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We Know More About Time Than You Think
Sir Isaac Newton claimed time flows universally. Albert Einstein said that time is relative to the observer. Theoretical physicist Professor Brian Greene rejoins WIRED to break down the emerging theories that tell us everything we know about time; from the impact of speed (special relativity) and gravity (general relativity) on time dilation to the role…
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Rhett & Link Answer The Internet’s Best Questions
This is the the WIRED A̶u̶t̶o̶*Complete* Interview. WIRED turns on dark mode as we hand-pick the very best Rhett & Link questions from the internet. Why is it “Rhett & Link” and not “Link & Rhett?” Why is Link even called Link in the first place? What do Rhett & Link think about fans approaching…
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@taxman9985
August 7, 2026 at 3:29 pm
What’s happened, happened. Which is an expression of faith in the mechanics of the world. It’s not an excuse to do nothing.
@BitSquareStudio
August 7, 2026 at 3:33 pm
I like your funny words, science man.
@bradshema6182
August 7, 2026 at 3:34 pm
11:48 So measuring time is measuring how disorganised the room is compared to another point in time?
@slowliving2
August 7, 2026 at 3:34 pm
He was in Epstein files. Stop giving him platform.
@Pengunjung
August 7, 2026 at 3:35 pm
I’m not sure that the light moves, bruh.
The source of the light could move but the light itself doesn’t.
It is exist (appear) and (inexist) dissapear, without impacted by the distance.
The ‘range of the light’ depends on its power (energy).
That’s my opinion.
@ChadwickJames
August 7, 2026 at 4:23 pm
He has no idea, I wouldn’t give him a second thought.
@IndigoHexLine
August 7, 2026 at 3:37 pm
How do you make this video sound less like it was researched by a group of students who didn’t care about their grade in physics class?
@IndigoHexLine
August 7, 2026 at 3:41 pm
2 seconds; everybody exists in the *NOW* but by the time a word has left your mouth to a recipient, 3 seconds has elapsed
Enough time to formulate a joke about their dumb comment, and enough time for them to no longer be in the vicinity to hear it
@holgerjrgensen2166
August 7, 2026 at 3:37 pm
The Stuff-side of the Eternal Life, is a Motion-Ocean,
Time is the ‘Shadow’ of Motion, Stuff-side,
Time do Only exist in the Consciousness of Living Beings.
Forget about Newton, Einstein, and Brian Greene.
Every child knows what Time-Space is, ”space-time”, is Doomed,
because it give NO meaning.
”Time Dilation”, is another Dead mantra, there is NO time dilation.
@User-54631
August 7, 2026 at 3:50 pm
When my parents told me to get a job. I asked them “what is a job”
@newinformation1942
August 7, 2026 at 3:50 pm
Everytime I see light it is stationary, unless shifted by a shadow casted by a moving object…
@metawolf987
August 7, 2026 at 3:52 pm
It’s more like a ball, of wibbly-wobbly, timey-wimey…stuff.
@MKG1949Nash
August 7, 2026 at 5:40 pm
Thank you Dr. Who! I think that I agree, lol.
@Loxo74
August 7, 2026 at 4:14 pm
Still there’s no time in space and on earth, and no one can prove it’s existence
@Masterstroke39
August 7, 2026 at 4:17 pm
I think time is manipulated like ripples in a pond; something that will affect the future will affect the past.
My believe that time travel works like a loop that occurs countless quadrillions of times, and every line carries an infinitesimal change. After a certain number of rotations, that change can cause the loop to change itself. This explains the grandfather paradox, where you can kill him and still go back, to alter your creation. I also believe the universe will naturally auto-correct changes to the fabric of time to prevent total collapse.
Just because Kyle Reese was sent back in time doesn’t mean he was John Conner’s original Father; maybe Kyle’s son just took on the role, carrying a different loop.
@LennartÖstman
August 7, 2026 at 4:26 pm
Enter God….
@118ghost
August 7, 2026 at 4:26 pm
I agree with Brian when he first informed us of his theory on the Island with all us nerds and Jeffery
@nevetstrevel4711
August 7, 2026 at 4:50 pm
Time probably doesn’t exist
@margauxh2701
August 7, 2026 at 5:04 pm
I had this exact conversation with a friend at 3 am that covered all his talking points, I feel big brain
@MKG1949Nash
August 7, 2026 at 5:38 pm
Hmmm, not being a scientist I’m in the dark here. Everything that you explained, to me, is a representation of time, not actual time. Time is not an object or a sentient bring but an ethereal thing with no actual body. If time stops, as in your black hole theory, then it would seem that the person would not exist at that moment. The measurements of time may cease but time itself carries on in spite of that unless everything ends at that moment. Please elucidate.
@plasmaburndeath
August 7, 2026 at 5:40 pm
Bro drops what will soo be a $100 single egg on the floor in this economy you know he be ballin’
@user-yl5rl7tg2j
August 7, 2026 at 6:53 pm
hard to believe anyone who tries to force a BS theory like string theory
if you have 3 apples and it requires 9 for a pie… pretending you have 9 and saying, “we have PIE” is kinda insane it doesnt matter that apples + crust = pie…. apparently numbers matter in physics, who knew?
@xaviertayo6208
August 7, 2026 at 7:00 pm
I need to watch this again.😊
@vesuvandoppelganger
August 7, 2026 at 7:09 pm
Here are 2 ships passing each other.
Ship1 at rest at top.
10;00 10;00
T——————–N
<--- N----------T 10;00 10;02 Ship2 at rest at bottom. 10;00 09;58 T----------N --->
N——————–T
10;00 10;00
Are the 2 ships passing each other once or twice?
T1 passes N2 twice. T1 passes N2 when the clock at N1 reads 9;58. T1 passes N2 again when the clock at N1 reads 10;00. If T1 meets N2 once then what is the time displayed at N1 when this happens?
