Can Space Be Infinitely Divided?

[@Alche987]

It was proven some time ago that the X to close an ad is indeed smaller than the planck scale

[@Bass17yl]

This seriously needs more upvotes! 🤣

[@TheDamian58c]

I would say its delta x in the uncertainty principle exceeds the area of the ad itself

[@valacarno]

What exactly are these ads?

[@Alche987]

@@valacarno pop up advertisemets

[@valacarno]

@@Alche987 How can you get them? Is it some Premium thing or extension?

[@edwardstiffler1734]

I'm continually disappointed that the Planck Length is never represented with a tiny wooden plank.

[@vampyricon7026]

Because Planck is pronounced /pla:ŋk/

[@bacicinvatteneaca]

@@vampyricon7026 so is plank ;)

[@T3sl4]

Spacetime has many wormholes, Ed-boy!

[@alphalunamare]

Here is an in depth explanation kzbin.info/www/bejne/lWK8cnpsdp1madE

[@GetawayFilms]

@@alphalunamare And BOOM.. The fun STOPPED!

[@TheRealBoof]

I'm an astrophysics PhD student and this KZbin channel teaches me new things. What an extraordinary time to be alive, when these kinds of resources are readily available and presented in such an engaging way!

[@kornelabramczyk5948]

That's a new time old man

[@geesunn8101]

@@richardromero6193 h huh. Jjjj j. J. Hi j jjj. Jj.

[@Kitsudote]

People start to understand that sharing knowledge helps everyone. It is truly a beautiful shift.

[@sarvhere]

I also want to do phd in astrophysics can u guide me pls

[@zs8784]

N0ob

[@RR-qp4kp]

Your contribution to communicating physics to the public is brilliant - always concise, but pitched at an intelligent level and understandable. I’m very grateful for what you do and thankful that you’ve been doing it for this long. Just wanted to say thanks to Matt and the team

[@haudace]

You understood this?

[@JohnDeck1]

sometimes (:^)

[@annakeye]

@@haudace I'm uncertain if I did.

[@letstalkpoliticsBDG]

yes

[@vesawuoristo4162]

I cannot accurately measure whether I understood it or not.

[@keonix506]

10:22 "distances are *undefined* " We are all doomed, universe is written in C++

[@leogama3422]

Or Javascript. Makes sense...

[@keonix506]

@@leogama3422 I'm talking about UB - undefined behaviour. C++ specification is full of it, it's a damn minefield and you are at mercy of the compiler to not mess up your logic. AFAIK JavaScript doesn't have UBs, it's just convoluted and unintuitive

[@Merennulli]

@@leogama3422 Yep, we've seen already that particles are dynamically typed based on their energy level.

[@NTmatter]

@@keonix506 That's an interesting take on Multiverse theory. The laws of nature are the same in all possible universes, but the undefined behavior is enshrined in the spec and varies between compilers. Perhaps two differently-compiled instances of the same dynamically-loaded library are sharing the same memory space, giving rise to quantum uncertainty!

[@keonix506]

@@NTmatter "Your measurement of program output caused wrong branch of multiverse to be chosen! You see, it's not my fault it crashed!" I will add this to my list of excuses

[@falco830]

Physics: How small can we get? Heisenberg: Maybe.

[@Argonaut320]

yes

[@TheOhhhReallyChannel]

Your god damned right

[@nenmaster5218]

@@TheOhhhReallyChannel Would it be too random to declare my intend to recommend my fellow science-youtuber-fans some... well... more science-youtuber? I mean, in my mind, it just makes sense, but many call me B0t, so... your choice...

[@T33K3SS3LCH3N]

"You'll have to stay tuned to the future of physics" well damn that's a cliffhanger if I've ever seen one

[@souulja]

😹😹

[@SpindlyScoundrel]

When is the new season of physics?

[@ObjectsInMotion]

@@daedalus-7 Technically quantum mechanics was discovered before relativity, if anything the two revolutions in physics were near simultaneous.

[@T33K3SS3LCH3N]

@@ObjectsInMotion yeah but the release order is different from the watch order!

[@1adamgriffin1]

#entanglement

[@T33K3SS3LCH3N]

Physicists in the 19th century: "It's basically solved, we already know everything" Physicists in the 20th and 21st century: WE DONT EVEN KNOW WHERE THINGS ARE

[@shannonbloom4133]

Nor do we know "What" "Things" are.

[@jari2018]

@@SpecialDepartment 2 . Thruth is always racists. Non gender and gender - equals rasism also which equals some aliens who divides like a worm or makes copies as male or female .Redefine rasism . Good and bad -nneds also redefining -so does success from faliure .The big problem are peoples thought and what conclusion they make -to lie and unlie

[@GodKing804]

BUT GLOBAL WARMING IS 100% MAN MADE

[@misakamikoto8785]

The more you know, the less you know... being ignorant is truely a bless, it saved you from the burden of infinite knowledge.

[@Tim0feyK]

@@shannonbloom4133 Nor even what "what" is...

[@klauskervin2586]

This is the best explanation of the Planck length I've ever heard. Bravo and thank you PBS!

[@dembro27]

The Tortoise sure hopes space is infinitely divisible so Achilles can't ever catch up to him.

[@CharlieQuartz]

Actually the infinite smoothness of space would still let Achilles catch up to the Tortoise, since adding an infinite number of distances/times can give you a total finite distance/time.

[@jiffylou98]

Achilles hopes space is infinitely divisible so his atoms don’t overshoot the tortoise at infinite velocity

[@kaizokujimbei143]

@@CharlieQuartz You can finish an infinite series in finite time?

[@yonatanbeer3475]

@@kaizokujimbei143 yes

[@tonydai782]

@@kaizokujimbei143 If the amount of time given to each term in the series shrinks fast enough, then yes.

[@ativjoshi1049]

This is the most intuitive explanation of plank length I've seen so far.

[@brandonkidd3408]

Maybe photons are the answer to light speed travel or atleast close to light speed

[@BrokenSymetry]

The amount of work this channel has done promoting science on this platform is just amazing

[@djbslectures]

Space time tag line: "We need a theory of quantum gravity to answer that"

[@sogerc1]

DJBsLectures Isn't that the truth :D

[@avhuf]

If I had a cent for every time I heard that...

[@adrianordp]

I read this comment at the exact time he says it! O.o

[@PrivateSi]

