What If Gravity Isn’t Quantum? New Experiments Explore

[@BrianMelancon]

Congratulations on PI million subscribers

[@A-lik]

Give me 314 likes and not a single like more.

[@tiffanymarie9750]

🥧

[@tambourine_man]

An approximation, but still worth of congratulations

[@Elviscapataccio]

🎉

[@ObjectsInMotion]

Congratulations on PI hundred likes! I didn't like your comment!

[@oniondip_420]

Have we ever considered if gravity is Baroque instead of Classical?

[@KSignalEingang]

This could be tested if we can detect (or rule out) minute variations in the value of G at short ranges or on small timescales. The current evidence all points to the value of G being fixed. And as we all know, if it ain't Baroque, you can't fix it.

[@cesarestrada7045]

For a moment I thought Philomena Cunk posted this.

[@qclod]

As an attractive force, I always found gravity to be quite Romantic.

[@erinm9445]

And if it were Baroque, it would have the advantage that we could fix it.

[@jxsanche]

That would trigger a renaissance in contemporary physics

[@jajssblue]

Classic Quantum

[@pleasedontwatchthese9593]

Anger

[@AdrianBoyko]

Post Quantum

[@GuardianOfUltima]

Each dimension has its own laws. Energy is quantized by its ability to break the laws of a given dimension. So breaking the laws of the second dimension takes place when the energy amount within a particular field of space grows too much to be constrained to a lower dimension. The way to bridge the physics is to look at it from the lens of what the current laws are. Classic Quantum to me is the second dimension and the first dimension mixed together which is the mistake; separate those two things so they can be cross analyzed and the math can then predict general relativity when it is correct.

[@voinea12]

@@GuardianOfUltima 🤓

[@GuardianOfUltima]

@@AdrianBoyko Are neutrinos or photons even 2 dimensional energy? It seems to me like energy space and time exist in the first, second and third dimensions. With only one direction to travel in the first dimension, energy cant interact with itself. But it can vibrate in a perpendicular direction, which could be the foundation for the second dimension. Now with two directions to travel, energy is like a sheet of paper, vibrating up and down and outward from the source. In all directions. Hence, interactions between energy mixed with this natural vibration field in the second dimension are the foundation for the third dimension. Energy continues traveling in one direction, and two, and then all directions before approaching the speed of light and then breaking it, curving out of existence - potentially into a new one as the equation flips back and forth between 0 and 1 and 1 and 0. It's just a battle between energy's infinite expanse and space's infinite vacuum.

[@Valdagast]

Justice for Alice and Bob! They deserve a Nobel Prize!

[@michaelsommers2356]

What about Carol and Ted?

[@LuisSierra42]

Wasn't Bob stranded inside a black hole's singularity?

[@Mr.Anders0n_]

​@@LuisSierra42yes, and he made it out! He definitely deserves a Nobel prize

[@temptemp563]

If only they had lived ...

[@asifkarim75]

you got a Nobel prize that does not mean you are the greatest

[@dyershov]

Thank you for an episode on experimental physics! The extreme engineering that has to go into these kind of experiments is absolute fun.

[@robertsaget6918]

You're welcome!

[@Eianex]

wouldn't the atoms entangle via electromagnetism if you put two stern-gerlacs near one another? how can you make two that two stern-gerlacs avoid electromagnetism and only interact via gravity?

[@michaelsommers2356]

Just for your information, it's Stern-Gerlach.

[@Inuyasha10121]

I had a similar idea. Without using a fundamental particle with no charge, ie neutrinos [which, good luck...] I don't know how you would avoid entanglement via the EM force, especially since it is orders of magnitude stronger than gravity. With macromolecular structures like nanodiamonds its even worse, since the close the streams get the more orbital overlap can happen (kinda like Van der Waals interactions) which I think makes the problem worse, so maybe neutron beams would be the way to go...but then you have to worry about the quarks zipping around in the nucleon causing short lived distribution imbalances that could cause coupling.. One thought I had, no idea if this would really work though, is that maybe you could calculate how you would expect the correlations to change if the entanglement correlations were purely via entanglement through the other fundamental forces. Then, if you build up enough data, you can see if you are observing more entanglement than you would expect (0.700000000 vs 0.700000001 type of thing) and, with enough measurements, be able to claim "There is a 5+ sigma result that we observe more entanglement than expected when accounting for all other known fundamental forces capable of entaglement. Therefore, gravity must be providing an additional avenue for entanglement and must be quantum. You can make out my Nobel Prize to Dr. P. Sherman, 42 Wallaby Way, Sidney, Australia..."

[@armagetronfasttrack9808]

Haven't looked into this topic in detail, but the nanodiamonds are charge-neutral so don't have direct charge-charge interaction, and the dipole-dipole interaction potential decays as 1/R^3 whereas the gravitational potential decays as 1/R^1. So possibly, if the nanodiamonds are far enough away (while still being close enough to see some gravitational effect), the gravitational interaction might dominate over any EM interaction.

[@danij5055]

They were talking about spin, not charge.

[@Inuyasha10121]

@@danij5055 I know, but they are talking about how a fundamental force can induce an entanglement effect on two particles, which you then can observe via correlations in the particles quantum properties, in this case, correlations in the spin of the two particle streams. You still have to contend with the fact that electromagnetic interactions can ALSO induce entanglement between particles, as it is also a quantum mechanical force. The concern is that, because EM is orders of magnitude stronger, the effects of gravity can be washed out so that you only see how EM is influencing the correlations in spin and, by proxy, the entanglement of the particles in the neighboring streams.

[@paulbennett772]

I'm constantly amazed that you can make understandable concepts which I shouldn't be able to understand.

[@DeJay7]

"shouldn't be able to understand" is a horrible mindset to have, especially for physics.

[@John-jc3ty]

"We just have to figure out how to adjust Newton's law of universal gravity with the weird but small behavior of mercury and physics is done" "We just have to figure out how to connect gravity with quantum and physics is done"

[@LuisSierra42]

It's just like fusion or quantum computing

[@TlalocTemporal]

We just need to explain this weird thing with ultraviolet light, then physics is solved!

[@jax9976]

If you guys are saying "we JUST havte JOIN or ADJUST the thoeries", then you might wanna do it yourself 😂😂

[@sidgar1]

The more we discover, the more we realize how little we truly know.

