown in the Schrodinger equation, which states that total energy is equal to kinetic energy plus potential energy. Energy is conserved according to this equation. So there is no problem at micro scales.
But at the largest scales, where Einstein’s theory of general relativity applies, this is not the case. What his field equations show is that the derivative of the energy-momentum tensor is zero. So the simplified way to think of this is that the change in energy and momentum remains zero. This is called the principle of energy momentum conservation.
This equation is not saying that energy stays the same, only that the combination of energy AND momentum remains the same. This means that energy can change, as long as the combination of energy and momentum doesn't change. So, it tells us that at large scales, energy is really not conserved in the universe.
Several observations confirm this. First is the expansion of the universe. Empty space has energy. If the volume of this space is increasing then energy is increasing. We know that the energy density of spacetime doesn’t change, but energy density is energy over volume. If the volume increases, then energy also increases.
Another consequence of an expanding spacetime is the observed redshift. The light from distant galaxies is redshifted. As the universe expands, the wavelength of light also expands, which means it loses energy. So light is losing energy within an expanding spacetime from our perspective.
Could it be that the energy that light waves lose turns into dark energy, thus conserving energy overall? The answer is no. I explain why in the video.
In an expanding universe, we don't even know what the size of the universe really is, so we can’t define what the isolated system would be. We only know the observable universe, which is about 94 billion light years in diameter. But there is a cosmic event horizon which is the end of this observable universe. We don't know how big big the universe is beyond this horizon.
If the universe is infinite, then we would have to conclude that the universe likely does not conserve energy.
Evan if the universe is not infinite, it is probably still the case that it is much much larger than the 94 billion year diameter that we observe. We are losing energy of the galaxies that are moving out of the observable universe.
#energyconservation
Some experts believe that overall energy is conserved in an expanding universe because, they say, you have to include the energy of the gravitational field along with the energy of the matter and radiation. In other words, as distances between objects increase, the increasing gravitational potential between them, which is a kind of negative energy, also increases, balancing overall energy.

[@baptiste5216]

I've read somewhere that conservation of energy is such an important concept in physics that each time it didn't seem to work energy was just hiding somewhere else and it lead to immense breaktroughs in physics. I hope this will be the case for this as well.

[@noneofyourbusiness-qd7xi]

Nope. On non-intergalactic distances is energy always conserved, just on intergalactic distances (or rather on distances between galaxy clusters) this is no longer the case. This means that the effect can only be used if your machine is of a size of several million light yearsm, which is of course impossible. Energy conservation is indeed not perfectly strict, when ,looking at the universe,, but on human scales (eg on any distance within the milky way) it is, absolutely without exception. This means for all practical purposes: the law of energy conservation is still valid.

[@Dragrath1]

You might be onto something in some sense as the simplified form of the Einstein field equations used by cosmology does not conserve information a.k.a. the mathematics with the chosen constraints can not be made internally self consistent according to the implications of the No big crunch theorem. In essence this comes down to the nature of derivatives within the field equations or rather to be more blunt any and all possible systems of differential equations due to one of the defining properties of differential equations being that there is a unique solution for each and every possible set of initial conditions. Because of this property it turns out that in general the rate of expansion of contraction must be dependent on the local spacetime curvature's effect on the rate of time passing else there can not exist any valid solution to the Einstein field equations which is internally self consistent, i.e. logical self contradictions become inevitable in that the metric must simultaneously display two mutually incompatible conditions for such a solution to be able to exist. Ergo the Friedmann Lemaitre Robertson Walker metric while a valid solution to the Einstein field equations is not a mathematically stable solution meaning any and all perturbations from this will result in an irreversible runaway divergence and no other possible linearizable solutions can exist within the set of all possible valid metrics to the Einstein field equations. From this it can be shown that the cosmological principal and is causally forbidden for all possible nontrivial metrics as there will always be more underdensities produced by gravitational attraction than underdensities and this will in the limit of a sufficiently large universe (size much larger than the rate of causal information propagation) result in the rate of expansion even if it was initially the same everywhere rapidly becoming locally dependent on the past light cone's curvature imprint. This implies a coupling between the metric and its own derivatives in a way that the simplified linear Einstein field equations doesn't allow which implies that the metric of spacetime itself necessarily must carry information on its past evolutionary state imprinted into the local expansion rate which can at its simplest only every be a nonzero rank 2 tensor system of differential equations that depend on both space and time. But there is more as we can also derive that this means the off diagonal terms of the metric tensor must always be irreducibly asymmetric and nonzero to avoid this logical paradox and this has big mathematical implications as it means that in order for causality to be preserved in an expanding (or contracting) universe the metric of the Einstein field equations must at the very least be nonlocal for off diagonal terms with computational numerical simulations showing that these off diagonal contributions are naturally repulsive for an expanding universe and grow nonlinearly with distance based on the cross sectional volume curvature of any path through spacetime. This is striking because unlike the conventional assumptions that these terms should become small with large distances we see that the distance dependence is in the numerator and thus the magnitude of these terms rather than dropping off in fact must grow with distance. These terms due to not dropping off with distance means we need a natural nonlocalizable and quantized ground state contribution to the metric in order for the Einstein field equations to be mathematically valid for any and all possible choices of initial conditions and thus we naturally recover Bells inequality as an essential property of the Einstein field equations at the cost of revealing that General Relativity is intrinsically a nonlocal variable theory in any sufficiently large expanding or contracting universe. The most obvious implication is that if any observer in such a universe applies the invalid linearized model we can see that the apparent acceleration of spacetime is inevitable and independent of all possible choices of lambda (including zero). In essence this dark energy term is based on Occam's razor likely just the off diagonal contributions which are by definition always nonzero for any and all possible nontrivial solutions. Moreover from the asymmetry we can tell that all terms must in effect be a sum of causally possible interactions between information which is strikingly similar to the ER=EPR conjecture if the metric itself gravity +dark energy itself is really just the sum of all current and past causal interactions (i.e. quantum entanglement==gravity). More striking however is the asymmetric character of these contributions as this asymmetry is a property of spinors which tells us mathematically that only terms which obey Fermi Dirac statistics can be quantized in general relativity at least in the case of off diagonal terms, i.e. the argument based on symmetry used to produce nice and simple metrics is invalid because exact symmetric canceling is logically forbidden at large scales and thus symmetric metrics can only exist in a particular size limit where the relative off diagonal contributions are comparatively small. This is somewhat shocking as it goes against the established theory yet logically and mathematically we see it must be true if the Einstein field equations are to be a valid system of differential equations. It is also in hindsight fairly obvious from the framework of mathematics as any mathematical system must be internally self consistent in accordance to Gödel's incompleteness theorems. As a potential extension of this nonlocality via quantization if we make the quantization general for all terms then so long as the universe is large and full of matter outside the cosmological horizon of any observer then we should expect nonlocal gravity terms for the linear contributions too. These would be small proportional to the minimum value however they would be cumulative for all massive bodies in the Universe, specifically all those which have ever had the potential to exchange information when the Universe was small and dense. This would thus result in a threshold where the behavior of gravity would change as the relative magnitude of local gravity becomes comparable to the non local contributions a.k.a. you derive MOND as the general formulation for gravity. So it turns out we also might not need dark matter or at least the amount of dark matter and thus the abundance of any dark matter particles may be significantly lower than astronomers have assumed. Again remember that these terms arise as a consequence of the past light cone of the observable universe at earlier times imprinting itself onto the rate of change of the metric. If you don't have these nonlocal terms then you have broken causality or equivalently either deleted information from the history of the universe or created information from nothing. The true beauty of this is the implications of this as it turns out we can use this result to completely eliminate all the sources of apparent incompatibility between general relativity and quantum mechanics. No most naturally of these is the singularity which typically appears in symmetric solutions at small sizes as Fermi Dirac statistics place a hard limit on how tightly space can ever be squeezed eliminating true causal horizons from actually being able to occur. Instead its an asymptotic limit which appears to have gravity's strength weaken the more densely space is full of matter since the off diagonal terms naturally oppose the attractive component of linear terms. Instead space and time get distorted in such a way that distances effectively appear to be larger with smaller relative intervals of time and thus it seems highly probable (this requires more computational testing of course) that the escape velocity of any massive body can only ever asymptotically approach the speed of causality. In other words the information paradox and the infinites appear to vanish quite trivially. We can also see a natural mechanism for the "spooky action at a distance" since now the metric always holds the information on the paired state of any information which has been moved out beyond the local causal horizon within the rate and direction of change due to expansion in any region of spacetime. So from simple limit analysis we can find that dropping the single assumption of the cosmological principal and enforcing the conservation of information (of the initial condition) to ensure that the Einstein field equations obey the definitional rules of all systems of differential equations eliminates the incompatibility between the Einstein field equations and quantum mechanics at the cost of making all nontrivial solutions irreducibly nonlinear. The advantage however is that we get a number of add-on's which have conventionally had to be added as a parameterization for free as a natural consequence of the nonlinear terms which have conventionally been neglected. Dark energy? nope just asymmetric gravity contributions, dark matter? possibly goes away or at least greatly less of it needed, information paradox? turns out to be a trivial consequence of making n assumption which unequivocally must break information conservation for it to hold in an expanding universe. There is probably a lot more than this as this is just what can be gleaned from limit analyses of the implications of the "no big crunch theorem, the low hanging fruit if you will. I would bet that these nonlocal contributions if calculated explicitly for an ensemble of numerical solutions would turn out to close energy conservation