@meltz87
August 7, 2026 at 7:16 pm
I got about half of that, and I liked it
@cerboris521
August 7, 2026 at 8:04 pm
I think time is a result of movement through space like how charge is electrons moving through a magnetic field. If u could stop all your motion in relation to space time would stop. You cannot reverse time because you cannot reverse your motion in space. you just change direction.
@willivonen
August 7, 2026 at 8:05 pm
You guys need to learn Kurt godel’s incompleteness on a deeper level.😊
@sub-harmonik
August 7, 2026 at 9:22 pm
We are always time-traveling backwards and forwards in time. It’s just that we can’t remember doing so because the neurons and chemical reactions in our brains are also moving backwards and forwards in time
@brianvarner3169
August 8, 2026 at 6:36 am
He still doesn’t know what it is or how it got started. I don’t like entropy. It can’t explain life. 100 and something years ago there was an acorn. It grew into a massive oak tree in my backyard. It was majestic, until it started dropping giant limbs and I had to have it cut down. Life is finite. It keeps wanting to reproduce an ordered system. Of course, after 30 years old, my order system started falling apart. Darned old entropy.
@Dr.D00p
August 8, 2026 at 7:45 am
Physicists = Agents of existential crisies. 😅
@citogrid
August 8, 2026 at 8:05 am
Time began at minimal entropy (“big bang”) and will end at maximal entropy.
Time, therefore is motion towards maximal entropy.
@atticuswalker
August 8, 2026 at 9:25 am
Nope.
@Shat_Tastic
August 8, 2026 at 9:54 am
Why does our mind spend so much time in the past and the future instead of just being present in the now? ;/
@marlzipan
August 8, 2026 at 10:17 am
the weird unexpected qualities of space and time also emerge in very high states
@КсенияКлинг
August 8, 2026 at 10:44 am
Invite Brian Cox it’s gonna be a banger
@FishKungfu
August 8, 2026 at 10:53 am
1:49 The Earth is spinning the wrong way.
@chumark54
August 8, 2026 at 11:05 am
In other words, we still don’t know enough.
@jonathanbyrdmusic
August 8, 2026 at 11:18 am
After taking Thermal Physics, I suspect that time is like temperature.
@anthonyarmstrong5005
August 8, 2026 at 11:26 am
The Lazer wasn’t invented until 5 years after Enstines death.
@mephisto9405
August 8, 2026 at 12:22 pm
Or ever.
@DuncanStewart-w8w
August 8, 2026 at 11:26 am
The 4th dimension is a human invention.
@ywtcc
August 8, 2026 at 12:02 pm
Time symmetry and predictability are closely related.
A requirement that physical laws be predictive is an imposition of time symmetry (and by implication, energy conservation.)
The problem with pure disorder is it’s not, strictly speaking, physics or mathematics, though we can use physics and math to frame the question.
Personally, I suspect the unification of space and time into spacetime is equivalent to a unified theory of order in context.
Spacetime should be the more primitive question, the question of order. (Though it may produce more complicated answers!)
If we didn’t have space and time, or spacetime, we’d invent questions that function in the same manner.
@kingrama2727
August 8, 2026 at 12:25 pm
We know who imposed the order of the Big Bang and who created time. It was God…
@CockleAndHen
August 8, 2026 at 12:33 pm
Time is an abstraction that accounts for and measures the variable actuality that everything doesn’t happen simultaneously.
@CRzero92
August 8, 2026 at 12:33 pm
Time is a mirror image, and time is the mould in which all matter is formed.
@Chris-op7yt
August 8, 2026 at 12:38 pm
order is a human made up concept.
the universe is in a perfectly pre-determined dance of everything at once. what we glean as forces etc is the repeated patterns in choreography
@Venomous6942
August 8, 2026 at 12:41 pm
13:33
HAWK TUAH
@hylianchriss
August 8, 2026 at 1:23 pm
This video came out just in time
@Zenithx3
August 8, 2026 at 3:30 pm
Light cannot be stationary. It must Always be moving at an exact speed.
The stronger gravitational pull you experience, the slower time will elapse.
@МатвейДанатов
August 8, 2026 at 3:53 pm
Ok bro I already know all of that, I’ve read your books in my childhood
@danielstone869
August 8, 2026 at 5:27 pm
It’s all about curvature. The speed of light is constant because it always goes as fast as it can in a given curvature frame of reference relative to the observer’s location and the curvature at that location. Then time is the change in correlations between configurations of geometry and matter.
@AllenProxmire
August 8, 2026 at 7:24 pm
Time is the first fundamental. It doesn’t go backwards. Start there and you get:
𝐺 = 𝑐^3 ℓ_𝑃^2/ℏ
𝑎0 = 𝑐 𝐻0/(2𝜋)
ρ_Λ = (3/8π)H₀²M_P²
the Born rule
S = A/4
and more.
but what do I know.
@tsbob7847
August 8, 2026 at 7:47 pm
Time may become less clear in the subatomic or relativistic speed realms but then please use an appropriate example. Explanations like the egg can result in people disbelieving or disparaging scientists because it gets described as: ‘’Their ‘laws’ say you can reassemble a dropped egg. Their laws are thus clearly wrong and you shouldn’t listen to them.” Describing initial conditions may not be easy to a general audience but this ‘it’s so complex’ stuff can come across as condescending rather than encouraging people to examine their assumptions. I’m an engineer not a physicist nor Brian’s intellectual equal. On a fundamental level though, if your equations do not fully describe reality then your equations are incomplete. Equations have to conform to reality, not the other way around. Calling them ‘laws’ does not change this. It can come across as arrogance. Equations may suggest looking for something you haven’t seen and lead to discovery 👍but just because your equations allow something doesn’t mean reality has to comply.