[@kingeternal_ap]

We Just need to see why this Cobalt isotope prefers to pewpewpew to just one side, then physics is complete!

[@Gizzeit]

Yesterday I've aquired strong evidence of *macroscopic objects being in superposition.* I was maintaining my bicycle and after disassembling rear wheel bearings I've extracted 9 bearing balls from one side and 8 balls from the other. What's the heck, I thought, it should be equal, so I searched everywhere around to find that shiny metal ball of almost size of a pea - and it was nowhere. Well, I carefully inspected the casings, and couldn't really tell if they are equal in diameter or slightly different, as they have a bit unsimilar design, and I hadn't got any appropriate measuring tools to get casings' inside. Well, I thought, maybe they are inequal, as one I've extracted less ball from is indeed located it more tight spot, thus it theoretically could be narrower. Long story short, I wasn't sure if it should be 9-9 or 9-8 balls, and had no way to properly _measure_ needed quantity, so the missing-or-not ball stayed in this superposition until I performed all required maintenance, applied new grease to the bearing and started filling casing with balls. And after I've put 8 balls in there were surely a gap for the 9th one, and *immediately wavefunction have collapsed* and I saw the freaking 9th ball right in front of me, completely exposed and not covered by anything happily laying and freaking shining at lights! The only way I can explain why I haven't seen it before is superposition. No other way, really 😂😂😂

[@edwardproctor3619]

👎

[@lextorcreeper4474]

Nah bro the other ball just noclipped to the backrooms

[@DeJay7]

Goated story

[@spoiledbrat3929]

You don't know how to count

[@Gizzeit]

@spoiledbrat3929 _"I can only count to four"_ (google for it just in case))

[@chrismuratore4451]

Couldn't help but hear a beat drop once Matt said, so rhythmically, "spin fully up, or spin fully down.".

[@blandprix]

Haha, same! Reminded me of "Flower" by Moby.

[@kingeternal_ap]

Summon Vinjent here

[@DeepeningTheListening]

Now I want to hear an actual song with Matt rapping about space time. 😄

[@albrecht-sebastianwitte-re4280]

Everybody do the flop!

[@modernwarrior-bf4ut]

what about that new paper which says we need to cool down a ton of metal to near absolute zero and then it can act as a single particle and using that we might be able to detect graviton

[@trixinreno419]

Im finishing up a BS in Biochemistry soon and I understand about 85% of your content, you make information very digestible and easy. Keep being amazing!

[@byronryan4216]

🤔

[@oskarskalski2982]

I didn't know that you can earn BullShit in chemistry;).

[@trixinreno419]

@@oskarskalski2982 you obviously don't know about my hero, Walt White... sorry for ya 🤷‍♂️

[@oskarskalski2982]

@@trixinreno419 he's from one of my favourite TV series:) although I know him as Heisenberg;)

[@rachel_rexxx]

Woah, that QGEM experiment is pretty ingenious! I'm sure you'll let us know when it is carried out and peer-reviewed, whether it is successful or not.

[@ruanholtzhausen4000]

What if Gravity is emergent, like temperature.

[@gsusreloded]

IIRC that hypothesis is called "Entropic Gravity". I think it has already been debunked...but I could be wrong.

[@pacotaco1246]

You would probably find the Thermal Time Hypothesis an interesting approach to the Problem of Time in Quantum Gravity

[@axle.student]

Thanks. I have been asking much the same question for some time now. I feel just a little less alone now :)

[@axle.student]

@@gsusreloded Thanks for the hint. I will see how it compares :)

[@XEinstein]

​@@gsusreloded entropic gravity certainly hasn't been widely accepted yet, but debunked it isn't. It is still a viable path to follow

[@elishmuel1976]

Hi PBS Space Time, love your videos. I did prefer the ones with more equations and space-time diagrams instead of the ones with cool pictures.

[@miklosprisznyak9102]

I find Rovelli's relational quantum mechanics the most convincing interpretation. It doesn't require "wave function collapse". Read his popular book "Helgoland".

[@n0bl3hunt3r]

The classical gravity collapsing the wave function seems to make gravity into the hypothetical observer. That deeply appeals to my lay understanding of quantum physics

[@spectator5709]

I gave out an audible disappointed "Aahh no way" when hearing "That would mean spacetime itself is in a superposition between states". That's a way more complicated reality than I even want to consider! 😂

[@brothermine2292]

Could a quantum gravity test be designed that's analogous to the photoelectric effect experiment, which showed that light is quantized? Low frequency light had no cumulative effect on a metal target, but if the frequency was high enough, a single photon's quantum of energy was large enough to kick an electron out of the metal. In the analogous experiment for gravity, a stream of small masses passing near a test object might or might not have a _cumulative_ gravitational effect on the object.

[@LaserFur]

one thought would be to send a beam of neutrinos threw a cooled crystal. each gravity interaction would be really tiny, but could add up to produce a sound based on the speed of the neutrinos.

[@brothermine2292]

>LaserFur : I like that idea, because neutrinos wouldn't interact with the crystal via the electromagnetic force or the strong nuclear force and would only rarely interact via the weak nuclear force, and we know how to make a stream of neutrinos (as in the DUNE experiment at FermiLab). But neutrinos weigh so little that it might be difficult to distinguish their tiny gravitational pull from thermal noise or Heisenberg uncertainty. Instead of passing the stream through a cooled crystal, another possibility is to pass it near a small mass floating in zero gravity, looking for a statistically significant change of its location. Because gravity is such a weak "force" it might make sense to start with a stream of particles or atoms or molecules much more massive than neutrinos. The device presumably wouldn't need to be as sensitive.

[@brothermine2292]

>DebateTactics : Even if Heisenberg uncertainty doesn't apply to measurements of curvature, it applies to the relevant measured properties of the test object, such as the location of a free-floating mass or the vibration of a cooled crystal. It was the latter context, the crystal, in which I mentioned Heisenberg uncertainty. Do you have a point you're trying to make? The video is about a proposed test of whether gravity is quantum; did you watch it?

[@brothermine2292]

>DebateTactics : Why do you mention Planck's experiment? It wasn't the photoelectric effect. The video isn't about trying to detect a graviton. It's about trying to test whether gravity is quantized.