[@sethrenville798]

This is actually really neatly resolved if you assume an hyperbolic, Anti-desitter space universe, that just appears flat, possibly due to the fact that our sensory apparati and tools are all warping spacetime to near flat due to the fact they're all contained within masses, which bow spacetime outwards. You can see this effect by looking at how motion appears when you move, with farther objects appearing to move more slowly than those up close.

[@AfricanLionBat]

This is actually how the neutrino was predicted because they couldn't figure out where the energy was going so they searched for an extra particle. Hey, maybe all that energy that's lost from light redshifting is making it's way into some field and lending itself to dark energy or something. Nobody can say it's not considering we have no idea what dark energy is.

[@AfricanLionBat]

​@@noneofyourbusiness-qd7xiyou're missing the point he's saying that every time they thought energy wasn't conserved it turns out it was so that could be the case considering we have so much we don't know. You can't say no with such certainty.

[@Quadflash]

My mind just exploded. That's a good thing. One valuable insight is that I don't understand momentum well enough. Thank you, Dr. Ash!!!

[@CaptainPeterRMiller]

Arvin, that is a great video. When we first intreracted, I told you my brain had suffered. Now it has melted. I can get much more out of your explanations. You're a really great presenter who knows his subject. I will add, your presentations have acquired a subtle gloss and a wonderful technical advancement. If we are to continue to attract juniors into the STEM subjects at school, we couldn't do better than making your series part of the curriculum. Learning is sometimes difficult, but if it is attractively and coherently presented, students will assimilate the information easily. Knowledge is power and we will need more and more science students to lead us into the future. Thank you for your keen interest and your work.

[@ginnyjollykidd]

Brain m meltdown! Awesome!

[@Pain53924]

Hi intelligent person Question: Normally a star is stable because the its own gravity is balanced by force produced inside the star due to nuclear fusion. How are black holes stable then i.e. why isn't all the mass of a black hole in the singularity?

[@rainofrest7778]

it is@@Pain53924

[@user-up5zm1mw2x]

Thank you for the video! Energy is the conserved quantity that arises from time translation symmetry. Our Universe as a whole doesn’t seem to have time translation symmetry.

[@mikegeld1280]

Good deal man,I always enjoy watching ur videos then thinking about the universe, keep making these great topics 😎

[@TM-yn4iu]

A wonderful, condensed video on a complex subject. I truly appreciate your simplification to accommodate the time. Thank you! I've been looking for a new video , concerns for your health after the long period of treatment/cap. Thanks

[@Pain53924]

Hi intelligent person Question: Normally a star is stable because the its own gravity is balanced by force produced inside the star due to nuclear fusion. How are black holes stable then i.e. why isn't all the mass of a black hole in the singularity?

[@stephencarlsbad]

Fascinating observations as always, Arvin!

[@ginnyjollykidd]

I remember the first and second laws of Thermodynamics this way: 1. You can't win (matter and energy are always conserved; you can't get more out of a closed system than you put in; there's no such thing as a perpetual motion machine) 2. You always lose (entropy always increases, and also no perpetual motion machine) As for the third, "a perfect crystal at 0K has zero entropy," I'd not be able to remember even on a multiple guess quiz. But discrepancies occur at the small end, too. Certain quantum mechanical studies seemed to say that particles wink in and out of certain fields. We need to explore these.

[@thebogsofmordor7356]

I always used 1, 2, 3 strikes you're out of entropy for the third.

[@aviecenna8579]

I've read it as "You can't even get out of the game", i.e. you can't reach absolute zero

[@wefinishthisnow3883]

Sabine Hossenfelder (a friend of Arvin's channel) recently released a video about her reservations on the 2nd law of thermodynamics.

[@ginnyjollykidd]

@@wefinishthisnow3883 Yes, and she gives recent evidence. I like her.😊

[@theultimatereductionist7592]

1:33 I have a BChE in chemical engineering and even *I* long forgot this clear distinction. I've seen KZbinrs toss these words around but NOBODY stated the definitions THIS clearly like YOU did, Arvin Ash! Thanks!

[@j121212100]

Finally, I have been saying this for quite a long time. Nice to hear someone else break it down.

[@paulc96]

Thanks Arvin, for another well explained, interesting video.. Please keep on making them.

[@robk2167]

Nothing more but bunch of nonsense. Quantum mechanics is false and completely wrong. You have your physics wrong and Einstein was wrong and he is a fraud.

[@conrmckocoa9352]

Thanks for another science-heavy video and breaking it down into smaller bits

[@mariodegroote6756]

great work, respect for your work sir!

[@emergentform1188]

This is gold! You are a scholar and a gentleman my friend, love your content and your style.

[@bosuttlutt]

A scholar and a gentleman, foresoothe!

[@meet560]

Sir Arvin thanks again for providing us all with such high quality videos , in the future I would like to work with you in Science field as it's my passion and I get really excited by it. I think that nowadays we are not having that many breakthroughs in science as compared to the previous century. It could be due to some reasons. I rarely comment, cos i think its not worth the time. But on your videos, i really love all your videos. GOD BLESS YOU, SIR😊

[@Pain53924]

There's no evidence for existence of god though

[@meet560]

@@Pain53924 There's also not any evidence against it either.

[@somethingirreversib]

@@Pain53924 no evidence against it though

[@antispamman4795]

Interestingly God finds your conclusion a sad one because it means you are refusing his love and forgiveness.