Start with the simplest possible all-pervasive, quantised physical particle field as the subspace matter-energy (CHARGE) field from which to emerge the forces of nature... -- +ve charge balls (quanta cell, +1, pixie dust) held together by -ve 'subspace gas'.... A close-packed magic crystal ball.. I mean dual particle field theory. -- Cells knocked free form a positron and the hole left behind an electron. These vibrate the field at C, sending out 'blip' spheres. Blips are a cell moving outwards and then back into its balance point... Blips compress the the field laterally as the blipping cell squeezes through the 3 in front, and back... A e- or p+ moving up and down (ie, from-to an atomic ground state) forms, a transverse light wave blip pattern forms. -- All electrons and positrons have the same phase in time but are half a cell apart as electron focals points move from cell to cell, and positrons' from cell gap to cell gap, so their blips are opposite phase... A universal clock emerges as the first load of e- / p+ pairs formed during the Big Bang formed at exactly the same time.. -- Same charge, opposite direction blips repel when they collide, sending repulsive force back to each charge particle... Opposite charge, opposite direction blips are in sync, resulting in a 'flux tube' as an AC field vibration (each cell moves back and forth by half a cell, in unison, with -ve gas and +ve cells moving back and forth in perfect contrary motion, never finding their balance)... Vibration recoil experienced by charged particles at all times pushes the 2 particles together along this smooth, in-sync path. -- When 2 positrons collide with enough energy and/or ar precisely'roughly the right angles another field cell is knocked free, with the newly created electron-positron pair and one of the 2 original positrons forms a Proton in an instant, as 2 half neutralised positrons sandwiching 1 electron,, with the spare positron ejected by the positive Proton... NO ANTIMATTER CATASTROPHE.... Also, when a high energy photon hits a Proton it can bang the two positrons closer together, so they squeeze out another field cell, forming a * NEW * electron-positron pair... -- All atomic structures can be balanced using only Positrons and Electrons as the building blocks of matter... All nuclear reactions can be balanced using * NEW * electron-positron pairs where needed... A 3rd neutral charge to better match QCD is possible but not required to balance nuclear reactions -- POSITRONS ARE GRAVITONS too..... Each positron attracts -1 of -ve subspace gas away from the rest of the universe... This CAN mean voids expanding (DARK ENERGY) as matter forms. possibly with local cell gap and/or size shrinking around matter, possibly with a quantum gravity well around each nucleus as part of The Strong Force... Gravity is an all pervasive subspace charge gradient... -- Relativity can be added in by saying light (electrostatic blip) energy moves from cell to cell in an absolute fixed time + Dark Energy expansion with Big Bang expansion on top leads to red/blue shifted galaxies.. You can have as much or as little quantised gravity and dark energy as you like.. It's a powerful model. -- Double Slit Experiment fires an electron at the right hand slit out of two... The preceding electron blip field diffracts through the slit and interferes, forming regions of turbulence and calm... The electron focal point always goes through the slit it is pointed at, but hits a random calm path as it leaves the slit, then follows the calm path to the detector, forming interference patterns... Extra detectors interfere with the diffracted interference pattern.

[@PetraKann]

The Quantum Mechanics and General Relativity theories dont talk to each other. And in the case QM, there is no agreement on how to interpret the theory with serious fundamental problems involving the measurement/observer problem and other issues. GR fails at the singularity. It’s not entirely clear how these issues will be resolved, but one thing is certain, a new theory and approach is required. It’s insufficient to simply say “shut up and calculate” or the equations predict most phenomena with great accuracy. If that was the criteria, scientists would not have moved past Newtonian or Classical mechanics. Of all the Scientific disciplines, Physics is the least complex. It also relies on the most number of spherical cows. It is the soft bed which science rests on - the easy science. It hides behind its idealism and childish mechanistic neuroticism

[@MrAndersson579]

- Say its name! - Heisenberg's uncertainty principle - You're god damn right!

[@FuttBucker42069]

It is the one that knocks

[@DragonsFrogs]

Maybe that’s why he wanted someone to say his name? He was uncertain

[@geordi5054]

I can tell the exact moment that the uncertainty principle turned into the Heisenberg uncertainty principle.

[@galaxycoffee933]

let's start calling it the Matt Uncertainty Principle

[@sionnach1311]

I've often heard this heisenberg principle mentioned I'm just not certain about it

[@Tom_Quixote]

I understand your position, but I'm not sure where you're getting with this..

[@tomfly3155]

Lol

[@joshurlay]

@@Tom_Quixote I don't understand your position, but I see the momentum in your argument

[@crystaldazz]

"You may see where we're going with this" Me: You vasssstly overestimate my brainpower.

[@chrisd6736]

Ha this one was particularly confusing. There are a few better explanations of plank length I’ve come across (with a lot less math).

[@DemonKyle]

@@chrisd6736 I personally liked this explanation a lot. There are dozens of math-less channels on physics on KZbin, we need more with math in the explanation. Without math, you aren't doing the idea justice.

[@chrisd6736]

@@DemonKyle- I like math and appreciate that they’re not trying to oversimplify the concept- but this much math is definitely gonna go over a lot of people’s heads. Like I understood everything in this vid but I also tutored calculus for engineers in college. Made my wife watch it and she understood exactly nothing. She’s not dumb she just doesn’t understand math.

[@l1mbo69]

@@chrisd6736I do not understand how one doesn't get the math here- he's just rearranging symbols. And yours is not a very good example if she doesn't have much exposure to modern physics beforehand because then too much of the explanation even other than the math would be flying too fast to comprehend, and make you lose focus so you don't get what he did with the math

[@ShadSterling]

@@chrisd6736 Link to better explanation?

[@Abstrac888]

I thought the episode was going to end after he said “We’ll come back to the true nature of space another time”

[@7shinta7]

Nope, the ending with "Spacetime" is as constant as the Planck constant. :D

[@genghisgalahad8465]

There was (another) space between space and time...it was purposeful, I imagine! 😀

[@barretprivateer8768]

Matt just works in as many 'space time' title drops / puns as often as he can but completely deadpans it every time. What a legend.

[@Marcel._B]

I thought the same lol

[@84Supervisor]

If he hasn't already, I hope he'll look off camera one day and just say "time" while pointing to a non-existent wrist watch 😁

[@radishpineapple74]

4:03 I burst out laughing at this animation, I couldn't help it. Video editor, whoever you are: you need a raise.

[@Sk4lli]

What I learned: If I want to measure the distance to a guinea pig very precisely I just end up shooting tiny black holes at it without learning how far away it is.

[@myaccountishacked6417]

It's a Capybara

[@andersjjensen]

You will in fact have fried the poor bugger crisp before you found out exactly where it is. The energy bill you receive for this is astronomic, so you'll be living on fried guinea pig for a while...

[@ballswalls8189]

Good video kzbin.info/www/bejne/pZ60Xnptmd2kbtU

[@JeanPierreWhite]

You have two problems. Your mesurement will not be as precisise as you'd like. Measuing the length will "bump" the capybara a smidgen changing the distance you were trying to measure in the first place.

[@SneakyTravels]

@@JeanPierreWhite What if I shoot/measure capybara 3 times and results show 1m and 25plancks, 1m and 28plancks, 1m and 31plancks. Would this mean that each measurement moved/moves capybara by 3 planck distances and now all I need to do is reduce result by 3 planck lengths?

[@elib2670]

Finally someone explains how one arrives at the planck length

[@Left-is-right-8192]

I’ve always wondered this.

[@travis5732]

Yea

[@Kumquat_Lord]

Honestly it would make a much better base unit of measure over the meter because it is truly universal

[@mr.rogers1019]

It's funny, the shorter the measurement the longer the explanation. Lol

[@kevincronk7981]

I still don't get if planck length is like a pixel, or the smallest an object can be

[@nopeno9130]

Planckstronaut 1: "Wait, it's all undefined?" Planckstronaut 2: "Always has been."

[@wesleybantugan5604]

There’s something unbelievably beautiful about just trying to stretch the limits of quantum physics is thwarted by the fundamental laws which govern it.

[@stanimirborov3765]

@@zarkospasojevic6272 -- the matrix

[@nenmaster5218]

@@zarkospasojevic6272 Would it be too random to declare my intend to recommend my fellow science-youtuber-fans some... well... more science-youtuber? I mean, in my mind, it just makes sense, but many call me B0t, so... your choice...