[@brothermine2292]

>DebateTactics : No, the experiment that Planck reproduced, and famously theorized about, was about black body radiation, not the photoelectric effect. Planck's analysis of why there was no "ultraviolet catastrophe" (predicted by classical physics) suggested the _emission_ of light is quantized. That did NOT demonstrate the photoelectric effect, in which the _absorption_ of light was shown to be quantized. The photoelectric effect was discovered by Hertz and analyzed by Einstein (for his Nobel prize), and Planck rejected Einstein's conclusion until Einstein convinced him in 1911. Black body radiation is in no sense analogous to the experiment sketched in my comment. Although I appreciate your reference to the paper about a proposed experiment to detect single gravitons (produced by massive astronomical events such as neutron star mergers) by stimulating emission in a large resonant mass, that's NOT the aspect of the photoelectric effect that my comment is about. My comment is about trying to detect a _cumulative_ gravitational effect in a situation where the gravitons, if they exist, should have too little energy to have a cumulative effect... analogous to the low frequency photons that had no cumulative effect in the photoelectric effect experiment, contrary to classical EM theory. Detection of this cumulative gravitational effect would indicate gravity is classical, not quantized. If you reread the last sentence of my initial comment, you'll see my comment is about trying to detect a cumulative effect of weak gravity, not about trying to detect gravitons.

[@lrwerewolf]

Woot! Dr. Eyebrain's brother made a showing around 9:30!

[@zemm9003]

The action in the Lagrangian approach is classical despite summing over all possible paths.

[@nicolasolton]

Infinite paths, or just a really big number?

[@zemm9003]

@@nicolasolton in the theory the number is infinite but it could be just a really big number and the calculations would still go through unchanged.

[@r1ECee]

I’ve been watching for about ten years

[@byronryan4216]

🙀

[@gianluca4744]

How can this man have all the topics I need at the right time!

[@byronryan4216]

🤫

[@AM180x]

Win physics? I feel like finally uniting the two will just open new questions and problems to solve.

[@geekjokes8458]

that's kind of the point of science! in this case, with either result we would have to rewrite both theories: if gravity is quantum, then the assumptions of classic (minkowski - remember that we use special relativity) spacetime used in QM isnt true! so all of the math is just... wrong? even if it arrives at the correct answer (tbf, thats already a problem in most of QM, the math works but it's really weird and feels like youre not doing what youre supposed to), then try to explain why the equations of GR work so well in big scales if gravity is *not* quantum but still not-quite-classical at a fundamental level... honestly im not sure, but the equations of GR would probably change

[@FVLMEN]

You throw away one. GR is the most useless theory imagined.

[@tanmay2340]

​@@FVLMENGPS couldn't exist without GR lol

[@FVLMEN]

@@tanmay2340 it’s pathetic people still regurgitate that myth. Shows how blind and behind people are in their understanding of their reality.

[@tanmay2340]

@@FVLMEN expect its not a myth. You can literally read about it

[@Geraduss]

Gravity is entropic decay of the fabric of Space time and thus also Dark Energy it self. Thus vacuum energy is dark energy, is gravity caused by entropy of space time decay back in to energy.

[@SteveSiegelin]

Another weird thought that comes to mind, and I know I've had some outlandish thoughts here, what if we're misinterpreting quantum entanglement and it's actually dimensional entanglement. This could explain why they can show such a instantaneous reaction mathematically. That also makes me think with my last comments, what if we're misinterpreting the true state of the fabric of space and it really needs to be looked at dimensionally. To reiterate with the end of my last comment if space is a fabric it has to have a certain tautness. That tension has to be the same throughout the whole universe for masses to show different gravitational forces on an equal and measurable scale. This means that I don't think we'll ever truly understand gravity until we understand what that underlying fabric and the forces acting on it really consist of.

[@isitme1234]

Spoken like a string theorist. Cant find out why? Add extra dimensions. Cant find out how? Just add extra dimensions. Doesnt work with 13 dimensions? Add dimensions.

[@SteveSiegelin]

@@isitme1234 I didn't add any dimensions and can you describe what a dimension is because the way we describe dimensions right now is through perception. A two-dimensional object is drawn on a piece of paper you cannot see on the third dimension which is the sides. We are a technically three-dimensional object because we can move any direction within the three axes. I am at no point arguing that there's another dimension. String theory also works in the third dimension. All it is saying is that everything is made up of a series of strings and if you look at the waveform of the particle you can almost see the string structures protruding from the center out toward the edges making a ring structure. This is because the particles are vibrating at such a speed that they look connected and look like strings. Is constant vibration can be thought of as a piece of yarn joining with another piece of yarn and when they oscillate fast enough they will become one. Essentially they will tangle themselves up and not at the point where they lock. This is how mater binds to matter. It's the same reason why tendons tend to knot at the end. Do fibers have become frayed. Fractal geometry shows that if we zoom in on something the design stays the same but miniatures. If we are saying string tendons on a macro scale imagine what we will see on a microscale watching them bind to each other. It's the same thing throughout the universe. Everything is made up of small vibrating particles that we perceive as strings due to the fact that they are moving so fast we cannot comprehend the individual particles. That's what string theory is, it has nothing to do with another dimension. Hopefully this opened your eyes and explained things a little bit better. I still don't believe in a technical fourth dimension unless we're looking at it on an electrical side. If I'm going to look at things in dimensional structures I'm going to look at them as their ability to interact with things that we can't quite interact with. Something like a neutrino would be operating on the 4th dimension in my opinion because it's moving so fast and with such little mess that it can pass through almost anything. I do not think any kind of dimensional being has ever been here nor do I think we will be able to cross into some other dimension. If we do ever make some kind of Transit it will probably be from physical to digital. At that point I would argue it once the body is gone you have died and what is left is an echo in a machine. You are completing string theory with dimensional theory.

[@SteveSiegelin]

@@isitme1234 in other words when I use the word dimension I literally mean ability to travel through certain fields of space. Not in the way Hollywood depicts it. Dimensional literally means directional plane of interaction.

[@isitme1234]

@@SteveSiegelin "String theory works in the third dimension" 😂 So, first of all we currently use 4 dimensions. X y z and time. Second there is no evidence for a fifth dimension at the time.

[@isitme1234]

@@SteveSiegelin What do you mean "string theory has nothing to do with other dimensions"????? String theory literally has added new curled up dimensions in order to function properly.

[@andrewclimo5709]

Thinking about the quantum properties of fields, including superposition, could be the biggest breakthrough in physics ever. It could unlock a true understanding of space time. Exciting stuff.