[@Pain53924]

@@antispamman4795 Innocent children get murdered everyday. If god exists, I abhor him.

[@thedeemon]

I'm surprised you didn't mention Noether's theorem: it shows precisely when (and why) energy is conserved and when it isn't. It's all about certain symmetries, and for energy it's about time translation symmetry: if the system works the same way on Monday as on Thursday, i.e. the Lagrangian doesn't depend on time directly, then energy is conserved. In an expanding universe it's not the case, so by that theorem total energy is not conserved.

[@crazieeez]

Noether's theorem doesn't explain retrocasuality. It makes the theorem incorrect. Noether's theorem takes a subset of data to generalize a solution and called it a theorem.

[@thedeemon]

@@crazieeez It's a purely mathematical theorem, showing 100% precisely how from certain continuous symmetries certain conserved quantities arise. It doesn't care about retrocausality which is most probably not a thing anyway.

[@noneofyourbusiness-qd7xi]

Very likely because he's never heard about it, otherwise he wouldn't have given several pseudo-explanations.

[@Dragrath1]

@@crazieeez This is false you can actually use Noether's theorem in the context of information to arive at why an arrow of time will arise in General Relativity. In all comes down to the implications of the proof of the no big crunch theorem which show us that the conditions needed for any universe's net expansion/contraction to reverse direction can never be met so long as we account for information conservation. Ultimately this tells us that no equilibria or inflection points exist for the Einstein field equations other than the Friedmann Lemaître Robertson Walker(FLRW) metric but that this solution is unfortunately an unstable equilibrium in the sense that all possible deviations from this solution are irreversible and divergent, since if such a solution did exist then you would have to have two mutually exclusive properties within the metric tensor be simultaneously true. Effectively this comes down to the defining property for differential equations namely that they always have a unique solution for each and every possible valid set of initial conditions. Or to be more blunt this says that the paths information propagates out into spacetime takes are not the same i.e. gravity is path dependent. This has been experimentally been proven when scientists showed that spacetime curvature does bend light but this also says that the Einstein field equations can not be linearized in general especially at cosmological scales. This has big implications as well as perturbation theory is only valid for convergent solutions which it has been shown can not exist within the set of all possible solutions to the Einstein field equations. (In essence the sign between the differential time of any time slices of spacetime always has the same sign as the change in volume for those two time slices. If you are astute you might notice that this has the same mathematical formalism as the second law of thermodynamics, and this is no coincidence as following from the definition of entropy in information theory we can show that the volume information can have propagated over via the 3 space +1 time dimensional light cone does correspond to an entropy proportional to volume. Note that through limit analysis and the case where the paths are effectively identical we can apply the general stokes theorem to derive that this is equivalent to Hawking's area dependent entropy for the surface area of that horizon. You might have noticed that this causes big problems for the whole standard model of cosmology as it shows the assumption that the off diagonal terms should become negligible at large distances if false. This means you can't use perturbation theory to simplify the solutions to the FLRW metric and running numerical solutions have shown that the errors of falsely assuming the standard model of cosmology in a universe that is anisotropic and inhomogeneous and expanding trivially recovers the affects proscribed to as the Hubble tension and dark energy. In the context of "retrocausality" you can in some sense formulate things around that as an interpretation of quantum mechanics but here we see that the direction of the arrow of time is in fact proportional to the change in volume because once a net direction of change has been made it can not be unmade/ Mathematically speaking it might be more apt to say that a trivial(empty set) FLRW metric universe breaks down into a forward and reverse direction "universes" which can only evolve to more asymmetric and inhomogeneous states with this mirror universe appearing as a result of the use of the method of images. Thus no idea if the reverse universe is real or not but at least the transition mathematically involves both, and there might not be a way to tell if its real or not. Point is the internal consistency of the Einstein field equations turns out to be linked to the existence of a fixed arrow of time and the conservation of information(of the initial conditions). In this sense weirdly enough the apparent asymmetry of time is itself a logical symmetry in spacetime corresponding to the conservation of information.

[@henkema22]

What i really like about Irvins viedeos is his famous "... I am going to explain that RIGHT NOW! " at the start and then it really begins a couple of seconds later!

[@seanspartan2023]

Mind blown 🤯

[@TheMemesofDestruction]

Keep up the great work Team Ash! ^.^

[@GreatestPhysicistOfAllTime]

Our universe is not losing energy but rather gaining energy as it expands. You can see that the density of the universe decreases in an inversely proportional manner to the square (instead of the cube) of its radius (the current density of the universe is ~10^120 times thinner than the Planck density, whereas the radius of the universe is ~10^60 times larger than the Planck length), which means that the total energy contained in our universe is increasing, being proportional to its radius.

[@shadowoffire4307]

"Quantum mechanics: the science that proves that, sometimes, even the universe doesn't quite know what it's doing."

[@wilfredoaldarondo5649]

Do you really believe the universe has consciousness?

[@drbuckley1]

@@wilfredoaldarondo5649 Of course the Universe is conscious. They're called human beings.

[@alexneshmonin4743]

😂😂😂

[@shadowoffire4307]

@@wilfredoaldarondo5649 pure awareness become universe to know itself and it's our consiousness

[@smlanka4u]

Material energy in Dark Energy and Dark Matter can help to grow Black Holes according to new research. Therefore, the universe can conserve the total material energy.

[@murtazaali3946]

Thanks in billions for explaining in a precise way ❤

[@williejohnson487]

Great video, Arvin.

[@ryancormack6934]

If particles can briefly appear and annihilate themselves and not violate conservation rules, maybe at the scale of the universe, borrowing of energy can also take place. Perhaps energy is conserved when looking at the universe at different points in time (eg big bang vs the end of time).

[@facethesky1066]

Watch one of those self driving cars blow up and know... you can't hold back energy from escape!

[@debrachambers1304]

The model of particles briefly existing is mostly mathematical, I think.

[@hoon_sol]

@@debrachambers1304: It isn't, though, because we know these so-called "virtual" particles have real effects. For everything we know, everything we see could be "virtual" particles. The entire universe could potentially be a vacuum fluctuation; see the classic paper _Is the Universe a Vacuum Fluctuation?_ by Tryon.

[@debrachambers1304]

@@hoon_sol They have real effects, but the exact image of a pair popping into existence then ceasing to exist isn't necessarily accurate to my knowledge

[@hoon_sol]

@@debrachambers1304: When they have real effects, then by definition they are real. And they work exactly like particle pairs popping into existence. See _Are Virtual Particles Less Real?_ by Jaeger: _The question of whether virtual quantum particles exist is considered here in light of previous critical analysis and under the assumption that there are particles in the world as described by quantum field theory. The relationship of the classification of particles to quantum-field-theoretic calculations and the diagrammatic aids that are often used in them is clarified. It is pointed out that the distinction between virtual particles and others and, therefore, judgments regarding their reality have been made on basis of these methods rather than on their physical characteristics. As such, it has obscured the question of their existence. It is here argued that the most influential arguments against the existence of virtual particles but not other particles fail because they either are arguments against the existence of particles in general rather than virtual particles per se, or are dependent on the imposition of classical intuitions on quantum systems, or are simply beside the point. Several reasons are then provided for considering virtual particles real, such as their descriptive, explanatory, and predictive value, and a clearer characterization of virtuality-one in terms of intermediate states-that also applies beyond perturbation theory is provided. It is also pointed out that in the role of force mediators, they serve to preclude action-at-a-distance between interacting particles._ *_For these reasons, it is concluded that virtual particles are as real as other quantum particles._*

[@hillz7016]

Another great explanation.. thanks arvin

[@ywtcc]

If you're going to say that the observable universe isn't an isolated system, then I don't think it's makes sense to say that energy conservation is violated. It makes more sense to say the preconditions were never met. While it is true that no perfectly isolated systems exist in our observable universe, it is also true that science has made good use of the concept, despite having no real world examples. Besides the ambiguity of what it means to be a closed/isolated system, there's also ambiguity as to what it means to be an "observable" universe. I'm sure Heisenberg uncertainties are well defined, but that only describes the observability of small scales. On cosmological scales we're not limited by an established physical law like the uncertainty principle, we're limited by the power of our telescopes! At this scale we don't have an uncertainty principle, we just have specifications for our technology. To me, energy conservation has philosophical significance. It's always been an incomplete theory, we still don't know how to convert energy between all its different forms. What we do know is that there's some variable that we can account for in the experimental data that always seems to balance cause and effect. When we do the accounting, and follow the missing energy, we always seem to find it.