[@prashank]

Chief, you just so casually dropped the fact that photons can wrap spacetime which blew my mind, we will need an episode on that.

[@umbrascitor2079]

By my understanding... a photon itself has no inherent mass, but its energy is equivalent to mass (E = mc^2). So as the photon's energy increases, its energy "mass" has a greater effect on space, until at a certain energy the extreme curvature forms an event horizon.

[@AliothAncalagon]

Its really a big realization for many at a certain point. If you direct a flashlight towards a black hole, it also grows. You could even focus so many superlasers to the same point, that you create a black hole in the process.

[@paulgoodwin8840]

@@AliothAncalagon There's actually a specific term for that kind of black hole creation: a kugelblitz.

[@jorgepeterbarton]

@@paulgoodwin8840 yes yes isnt there a pbs episode on it from ~5 years ago. Making a black hole from light is *theoretically* possible, sort of, if you find a way to concentrate so much light, which is likely the impossible, but if it were to exist in a concentrated volume (the difficult bit) it would form one.

[@TNaizel]

Energy bending spacetime happens constantly around you when you feel gravity. The mass of our planet and of your own body comes mostly from energy, the energy of the quarks in your body and of the gluons binding them together. The inherent mass of quarks and electrons (due to the higgs boson field) makes up a very very tiny percentage of our mass.

[@XKloosyvv]

I'm loving this channel. Halving numbers to infinity is always a concept that fascinated me as a child. However, learning about Planck values has completely shifted my way of thinking about an infinite universe.

[@shutupimlearning]

that feeling when all the studying and hard work you've put into understanding the individual concepts within this video are beautifully arranged together; when everything just "makes sense now". That is probably the best feeling in the world.

[@kevincronk7981]

But I still don't get it, is the planck length like a pixel or is it just as small as an object can be?

[@aidenstern5254]

@@kevincronk7981 it's the smallest length that you can measure something. measuring takes energy, and measuring the position or momentum of something smaller than the planck length causes a black hole the size of the planck length

[@KohuGaly]

@@kevincronk7981 It's a bit more abstract than that. Planck length is the minimum meaningful distance between distinct features. In case of pixelated images, planck length is the inverse of resolution. If you try to zoom into the image beyond that point, you are no longer getting any more details. You're just getting an upscaled blurrier/blockier version of the original image, with no additional detail. The important bit to understand, is that pixelization is not the only thing that can create this effect of minimum meaningful distance. There are other mathematical ways you can get that effect. Pixelization is just the most intuitive one, that people are most familiar with.

[@l1mbo69]

@@kevincronk7981 No, if the universe was made out of small cube pixels, there would be 3 special or privileged directions. The universe would not be isotropic and we would probably be able to detect that. The creation of new cubes in an expanding universe would also be problematic. This problem is eliminated in theories like Loop Quantum Gravity. Here little loops get created in a isotropic way

[@spindoctor6385]

Excellent episode, please do not be afraid to continue to use the equations. Even if not everybody understands them, they help a certain % of us better than the words or diagrams alone.

[@nenmaster5218]

Yep

[@tryst1384]

planck length is smallest possible length....n it was proposed by MAX...😅

[@sodiumsalt]

Omg this is KZbin gold

[@peoplesrepublicofunitedear2337]

Whoa 🤣

[@yoseyoda]

Ever heard of the Min Max Theorem? :-)

[@bazpearce9993]

I watch these vids to confuse me, and i never seem to be disappointed.

[@justin79811]

This is easy, just break it down to the simplest equation: Pie ÷ 45 × the speed of light = Fish!

[@MarkusAldawn]

@@justin79811 we derived the ÷45 term by whacking a badger until it told us it's secrets

[@justin79811]

@@MarkusAldawn - Oh that's right, if I remember Correctly it was just after the 45th whack that the badger turned over state secrets and that is when the equation was solved.

[@MarkusAldawn]

@@justin79811 one of the great events in not only scientific progress, but also politics, as that badger provided the first indications of the Watergate scandal. The badger was, in fact, a mole.

[@ballswalls8189]

Good video kzbin.info/www/bejne/pZ60Xnptmd2kbtU

[@paulão-72]

So, when Aquiles is about to reach the turtle space loses all meaning and he never catches it

[@avhuf]

Achilles.........

[@AhmetwithaT]

@@avhuf Spanish spelling.

[@fighteer1]

An earlier episode addressed this. Once Achilles comes within a Planck length of the hare, his distance to it becomes undefined. Uncertainty in position means he could be ahead of it or behind it, and enough measurements at that instant in time will show him ahead. At that point the distance increases again.

[@MusicalRaichu]

no, he said that when he's within a Planck length of the tortoise, they both get swallowed by a black hole and re-radiate as a new tortoise and Achilles.

[@lomiification]

@@fighteer1 enough measurements will stop him from moving at all though

[@Gnurklesquimp]

I remember this idea was very surprising to me when I first heard it, large and small scales have always been some of the most interesting concepts to me, easily in my top 10 of areas where I'd love to see major breakthroughs.

[@Ncaa67]

Maybe when we look at the largest things consolidated like black holes we are seeing a clear vision of the smallest. After all black holes are supposed to have a quantum singularity inside. We are just in between.

[@ponyote]

Okay. I just have to know what you have against that poor capybara.

[@nenmaster5218]

Would it be too random to declare my intend to recommend my fellow science-youtuber-fans some... well... more science-youtuber? I mean, in my mind, it just makes sense, but many call me B0t, so... your choice...

[@tehlaser]

This one faked me out a few times. A lot of sentences there at the end could've ended in "spacetime."

[@SpineshatterFilms]

Ikr! I end up trying to predict how his sentences will end at the last couple minutes of every video in anticipation

[@nopeno9130]

I hope I'm not the only one who makes a game out of stopping the video before he can say it.

[@paulembleton1733]

@@nopeno9130 Based on me being average and never doing that, you are definitely in a minority. Viva la difference.

[@naveen513]

Yeah especially when you are listening to the audio, with minimised video and you can’t see the time bar, of this episode of SPACETIME . . Ha!

[@Kuwaie10]

As a casual space enthusiast, this video made me understand the basics of Planck Length and also Heisenberg Uncertainty. Big thanks to PBS for giving us these precious informations with great visualisation.

[@joshyoung1440]

Great comment, but the word 'information' is not countable. So there are no "informations." There's just information.

[@CodeKujo]

Just wait for the universe to expand, and then you can divide again

[@nexus3112]

nice one bro

[@lonestarr1490]

Huh. Interesting question. Does the Planck length grow with the universe's expansion? But yeah, I already see the issue with that question: grow compared to what?

[@nexus3112]

@@lonestarr1490 smart thinking ... but our reference frames are not fixed to space-time. If it were then we would have been unable to measure the effects of the expansion at all which is definately no the case(#hubbleexpansion#darkenergy#cosmologicalstandardmodel). So, the answer according to me(I'm just a teenager so I'm not 100% sure tho) is that with the expansion of the universe more of these plank units get added to fill the space or should I say 'spacetime' ... the plank length is just an unit so it does not have to follow any 'conservation of energy' stuff!

[@ChilledfishStick]

There's a video from the early days of the channel about the Plank constant, explaining its origin in the "Ultraviolet Catastrophe", how it solved the problem, and gave rise to the field of Quantum Mechanics. I highly recommend watching it. This is a great video on its own. I managed to follow along (when my mind wasn't drifting) pretty easily, and that's no easy feat.