[@keithtwombley]

13:25 B A Start

[@CalamityStarForce]

This comment needs more likes.

[@darkroast9907]

Exactly what I thought lol

[@PhilippBrandAkatosh]

2:43 brilliant way of thinking

[@bejibx]

0:20 one could say it's better to be SmarterEveryDay instead of HarderEveryDay 😅

[@Sam_on_YouTube]

And even better not to promote creationism. Still love Destin's channel overall, but that video was heartbreaking to see him spread misinformation on an otherwise great channel.

[@waltermiller-hw9bw]

I will choose harder everyday!!!

[@Anonymous-df8it]

@@Sam_on_KZbin May you point me to a specific video of creation being promoted?

[@Sam_on_YouTube]

@@Anonymous-df8it His 300th video, which I think is his 2nd newest currently. It's about flagella. Most of it is cool science. But at the end he talks about irreducible complexity, recommends a book by a creationist and gives buzz words for people to look into for more info that would point people toward sources that lead them to articles that look like peer reviewed science, but are actually creationist propaganda that can be convincing to non-professionals. And in the comments, he was deleting any critical comments he could. Responses to his pinned comment that you can't just delete so easily, he told people to look at the research, but didn't respond to anything substantively, despite many really substantive critiques. The whole thing was antithetical to what I had come to expect from Destin. REALLY disappointing. He was always explicit about his faith, but he never before used his faith to distort the science. I haven't stopped watching his channel, but it has changed how I view him.

[@Anonymous-df8it]

@@Sam_on_KZbin Oh, dear...

[@aresaurelian]

If we leave quantification and enter the continuous field hypothesis, quantification becomes a special case of the continuum of the seamless field, and it is most likely in a higher order solution set than the classical model.

[@Roope00]

3.14 million subscribers, neat!

[@Tom_Quixote]

What do you care?

[@arcan762]

🥧

[@sercero]

Not only that at some point they must have had pi with 5 digit precisión

[@dbarnholdt]

Another great episode ❤ Had real abstinence syndroms waiting. I must have seen the majority of PBS Spacetime videos and even though much is very hard to fully understand I constantly feel that I understand more of physics and astrophysics for every episode. I would have taken up an astrophyicist career if I could live my life again. Matt is the greatest tutor ❤

[@Dedjkeorrn42]

Congrats on 3.14 million subs!

[@polyrhythmia]

3.14159.... million?

[@tom0hawked187]

They should get a pi to celebrate it

[@connorlarkin3083]

I understand about 1% of these videos, yet I watch every week, I feel like we are on to something big these days

[@leo3.14]

Thanks 🎉

[@joyl7842]

Can you do an episode on merging black holes, specifically about the effects on time? I saw Neil DeGrasse Tyson say it theoretically allows for backwards time-travel and would love to know more about it. I mean, I know nothing would survive that trip - but want to know more about how it works mechanically.

[@LandonAshworthDirects]

PhD astrophysicist here and getting a 2nd PhD in quantum physics- there is no and will ever be a quantum theory of gravity. Gravity isn’t quantum.

[@1amTheory]

I believe the same but would love to hear your reasons

[@Caboose117111218]

same! i'm curious.

[@willyamricardo491]

tell us why

[@toddblankenship7164]

Said humans throughout history but always seem to be wrong

[@arthurs5099]

lol i hope this is a joke, don’t be like those people in their 3rd post doc, let it go!

[@truejim]

I like to imagine that spacetime is discrete, but in an irregular fractally shattered-glass sense, rather than quanta of regular sizes. It just makes me happy. 😊

[@jusore]

🪆

[@caleschley]

Just saw a topic by Anton about the new atomic clock that may be able to help test if quantum objects obey the laws of gravity.

[@GaryPater-b3y]

Genuine sincerity opens people's hearts, while manipulation causes them to close.

[@ShawnHCorey]

Here's a question: if a clock where placed equal distance between two equal masses, how fast would it run? Einstein's gravity tells us that the closer a clock is to a mass, the slower it will run. For the above clock, the two forces of gravity cancel each other out. So, will the clock run at a speed as tho there were no nearby masses? Or would it run twice as slow as when it is that close to just one mass? Or will it run at some different speed? If it runs at a speed that is not the same as if the two masses weren't there, then gravity is not a field and neither the classical or quantum descriptions would apply.

[@YandiBanyu]

The problem is that the force does not cancel. Gravity only compound with positive mass

[@duaneeitzen1025]

A fun question. Google Gemini claims the gravitational fields do not cancel wrt time dilation. It gives a very cogent answer, which doesn't mean it's right but it's worth a read. I don't think this rules any theories in or out though.

[@ShawnHCorey]

@@YandiBanyu One mass is pulling the clock in one direction and the other mass is pulling equally in the opposite direction. The clock is exact between the two masses.

[@ShawnHCorey]

@@duaneeitzen1025 That would mean the gravitational fields are independent of each other. Which makes them stranger than other fields.

[@brothermine2292]

It's the local curvature of space (where the clock is located) that affects the clock's rate. Not the clock's distance to a mass. At the center of gravity between two masses, space is flat (not curved) just as if there were no masses.

[@FelixEva-o2l]

Everyone has been made for some particular work, and the desire for that work has been put in every heart.

[@bulentkulkuloglu]

The second set of experiments should also have some property to indicate whether gravitons or a loop quantum foams are responsible for the results. Theorists from both sides should work on predictable test results for such tests, so that we also get a clue to which theory we whould devote our future resources

[@jounik]

The Stern-Gerlach experiment assumes that the actual direction of the spin is contained within the three dimensions of the measurement device. If there were to be an additional dimension to play around in, the first measurement only assures that the direction is in something the _projects_ to the direction implied by the field and _picks up one_ where that applies.

[@Nihongoman]

after observing this video the wavefunction collapsed and left me in a state of being not smart enough

[@thingsiplay]

I argue it happened somewhere in the middle of the video, you just was not able to measure it until you observed the entirety of the video. :D

[@etc4xg]

​@@thingsiplayyet Bell test results seem to imply otherwise...

[@LuisSierra42]

I was entangled

[@thingsiplay]

@@etc4xg I knew it would tickle someones Bell-y. ;-)

[@spinnetti]

Same.. couldn't hang with this one!