[@stevenschilizzi4104]

Brilliant, as usual!

[@drvivekan2530]

Most thought provoking ideas

[@debrainwasher]

I think, there are some little inaccuracies: Not the size of a systems dictates conservation of energy/momentum, but symmetry. This is described in the famous Noether-theorem (details see Wikipedia). The second problem is a widespread misconception about gravitation. While already Newtonian mechanics has found out in accordance with the gravitational law F=G·m·M/r², the Integral of a force along a distance constitutes potential energy, masses «create» gravitational force with the gravitational constant G as the coupling factor, Einstein recognized, bent spacetime itself create the gravitational force, while presence of masses - coincidently - create a spacetime curvature too, that differs from «flat» Minkovsky-metrics. This has a bunch of implications. The first is, there must be other means to bend spacetime - without presence of masses, or expending significant amounts of energy. Without masses, a particular spacetime-curvature has no intrinsic energy (sic). This follows from the Lagrangian equation set of the accepted (!) physical standard model with its «ghost photons» most people ignore, since they cancel out each other - apparently, when no masses are involved. The second misconception is about gravitation itself. since spacetime itself can be bent in two directions (concave or convex as visualized by the rubber-sheet model) - or both at the same time (more difficult to visualize). The latter forms a dipolar force - like a magnet, while same polarities repel each other, and opposing attract. Since multiple spacetime-curvatures can be superimposed, we can use Maxwell's equations set to calculate every relationship, while the electric field E is flipped to Eg (gravitoelectricity) and the magnetic field B goes into Bg (gravitomagnetism). Both can be tied together as gravitoelectromagnetism (GEM). And this is much more, than a formal analogy. Spacetime can be quite easily bent in an arbitrary direction by means of condensed matter physics. A bulk-piece of coupled electrons-pairs (e.g. Cooper-pairs within a topological insulator at room temperature), that are ruled by Pauli's exclusion principle, can be hired for this job. Normally, Cooper-pairs follow a bosonic statistics, but when accelerated within a RF-field, superimposed with a DC electric, or magnetic field to polarize them (align in the same direction), they turn periodically into fermions at the maximum of acceleration a=d²'(f(s)/ds=d²'sin(wt)/dt=-w²·sin(wt). This corresponds exactly to the quenching-current in superconductors. Since two bound fermions can not possess the same quantum state at the same time and location, they overcome this restriction by the creation of extra-space. Extra-space within a confined piece of spacetime is an euphemism for bent spacetime. This adds up to a dipolarly bent spacetime, as everybody can watch in aerobatic shows, as officially presented in a couple of US-DOD USN-UAP videos (these are ours, BTW). 😁

[@donwolff6463]

You're the best Arvin! Luv your content. I was wondering if you might consider doing a series on each (or at least the most commonly used) of the physics equations? Really break down each of the variables in what they represent, how they are measured/derived, and what is implied by their relationships. I know it sounds kind of dry, but folks like me would really appreciate it! Thank you 🤗 Or if there is a really good library of such content out there to freely access, please point me in the right direction, anyone.

[@__momentum__9934]

go buy a textbook.

[@donwolff6463]

@@__momentum__9934 Go buy a life, troll.

[@ritiksinghchauhan4021]

WoW...what a beautiful explanation

[@juantkastellar2655]

Maravilloso vídeo.

[@jonaswhitman8071]

One thing I noticed in your explanation about the small scale was the in the conservation on energy, the weak force can break that rule in a couple small exceptions.

[@thedeemon]

I think this is a misinterpretation of how QFT works. Virtual particles are not counted in energy conservation, and so appearance of virtual W bosons doesn't violate anything.

[@thedeemon]

@@paulthomas963 Textbook definition of a quantum field relies on particle creation and annihilation operators, mathematically the field is "made of" those operators, so you can't talk about a quantum field without its quanta - particles. Whether they are physical objects or just mathematical abstractions is a different question, a well worthy one.

[@ScienceAsylum]

Awesome video! Seems like you addressed all the typical questions 👍

[@educatedguest1510]

Have you checked recent article Medium: Einstein: Energy-Time Equivalence which presents 3 Einstein's energy formulas in conservative manner. For example E = ℏ×𝜈 does not conserve energy because of apparent Hubble Redshift, but E = ℏ(D)×𝜈, where ℏ(D)=ℏ/D³, with time dilation D, conserves it.

[@Pain53924]

@@educatedguest1510 Hi intelligent person Question: Normally a star is stable because the its own gravity is balanced by force produced inside the star due to nuclear fusion. How are black holes stable then i.e. why isn't all the mass of a black hole in the singularity?

[@educatedguest1510]

@@Pain53924 Good explanation on Medium "Unrealistic Einstein and Dogmatic Modern Physics"

[@Pain53924]

@@educatedguest1510 Bruh what is this article? Who is the noob who wrote this? The article says black holes don't exist. We've a photograph of a black hole. Stop believing in such nonsense

[@educatedguest1510]

@@Pain53924 By definition of black hole, nobody can photograph it, because light don't escape it - it cannot rich your camera. The same about space expansion - as if observed - but it is not observed.

[@derrick211000]

Helluva good video! Great information.

[@binbots]

General relativity and quantum mechanics will never be combined until we realize that they take place at different moments in time. Because causality has a speed limit (c) every point in space where you observe it from will be the closest to the present moment. When we look out into the universe, we see the past which is made of particles (GR). When we try to look at smaller and smaller sizes and distances, we are actually looking closer and closer to the present moment (QM). The wave property of particles appears when we start looking into the future of that particle. It is a probability wave because the future is probabilistic. Wave function collapse happens when we bring a particle into the present/past. GR is making measurements in the predictable past. QM is trying to make measurements of the probabilistic future.

[@wilfredoaldarondo5649]

Good argument. Are you a theoretical physicist? Do you mean physicists need to better understand the concept of time to understand the far and the near laws of physics?

[@drbuckley1]

No two observers experience a common "now." Your "present moment" is not my "present moment."

[@albertocaruso5200]

Congratulation!

[@hidemytracks]

You seems to realize that they happen in different moments in time, then what is stopping you to combine them?

[@hidemytracks]

You seems to realize that they happen in different moments in time, then what is stopping you to combine them?