[@christopherblack3610]

That is a great video, makes the whole thing easily understandable without oversimplification. I internally refer to it often when musing on the quantum world.

[@brucebrown7691]

If space is discontinuous and quantised, how does the universe expand? If new bits of spacetime are spontaneously created, where is the energy coming from?

[@electronicsandroboticsclub750]

Good question

[@twistedtachyon5877]

This just sounds like another way of asking "what is dark energy?" So, uh... they'll have to get back to you on that.

[@Yal_Rathol]

when someone figures it out, you'll be on the list of people who should know.

[@biblebot3947]

Sabine hossenfelder has a video about what energy is

[@slkjvlkfsvnlsdfhgdght5447]

who said that you need energy in order to create more spacetime?

[@NewMessage]

Space Time: Making Plancking cool again.

[@Cassandra_Johnson]

No, pretty sure that was Cosmic Inflation actually ;-)

[@genericytprofile852]

Beyond the Planck Length are just a bunch of quantum dudes plancking over the fabric of our reality. Some call them strings but I prefer the former description lol

[@Hy-jg8ow]

@@genericytprofile852 Or maybe we are in a simulation and Planck length is the smallest bit-size?

[@innocentbystander3317]

@@Hy-jg8ow If simulation is possible, then I bet you an entire universe that we are simulated...

[@nenmaster5218]

Would it be too random to declare my intend to recommend my fellow science-youtuber-fans some... well... more science-youtuber? I mean, in my mind, it just makes sense, but many call me B0t, so... your choice...

[@MarsJenkar]

"Matt is currently wandering the universe at Planck Length trying to gather new insights for future episodes." So, in order to reveal the secrets of the universe, he's walking the Planck?

[@svennoren9047]

At the risk of getting in over his head...

[@AJBlue98]

When I think about space-time being quantized on the smallest scale, I imagine a 3D grid of Planck-length cells. Never minding how they’re arranged, wouldn’t the idea of a particle/photon moving from one cell to the next be identical to its instantaneously disappearing from one cell and appearing in another? If so, what’s to guarantee that any such move would have to be to an adjacent cell? Also, wouldn’t this mean movement itself must be quantized, so that certain motions must be fundamentally disallowed?

[@daemonxblaze]

That's pretty much the basis for quantum teleportation.

[@biblebot3947]

The plank length is the smallest length MEASURABLE, not the smallest length that exists

[@michalbreznicky7460]

I'm not a physicist, but I think a cell-like quantisaton would be problematic because it would violate the principle that physical laws work the same regardless of one's position and velocity. For example, if we use a 3D cube grid, then the movement along axes x,y,z of that grid would (presumably) be fundamentally different from a diagonal movement. Moreover, one would be able to tell if they're moving with respect to the grid or not (which is not allowed either). I wonder if there's a way to quantise the space that does not suffer from these violations.

[@AJBlue98]

@@biblebot3947 If you’re going to contradict Matt, please back it up.

[@biblebot3947]

@@AJBlue98 I’m not. I’m going with what he said.

[@marcelo55869]

Next project: 1 - Program Minecraft with blocks of Planck length instead of 1m. 2 - Simulate reality. 3 - ??? 4 - Profit

[@WillArtie]

Lol

[@JohnnyWednesday]

That's why quantum states break down when observed - the computer is running an approximation of electromagnetic waves - until higher precision is called upon. This suggests that the simulation isn't to study life like us - a super-intelligence wouldn't allow us to see anything afoot if it cared that WE did. Probably just studying the formation of a universe and we are just emergent properties of a highly detailed simulation.

[@ghabsterlol7768]

so i need 1 billion years to make a torch i guess

[@sparrowthesissy2186]

@@JohnnyWednesday I've also considered this, that when we get to measuring stuff that's too small, the system just relies on random number generation to give us any kind of answer, because it doesn't really matter that much in terms of how things are observed at whatever scale the simulation is built to model. Much like a weather simulation doesn't need to map the temperature of every last inch to get an overall picture of how the air pockets are going to interact over miles and miles. Of course there's no way to prove this idea, but to me it seems like a possible answer as to why we can't be certain about things that are so small.

[@williamcrosby1061]

Quantum gravity research on youtube is trying to simulate physics with a penrose tile related higher dimensional quasicrystal with imagined planck scale tetrahedra. The system may naturally develop into an effective AI aswell. kzbin.info/www/bejne/rHvMZJKwo9JqkKc

[@davroscaan1318]

So, I'm going out on a limb here and guessing that shouting "I'm hung like a plank!" will get a different response at a party full of sawmill operators than one with physicists.

[@nephilimnameless9809]

This should have more likes.

[@jeffreyjefferson536]

Well done, Sir.

[@djtan3313]

Oh I c wat u did thr . Claps

[@kh_qft762]

The Planck PP

[@burkhardstackelberg1203]

This is the best explanation I have heard of what happens at Planck scale I have heard so far! My personal idea on Planck scale, partially derived from this show: At Planck scale, space and time do not get foamy, they get fuzzy: You get a whole spectrum of virtual metrics, curvatures, parallelisms (and, maybe, even torsions) that even out at larger scale to give us macroscopic spacetime.

[@asmithgames5926]

This is excellent! So suppose mass and energy produce more of these small scale curvatures and torsions. On a macroscopic scale, they might be experienced as a sort of fluid friction. Which would slow things near the massive or energetic particle down a little. Which would cause it to look like spacetime was bending!!!

[@asmithgames5926]

Mass and the passage of time would be emergent properties of plank space curvature rippling!

[@bastiaanwilliams8398]

Thank you so much for this video, and all others that you make. Concerning the question: "Can space be infinitely divided?" Yes! Does it make sense? No.

[@teardrop720]

Thank you Matt and team for giving us insight, access and update into the vast and ever progressing field of physics...its fantastic to have a place like this to come back to ... thank you!

[@worc2187]

I'm an English teacher but boy has this channel made science and math so interesting for me. Thank you for allowing me to understand reality less but teaching me alot all the same. 🙏

[@joshyoung1440]

You're an English teacher, and you don't know that "alot" isn't a word? 🤦‍♂️ it's things like this that make me glad I stopped college before becoming a music teacher. I'd rather change my job than not be well-suited to it or passionate about it.

[@thezipcreator]

@@joshyoung1440 _alot_ (adv.) (nonstandard, proscribed) Alternative form of a lot (compare to awhile). according to wiktionary

[@WarmongerGandhi]

Zeno: That which is in locomotion must arrive at the half-way stage before it arrives at the goal. Planck: I'm about to end this man's whole career.

[@0urmunchk1n]

Credit where credit it's due. Gottfried Leibniz and Sir Isaac Newton did that with calculus.

[@zombieinjeans]

Please do an episode on emergent spacetime! Theories where the graviton is a composite particle, bypassing the Weinberg-Witten Theorem by not just emerging the graviton, but the entire spacetime metric. I've been trying to understand and you're so good at explaining these things 😅

[@ITSME-nd4xy]

Years ago as a teenager I was greatly interested in physics, especially quantum mechanics. I remember coming at an impasse, when learning about spacetime and some of its conundrums. After one exploration, I remember asking myself, "So maybe space itself is quantized?" For years I asked every physics teacher, professor, and professional I met, but none could answer it (most didn't even understand what I was asking). One cosmology professor at a top university sidestepped the question, not answering it. This video answers that question -- many years later. Thank you! This video also gave me a better understanding of "quantum foam" - more detailed. :)

[@Efrendo]

Can we get a super-cut video of all the times Matt has said "Space Time"

[@RandallStephens397]

Actually, quantum mechanics forbids this.