@markschannon8797
August 8, 2026 at 7:55 pm
This guy is universally charming. A great scientist but also a great science communicator. He ranks right up there with Brian Cox.
@MattyFieldy
August 9, 2026 at 12:16 pm
I wish I could care about this. But I don’t. Why?
@alfadog67
August 9, 2026 at 8:01 pm
You don’t have time to 🤣
@MaraeTribeno-ty8ng
August 9, 2026 at 12:30 pm
Big Bang itself is a theory
@JayDubbya
August 9, 2026 at 12:45 pm
What is love? Baby don’t hurt, baby don’t hurt me. No more.
@brutusl2786
August 9, 2026 at 1:08 pm
Great video. All our processes depend on the speed of the basic particles, like the quarks within protons and neutrons. These are fixed, so if we move faster this motion also moves these particles, so if you approach the speed of light these particles seem to get relatively slower in the direction of motion. Time is like any other measurement, there is no such thing as a meter or lb. It’s all relative.
@gingerelvira6587
August 9, 2026 at 1:49 pm
So as long as were traveling through space there’s time created
@CSJ-CSV
August 9, 2026 at 2:00 pm
When?
@YeamanME
August 9, 2026 at 2:09 pm
Well to solve this mystery, as Henry Bemis would say…. “there’s time enough at last”.
@SomeRandomGuy_id
August 9, 2026 at 2:09 pm
stop stop stop, stop posting about string theories, it is dismissed already.
heck now I have to clear yt watch history I clicked this.
@Thelastetherborn
August 9, 2026 at 2:10 pm
What bothers me about time as a “dimension” is this. Ignoring decay, if we change one of the other dimensions an “object” we’re measuring changes. Whether it is its position or its shape, the object will change even if you don’t change the other dimensions. Time however, ignoring decay for simplicity, doesn’t change the object and that fact makes me wonder “what” exactly we’re measuring 🤷
@benzos5704
August 9, 2026 at 2:33 pm
If we make an arbitrary cut off of the last 200 years and divide that by the approximate length of time modern humans have been around (modern meaning creating fire)…
You had about a 0.06% chance to have been born in the last 200years.
@ywtcc
August 9, 2026 at 2:47 pm
Newton’s major contribution to the study of time wasn’t universal time, it was his use of infinitesimals.
I’d be interested in hearing different physicists’ views on infinity and infinitesimals.
It seems infinity is both indispensable and controversial.
Personally, I think infinity is as natural as the number of symmetries in a circle, you just need to find a convenient geometric interpretation..
@ianrobbins
August 9, 2026 at 2:49 pm
These videos always focus on eggs or ice cubes coming apart and never talk about how the ice cubes or eggs came together in the first place.
@alfadog67
August 9, 2026 at 8:22 pm
Interesting point! Did the carbon and oxygen and calcium entropy into an egg?
@UFOUAPMagnet
August 9, 2026 at 3:04 pm
Time appears to be the entropy effect of spacetime passing through the universe, and therefore matter. Spacetime passes through us and wears us out. The perception of being worn down by this process in relation to gravimetric cycles, one could see this as “Time.” Its a starting point, anyway.
@TimVy-r9c
August 9, 2026 at 4:03 pm
Time is a Measurement, they created Metronome. To master Time. 😅
@Raging.Geekazoid
August 9, 2026 at 4:56 pm
And yet the astronaut who goes on a space voyage in the Twin Paradox is younger than his earthbound twin when they reunite on Earth. That can’t happen without some kind of universal time, because the quantum wave function of the astronaut and his spaceship has to evolve more slowly than Earth’s wave function. It doesn’t matter if the astronaut doesn’t notice the effect while he’s out in space. His wave function evolves more slowly, whether he knows it or not, and any arguments to the contrary are just cultish mysticism.
@alfadog67
August 9, 2026 at 7:42 pm
Exactly. It’s a paradox. it cannot happen. Acceleration can slow clocks – velocity alone cannot. And Albert himseld defined the equivalence principle, but he was more correct than he understood. Acceleration and gravity ARE the same phenomena – not just equivalent. Kinematic Time Dilation is nothing more than a Doppler Integral. Doppler requires a medium.
@GeorgeAbruzzo
August 9, 2026 at 5:23 pm
0:21 an illusion
@gulie94
August 9, 2026 at 6:05 pm
If the earth didn’t spin, if it didn’t have a sun to produce light, would people still have invented the concept of time? Would time still exist?
@danthesquirrel
August 9, 2026 at 7:01 pm
“Physics demands that entropy increases going backward in time in perfect symetry with the increase going forward in time”. I provide no proof just believe me that all of the really smart people in the world agree with me. I feel like I just watched a History channel after school special only with the parts about aliens edited out.
@alfadog67
August 9, 2026 at 7:13 pm
“Time is a count of motion with regard to a before and an after.” – Aristotle
“c is not the speed of light, but rather the rate of recovery of Maxwell’s ε₀μ₀.” – DJ Hallman
Spacetime has a time axis because of Albert’s assignment of second-order Doppler to a moving clock. That assignment created Kinematic Time Dilation. But gamma is the circular integral of Doppler. Doppler requires a medium. Time is not an axis. It is not an arrow. No more than the comparison of the temperatures of two cities is an arrow. Without an arrow of time, the big bang is not required.
@neverman001
August 9, 2026 at 7:13 pm
I’M SURE THIS ISN’T AN ORIGINAL THOUGHT: A layman trying to understand.
Time is only real if observed (relativity)? So observation “creates” time. Proving observation affects outcomes by inclusion of the variable of time? My brain hurts, in a good way.