[@Raptor302]

So crazy idea (that’s probably wrong), but here it goes. Space(time) is not just curved, it flows into matter and is ‘consumed’ by it. A couple points: 1. Time is the emergent property of matter/energy moving through space. This is evidenced by the fact that a spatial freeze would be indistinguishable from a temporal freeze, and that time dilation is simply a product of the geometry of matter/photons moving at velocity. 2. The Equivalence Principle’s case example of a man falling postulates that man is actually at rest with respect to his space(time) until he hits the ground. At that point, hitting the ground constitutes a change in direction, an acceleration. In order to stay still in spacetime, he would have had to continue traveling towards the planet’s interior. Space(time) is falling into the planet, and indeed every particle of it. 3. Gravity is the relationship between mass and space(time). It drops off with distance similar to the inverse square law of light, illustrating its relationship with mass. 4. Gravity is where the flow of space(time) becomes extreme. Matter consumes tiny amounts of space(time) to exist. This creates a vacuum, which must be filled by the surrounding (spacetime) and constitutes a form of pressure. a. This pressure has the potential to explain observed phenomena. Space(time) is flowing from where it is abundant to where it isn’t. Hence why the universe is expanding, space(time) is expanding outwards into the surrounding nothingness. This may also explain dark matter. Rather than think of galaxies as individual stars, we should think of them as networked whirlpool structures where a star’s own gravity can contribute to the feedback that holds it in place within a galaxy. b. This may also explain the relationship between relativity and quantum mechanics. At the quantum level, a particle would exist and move within space(time) while also devouring it to maintain its existence. On its own, it would appear to move erratically and unpredictably due to constant changes in velocity from the inward flow of space(time) and would only be stabilized in the presence of other particles. 5. Space(time) flow is already assumed to some degree with the acceptance of gravitational waves, but from a perspective where the universe is a dynamic crisscross of currents rather than a static ocean, gravitational waves are simply turbulence. No math or formal education to back any of this up. It’s probably wrong, but I find it a really elegant explanation (which leads to more questions such as ‘Is there an infinite or finite amount of space(time) and where is it coming from?’ Thoughts?

[@deviljelly3]

You can't fool me Matt... it's turtle quanta all the way down...

[@lessgrey]

Maybe entanglement is the spacetime “fabric”

[@PubicGore]

At 4:22 you say "Oppenheimer's post-quantum gravity." Poor Oppenheim. D:

[@Pecisk]

THANK YOU, you finally nailed that one issue I had with trying to quantumize gravity - it is spacetime ITSELF. I am not scientist, and there still might be something, but I suspect gravity IS different, because it is that spacetime, NOT quantum field inhabiting it.

[@Giantcrabz]

love the new editing, and i also loved the old editing lol

[@kicapanmanis1060]

Was actually wondering when the next space time video is coming……1 minute later this shows up in my feed 1 minute after being posted.

[@magneticbuttockputty]

Better call Alex Jones to calculate that numerology

[@ValidatingUsername]

Remember me when they start talking about harry ball theorem violations on the event horizon of a black hole and the inertial speed of a photon being additive with a systems velocity (+/-) from the reference frame but “absolute” to a third party observer who would see “spacetime expansion” (intermediary distance growing) between the photon and the object.

[@BENCMEN]

3.14 M subscribers?!?!

[@HankusSpankus]

Spooky action at a distance .

[@Lucius_Chiaraviglio]

As an alternative means of detecting gravitons, how about crank up their energy so that they start to interact significantly on an individual basis? Like if we could make enough Higgs bosons, some of them might decay into pairs of gravitons of 62.5 GeV each, which would be easily enough to alter particles in detectors in observable ways.

[@geekjokes8458]

thats the "galaxy-sized particle accelerator" approach

[@Lucius_Chiaraviglio]

@@geekjokes8458 Actually, no -- the existing Large Hadron Collider can already make Higgs Bosons. Maybe not enough of them, and likely making too much confounding other stuff at the same time, but definitely some. A lepton collider built with current technology would be able to make more Higgs bosons and less other stuff.

[@geekjokes8458]

@@Lucius_Chiaraviglio i dont know... the wiki page on the higgs boson mentions that at regular TeV energies, the higgs is produced about once in 10 billion collisions, so if a graviton pair has the same relative rarity, we'd need more than 100 septillion collisions, or over 5000 years at the current rate - you'd need a lot more energy to cover a 3 orders of magnitude increase (not that number of collisions is proportional to just energy, but still)

[@Lucius_Chiaraviglio]

@@geekjokes8458So what we need is not a bigger collider, but a better one. In particular, much brighter, and colliding leptons instead of hadrons, to get rid of a lot of the unwanted particle production.

[@WTH1812]

My liquor store says "thank you" for all you do for their sales.

[@jmcsquared18]

If that was a joke, I don't get it.

[@MAGA_Extremist]

​@@jmcsquared18 same

[@godnmaste]

learning about quantum mechanics and the fundamental basics of the universe can cause existential crisis’s or depression upon not being able to fully wrap your head around the concepts, etc

[@MAGA_Extremist]

@@godnmaste this

[@rossjames9267]

This question has driven the physicists to drink silly.

[@nibnob9]

this was a really good ep

[@LetsBeChillx]

What if gravity ocurred only AFTER the wave function collapse?

[@aggies11]

Any of the theories could be true, but I do have a fondness for yours, or any of the slight variations. Could be gravity AFTER the wave function collapse. It could be collapse *because* of gravity (not gravitational interactions) but rather once the quantum system's effects grow large enough to start to impact General Relativity, the wave function collapses right at the border of gravity to "preserve the nature of reality" (Ie. "QM happens in between the margins of GR"). Or maybe it could be that Quantum effects of mass lead to small scale classical effects on gravity eg. a quantum superposition could lead to extremely small oscillations of gravitational waves that represent all the potential states, that are either too small to make any differences or changes in GR. Or that the oscillations average out statistically to a net neutral effect. All of these are fascinating to consider. But any theories will require experiments with gravity, which with such small forces at play should necessitate extremely tiny scales. So I don't think the work needs to be done in theory, but rather a breakthrough by experimentalists who can come up with a brilliant insight on how to test these feasibly.

[@spencerwenzel7381]

This is an interesting idea! It makes me think, does the particle have mass before the collapse? I think this because it is mass that creates the gravity. The shape of the wavefunction is dependent on mass but perhaps the mass doesn't curve spacetime until after the collapse? This would be convient as it would preserve locality.