[@EvenTheDogAgrees]

If you think the world needs this, what's stopping you? ;)

[@stevensheffey731]

Then drop a beat to it...

[@calbetheastonish7970]

@@RandallStephens397 man you made me choke on my burrito from laughing

[@jiffylou98]

Make it like the “hi, billy Mays here” supercut

[@Kashis_Corner]

Im not nearly smart enough to get this, but I love it

[@EspHack]

I've watched through the years at first not understanding a single sentence, later on having to watch more than once, repeat many sections on the video, and so on. now I actually understand more than half of what he says and what it means for the world we live in, its fascinating how sheer perseverance through the seemingly impossible can eventually get you a win. it is so damn important to spread awareness that there's almost nothing left in modern life that can be understood within a couple sentences, before you get angry at something new, realize that it might take you weeks/months/years to even know what it IS

[@hunter2484]

This comment is underrated. And I think applies to ANY field. I had this same epiphany in my early days of computer science. And now much further in my career I realize it's more and more true. So many concepts I just didn't understand. I didn't have that "lightbulb" moment yet of "ohhhh now I get it". But the key is to keep pushing through. Keep learning the new concepts that build on it, and in your own time revisit the concepts you didn't understand. Asking questions is very important at this stage. Eventually - you get your "now i get it!" moment. Every person has this moment at different times. The problem is when you think of yourself as "dumb" because it's taking you longer then others. Every expert in every field had to push through his period of "not understanding" a topic. And don't let any expert lie to you and say they didn't. KZbin channels like this are amazing. They provide the tools to keep pushing yourself and your understanding. and for free! There's a lot wrong with the internet. But this ability to provide raw, unbiased, educational content to the masses is a net positive for humanity. I hope anyway.

[@MinistryOfMagic_DoM]

Obviously the smallest measure of spacetime is one KZbin Subscriber.

[@altrag]

Isn't the smallest number of viewers KZbin will display something like 23? I forget the exact number but there's some lower limit they stick on there for.. reasons I guess? EDIT: kzbin.info/www/bejne/pXrOmZqXnNuloKs Looks like I had the number wrong, and that its so old its probably changed by now anyway lol.

[@ivancarli1800]

This is mind-blowing

[@anthonymcwhorter6287]

The 3rd eye speaks

[@souulja]

@@anthonymcwhorter6287 bruh fr

[@WetPig]

I have had this dumb question in my head for a while. And this is the perfect spacetime video to ask it. If we had multiple reduction gears, to the point where it would take, let's say a googol number (or any really big number) of years for it to make one rotation of the final gear. How would it move, would it hop itself one plank length at a time? If so, what happens to the other gears, the last one isn't moving but the others are? I say this considering the plank length as being the smallest possible length. But even if it isn't, this should still apply, if the moment/per second is smaller than that length? I mean the timescale at which we look at events Is the important part here. My hand must move one plank length at a time, in some time scale, throughout it's movement. I asked the question because if it takes longer, maybe the effect would be more "perceivable"?

[@bobbyshen7826]

Physical gears have defects and and elasticity far larger than gears with a gear ratio like billions. The atoms vibrations will be larger than the average movement transmitted by gears (I am not an expert on these topics. search googol gear box)

[@WetPig]

@@bobbyshen7826 What if we use really small gears, Super small MEMS, and then cool it to near zero kelvin.

[@wolfdomination1905]

@@WetPig Physics also prevents 0 kelvin (absolute zero) from being reached. It would require infinite energy. Also the world of the quantum continues to move in the theorized absolute zero. I’m not an expert but it’s worth a google. Point is those motions would distort the gears motion from being more precise than the Planck length.

[@chrisrobinson7728]

Introducing the little known ‘capybara uncertainty principle’.

[@BlueFrenzy]

If space is discrete and quantized, would that imply that no force has infinite range? Gravity, for instance, becomes weaker over distance, so, if there's a point where the gravity cannot move a particle one "space pixel" of distance, then the force should stop right there.

[@TeodorAngelov]

@@mertkocogullar6485 So you proved spacetime is not discrete?

If it’s a quantum force then there’s a nonzero probability that the force might move one space pixel even if the objects are separated by a great distance

[@eljcd]

General Relativity and Quantum Mechanics are infamous for not getting along.

[@dennisbrown5313]

Gravity is not really a force - this has been covered in Space Time previously - so, gravity does not move anything but rather, space curvature/time does.

[@Merennulli]

Speed is distance over time. If your distance value is fixed by looking at it on the planck length scale, time is what grows. Gravity could thereby continue to have an effect regardless of distance because there is no maximum time interval.

[@MaryAnnNytowl]

Glad I found this - have always wanted to learn more about the Planck length, and this answered a bunch of my questions, and some I hadn't even thought of, yet! 😄 Very well done, PBS - another great video!

[@ldbarthel]

So the universe is like building blocks: expanding Planck by Planck....

[@brendawilliams8062]

Lol. Good one

[@darshangabani1203]

The time taken by a photon to travel a plank length is how fast my weekend passes

[@Rattus-Norvegicus]

Ha, I got fired a few weeks ago... #eternalweekend

[@brb23960]

The truest words ever written

[@rajarshirayphotography6964]

Drink Vodka and time will come to a standstill!

[@alfacentauri3686]

A shorter weekend is meaningless.

[@sancho7863]

Be glad you have weekends. I own my own business and i work 7 days a week. I’ve been in business since 2011

[@alexneil394]

Hey guys thank you for uploading this great content, and Matt , thank you for brilliantly explaining complicated quantum theories in a way average Joe’s like me, can HALF way understand. I wouldn’t even come close to understanding the fabric of reality, if it wasn’t for this channel, and for that I thank you !!

[@umeng2002]

The aliens need a new GPU to up our universe's resolution.

[@berkeliumk]

They can't afford new GPUs. Damn Crypto miners.

[@khai96x]

@@berkeliumk They somehow managed to utilize the Matrix itself for mine crypto?

[@AntonAdelson]

Actually a lot of physical limitations like speed of light is a strong case that we live in a simulation

[@ganeshkumarnalachandiran3413]

@@SimonWoodburyForget I agree with some of the implications you listed. I also like that you indicate we are better off considering ourselves as part of a "machine" rather than being in a simulation specifically. There either are beings with the ability to model our observable universe or there arent. If there are then we are in a system with a purpose relevant to our creators, whether it's a simulation or a dictated "pocket" universe. However ,I dont think that we should use the subject of the simulation (our universe) as the basis of an argument againt the likelihood of there being some structure that can run the simulation. If we are, in fact ,a contained virtual structure, we cannot directly interact with the physical universe running the simulation, and without any knowledge on the set of" possible universes " we cannot make any meaningful comments on its feasibility. Perhaps I did not understand your claims properly, in which case I hope you can elaborate. Otherwise, I mostly agree with you!