@DarkskiesSiren
August 9, 2026 at 7:29 pm
Great video Brian! Too bad it’s incorrect physics lol
@quantumzoflyne
August 9, 2026 at 7:54 pm
4:57 in VACUUM*
the Physics jargon, which totally omits the essential context being that the speed of light namely of massless particle like photons, namely light, is constant holds true in a vacuum , as in fact, according to Snell’s Law, it absolutely varies with the refractive index of the medium through which it travels, which is why we can explain the the Cherenkov radiation.
@NOVA92x
August 9, 2026 at 7:58 pm
So if entropy is forever and infinity increasing, is the universe expanding infinitely?
@tonyrainbolt9388
August 9, 2026 at 8:37 pm
When you pour milk into the coffee, it is disordered for a short time. But left alone long enough, the two mix thoroughly and are then orderly again. Just a different kind of order. Maybe we are in a rebounding universe.
@pmichaelbowden3800
August 9, 2026 at 9:24 pm
If there were no time, there would be no physics since physics describes how and why things move, which requires time to occur.
@johntitorii6676
August 10, 2026 at 1:28 am
Brian G. Getting older
@pHactory8_Arts
August 10, 2026 at 2:19 am
time = made by humans
@scottOlsonsoulson
August 10, 2026 at 4:32 am
The Big Bang theory is increasingly coming under question.
@jonathanclark5240
August 10, 2026 at 5:09 am
Doesn’t gravity itself decrease entropy in a system? The conglomeration of space particles into stars, and the fact that things naturally sort by density in a gravitational field are two good examples. So a high gravitational field at the beginning of the universe would create the high order.
@TheJOVVA
August 10, 2026 at 6:07 am
For me time is the perception of causality
@VapuR8
August 10, 2026 at 6:08 am
That dude just admitted that they still do not know anything about time except what Einstein figured out in his imagination experiments.
@briangriffin5230
August 10, 2026 at 8:09 am
Time is a measure, it’s not a noun. I really wish you’d start looking at things like mother nature does.
@MenosProblemos
August 10, 2026 at 8:44 am
Prove there is absolute vacuum before claiming speed in absolute vacuum has a fixed speed.
Or believe Santa is real since there are presents under the tree.
(this is rhetorical btw. I don’t think anyone will have a tool that measures with infinit precision)
@MenosProblemos
August 10, 2026 at 8:50 am
Meanwhile the child is annoyed at the parent for cleaning the child’s room. “I had my own order in here. But you messed it up”
@Jules_Diplopia
August 10, 2026 at 8:57 am
@1:15 “We all have agreement on what it means to meet at a certain moment in time” … no we don’t. If you take away our clocks and phones, then NO you would not be able to meet at a certain time.
Time is simply a measure of change. If there is NO change that can be observered then there is no time.
@matthewedon
August 10, 2026 at 11:07 am
Weird that people managed it for thousands of years before clocks
@Jules_Diplopia
August 10, 2026 at 11:28 am
@matthewedonBut they didn’t.
They agreed to meet after midday, or some other daily but unspecific time.
Even when clocks were used, the ‘time’ in one village was different to the time in another.
@frosted1030
August 10, 2026 at 9:30 am
That analogy for entropy is poor. Disorder in physics (entropy) is the movement toward an homogenous or equalized state we call “disorder” within systems.
@SamuelRemington
August 10, 2026 at 9:56 am
That’s why I believe the universe is in a black hole. The degradation of highly structured holographic space time being warped towards an inevitable end. the higgs field breaks down before singularity opening the possibility for big bang like conditions with repulsive gravitational effects. so maybe there isn’t a singularity at all but rather endless expansion.
@meyou118
August 10, 2026 at 10:58 am
we keep forgetting the other half. life takes disorder into order – high entropy to lower entropy, and there is no time travel, just constant causality. e.g. bacteria “reassembles” that splattered egg. maybe our attention is trapped in this micro-focused concept called “entropy”?
@donelgwapo
August 10, 2026 at 11:11 am
You just had to mention string theory?
@xUGLYTUCO
August 10, 2026 at 11:32 am
He knows less about time than I thought
@MilitantHitchhiker
August 10, 2026 at 11:50 am
About time these idiots started getting it half right
@RediffLallantop
August 10, 2026 at 12:36 pm
This time, that time, old times, everytime….
@travistlogic
August 10, 2026 at 1:40 pm
Highly ordered beginning logically implies an organizer. Things don’t organize themselves, you said that in this video. “No one has any idea “ That’s just not true. Many many people have known it just is a blacklisted concept due to the atheistic take over of scientific community and the academy ushered in by Darwinism. With that said, I should add, really well done explaining this, I appreciate the explanation. Mind blowing stuff.
@kevinroyfr
August 10, 2026 at 1:58 pm
While a black background is easy on the eyes (at least personally), it’s a bad choice for youtube considering how aggresive the compression can be. Great video tho
@rmy6079
August 10, 2026 at 3:50 pm
With Newton’s notions about time it was also connected to his ideas about God.
@mattkendall6261
August 10, 2026 at 3:54 pm
Once you’ve got your theory of time, you need to explain how things persist, the problem of personal identity (how is it that an object maintains its numerical identity making it that unique object).
@magstheonlyone
August 10, 2026 at 4:19 pm
So you guys can do a dark mode
@caffeinenation23
August 10, 2026 at 6:41 pm
“Lunchtime doubly so.”
@petrmilosh
August 10, 2026 at 7:15 pm
4:55 Come on, light isn’t constant. It can travel at different speeds. Something doesn’t add up here, or something is missing.
@stimpy1414
August 10, 2026 at 8:54 pm
Just stir the coffee and order is restored. Not the same as the two parts, but a new order.
@evildave8986
August 10, 2026 at 10:48 pm
Only a fool knows what he thinks
@Bestape
August 10, 2026 at 11:58 pm
Electromagnetism is and will always be ordered.