[@xtieburn]

One of my favourite little papers* is a thought experiment about two bodies in space stationary in one sense to one another but at such a distance that the expansion of space time is pulling them apart. An indestructible rope is anchored to one and wound round a generator at the other. It would seem that such a set up would tug the rope, spin the generator and produce energy, but where exactly that energy comes from is not at all clear. *Mining Energy in an Expanding Universe - Edward R Harrison

[@viralsheddingzombie5324]

That would only happen outside a gravitational domain, in other words, outside a galaxy.

[@blijebij]

It is ofc possible on a universe scale energy is conserved within something bigger that we have not defined yet! You are a superb explainer ^__^ great vids always!!

[@barefootalien]

Great explanation!

[@alexneshmonin4743]

Love it!!! Thank you!

[@marcocurrin8122]

You never get rid of the books , you always add you never subtract 🥰😇

[@nerdexproject]

Super interesting for sure!

[@davidtaylor3771]

Good discussion Arvin.

[@bestdani]

The question what's happening to the energy that gets lost during the redshift puzzled me and unfortunately my cosmology professor hadn't had such a clear answer to this question back then. But still then it is fascinating, that a process that happens at spacetime point A cannot be reversed at some arbitrary spacetime point B in the universe in general because the event arrives with less energy there.

[@jammiecg0001]

Interesting speculations. Very few people are willing to question it, let alone come up with a good argument.

[@sanahaskuranage8071]

There’s something big we don’t know! And that’s very encouraging to keep looking. I don’t think our universe is infinite. It definitely feels like it though.

[@ChrisMarkTvv]

Amazing thanks for sharing 👍

[@lucasf.v.n.4197]

I love how these physics channels speak of energy as something touchable rather than an abstract mathematical concept;

[@ArvinAsh]

Do you think that all "real" things have to be touchable? What do you think burns your skin when you lie in the sun for hours?

[@lucasf.v.n.4197]

hi Arvin; what a surprise to have u answering my comment; I'm delighted, and flattered; big fan of ur content here; way to go! here's my take on energy; newton's laws of mechanics can be rewritten in terms of quantities we called kinetic and potential energy: - kinetic energy: 1/2*m*v^2; - variation of potential energy: minus the line integral of a (conservative) force through any given path (just the end points matter); so intuitively, we say a moving body has kinetic energy (because it has speed), and the potential energy is associated to "storage" of "energy" which when "released" converts into motion ("kinetic energy"); examples of the latter would be a compressed spring, two opposite charges hold together within a "box", an object in a given height above the ground, fuel and oxigen in a engine chamber (prior to the spark), and so on; all this reasoning is to say that energy isn't as intuitive as mass, time, distance, speed; so when I hear it being treated as such, it makes me uneasy because it makes the concept of energy seem trivial we I bet must people just take it for granted without second thought; they appeal to the intuition as if energy is something "solid", which it isn't; and yes, I'm familiar with the Lagrangean formulation, Noether's theorem, u name it;

[@ragzpicker9848]

Wow it seems that we are going to have a wonderful idea

[@leticiashors27]

Simplesmente adoro suas explicações!

[@effectingcause5484]

I’ve had an amazing thought! In the beginning of the universe, (not the very beginning, but close to it) at the moment when the Higgs field gave rise to massive bodies, these bodies would be so energetic, they would be traveling at almost the speed of light. The relativistic speeds would cause space to appear contracted in the reference frames of these high speed particles. Since space was relativistically contracted due to high speeds between the massive observers, then as those massive observers slowed down relative to one another, it would have made space appear to start expanding due to relativistic principles of space dilating from the perspective of each massive bodies as they slow down relative to one another. I wonder, if the expansion of space we find today might be just that! As matter continues to slow down in the ever increasing relativistic expansion of space, this give the appearance that distances between massive objects continues to expand. The effect is a runaway expansion of space and a forever increasing slowing down of matter due to the increased volume of space for matter to occupy.

[@user-xn4wq4sv3r]

Regarding the conservation of energy in General Relativity, please see Landau and Lifshitz (1975), Vol.2, The Classical Theory of Fields, section#96: Pseudotensor of the energy-momentum of gravitational field. We can define the total 4-impulse so that it is conserved.

[@FrancisFjordCupola]

I'd like to see a scientist tackle the question of to which degree the bubble of the observable universe can be considered an isolated system. And what the expansion of the universe (but relative shrinkage of the the observable universe) means for it.

[@ZetaFuzzMachine]

So my final assignment for the physics degree is about the thermodynamics of dark energy and OH BOY LET ME TELL YOU the relief I'm feeling as this good man tells me that energy is, in fact, not conserved in the Lambda-CDM model

[@noneofyourbusiness-qd7xi]

If you are beginning to take on your physic's degree thesis and have never heard of Noether's theorem, you shouldn't have skipped ALL your classes. Seriouosly .. what kind of university is that ?

[@xarmanhsh2981]

For me the most important think of a platform is to be able to discuss the thing i just saw with other people. Does magelan has a comment section?

[@user-sl9gr9zk6r]

質子 一(與電子結合)→ 氫原子 氫原子 一(核融合)→ 重原素 重原素 一(衰变)→ 質子 *永遠循環，沒有熵增。

[@thebogsofmordor7356]

Arvin: Basing our energy density from the 94b LY diameter is foolish considering the edge of causality. It would be more accurate to add in all the energy from the lightcones of all matter in our own lightcone. Unfortunately we can't know that due to that part of the universe being beyond our horizon.

[@yinnky]

In 7:19, where Red shift was demonstrated, it is incorrect to go from blue to purple to red, the correct order would be blue, green, yellow, red while this obviously hyperbolated for simplicity i think this would better encapsulate the idea

[@jaymorse1417]

Great topic 👍

[@aresmars2003]

It is important to consider star-systems like our solar system are relatively compact compared to nearest neighbors, while galaxies are much closer to each other relative to their size, so easier to conserve energy and momentum at solar system level, while galaxies are something different, although also snail-slow over human time scales. Galaxies also show dark matter affecting rotation curves, so we only slightly know what's going on at galactic scales. We don't know what dark matter is, but generally assumed to NOT be ordinary matter, even if there is ordinary nonstar matter in galaxies too, which we can "see" as nebulae and dark clouds, second more visible with brighter backgrounds.

[@0ptimal]

Awesome video

[@Music_Creativity_Science]

Very interesting video, the combination of light (all frequencies) losing energy + the lost gravitational energy might be two of the components explaining the static energy density of the growing space vacuum. But something does not fit in the form of an equation: + Dark energy - light energy + (- Gravitational Potential Energy) + (- other unknown energy losses) = 0 The GPE should be a growing negative number with increasing distance between mass, but that's not how it normally works in GPE calculations, it then becomes a less negative number... going towards 0 with an infinite distance. Can someone form the correct equation, or correct reasoning ?

[@effectingcause5484]

Actually, energy can still be conserved if we consider that the galaxies and stars may be shrinking in size, while space remains the same volume. If viewed this way, then we see that the energy contained in the vacuum of space always remains the same, since the volume of that space always remains the same. We can view matter as shrinking which might better explain our universe. There is also no way for us to tell the difference between an expanding universe and a universe with shrinking matter, for those ideas are both mathematically equal. When we measure distances, our rulers would also be shrinking, and this would cause us to mistake our universe for an expanding universe. And really, since energy conservation is being violated in our views of an expanding universe, I think it should be thoroughly considered that a shrinking matter scenario may actually be the case. If this is the case, then it means that radiation does not shrink though, only matter shrinks. Here we see, that photons would be reddened in that case, having longer wavelengths after traveling across great distances of space, not because of space expansion, but only bcus our rulers will have had the necessary time to shrink substantially during the photon’s very long trip. Also, if we are a shrinking matter universe, then it means the constant C is also always slowing down, such that it matches constantly when our shrinking rulers indicate a measure of 1 second per light-second. I’m sure all of the math will be in agreement with an expanding universe. Since the math checks out, then this shrinking matter theory could prove to be a very possible scenario, so this model should be explored more I think, especially since it allows us to restore the principles of energy conservation.