[@aggies11]

@@spencerwenzel7381 Yeah, conceptually it really gets down to the core "mystery" of QM. If "reality" at it's lowest level only exists in discreet non-continuous "quanta", does that mean that "nothing" exists in the spaces between those quanta? Instead of the old "how can a particle be in two places at once", could the answer actually be the inverse, that a particle is in"neither" and for all intents and purposes, does NOT exist, until the collapse. Or to put it more nuanced, does not participate in our "classical" physical reality, until it collapses. Fascinating stuff to ponder. But this is science after all, and ideas are cheap, we need experimental evidence to really give us something.

[@axle.student]

@@aggies11 "... , could the answer actually be the inverse ..." I have been going over similar thoughts for a while. In some sense it creates 2 levels of reality in the universe. One reality within the "now" moment of the event horizon and classical reality surfing the trailing edge of the event horizon.

[@Audio_noodle]

I had a stupid shower thought, what if virtual particles form significantly more around curved space time than around flat spacetime, since said curved spacetime could "pull" the formed opposing charge particles apart a bit. So the quantum fluctuations in interstellar space would be negligible if not near completely zero while being "fairly significant" in comparison around really massive objects like black holes. Of course the force of gravity on such small particles would still be tiny, but if it affects formation rate, then could be significant.

[@Teth47]

I love statements like "If we can figure out X we'll have nailed physics completely!" because they're always false. We thought that about UV light, we thought that about the standard model, we thought that about QM, every single time, that thing we couldn't figure out led to something so radically new and unintuitive that we couldn't possibly have imagined it beforehand. Maybe there is an end to physics, but I see no reason to believe we're anywhere near it.

[@DukeLattimote]

I would maintain that thanks are the highest form of thought, and that gratitude is happiness doubled by wonder.

[@level9drow856]

I've watched this show for years and I realize that I cannot imagine Matt in any other place but standing in outer space. Not a forest, not a supermarket, always when I close my eyes or remember this show he is eternally in outer space.

[@SushiElemental]

Everybody is currently in space, so makes sense to me. Truly filmed on location.

[@level9drow856]

@@SushiElemental 😂 I saw this coming.

[@markzambelli]

I liked it during lockdown when Matt filmed from his apartment(?) infront of that gold painting (I think his wife did it). Outer space is also cool.

[@joyl7842]

We need a experiment where the magnets in a accelerator are turned off at very high particle velocity. The problem is a detector and setup that will allow measuring what effect gravity has when the magnets are turned off.

[@t3hPoundcake]

I'm still struggling to understand why gravity should be quantized and why it can't just be an emergent property of space that happens when you have "stuff" in "space". Even if space-time itself manifests from the entangled states of all the particles in the universe, whether that means a "quantum foam" of wormholes or whatever. Idk how to even word my own ideas about the emergence of gravity maybe some other people can chime in if they catch what I'm getting at.

[@patrickday4206]

I think gravity is a repulsive force of something like dark energy that wants to exist where matter isn't the voids of space.

[@danij5055]

It doesn't "have" to be. But these are possibilities that should be tested to confirm whether or not that's the case. There isn't enough experimental data yet to determine if that's the case.

[@jackricono]

I got this from a youtube comment so take with a grain of salt, but like it’s about issues with how gravity would interact with quantum effects if it’s classical, like in a double slit example if we can’t follow the particles path, what happens to its gravity additionally the two theories contradict a little in black holes so it would be nice to clarify that

[@thewizardtk]

The KZbinr formscapes has a recent video on this it’s really good

[@MyNameIsSalo]

The issue is more so about discovering the cause for gravity, and if we can quantize it then that means a graviton exists (a gravity carrying particle). Scientists want it quantised as it becomes very easy to work with if a graviton exists, and that would instantly be used to explain dark matter, dark energy, expansion of universe and more. It's a simple answer to numerous unsolvable problems. If it's something else, then these problems remain unsolvable.

[@steelersgoingfor7in2024]

If the big bang theory is correct, and everything was once quantum, shouldn't all particles and fields in the entire universe be correlated or entangled? If that is the case, doesn't that suggest that whatever instrument or consequence is produced during entanglement could be the foundation of the fabric of reality? Could whatever connects particles during entanglement also be the wave potential of superposition? If you imagine a singularity expanding, and suppose entanglement occurred, the force behind entanglement would have been stretched evenly and uniformly giving rise to a flat space-time. However, that would also leave room to manipulate that fabric in some way.

[@terryenglish7132]

Before watching, I'm guessing that after they rolled out quantum gravity, it proved so unpopular they brought back the original theory and called it classic

[@simongreen9862]

Ah, The Hollywood Interpretation, AKA 'shut up and imitate'. Ugh.

[@brandonvasser5902]

People want sci-fi physics because its a crisis to our existence if its not possible to achieve.

[@byronryan4216]

🤐

[@benjaminbeard3736]

Brought to you by Santa and polar bears.

[@elimiller958]

Nice reference

[@NirielWinx]

Could that be a candidate for dark matter? Galaxies are usually disks but the dark matter halo is a sphere. The orientation of the galaxy is its state. After billions of years of random micro quantum shenanigans, our galaxy is in a superposition of orientations. The average distribution of mass of that superposition is a sphere. Dark matter is the gravitational effect of the states we don't see.

[@3X3NTR1K]

What if, on larger scales, quantum mechanics actually *emulates* gravity? Like gravity emerging as an emergent property, rather than a separate force. Gravity being a kind of side effect could explain how its so "weak" compared to everything else in physics. EDIT: Wanted to add that what I hope for is unpacking time and space themselves through a deeper understanding of what quantum mechanics does on larger scales. And in the process of that, gravity would arise as an emergent property. Yeah, this is no small part me wanting to find some sense of elegance underneath a complex physical reality that I often struggle to process. But hey, sometimes that works. :)

[@birbeyboop]

like this? en.m.wikipedia.org/wiki/Entropic_gravity

[@3X3NTR1K]

@@birbeyboop I'm not actually a big fan of that one, but it is an example of what I described, yes.

[@HarryWhittaker-g7l]

What about my theory? kzbin.info/www/bejne/h5icpoqelNB1baM

[@mnrvaprjct]

Extra spatial dimensions could also be responsible for gravities weakness

[@3X3NTR1K]

@@mnrvaprjct Is there anything more convincing on that premise than string theory? Because "so arbitrarily complicated you can get any answer you want" never seemed useful.