@rootsradics
August 11, 2026 at 12:11 am
Greene’s clarity on relativity and entropy is elegant. But even the arrow of time is a measurement within awareness, not a property of awareness itself.
The witness is outside time, yet the void actively holds the entire timeline.
@TaoNoble-gd8rg
August 11, 2026 at 12:14 am
LOVE and LIGHT! 😊 ( JOIN the Disclosure Team ya’ll! ) [site is Romero]
@britty23
August 11, 2026 at 2:58 am
Einstein used his imagination. That was the key reason he was so successful. Able to bridge the gap between physical and non-physical worlds
@xerotigercat
August 11, 2026 at 3:44 am
It’s Event to cause.
@Tensorclock
August 11, 2026 at 3:45 am
i imagine tokenizing speed of light as a block
then we’d add the specs that maintain worldly coherency of blocks
we’d note the concurrency model of blocks, to what extent the blocks may co-appear in a world
blocks whose co-appearance is mutually exclusive
blocks that are indistinguishable in a certain world
we may name a data science: “atom-logic physics”
we’d note the futures of a world, and a sequence of operations that morph it
@Tensorclock
August 11, 2026 at 3:59 am
order?
how about 0 of commutativity? []
the empty braket
kets without bras
duality
@javedahmed8550
August 11, 2026 at 6:35 am
At last the great man is doing his lectures not the boring AI
@elliottamiller
August 11, 2026 at 7:27 am
could you better define the arrow of time as an increase in complexity? this satisfies entropy but may be more specific of a definition. we can look back in time up in the cosmos and the further you go back the less complex the molecules and atoms are.
@jeffellis1149
August 11, 2026 at 9:39 am
Always remembering that all the laws are human constructs in order to understand a process including the very concept of time. Our concept of time resides in change but change need not be driven by time, instead be a consequence of it.
@packetcreeper
August 11, 2026 at 11:16 am
Brian Greene is fascinating science communicator.
@HappyGuitarification
August 11, 2026 at 1:14 pm
Or is time nothing more than an explanation of motion? I find it very hard to believe that our one little planet in our one little solar system in our one little Galaxy is the gauge used by nature to determine time for the entire universe!😂😂😂😂
@humulos
August 11, 2026 at 1:31 pm
I fear for anyone who accidentally watches this video while stoned.
@Thatsclassicaly
August 11, 2026 at 1:35 pm
Love this video. I love these concepts. If time isn’t foundational, then it’s…a reaction? A result? Or ingredient? Or just a lens for perspective states that otherwise are always there?
Weirdly enough, thinking of time as separate of every possible state makes the infinite parallel universe theory easier to buy.
@urbanstrencan
August 11, 2026 at 2:58 pm
The time, the only think you can’t buy, or stop really interesting video
@chickenlover657
August 11, 2026 at 5:23 pm
I’ve heard this same crap hundreds of times and no one has really explained it yet. You just think they did because you too have heard it so many times you stopped questioning it.
@rocketships
August 11, 2026 at 7:12 pm
Maybe string theory is just the entropy increasing
@cdcondrici
August 11, 2026 at 10:50 pm
Never skip Professor Greene videos 💎
@reason2463
August 11, 2026 at 10:56 pm
I am just a reasoner. I have been saying for decades now, that time (and space), are emergent properties of energy. Energy is what breaths life into the universe. It’s what makes the scientist’s equations…. real. Thus we shall proceed. Energy is the fundamental reality, and absolutely everything else is and emergent property of energy. Understanding the true nature and behavior of energy is the only way forward.
@computerfile
August 12, 2026 at 12:29 am
All matter is merely energy condensed to a slow vibration. We are all one consciousness experiencing itself subjectively. There is no such thing as death, life is only a dream and we are the imagination of ourselves. – Bill Hicks.
@austin.valentine
August 12, 2026 at 12:29 am
Time is *moves hands*
@rupertkennedy
August 12, 2026 at 12:33 am
11:35
@tonyscaminaci7959
August 12, 2026 at 1:38 am
Profound
@Jack-y7q9c
August 12, 2026 at 1:46 am
ZERO of our universe, the zero has Planck to the unit of inverse Planck units processing capability so there is an opposite unit of ours, negative Planck units but that’s just our universe per Planck unit, not multiverse
@paulventer
August 12, 2026 at 1:47 am
Nice info. Much appreciated
@Jack-y7q9c
August 12, 2026 at 1:48 am
It’s like a spherical volumetric infinity per Planck unit of which there are how many in this universe? You’re confusing human biology time determinism with QM sub c scale; science fiction and not even science
@Jack-y7q9c
August 12, 2026 at 1:50 am
Sub c ‘geometry has an infinite number of degrees in the context of our 360; there is higher dimensions
@vhol93
August 12, 2026 at 4:30 am
Awesome !
@RafaelPolidoroBio
August 12, 2026 at 6:53 am
Fantastic thoughts and examples.
1) I used to think that the absolute zero could stop “time” or at least slow to almost the infinite. Light would, then, ignore that, while every other thing moves slower? If so, maybe light can force the arrow, and makes things more universal than relative.
2) I have a friend that believes in predeterminism. Which means he believes early after big bang, there was an equation describing each of my finger commands to type this message. I find this absurd, even though I don’t find determinism absurd. I’m not sure I’m being clear. I just think chaos and massive interference between things messes trajectory enough to make the world unpredictable in small doses. That has everything to do with time flowing in both directions and would be a fine video to follow up this one. Thanks
@philo2128
August 12, 2026 at 6:53 am
Time is the same everywhere, how matter experiences time depends on the presence or absence of other matter. I.e. gravity doesn’t change time or space, it changes how matter experiences time and space.
@shiroi201
August 12, 2026 at 7:35 am
i feel like my brain got a lot more wrinkles after that😆👏
@SolidSiren
August 12, 2026 at 9:38 am
The reason gravity also affects passage of time is because gravity as far as we know isnt a “real force’ but rather an apparent force that can be understood as just another result of a space and time relation.