[@roberthines2741]

Thanks for answering a question I've thought about for years. I have a science degree (BSc Chemistry) but I always suspected that conservation of energy was not absolute because of the expansion of the universe, it is nice to know that I was not wrong.

[@Chatsworth1979]

+1 I've been wondering about this for a long time too! Seems fundamentally "strange", for lack of a better word. Very odd but apparently (?) true.

[@noneofyourbusiness-qd7xi]

The expansion of the universe indeed destroys the symmetry, which would be the basis of the symmetry, for which Noether's theom would predict a conservation law. This indeed means, that energy is not strictly conserved conserved in an expanding universe. The issue is: the explanation given (or rather not given ) in the video is crap. It also forgets to mention, that the expansion of space is (at least currently) prevented by gravity within galactic clusters and takes only place outside of them. This means, that within any galactic cluster (and especially within any galaxy) the law of energy conservation is perfectly valid, without exception.

[@supercoupe7471]

Im pretty sure that refering to dark energy is the same as referring to gravity as dark energy. Galaxies expand because that's the way space is curved. On a larger scale, space is naturally curved inversely. I think this is a profound hypothesis. I wonder how many physicists will read or agree with it. Einstein level? ;) it would be a complete shame if the actual hypothesis to dark energy faded away with a single youtube comment. Or maybe im just crazy.

[@MukeshKumar-xv2fm]

Hello Arwin Ash Sir…. The world “Sir” I am using only because I really respect your work for the humanity….. And perhaps the time has come when your student can teach you something which you always dreamt off. I will first start by explaining the Hidden Reality of interference patter when one electron is fired and observation is made. Because I know you are very much eager to know the reality and you itself many times says that “May be we must wait for someone to come and explain it” This will soon be published in the top journal of world. But I was not able to resist myself to at-least tell you that soon you will have answers of every puzzle in our mind

[@alfadog67]

Eureka moment at 11:11... "Gravity must be negative energy". That statement seems to raise a question for me. Does spacetime bend toward a mass and stay there statically, or does the event continuously occur, churning, bending and straightening relative to the size, motion and distance from the mass? If it's the latter, it's almost as if mass "consumes" spacetime to cause the evident bending. I wonder if a black hole could "consume" so much spacetime that it had no more to consume. If there were no spacetime to bend, then the observed gravity inside the black hole would disappear. Maybe that would look like some sort of "big bang".

[@scottwells8064]

I clicked on this fully expecting to scoff and laugh at someone's magical/superstitious thinking. I'm pleasantly surprised that instead I watched a video that taught ke something and made me think. Well done!

[@Bassotronics]

@ 5:47 I like how (sarcastically speaking) many use this diagram to show how planets move around the sun but the diagram fails when we add satellites like the moon. The moon would wobble and crash into Earth if it followed that curvature while trying to spin around Earth at the same time.

[@JavedAli-pm9nt]

Sir I request you to do some work on spintronics... explain visual spin to charge current conversion, quantum hall effect and ishe etc

[@schlechtj1]

I have wondered about gravitational potential energy which increases with distance until the object goes over the cosmic horizon. Then, that potential energy drops instantly to zero. I understand that energy conservation only holds if the frame of reference does not change. If you accelerate then stop accelerating, you just changed the kinetic energy of everything in the universe from your point of view.

[@frankkolmann4801]

This is the best argument I have seen that actually confirms Prof Neil Turoks Universe/Antiuniverse . The sum total of energy of the Universe/Antiuniverse cancels out. Each Universe is not isolated, but both together muat sum up to what created the Universe/Antiuniverse, that is nothing.

[@JustMike4]

Gotta respect the boldness of an Energy Distribution pie chart that doesn't contain normal energy

[@antipoti]

This seems to make QM and GR even harder to unify.

[@TheBrainlessShow100]

Large scale energy density is assumed constant because of spacetime flatness but if the universe is flat then it is not a closed system, thus we cannot make energy conservation statements. Furthermore, dark energy proportion is a global estimate, not a local one. It only becomes significant on large intergalactic scales so it could be close to 0% inside galaxies and close to 100% outside galaxy clusters so the energy transfer between different energy types could be applied. Finally, it seems risky to make any energy conservation statements about energy sources that are not yet fully understood and could result to be intrinsically linked and turn out to be the same one.

[@DrakeLarson-js9px]

GREAT VIDEO!!! (FORGET Hawking conjecture, as just that, a semi-reasonable conjecture!) Short term conservation is more than OK, then not, then ?? but now with Inversion Physics ...and an expansion of space (analogous to the energy-momentum conservation of Newton, expanded with Einstein's altering time/space), then YES!!

[@galacticinfant]

I think i have born in the time where physics is in its primitive state and answered just basic works of the universe. I think i should've been born some 10000 years later. These are some of the questions that keeps coming to my mind. If any future physicist has been able to come to the past (now present) plz answer these questions. 1. What was before big bang? 2. Why the heck big bang happened? 3. What is there at singularity of a black hole? 4. Why is universe expanding? 5. How can universe theoretically expand with the speed more than light's? 6. What is the size of the universe? 7. What is total space that can be ever occupied by the expansion of the universe? I'm just lost in the universe and life is just a mere accident.

[@duggydo]

At 6:35 you say we know that the energy density of spacetime doesn’t change. My question is, how do we know that? An explanation of this would be a great follow up video.

[@Bankside1997]

Good video. In around minute 6:44 it is said that when Volume increases Energy also increases. Is this not an offset to the loss of energy?

[@chevasit]

Very good 👍

[@sdal4926]

Can we say in this case energy is conserved locally but not globally? Because covariant derivative of EM tensor is zero.

[@nexus3112]

Arvin simplified Hawking's idea so much that the whole theory was contained within 1 sentence 😂 But kudos for such a lucid explanation ❤

[@BrianSu]

how is that different from potential energy? When you pull 2 objects apart you’re building up potential energy aren’t you?