[@44Hd22]

10:34 or the entanglement unqunatums the gravity because it becomes a net 0 or it stays the same or it only matters if a new particle interacts with the gravity field. Maybe the position gets averaged but that'd be concerning. 13:53 if they are above each other like that, the entangled atoms would be closer to each other on average.

[@HankusSpankus]

Quantum space time is the key to quantum gravity , if the Graviton exists then its field like the Higgs field manifest its self as a particle given the extreme conditions of the Big Bang or a large hadron collider . This transient particle could be a vacuum force as the volume of the field is “sublimated” into a smaller volume and like the power stroke of a steam engine accelerates more fields to fill the void . In dense cores of planet of stars there could be enough pressure to cause this effect .

[@YerMahm42069]

Yes! You’re entangling the measurement instruments 👍🏽 15:22

[@Akirilus]

Crazy idea. What if there is no classical. What if classical is just a sort of wrong interpretation that happens to work. What if everything is in fact quantum.

[@christopheriman4921]

Another crazy idea, what if there is no quantum. What if quantum is just a sort of wrong interpretation that happens to work. What if everything is in fact classical. I have a feeling that everything is continuous and is always exhibiting non-local effects on everything else no matter how far away instantaneously and you can have both constructive and destructive interference in these between all these classical systems that ends up looking exactly like all of these effects.

[@maciejbala477]

I mean, it's not a crazy idea though. That's kind of what many want to discover, and suspect could be true.

[@MyNameIsSalo]

@@christopheriman4921 That's my take on it too. We use wavefunctions to predict behaviour of particles not because the particle randomly choses states, but because we lack the information required to show the particles progression. This is because whenever we take a quantum measurement, it is destructive in nature. You're firing photons, using magnetic fields to warp movement etc. It forces the particle to change state. Also quantum particles change states because there's so many things interacting with it that you cannot truely isolate a particle. If you could, maybe the particle would maintain the same spin state infinitely, we will never know because our measurements destroy that information.

[@christopheriman4921]

@@MyNameIsSalo I don't think that it necessarily destroys the information rather that it makes measurement inherently unreliable to get a perfectly accurate view of what is happening because the things we use to measure other things are also being affected by so many things we are unable to account for that there is fundamentally a limit on how accurate a measurement we can make. In other words the information exists but we can't access all of it.

[@axle.student]

Nothing crazy about it. The holographic universe leads in that direction, where the "Now" event horizon (hidden quantum universe) is the real universe and what we perceive is more like a screen projection emitted from that. We live in the screen projection and for us it appears and feels real.

[@LaurelHamlet]

Into each life rain must fall but rain can be the giver of life and it is all in your attitude that makes rain produce sunshine.

[@duard8652]

Isn't there was a recent discovery about some proteins that also happen in the brain experience quantum effects, and be quite big?

[@aggressivenipples8391]

Microtubules can have quantum properties and neurons have a lot of microtubules. Whether or not neurons are influenced by the tubules hasn't been demonstrated however. Not yet

[@costaldevomito]

Tryptophan networks and superradiance

[@S1nwar]

quantum effects are unavoidable for molecules, these clickbait articles are meaningless

[@CATinBOOTS81]

@@S1nwar there is a Space Time video about this topic, it has been published on July 25th of this year

[@costaldevomito]

@CATinBOOTS81 yeah it's actually really interesting but don't try to convince the skeptics lol

[@DirtyHarryNl]

Really great stuff!! ❤ Only the advertisement blocks make it harder to follow. 4 ad blocks of 40 seconds each in one episode.... Everytime my focus to follow the concepts is thrown out by an advertisement block..

[@frun]

Gravity🌌 and Quantum⚛️ are classical.

[@byronryan4216]

😱

[@elaadt]

Congratz on reaching 3.14M subscribers

[@AdrianRees]

Gravity isn't a force, or a field. In a sense, there is no gravity, just space-time curvature. So is quantising gravity just shorthand for quantising space-time?

[@Pecisk]

Yeah for me it is just spacetime itself, thus it is fundamental, and is not really a "force"? I feel insisting it has to be connected with rest of quantum fields are scientific dead end. But....totally not a physicist so there possibly are good reasons still diving into that direction.

[@oceandrop7666]

I'm getting real tired of people everywhere on the interent saying all kinds of that with certainty that are beyond their current ability to know for sure.

[@RodCornholio]

Yeah, I think the pedantic way to say it is "gravitational function". It clearly (i.e. factually) does two things: affects spacetime AND produces an _apparent_ acceleratory force (WITHOUT the object accelerating, e.g. you can sit still in a chair here on Earth with an accelerometer and it will show that you are accelerating). So, any theory of gravity will need to explain that.

[@nicolasolton]

Where is the next Einstein. He is overdue.😢

[@zemm9003]

​@@nicolasolton Einstein is easily the greatest Physicist in human history. We have been alive in our current form for over 50k years. He was the best in 50000 years so it is going to take a while even though we have more people now than ever before.

[@NeveChrono]

Don't we use Gravitational waves and study if it is possible to entangled photons ?

[@rudyj8948]

Holy moly the timing was wild

[@nunkatsu]

Because of Sabine hossenfelder's video talking about the same thing?

[@rudyj8948]

@@nunkatsu no I got the notification to watch and it was 18 seconds after he posted lol 💀💀

[@thomascaldwell184]

Yet another great video. Although... I miss the comments section.

[@byronryan4216]

😩

[@hibou-cool2]

I tested gravity at home and it’s quantum. I ran the experiment with 7 sigma outcome. However, I don’t feel like sharing publicly the details of the experiment.

[@liamdonegan9042]

I don't blame you. It probably doesn't fit in the margins

[@byronryan4216]

🫣

[@TheGreaterU]

I had no idea double slit experiments have been done successfully with larger molecules...whoa.

[@jyrinx]

It's obviously both quantum and classical at the same time. A superposition state, you might say.