@emitsienim
August 12, 2026 at 12:39 pm
Interesting
@BlaikeMcG
August 12, 2026 at 3:11 pm
Humans have an innate need to quantify everything. Recognition defining our disposition is an illusion.
@עופרגוטליב
August 12, 2026 at 3:45 pm
and the answere to the final qustions in your movie is- g-o-d… thank you Brian about wonderful explanion and movie. all your movies are amazing!
@stevekirkby6570
August 12, 2026 at 4:23 pm
Interesting thoughts, thanks.
Perhaps we are the ‘creators’ of time. Just by the observation we impose it.
@saikatghosh3577
August 12, 2026 at 4:43 pm
3D time ball
@frederikkargaard1919
August 12, 2026 at 9:00 pm
“Time” is relative to the “observer”, who is at the center of the “observation”…
The farther you look “up”, the farther you go back in “time”, so the closer, you are to the center, the closer you are to “here and now” (which is unique for the “observer”)…
On the “other side” of “here and now”, we find the “future”…
The “other side” of “up” is “down”…
Is “gravity” the “arrow in time”…?
Imagine “Spacetime” to be a consequence of the “observation” (because the “position” of the “observer” is required to provide the needed “perspective”)…
Our brains use “predictive coding” to be prepared for “here and now”, forming dreams and fears for the “future”…
Is “gravity” our emotional attraction towards our “predictive coding”, which is formed by a “point of common reference” (center of the Earth) around which, we all “rotate” in a shared illusion of “time”…?
@frederikkargaard1919
August 12, 2026 at 9:26 pm
Oh, and if “Spacetime” is a consequence of the “observation”, then we live in a constant “Big Bang” – explaining “spooky action at a distance”, since there were no “distance” to begin with…
@Part-RSD
August 12, 2026 at 11:30 pm
I’m hanging on with fingertips to this video. Man I shoulda finished school.
@DSAK55
August 13, 2026 at 12:16 am
Greene uses time to describe time, circular logic
@jerry8405
August 13, 2026 at 12:36 am
String theory is not real
@drmarcfpelletier
August 13, 2026 at 12:47 am
In the future tie will emerge???
@kennethholman6427
August 13, 2026 at 1:42 am
it is a tool for measurement. stop being dumb.
@Aurelius10-4
August 13, 2026 at 3:12 am
A sincere video at last. In the future, equations will not include t or T.
@xerylemountain7154
August 13, 2026 at 3:18 am
absolutely, an emergent quality! yes! finally… just sayin’😛
@Mr.JOG-
August 13, 2026 at 3:26 am
Physics 101 forever Green
@dmahan8841
August 13, 2026 at 4:41 am
You struggle with the concept of time do ya….??? Thats immbarrassing.
@WeekendTechBro
August 13, 2026 at 5:58 am
Love the video but ai thumbnail.. really guys
@Jossco1371
August 13, 2026 at 6:22 am
I already watched this video tomorrow 😎
@peterwood6875
August 13, 2026 at 10:04 am
Now do the thermal time hypothesis and Tomita-Takesaki theory. Maybe time does flow – but only locally
@GibsonianMathematics
August 13, 2026 at 10:19 am
I am going to be frank at this point. I have the discrete Lorentz worked out, I have fixed particle physics. And these people are not fit to shine my shoes, so my framework just sits on youtube. Physics has been solved, and you should be writing to these people complaining. Brian Greene was sent a copy, these people are no longer worthy of respect. 2 years this has been solved while you sit with your fingers in your ears only listening to people who couldn’t solve it for 120 years.
@Rominp82
August 13, 2026 at 10:43 am
does time exists if we had no humans is probably the best way to look at this.
@wilfredotour3
August 13, 2026 at 12:22 pm
My issue with the “speed of light” is that somehow if you were able to travel at the speed of a beam of light you’d still not be able to travel alongside it…the speed of that beam of light would somehow be the speed at which you’re traveling plus the speed of light, so you’d never be able to reach the tip of that beam…so how can the speed of light be part of any equation?
@kandaramanav
August 13, 2026 at 12:25 pm
On the concept of time Einstein also said there is while hole and it should be found more than black hole but no while hole exist.
similarly time is always constant otherwise no experiment can repeated and come to same result.
It’s completely nonsense that time is relative. it’s rather
when we measure time relative to another reference frame we measure it small wrong value in actual value so time seems relative.
Every measurement changes the things getting measured by some margin and that margins these nonsense calls time is relative.
I like your all videos though this one too but don’t agree.
@augustintamard3850
August 13, 2026 at 12:35 pm
Wasting an egg.. really !?
@Construct-pv8ps
August 13, 2026 at 2:53 pm
Yeah I don’t know if we’ve as cleanly delineated bewtween our psychological feeling of time (which is really just an extension of a feeling towards space) and what “time” we’re really talking about. For example surfaceology has mostly just abandoned the need for any of this. And I think these metaphors are hopefully on there way out.
@JoseDiaz-cf2rs
August 13, 2026 at 3:22 pm
Autocracies aren’t observing reimbursements of entropic value per Stephen Hawkings Equations Mr Simon
@Kill14u
August 13, 2026 at 3:42 pm
Time is the rate of change within a given dimension
@rooryan
August 13, 2026 at 6:16 pm
Ok… so if time is emergent, and not fundamental (in string theory) that could explain why we experience 4D space time in such a special way. I definitely think the theorists are on to something. Gravity, time, and space. Something about fundamental physics creates this intimate correlation.
@cole9799
August 13, 2026 at 6:19 pm
Decay is i think is the best evidence of time and i totally agree its all relative to the ojbect/observer.