[@stephenzhao5809]

5:34 ... What general relativity tells us is that if spacetime were standing still, that is, if it were flat and not changing, then energy would be constant. But if spacetime is curving and changing, then the momentum is changing, and thus the energy is changing as well. So, astonishingly, it tells us that at large scales, energy is really not conserved in the universe. We can point to several observations that confirm this. 6:02 The first is the observed expansion of the universe. The first empirical evidence of this was gathered in 1929 by Edwin Hubble. Then, in the late 1990s scientists (Saul Perlmutter, American Astrophysicist | b. 1059) discovered is not only expanding, but that this expansion is accelerating. This acceleration is called Dark Energy. The problem with expanding spacetime is that empty space has energy. If the volume of this space is increasig then energy is increasing. We know that the energy desity of spacetime doesn't change, but energy desity is energy over volume. If the volume increases, then energy also increases. This phenomenon appears to indicate that energy is not being conserved. Another consequence of an expanding spacetime is the observed redshift. The light from distand galaxies is redshifted. As the universe expands, the wvaelength of light also expands. And as we learned from Max Planck: E equals hμ, μ is the fequency, which we can rewrite as the speed of light divided by wavelength, lambda. Thus, we see that if the wavelength is longer, the engergy is lower. So the photons have lower energy by the time they reach us. This appeas to violate conservation of energy. 7:23 Where did this loss of energy go? Well, the energy of the photon is observer dependent. From our perspective, the photon loses its energy to the expanding spacetime between its origin and us. 7:41 Now I know some of you are going to ask, since we know that dark energy is increasing, could it be that the energy that light waves lose turns to dark energy, thus conserving energy overall? Well, the problem with that idea is that even if you take all the observed light of the universe into account, it would not account for the amount of dark energy in the universe. [] Dark energy is almost 70% of the energy of the universe, whereas all the matter and light that we can observe is only about 5%. The lost energy of light would be miniscule portion of all the energy needed too counterbalance increasing dark energy. The expansion of the universe presents a major issue with treating the universe as an isoloated system. [] We don't even know what the size of the universe really is, so we can't define what the isolated system would be. We only know the observable universe, which is about 94 billion light years in diameter. There is a so called cosmic event horizon which is the end of this observable universe. The galaxies at the edge of this cosmic event horizon are moving away from us such that the light beyond it will never reach us. 8:43 I was watching a video on Magellan TV, today's sponsor, which showed how it's possible that the universe beyond the visible universe could be infinite. [Very challenge, if the universe is infinite, the Christianity theologians will be frustrated, because it suggest the uinverse is not created by God the infinite, instead, it's parallel with the house of God, then Dualism is right, then Bilbe is wrong, right? Then what Stephen Hawking said is right: we don't need a God who's doing nothing to our unviverse] And if that's true, then the universe would definitely NOT be an isolated system, since we could not put any boundary around it. In this case we would have to conclude that the universe likely does not conserve energy. The Magellan TV documentary is called, "Is the Universe Infinite" - and 9:14

[@L2p2]

Thanks @Arvinn Ash for this video for explaining the fundamentals so simply. I only wish you had further delved into what the conservation of momentum-energy means and if it has any relationship with Heisenberg's uncertainty principle which says we cannot no position and momentum with a degree of accuracy. Since in quantum mechanics energy is conserved what is the implication then momentum is also conserved in small scales independently as we learn in classical physics ? The second question I have is the fact the the universe seems flat from where we are even though our measurements show universe if expanding at at accelerated rate, does this somehow indicate a conservation of energy ? if we were expanding at at accelerated rate and dominated by dark energy if the universe seems flat does it mean then the gravitational energy of dark matter , light and matter offsets leaving the rest as "stress energy" . This questions puzzled me for a while, but you have only touched upon it here. Only one term with T relates to energy in Einstein's field equations. Then what is the equivalent equation or (inequality) which has gravitational energy, stress energy and dark energy as terms in it. Sorry for the long question but could you perhaps clarify or do a part 2 if this video ?

[@thedeemon]

1. In classical mechanics both energy and momentum conservation are consequences of time & space translation symmetries, as described by Noether's theorem. Any continuous symmetry of certain kind in the Lagrangian leads mathematically to a conserved quantity. Energy is just the name for such quantity in case of time translation symmetry, which basically says the Lagrangian must not depend on time directly, an experiment performed on Monday should give the same results as the same experiment performed on Friday. en.wikipedia.org/wiki/Noether%27s_theorem In relativity theory energy and momentum are also related to time and space correspondingly as parts of the en.wikipedia.org/wiki/Four-momentum . In quantum mechanics energy & momentum are also related to time and space correspondingly: energy operator is basically time derivative of the wave function (this is what Schroedinger equation literally says), and momentum operator is spatial derivative of the wave function. Values of energy and momentum are eigenvalues of those operators. In QFT particles are represented as combinations of simple waves where frequency in time is energy and frequency in space is momentum, up to a constant of course (see Klein-Gordon equation). Their conservation (in flat spacetime) comes more or less automatically in equations describing scattering processes (see S-Matrix). 2. No, accelerated expansion of space means time-translation symmetry is not present, universe today is not the same as yesterday, so we don't expect energy to be conserved. www.preposterousuniverse.com/blog/2010/02/22/energy-is-not-conserved/ 3. In current cosmological models space (3D) is flat but spacetime (4D) is not. See FLRW metric: en.wikipedia.org/wiki/Friedmann%E2%80%93Lema%C3%AEtre%E2%80%93Robertson%E2%80%93Walker_metric 4. Regarding Einstein's equation, indeed gravitational energy and dark energy are not in T on the right side, they are on the left side - in the values of metric g_mu_nu and in the cosmological constant Λ. en.wikipedia.org/wiki/Cosmological_constant

[@kdw75]

If we know the age of the universe and its expansion rate, how do we not know its size and if it is infinite? If it is infinite could it still be within something larger?

[@christianfaust5141]

More than 90 billion light-years is the observable universe... and maybe infinite... such videos ground your position in this little world 😊

[@stephenzhao5809]

4:33 John Wheeler said, "Matter tells spacetime how to curve, and spacetime tells matter how to move."

[@Tenly2009]

Off Topic - but I have a couple of questions about time dilation and speed of light that I’ve never seen covered… 1. Are all galaxies that are moving away from us, moving away at the same speed as each other when they are the same distance from us? Or do they have variable speeds? I understand that as they get further and further away from us, they appear to be accelerating and moving faster due to the expansion of space - but when each galaxy reaches the half way point between us and the edge of the observable universe - are they all travelling the exact same speed away from us at the moment they get there? (Or could some be travelling faster than others and potentially even overtake one that is further away but moving slower?) 2. Time dilation occurs as objects approach the speed of light. So then how fast are the clocks running on the planets near the edge of our observable galaxy compared to clocks on earth? Suppose we parked a wormhole between their solar system and ours when they were much closer to us and our clocks were ticking at roughly the same speed. How far off would they be now? With the expansion of space, they could appear to be traveling away from us “faster than light”, right? Wouldn’t that mean that to them, our clocks would be frozen (or even running backwards)? So then what would happen if we traveled through that wormhole? Thanks for the weekly videos!

[@edwardjenner1381]

1. The EXACT same speed, no. But very, very close. Any differences will be due to local relative velocity. For instance Andromeda is moving towards us. So from a far away galaxy we would both be moving away, but with very slightly different speeds. By the time you get to a few hundred million light years, no galaxies are going fast enough to overtake up from any vantage point. 2. wormholes. I know nothing about wormholes.

[@thedeemon]

1. As Edward rightly said, there is some relative motion of galaxies, so not all speeds are the same. 2. This is tricky. Kinetic time dilation (due to relative speed) is about how clocks on some object moving in your frame of reference seem to tick relative to your own clocks "stationary" in this frame of reference. In flat (non-expanding, no gravity) spacetime of Special Relativity you can apply this effect for any moving object no matter how far it is, your frame of reference is good enough to describe distant objects. But in curved spacetime of General Relativity it's no longer the case. Your frame of reference only works locally, for nearby objects. For distant objects the very notion of relative velocity starts to lose sense: velocity is a vector and in Riemannian geometry of curved spaces two vectors can only be compared locally, at the same point. To compare a vector from some distant point with yours, you need to parallel-transport that vector to your location first and the result will depend on path you use to transport it, so it's not objective, there's no single answer. The way space expansion works, those distant galaxies are not actually moving through space with those ridiculous speeds (often faster than light). They hardly move at all. But the distance between us grows, in fact all distances between very remote objects grow by the same amount. It's a bit like monetary inflation: you wake up tomorrow and all prices in the shop grew a bit, did milk become really more valuable than the day before? The redshifts of galaxies we see are not due to kinetic motion as in Special Relativity, such motion would only be possible up to speed of light, yet we can still see galaxies who "recede" much faster than light speed. Because it's not real motion through space but rather inflation of all space between. Which means in case of wormhole between us we would probably see each other at the same time rate, no real differences in clock rates expected.