[@aislingvandegejuchte9818]

@@SimonWoodburyForget although I'm not buying into the simulation thing as anything more than a fun flight of fancy, you made a false assumption in stating that 99.99% of the simulation is star dust. if the goal is to provide a consciousness simulation, then we only need THINK there is a universe out there, with models of physics that agree that there should be stars and such going on. Only the bare minimum of data needs to ACTUALLY be rendered out; some data from our long-distance probes and then a bunch of data from our telescopes and other local observations. We don't have the technology to inspect and verify the inner workings of a star and can hardly even manage to verify the inner workings of our own planet. TLDR: we only PERCEIVE the universe as being complex. in reality, it's a cardboard cutout designed for our consciousnesses

[@0whitestone]

My understanding of how Max Planck first conceptualized planck length was by thinking about black body radiation and how if space was truly infinitely divisible, then that would lead to infinite energy levels in a perfect black body, which would be impossible. He realized that if energy levels were divided into discrete amounts, then this would solve the issue, and in fact, this is what we observe in the real world. Assuming that my understanding above is correct, would that not mean that the planck length not only represents what can be measured, but is what actually exists (like pixels in space time)? If the planck length only represented what could be measured, it seems to me that we would still have infinitely divisible energy levels and therefore would still reach infinite energy density, even if we lacked the ability to measure all of the subdivisions.

[@Smitology]

Note that discrete energy and discrete space are not the same thing. Quantised energy is well established and experimentally proven. Quantised space/time is not.

[@ITSME-nd4xy]

Fantastic job explaining a very complicated question. You used a technique from mathematics and philosophy, using multiple explanations that each resolve different parts of the boundaries/edges of the central question -- similar to the proverbial group of blind men who are in a dark room together, trying to sense and understand the confusing object also in that room (the "elephant in the room"). These multiple explanations each showed the "tail" and the "trunk" and the "thick leg" and the "big floppy ears" of this elephantine question -- and together provide an intuitive understanding. Bravo!

[@david_junior]

I mean your thumbnails ✨✨ Just wonderfully made, just as the content itself Really love this channel

[@LuckyNobody1]

Me too, i love this channel. What a thumbnail

[@lordcypher5889]

What a wonderful video explaining Satoru Gojo’s power.

[@op-bv7cs]

I was looking for a comment like this

[@ms-ds3wv]

Great episode as always, also best in a while. If you are open for suggestions on future episodes. How about more episodes on thermodynamics, would be awesome to have an episode that delves deeper into Gibbs free energy and Helmholtz free energy.

[@Tylerwithfire]

Me, high as a kite: I like your funny words magic man

[@duncanmacduff559]

"no fair, You changed the outcome by measuring it!"

[@greensteve9307]

I understood that reference!

[@diogocanina7097]

One of the best episodes of them all. From time to time I come back here to check it out again. Really well done! Thank you!

[@brianjlevine]

The distance between my computer and my bathroom exists in a very meaningful way.

[@DrOtto-sx7cp]

🤣

[@kreechrr]

And I swear that distance is expanding. Idk why else I'm becoming less and less sure I'll make it in time!

[@robinsonhere4820]

Does your pee come out in quantum chunks?

[@feebleterrance]

dude get a laptop and poop while you browse, or better yet, get a chamber pot

[@racheline_nya]

@@kreechrr you're trying to measure energy too precisely. according to the uncertainty principle, a low energy uncertainty makes the time uncertainty large.

[@matthewfeldpausch2728]

Love the channel!

[@Michael-hn5cj]

I love this youtube channel so much. I love PBS and Matt O'Dowd. This is the only youtube channel that I always make the spacetime for... for spacetime.

[@davidolden971]

My Brain just generated a footnote for this: “* For any understanding of less than a Plank length, please go back to any understanding OVER a Plank length.”

[@jasondelong83]

It's like, if you are not smaller than a Plank length, you cannot fit into the hole, thus you bounce against the screen/net/universal blanket/fabric of spacetime.

[@TlalocTemporal]

@@jasondelong83 -- That's like how superluminal warp bubble could exists, but there no way to get anything to that speed to make them.

[@pappalasiddhartha5518]

What ar you talking! It's like watching English movie in Japanese language! But I want to become an intelligent person in the world! What's your ambition?

[@fvckyoutubescensorshipandt2718]

So when's the new season and episode of physics coming out, the one where quantum gravity is a tested theory as much as Relativity has been?

[@ballom29]

I prefer the manga over the anime adaptation, sure it's full of complicated formula and sometime quite boring but at least there isn't ton of cut content.

[@rubiks6]

Wow. This is probably the most complicated "PBS Space Time" that I think I completely understood. Good job Matt and writers. ----------------------------------------- (07:53) "Imagine now that you're trying to measure the distance across a one-Planck-length object. You need a photon with a wavelength smaller than one Plank length. But that photon has enough effective mass to produce a black hole with a Planck-length event horizon - so any attempt to measure something that small swallows it in a black hole." I got that immediately and surprised myself and I really laughed out loud.😄 Learning is great and new insights give a warm fuzzy feeling inside.

[@augustoo.5099]

I Matt is wandering the universe at Planck Lenght does that mean he will only come back 5 years later when a rat accidentally presses a button?

[@HypeVectorPrime]

Almost as if whoever is running the simulation doesn't want us to find out.

[@actionms8566]

Same with the incompleteness and (maybe) inconsistency of mathematics itself. As if the universe itelf was made with an intrinsic limit of understanding.

[@ethanwilson9406]

@@actionms8566 I think it's not really The Universe itself that has a limit, just our ability to understand it. We're really pushing the limit on what we have evolved to be able to perceive.

[@JACKRAIDEN97]

@@actionms8566 mathematical incompleteness comes from this reality being a subjective experience with 0 objectivity. Thus the axioms we choose to base math on, math cannot verify the validity of the very same axiom.

[@HypeVectorPrime]

@@SimonWoodburyForget But whoever designed the simulation might not want us to know... If there's any chance that any series of events could occur in which we gain the ability to observe things at a certain scale, there must be something there for us to observe, otherwise we would know we were in a simulation and the whole thing would break. So to say that there would be no reason to process the universe at a specific scale is ludicrous. If atoms didn't work the way they do, you would not exist, and just because we don't understand the quantum universe or whatever you wanna call it, doesn't mean that it doesn't also play a vital role in the continued functionality of the system.

[@lonestarr1490]

@@SimonWoodburyForget Maybe the intent isn't simulating humans, but just simulating a universe. for all we know, we could as well just be a random quirk.

[@gregboi183]

That's a really intuitive explanation of the uncertainty principle. I'd never really understood it before, except from the perspective of the mathematics. Thanks!

[@Aphasial]

The Plank Length is inherently interesting, but I'm more interested in the 20 orders of magnitude between the "size" of subatomic particles and the "point-like" electrons and anything else that scales down infinitesimally. Are there any theories at all for what might be happening between that 10^20? That's a whole lot of graph paper to be using... For my part, I feel like this actually leads some credence to CCC, as it might start to give a justification for vast scales at the smallest (to us) levels of reality.

[@geekjokes8458]

we dont know of anything at that scale unfortunately, and i have never heard someone talk about it besides lectures mentioning "yo it's really weird that there's *nothing* at these in between scales"

[@chrisd6736]

Fun fact: Plank distances are really hard to explain to people who don’t understand physics.

[@ThomasJr]

*FUN FACT, THE PLANCK LENGTH IS NOT THE MINIMUM POSSIBLE LENGTH IN THE UNIVERSE, PER THE VERY OWN PERSON WHO CAME UP WITH THIS NUMBER.*

[@jjt1881]

@@ThomasJr until a better theory of quantum gravity is devised, the Planck length is the best estimate we have for a minimum length. Fun fact? 🤷

[@MEUAR]

More like sad fact.