@SinCosTan1by0
August 13, 2026 at 7:29 pm
we have learned nothing about time,wait for my response.
@genedussell5528
August 13, 2026 at 8:53 pm
maybe the question we might be asking is: does the notion of Time exist in behavioral actions by animal or plant species, obviously nor including humans, that such a notion seems to have no effect on the behaviour of those species. and because that is impossible to answer, the notion of time is a construct of our awareness of being aware. if a photon has no “rexperience” of time, than space must have zero dimrensions, for the photon. ?
@genedussell5528
August 13, 2026 at 8:55 pm
maybe “reality” is just a self fullfilling prophecy.
@craigwillms61
August 13, 2026 at 9:54 pm
Motion = time. If everything in the universe stopped moving, time would stand still. Unprovable, yes, but, it makes intuitive sense.
@ktv9247
August 13, 2026 at 11:58 pm
yea i went down this rabbit hole too when i made an equation for time and concluded its not fundamental.
@johnsongibbs6567
August 14, 2026 at 12:26 am
Aristotle first described time as motion. Around the world, we all use clocks calibrated by the earths rotation. This is how the entire world uses the concept of time, a rotational velocity which gives us a reference to motion in the universe. This creates a direct relationship between time and motion, as used by everyone. Time dilation is what makes everything unique. Particles exist within their own time dimension, molecules share a time dimension and everything goes through time dilation in proportion to its energy levels. A piece of fruit cut into thirds, placed in the freezer, refrigerator and left on the counter will progress through time at three different rates, dependent on temperature, which is a measure of motion. Time is easy to understand, it is motion.
@selliantuttimusi6735
August 14, 2026 at 1:02 am
Time is just a human tool. The universe doesn’t care about it.
@johnwilliamscoffin
August 14, 2026 at 1:30 am
Loved this video, thank you ❤️
@kaarlimakela3413
August 14, 2026 at 1:57 am
Time has yet to appear??? LANGOLIERS!!! Aaauuuugghh!! 👹
@athenaathena675
August 14, 2026 at 2:55 am
Which is why the universe is not 13.8 billion years old it doesn’t care when it started or how long it’s existed it just keeps going and the things that exist within the universe apply this construct of time to make sense of the environment they’re in and to give themselves a sense of order and control over their existence that has occurred occurring and will occur
@azadr9231
August 14, 2026 at 3:36 am
Time is the defined by the rate at which something changes. Time can cease to exist if there is nothing that can change like an absolute vacuum.
But where things change time exists. Like a comet moving f through the vast expanses of space, or the sun running out of fuel or a flame burning. Or a puddle of water freezing.
@Luthando-c6b3y
August 14, 2026 at 5:06 am
Does gravity affect time or is the slowing of time gravity?
@martineden8389
August 14, 2026 at 5:20 am
Entropy, like any other concept in physics relies on time rather than explains it, or even describes it.
@donaldolin7219
August 14, 2026 at 7:02 am
Brian looking old as time.
@nathanmcknight187
August 14, 2026 at 9:20 am
Like space, time has frame of reference
@mp_science_of_fairness
August 14, 2026 at 9:42 am
Why ignore thermal time and D squared
@jamandwhines
August 14, 2026 at 11:02 am
but a puddle of water cant form an ice cube right. it can freeze as a puddle of ice but not as a cube right ?
@Youtubepurplebelt
August 14, 2026 at 11:08 am
So much less annoying than listening to Sean Carroll
@ehsanmansoorian6949
August 14, 2026 at 11:51 am
Kant apparently still wins, you neither know anything about time and space in itself nor you are capable of knowledge concerning time and space. You just talked about many things but time. Which is not necessarily the sequence of before and after. We know much better now that just like Aristotle physics we don’t know what time is. 👌🏻👏🏻👍🏻
@obaz91
August 14, 2026 at 12:44 pm
brian greene is einstein 2.0, i love him sm
@bowettjono
August 14, 2026 at 1:51 pm
There has never been a lowest state of entropy.. If there were, we wouldn’t exist… Really enjoyed this video!
@ondinablokar2221
August 14, 2026 at 3:41 pm
Finally someone said it like I see it in my head. It does not move, all of it is at the same space simultaneously. I am the one moving through it.
@frontech3271
August 14, 2026 at 3:58 pm
What if… What if Time is a thing “absorbed”, an constituent necessary to existence and motion. The older one becomes, the more “time massive”, one is. If absolute zero could be attained, heh, would time stop as motion stops? Could enough gravity bring about absolute zero as time (and motion) is brought to a standstill.
Also, can three dimensions be perceived with no motion?
@ledaros6348
August 14, 2026 at 4:57 pm
0:07 already leaving out the most fundamental insight that time elapses at the normal rate according to you. We don’t feel seconds getting stretched if we go faster or are experiencing gravitational anomalies. It’s all relative to a distant observer..
@JFarazf
August 14, 2026 at 5:11 pm
When scientists talk about “emergence “ they really mean they have no clue and are as puzzled as anyone else. Emergency in the new scientific vocabulary simply means “I don’t know “.
@MiryamBar-t7m
August 14, 2026 at 7:38 pm
We are so lucky to have you, Dr. Greene!!!!❤
@Jsnborn
August 14, 2026 at 8:08 pm
I do very much like the idea of coming up with ways to understand our universe without “needing” time. It’s a very interesting concept and I’m all for it. I’ve always had a sneaking suspicion as a psychologist that time is tricky for us due to the operations of our brains. Definitely looking forward to more explanations!
@BorisMiljkovic
August 14, 2026 at 9:53 pm
Every time someone explains relativity of time, they talk about relativity of measuring of time.