[@Tenly2009]

@@thedeemon Thank you for the answers. I did realize that a solar system in a distant galaxy may be moving through local space at pretty much the same speed that we move through our local space - but that new space is being created in between us. I would think that to observers here, it would look like time was running slower in the distant solar system - but time dilation is hard enough to understand without taking expansion into account and I just got lost. 🤷🏻‍♂️ In any case, thank you and Edward both for taking the time to reply!

[@zakirhussain-js9ku]

Space is another form of matter which makes it an energy reservoir. Particles can exchange energy with space. Photons lose energy to space & particles gain energy from space fields around mass, electric & magnetic charge. Net energy remains constant.

[@mikebermea9366]

The energy conservation conundrum here is because we don't understand "time" correctly. I have been working on a hypothesis I call the Time Force Hypothesis that attempts to answer the question What is "time "? My hypothesis posits that our universe is a 3d membrane suspended and moving through a higher spatial dimension we currently know as time. This idea uses a 4 velocity that must always equal "c" as suggested by special relativity. This is why E=mc^2. Our experience of "time" becomes our experience of motion through the fourth dimension. From this perspective, we can now understand time dilation as an objects change in 4th dimensional trajectory compared to any other object. The implications on energy conservation become quite intriguing. The transition between potential to kinetic energy and vice versa becomes simply a change in 4 velocity caused by interaction.

[@schmetterling4477]

Yes, that was also bullshit. ;-)

[@pmhwoodcraft9934]

Could the following descriptive view of the universe, or something similar, account for what you describe in this video? I think energy conservation would hold in this view. What if the universe’s zero point energy were an elastic solid with a viscoelastic liquid suspended in it due to ripping energy apart from the underlying solid and coalescing into quanta from a plank scale event (a big bang) - similar to an elastic solid/viscous liquid colloidal suspension with gravity being the relationship between the analog energy of the elastic solid and the quantized viscoelastic liquid? That could make space-time the elastic solid, could account for the randomness of black hole evaporation, account for effects attributed to dark matter, account for wave-particle duality, account for the expansion of the universe, and could account for the redshift as well as potentially be the source of another big bang as quanta become unstable and then critical due to energy dissipation. Could then gravity be just a matter of conservation of energy? I can’t see why this descriptive view couldn’t accommodate the standard model as applied to the viscoelastic liquid and general relativity applying to the relationship between the elastic solid and the viscoelastic liquid. These questions have been nagging me for a number of years. Please let me know if this description could be at least partially correct or not?

[@tolgakacgn7079]

Information which is kind of energy always conserved

[@noneofyourbusiness-qd7xi]

Nope. Information is not a jkind of energy, because you can't use it to perform work. Completely different things. Information equals entropy, not energy. Like entropy, information alsio increases over time in a closed systems, thus it is not "conserved" (=stays constant). Information can't be destroyed, but that's to equal to being conserved.

[@tolgakacgn7079]

I mean,Information is consist of everything including,matter,mass,gases even energy.Some scientist said entropy is not only equals entropy.Entropy is already information and we dont even know how information is change by time.If you consider arrow of time is key.I said you in subatomic world time is not going forward also backward so that information is conserved.

[@Zayden.]

How can the whole universe be accounted for if it's infinite in both time and distance?

[@ArvinAsh]

We don't know whether it is infinite.

[@noneofyourbusiness-qd7xi]

Infinities are a mathematical construct, not a physical. There are no infinities in reality. Whenever someone talks about physical infinities, you kow he/she doesn't know what he/she is talking about.

[@wayneyadams]

5:18 Covariant tensors use subscripts while contravariant tensors use superscripts. No one teaches energy conservation, we teach mass-energy conservation (or momentum-energy if you like). Nuclear fusion and nuclear fission both convert matter to energy, so energy is not conserved, rather it is created. 6:31 the expansion is not called dark energy, rather dark energy is posited to be the cause of the accelerating expansion. Wayne Y. Adams B.S. Chemistry M.S. Physics

[@thedeemon]

Mass, through mc^2, is just one component of total energy, when we talk about energy conservation. In a certain sense, rest mass is just confined energy, especially if you look inside protons & neutrons.

[@LQhristian]

A good subject of discussion! To keep conservation laws from being broken, it seems, at the moment anyway, that it would be more practical to assume the universe is a isolated/ closed system, until proven otherwise?! :-)

[@noneofyourbusiness-qd7xi]

Conservation laws only exist if there is a symmetry, upon which it they are based (Noether's theorem). That's true for all conservation laws. As the expansion breaks the symmetry, there is no conservation law anymore (in astatic/non-expanding universe energy would be strictly conserved). Postulating something for which there is no theoretical basis, just because it suits one's world view, is not scientific.

[@JavedAli-pm9nt]

I also request you to work on quantum zeno effects

[@edweinb]

At 5:50 it would seem that the momentum is constantly changing since it's a vector and direction is constantly changing, but given a circular orbit, the energy which is not a vector would remain constant.

[@debrainwasher]

In rotational systems, you have to transform all equations from translatoric motion into the rotational ones: E.g.: E=m·v²/2 -> E=J·w²/2, m=m·v -> L=J·w, F -> M·r. Additionally, Keplers laws must be observed.

[@edweinb]

@@debrainwasher But the energy stats the same, right?

[@debrainwasher]

@@edweinb Energy is energy. No matter, how you convert, store, or transform it. Simply the math changes. When you swirl around a mass on a thread, rotational equations describe every property. In the moment, you let the mass go, its movements turns into a linear motion, and translatoric equations are applicable. Things can really become strange, when quasi-particles are involved (read my post above) but it works - ruled by the Noether-theorem BTW.

[@marcocurrin8122]

Words take what we call TIME to think of form words sound them out and put in sentences along with thinking about WHAT the other person said and your response…way way back in time and if your back in time you ARE NOT EXPERIENCING LIFE IN THE MOMENT…near the creator of all of this…I remember as a child how hard it was to make words…so if you are NOT NEAR the creator , it DOES NOT CARE for words WE NEED words …it talks in thought….so all the books are USELESS except to help us get back to the creator where we DONT NEED WORDS

[@georgerevell5643]

If its the divergence of the combinaton of momentum and energy that is conserved, then how does that work out with the expanding universe adding ever more dark energy as it expand? Thanks in advance!

[@noneofyourbusiness-qd7xi]

You seemingly don't get the point: Noether's theorem tells us, that a conservation law exists, when there is a symmetry in the corresponding action. For energy there is such a symmetry for a static (non-expanding) universe, but not for an expanding universe. The result is, that there is seemingly a law of energy conservation on low scales (as on all levels we can observe space does not increase), but that there is no strict energy conservation on large scales, as the universe is expanding and for an expanding universe, there is no symmetry and thus no conservation law and hence no conservation. The point: there is no conservation law because there is no symmetry and if there is no conservation law, an entity will not be conserved.