[@vblaas246]

Fun fact plank is dutch for plank in english. I will see myself out now, walking the plank.

[@ThomasJr]

@@jjt1881 you ignoramuses are believing a debunked myth. AGAIN, the person who created the Planck length didn't mean for it to be considered the least possible length in the Universe. Go educate yourselves, go research. Even its wikipedia page doesn't mention it.

[@ClayFarrisNaff]

I realize that I'm nearly the 3,000th person to comment, but even if no one hears I have to say it: this is incandescent exposition of physics. As a professional science writer, I've studied physics for decades, and I'm familiar with the topic here, yet I've never understood it so well -- and I've never encountered anyone able and willing to explain it so well, and to make the fine distinctions -- e.g, no meaningful measure of distance versus no actual length below Planck -- without losing sight of the topic. To do all that in 12 minutes is astonishing. I can only imagine how many hours of careful writing, editing, and crafting went into those minutes, but know that you've inspired admiration and gratitude.

[@soumyadebdey5747]

Does the Planck time has a similar explanation? May be virtual particles are stable at that timescale. Would love know the details before deep diving into the next adventure of PBS SpaceTime.

[@7shinta7]

Isn't the Planck time just derived from the time that light would need to travel one Planck length? But indeed it would be intreresting to know if there are some other meanings or physical implications behind it.

[@soumyadebdey5747]

@@7shinta7 Yes, you are absolutely right. However, I am looking for an equivalent explanation.

[@eljcd]

The formula: Planck time== √(ℏG/c⁵) =5 x 10^-44 seconds (the time it takes light to travel one Planck length.)

[@soumyadebdey5747]

@@7shinta7 Got it: Measuring time less than the Planck time is forbidden by the uncertainty principle in the same way that it would increase the uncertainty in energy (canonical conjugate of time) and hence the total energy to create a black hole with the Schwarzschild radius of Planck length!!!

[@JulianPlaga]

So when Matt brings his hands closer and closer together, approaching Planck length. What's the distance when they touch? Are all things at least a Planck length apart? Is he then touching space time foam? So many questions...

[@mjt2231]

nice :)

[@Tacet137]

Atoms interact with themselfs at scales extremely larger than planck lenght, molecules even more so

[@leogama3422]

Atoms are kept apart by distances orders of magnitude larger than Plank's length by electrostatic forces. One could argue that when they "touch" they are in a chemical bond.

[@leogama3422]

Touching means getting close enough that repulsive forces dominate and prevent further approximation

[@mertkocogullar6485]

@@leogama3422 just like in crystal lattices or you could say that the minimum distance is equal to a grain boundry. But it's not a chemical bond it's physical as far as i know but i can be wrong difference between chemistry and physics become obscure at such small dimensions. To my knowledge chemical bond means that they exchanged or are sharing a valance electron. Even if we think the fingers were metal then it should've been melded together in atomic scale for it to have a metalic bond and idk if joining hands generate enough pressure for some atoms to meld together. One thing i know is breaking or making bonds require great energies we can only bend metals and stuff so easy because they have vacancies.

[@captainzappbrannagan]

This was a gap in my understanding that was so well explained I can't believe it. Thanks! There is no smaller than plank length and for good reason the universe doesn't allow it.

[@senavarr]

So if I make a laser of sufficiently short wavelength what I have is actually a Kugelblitz gun. Nice.

[@twistedtachyon5877]

Next up: Kugelblitzkrieg tactics.

[@NeonVisual]

If there was no such thing as the speed of light (causality), would all of the universe happen in one brief moment, or would it look and evolve much like we see around us?

[@silentobserver3433]

I think that would mean one brief moment. There is literally no known way to define flow of time without mentionin speed of light somehow: pendulum clocks and astronomical clocks - defined by gravity, which is defined through GR, which uses speed of light as a space-time conversion factor, spring clocks - use properties of materials, which are defined by interactions between atoms, which are defined by electron orbitals, which are defined by strength of electromagnetic interaction, which travels at speed of light. Same for biological and chemical clocks, same for atomic clocks etc. The speed of light is literally just the conversion factor, so if you make it infinite you essentially squish the whole history of the universe into the infinitely small interval of time.

[@Mp57navy]

Not a Scientist. I think you just accidentally explained what the big bang is.

[@silentobserver3433]

@@Mp57navy There's probably even more to this: you can view infinite speed of light not only as speeding up time, but by making all the distances much shorter, so basically the whole universe is contained in a small volume and everything is able to interact really fast with everything else. So yeah, basically big bang. I wonder if it's possible to formulate a consistent expanding universe model by just slowing down the speed of light

[@ryantwombly720]

I would like to point out that to an object traveling at light speed, all of history happens instantaneously, so the situation described is not that of an altered universe, but an altered perspective. As to an actual answer to the question…my guess is that a spacetime with no speed limit could be constructed, but no objects in such a universe could be massless. Would that obligate photons to take on mass? And other questions….

[@NeonVisual]

​@@silentobserver3433 So the big bang was in essence a sudden eruption of (or change to) the speed of causality, slowing just enough for expansion to be dominant, but not so much that the universe collapsed back into a singularity. I wonder if the finely tuned constants we see are signs of many worlds at play.

[@willo7734]

I just ordered one in 7mm PRC. Most of the comments are negative but the folks i’ve seen shoot them love them.

[@Post-ModernCzechoslovakianWar]

Absolutely astounding! I feel like a midwit when listening to this stuff, and I'm not 100% certain I understood everything. How would I get into this stuff if I'd like to learn more, but have no idea where to start?

[@CATinBOOTS81]

Have a look at other KZbin Channels like this one, every one explains a topic in a little different way, and that way every time you learn a little more.

[@Tacet137]

Enroll into univeristy and major in astrophysics, without understanding mathematical fundations all you know is poor oversimplifications from yt videos

[@panner11]

This channel has a lot of videos explaining the prerequisite concepts mentioned in this video. The videos at the beginning of this channel might be a good start, though still might be quite difficult.

[@panner11]

@@Tacet137 If you want to make a career out of it, then sure. But there's no harm in people having a passing interest in these things. It's a breath of fresh air seeing people that want to learn.

[@JeanPierreWhite]

This was one of the easier episodes to understand. I came away knowing more, often I come away more confused than prior to watching.

[@alfrednyakinda5939]

Aah, yes; I remember the time when I was learning physics when I amused my peers and infuriated my teacher in equal measure by implying that the units of Planck's constant were 'splinters'. Since then, I have learned to appreciate the value of physics in understanding the way our universe and more specifically our world functions (e.g. Gravity displacement of time on GPS satellite clocks); not to mention the value of scientifically accurate, physics-related puns; as well as the semicolon. (Please note that I do not pretend to understand the more complex aspects of this video without taking time to study the fundamentals, an activity which such videos support as a worthy endeavour.)

[@FunkyDexter]

This episode blew my mind. The fact that basic equations of QM directly come from literally plugging in relativity into logical arguments made me realize how strong the foundations of the "quantum stuff" are. Merely the direct consequence of assuming a space dimension and moving objects.

[@CircusNarcissus]

The word people are trying to remember : Capibara

[@rudivonstaden]

Heisenberg’s lesser known second uncertainty principle: you can either understand the fundamental laws of physics or remember the names of obscure mammals, but you can’t do both.