[@kallianpublico7517]

What is gravity? A force? A shrinking or expanding of time that humans experience as weight or...resistance to motion? Why then, when you jump off a height your motion accelerates till you reach a terminal velocity? Does gravity aid motion or resist motion? Does gravity posess something like a charge? A positive and negative field given by spatial geometry? What kind of geometry would continuously aid motion, and what kind would continuously resist motion? Is the creation of a black hole the natural result when geometry resists motion or aids it? Is there a particle that doesn't move? A particle that never stops accelerating? Do such particles posess two distinct geometries; or two distinct time sequences?

[@JanVerny]

We must be missing an extremely important piece of a puzzle. And I don't think any progress will be made without it. Most likely something about our understanding of particles is completely fundamentally wrong.

[@stoatystoat174]

my money is on distance only being a concept, so the pre big bang singularity and accelerating expansion infinitum, multiverses, gravity etc. are all just silly. Or what you said. Or something. Like the earth going round the Sun concept made all the orbits of the other plannets make much more sense

[@stephenspackman5573]

I think people aren't thinking hard enough about whether “worlds” are local or global, and if local, what the relevant metric is. Certainly no observer can collect enough information to determine a unique universe, so the question is a natural one. People seem to be hung up on trying to keep their geometric intuitions working when the very fact of entanglement seems to tell us that this isn't the right topology.

[@LordWaterBottle]

​@@stephenspackman5573We definitely agree that the standard quantum topologic model is not quite correct. The breakthrough will probably come from some portal nerd figuring it out.

[@zacharywong483]

Absolutely spectacular video, as always!

[@markanthony2919]

Perhaps Gravity is in a super position of being both classical and quantum

[@VideoFusco]

Nonsense

[@JaelPendragon]

​@@VideoFuscowoosh!

[@VideoFusco]

@@JaelPendragon ?

[@PlanXV]

By definition gravity is a consequence of space time and special relatively is a classical model since Einstein inferred it before quantum theory became the norm. The equations are borrowed from flat space 'Hilbert Space' Minkowski space and Lonrenzt variants. The space time matrix can only be solved classically as it has no Particle ti carry the force ' graviton'

[@dc3581]

This exploration into the nature of gravity is fascinating! If gravity isn’t quantum, it could further support the idea that gravity is a fundamental force distinct from quantum mechanics, aligning more with universal balancing. I believe gravity is one of two infinite forces-the other being entropy-and the interplay between these two forces shapes everything in the universe. Gravity acts as a stabilizing, inward-pulling force, while entropy pushes outward in all directions, and together they create a dynamic equilibrium. Perhaps, gravity isn’t quantum because it’s part of a different, larger-scale process, functioning beyond quantum effects to maintain this cosmic balance. I’m curious to see if these new experiments reveal more about this duality.

[@binbots]

We see gravity as classical because we can only observe it in the past. Because causality has a speed limit (c) every point in space where one observes it from will be the closest to the present moment. When one looks out into the universe they see the past which is made of particles (GR). When one tries to measure the position of a particle they are observing smaller distances and getting closer to the present moment (QM). The wave property of particles appears when we start trying to predict the future of that particle. A particle that has not had an interaction exists in a future state. It is a probability wave because the future is probabilistic. Wave function collapse is what we perceive as the present moment and is what divides the past from the future. GR is making measurements in the observed past and therefore, predictable. It can predict the future but only from information collected from the past. QM is attempting to make measurements of the unobserved future and therefore, unpredictable. Only once a particle interacts with the present moment does it become predictable. This is an observational interpretation of the mathematics we currently use based on the limited perspective we have with the experiments we choose to observe the universe with.

[@drdca8263]

QFT treats space and time in a relativistic way, and so the thing you are claiming about past vs future and GR vs QM doesn’t make sense.

[@whiteeye3453]

Or what we see in space happening now

[@Fellowtellurian]

I have no idea what any of this means but I feel smarter. Thanks ☺️

[@Kraflyn]

Question: "Is Gravity Quantum or Classical?" Answer: "Thanks to Brilliant for sponsoring this video." There.

[@sidgar1]

Science is beholden to the ones funding it, after all 😉

[@Kraflyn]

@@sidgar1 :D :D :D Truth is beholden to the ones funding it, after all :D :D :D

[@syeddanishanwer]

Truth seem to be entangled by the funding it receives.

[@Kraflyn]

@@syeddanishanwer Yeah, it is symptomatic

[@bigsarge2085]

Fascinating.

[@Nobody_114]

@9:40 "if the first coin is measured so that its wavefunction collapses to either heads or tails, its entangled partner's wavefunction will immediately collapse to the opposite." That is incorrect. You would have to measure the second coin to confirm its collapse to the opposite, otherwise you cannot confirms its entanglement or correlation. Also, for any reason, if the second coin interacts with any other field or particle, then that entanglement is lost.

[@blahsomethingclever]

What's clear is that gravity travels at the speed of light, but unlike light etc it has continuous interactions with matter and energy along its radiative path. Further, its effect is a physical movement of particles smaller than any wavelength we can measure. It also slows time down. It can accumulate into black stars (holes) where the gravity radiation leaves unencumbered but light and particles do not. This gravity radiation is emitted continuously by all matter and energy, but not vacuum. Something hints at an underlying structure 'sticks to' matter but whose essence can be separated in black holes. The essence of gravity seems to have no self repulsion. Its link to time is that at dense concentrations of the essence, such as around black holes, matter moves slower as if caught in viscous jelly.

[@fine93]

what if your mom, is your dad?

[@nicholaskarig952]

Genetically, one parent?

[@GeorgeBurkhard]

Wouldn't the neighboring paths in the Stern Gerlach experiment interact much more strongly via the EM interactions? We're talking about particles with magnetic dipoles (and charge, if electrons!). It would seem hard to make gravitational- the only interaction.

[@geekjokes8458]

we should be able to account for that, but im not so sure

[@garypalmer997]

I gravitated to this 😅

[@qbtc]

I'll summarize the video: 1) If the quantum is gravitized, ie, gravity collapses the wavefunction/gravity is random, then very precise measurements of mass will vary slightly. 2) If gravity is quantum, then we can use graviton entanglement to do Bell's theorem type experiments many times over to find whether results differ slightly statistically from standard QM predictions.

[@jamesgartrell4462]

Matt, please tell us that PBS Space Time is not really circling the proverbial black hole and is instead precessing relatively well.

[@heartofdawn2341]

My thought would be that with the semi-classical approach, all matter gets pulled back towards the expectation value. Too large a mass and gravity wins out over Heisenberg and all superpositions are forced to stay in that one spot.