[@MajorSebbaa]

Last time I was this early, the hare could not overtake the turtle.

[@pablocopello3592]

The video mixes QM arguments with GR arguments, but there is not a “standard” accepted theory encompassing both, so, we should take the ideas on this video as “clues” for a future theory (model) encompassing QM and GR. What I just said, could seem redundant and “silly” to many, but it is not, because most people think that we should deal with the “real” nature of space-time, and that the video refers to the “ultimate” truth about the discrete or continuous nature of the “real” space-time (but we are talking just about future possible models that never can be “ultimate” about anything). A better way to think in physics is that any affirmation about reality have no meaning (and less a value of truth) outside a model (predictive theory). In most other areas of knowledge we still can use the “simplified” view that we can know “truths” about reality (because the model used is almost always “implied”: it could be the currently most accepted model or our “worldview” (a not very precisely defined model responding to our common views and intuition)). With an analogy maybe it can be better understood: to specify a position in space we can give 3 coordinates, but giving the coordinates (3 real numbers, for instance), have absolutely no meaning if we do not specify the reference system (including units of measure used, and coordinate system). But anyway, in most simplified situations it is still a practice to specify a position just giving 2 or 3 numbers, because the reference frame and coordinate system is implied (for instance for a ship, frame is Earth, coordinate system is latitude and longitude, the ship is in the “surface” of Earth etc. etc.). GR and QM are valid theories within different “realms” of reality, a theory (model) encompassing both will refer to a “realm” (domain of reality) that is much more ample than the union of both realms, and will require concepts that will greatly depart from both conceptual structures. About the specific topic of this video: space-time is the structure of causality in the classical realm (and also for the unitary evolution in QM), but QM is showing that there exist a more basic causality whose structure is not a “space-time” and from which the “classical” causality emerges (and with it, space-time itself emerges). Much before reaching the plank scale, space-time itself ceases to be a useful concept (but to test the phenomena for which space-time has not yet emerged, we will need to causally relate them to space-time phenomena which we could perceive). I’m sure this is not the place for these thoughts, I wanted to see if I could summarize some of my views in a small a space… In spite of my unorthodox views, I appreciate very much this PBS Space-Time series and Matt’s contribution to communicate deep scientific concepts to (mostly) non-professional scientist in the field.

[@paulbradshaw9046]

In virtual realities, there's a fixed resolution or a defined pixel pitch. If you're saying reality is the same, then does this further reinforce the theory that we are all living in a simulation?

[@333STONE]

IN VR AND R THE OBSERVER IS THE DEFINER.

[@EvenTheDogAgrees]

No, it doesn't reinforce it. It just fails to rule it out as a possibility. Water can be poured. But if you saw someone pour something out of a bottle, you wouldn't say that reinfoces the theory that the bottle contained water. Might as well be olive oil, sulphuric acid, alcohol, ... About all you can say is that the possibility exists that it is water. But there's no reason to prefer this hypothesis over any other.

[@lubricustheslippery5028]

The "simulation" don't need to be discrete even if our computers we use for simulations only works with discrete data.

[@CATinBOOTS81]

This video was about Planck Length as the minimum meaningful length, it wasn't about quantization of Space-Time. It was clearly stated that we don't know, for now, if that's true. We need a Theory of Quantum Gravity for that, and such theory could be possible even if space it's not quantized.

[@sogerc1]

No, the video doesn't say that. If you look at this: 10:54 space isn't built from 3D pixels (according to the video), you can move half the Planck length to the left and everything is the same.

[@BryonStice]

My twin sister and I tried this experiment when we were about 5 years old, her cutting a string of yarn in half repeatedly while I held the string. Our results suggest that a length can be divided up to the point that one experimenter loses part of their thumb and has to go to the hospital.

[@raymondmulholland8303]

The problem being discussed here is nothing new. It was a favorite parlor game among Ancient Greek philosophers, who logically proved that Achilles could never win a race against a turtle if he gave the turtle a head start. George Berkeley promoted his brand of Idealism as a solution to the absurdities inherent in the materialistic approach to space and time (which are are still popular today, as suggested by the efforts in the show that reality might yet still be smooth). As an engineer, I was told a slightly vulgar joke about aliens who kidnapped an engineer, a mathematician and a physicist and put them in a hallway with a beautiful girl at the end. A force field that separated the men from the woman was moved periodically so the distance between them was reduced by half each time. The mathematician and the physicist were despondent, but the engineer was delighted. When asked why he was so excited about running to a girl he could never touch, he replied "I can get close enough." Planck's constant proves the Engineer was the wisest of the three. But I think the best advice I was ever given came from my 9th grade science teacher, when he said something to the effect that "reality is more like watching a movie than people think", referring to how the smooth operation of life is an illusion because the quantum jerkiness that takes place at a level so far beneath our ability to observe it. I have come to believe that one can either accept the "movie reel" idea of materialism or Berkeley's Idealism (which will eventually bring one to the Christian God, but that is another story). The concepts of a smooth reality that cannot be measured is simply another way of saying "undefined." As most undefined things are shunned by science and math, all the talk here on what reality might look like at sub- Planck space suggests to me that this is a "guilty pleasure" within the mathematical and scientific communities. And it is of little surprise that it is, as so many popular concepts would have to be given up if they gave up on infinitely divisible space. If Plancks constant is indeed a limit of reality, then all the speculation on what happens with Black Holes will have to make way for new ideas because the old ones are based on an infinitely divisible unit of space. Likewise, many popular ideas of the beginning of the universe where there was no absolute start time will have to be rejected (and their rejection would gain point one back to the Jewish and Christian idea of God). I do not mean to suggest this was video was a skeptical approach to religion, but rather I am holding it as yet another example of how science is slowly catching up to Christianity.

[@damqnyohoho]

Does the Planck length change in regions of highly curved space time, for example near a black hole?

[@gandalf8216]

The speed of light is invariant, so no. The Plank length, being a ratio to the speed of light, is so to speak constant relative to c.

[@tanjirouzumaki444]

Could you potentially know both the position and momentum of an object if you first calculate it's precision (to a reasonable scale and without regard for momenta), then it's momentum without regard for position? Thanks!

[@ALittleLifeWithDriedTubers]

No, because you would be measuring over an interval of time and the position would have changed by the time you measure momentum.

[@tanjirouzumaki444]

@@ALittleLifeWithDriedTubers oh that's true.

[@redclayagain]

a much better explanation of what planck length is...an inhibitor from measuring anything smaller caused by properties of a photon...does that mean that measuring with ice cubes, rather than photons we would come up with a different limit> ice cubes don't degrade into black holes as well, do they?

[@pdxmusl1510]

No. Hes using a photon because its relatable but this is a fundamental measurement problem. All possible measuring devices have this problem. But to directly address your ice cube.. the smallest possible "ice cube" involves many many particles. Orders and orders of magnitudes greater than the plank length. So no. Ice cubes are not a good measurement stick on the tiniest of scales.

[@supermaster2012]

Who's the crazy haired guy? He's used as a scientist in many PBS shows.

[@jeannieh3661]

I have wondered that myself.

[@BarackLesnar]

that's reggie watts he's a musician and comedian

[@flaco777]

@@BarackLesnar no

[@jansegal6687]

its an actor, he starred in "back to the future" movies

[@colinmaclaurin407]

he reminds me of the UK comedian Richard Ayoade