@JennyBrisk8
August 15, 2026 at 10:47 am
Not really. You must not get around. Simply my clock falls behind yours (loses sync) if you stand on my head as I stand on a planet (diff altitude). Same thing happens if you and me float and I start accelerating due to rocks hitting me (not hitting you). Clocks lose sync when they belong to different circumstances (altitude in first case, accel in other case). That is not talking about “relativity of measuring time” It is simply saying that your clock (or your own body ageing) gains relative to mine. And if you don’t understand why that effect MUST happen, simply ask.
@BorisMiljkovic
August 15, 2026 at 11:09 am
@JennyBrisk8 I rest my case.
@JennyBrisk8
August 15, 2026 at 1:04 pm
@BorisMiljkovic good decision. i can tell you don’t like to be educated 🙂
@BorisMiljkovic
August 15, 2026 at 1:18 pm
@JennyBrisk8 I speak English. You?
@JennyBrisk8
August 15, 2026 at 5:18 pm
@BorisMiljkovic You need more than english to get by in Physics, kiddo 🙂
@citizen_of_earth_
August 14, 2026 at 11:08 pm
the only time is NOW
@rogermiller2159
August 15, 2026 at 12:22 am
10:36
I understand how disorder happens, but how did order happen?
@Panthercholo
August 15, 2026 at 2:23 am
Mek no cents to me.
@RobotYawn
August 15, 2026 at 4:29 am
Time is the prevention of paradox
@NewFieldFreePhysics
August 15, 2026 at 5:23 am
OK, so what is that “we” know more than what “you” think. Who are those we and you? Strange title. No information at all.
@JorgeP-z2b
August 15, 2026 at 6:20 am
Sorry but people have been doing accurate astronomy for thousands of years before Newton. Thousands of years before England, in fact.
@justinpaul9040
August 15, 2026 at 7:17 am
Time is a concept.
@justinpaul9040
August 15, 2026 at 9:58 am
Time doesnt flow so says the ones who say that they know more than the others when in all reality know absolutely nothing about time.
@RealNoUnboxing
August 15, 2026 at 10:09 am
GR is a religion more than science. It fails on the very large and very small scale. It’s a great mathematical model on the relevant and useful scale that it was developed on. The invocation of dark energy and dark matter to save the theory on large scale is what makes it ridiculous and makes it religion. The idea that dark energy is 68% and dark matter is 27% leaving 5% normal matter and energy and there is none of it where we are? Ridiculous… “But we can measure it!” Yeah, you can measure it based on the wrong theory that in no way explains it. Religion. Physics is still stuck in the dark ages.
@JennyBrisk8
August 15, 2026 at 10:25 am
Sorry, we did not invent DM and DE “to save” that theory. We also know GR is wrong, it’s close but wrong. You simply don’t understand current state Physics. DM and DE exist. They are placeholders for certain effects we observe in Nature, effects which GR does not account for. Kids like you are so clumsy as to go on insisting that DM means (by us) there exists a “matter” hiding over there we cannot see. No, it is a placeholder that stands for WHATEVER is there, matter or something else entirely (including a different understanding of Gravity) which explains THAT specific pull on that galaxy. That’s what DM means by us (us who invented the quick term). It is a reference to the (unexplained) effect. That’s what it means — not your cartoon “has to be an actual rock-like thing hiding there”. As for DE, that is also a placeholder, and operates the same way. It stands for WHATEVER is the reason, the prompt, for the separation to Increase between any given 2 neighboring galaxies (sufficiently separated, else separation contracts). Yes, that effect does exist. And your cartoon wishes and fantasies for it not to, does not change anything. Again, take a course so you don’t embarrass yourself with your over-confident tripping over your own feet.
@RealNoUnboxing
August 15, 2026 at 5:18 pm
@JennyBrisk8
And you’re not a scientist. It’s everywhere but here… Religion.
@RealNoUnboxing
August 15, 2026 at 5:25 pm
@JennyBrisk8
I find it strange that you admit GR is wrong but defend DM and DE when it’s a derivative of GR.
Not science.
@JennyBrisk8
August 15, 2026 at 5:51 pm
@RealNoUnboxing Smarten up. Take a course, then you won’t see strangeness everywhere as an illusion 😉
@Puertoricofilmclub
August 15, 2026 at 11:28 am
No you don’t. In fact you are mostly wrong in everything you said. Even worse about what you said about Newton.
@joe8188
August 15, 2026 at 11:36 am
I believe time is a human construct used to measure and explain change. Our perception of time is unique to us not the universe. If time is relative and a concept unique to us, does it really exist? We measure time using our technology that’s affected by motion. Is there a time change or is our technology affected which alters it’s measurements. I doubt our technology is a universal standard. More advanced beings may have moved beyond the concept of time. It wouldn’t be part of their existence.
@oldcowbb
August 15, 2026 at 12:35 pm
if we assume ergodicity (which we do for most derivation of statistical mechanics), then the big bang can simply be a lucky fluctuation. exactly like how there is a non-zero probability that all the air molecules in a room suddenly goes to the same corner of the room and diffuse back out
@TrondTillmanSynnes
August 15, 2026 at 2:48 pm
You can not understand time through QM.
You can not understand time through a non-eucledian system.
Time is synchronicity.
@BlendaBenza2020
August 15, 2026 at 3:21 pm
Its fascinating to see people say how the big bang was ordered when no one has ever witnessed explosions creating anything other than chaos and entropy. I think.being an atheist takes so much more faith than admitting that creation has a creator 😅.
@rockshow2080
August 15, 2026 at 5:15 pm
The best teacher in science of our times. Love his videos. Thank you
@Pepe29a
August 15, 2026 at 5:43 pm
The speed of light is about 300K m/s… in a vacuum. In other media, it can be slower. There have even been experiments in which researchers have managed to slow it down almost to a complete stop.
@JennyBrisk8
August 15, 2026 at 7:05 pm
No, that is the speed of a turtle. The speed of light is 300K km/s.
@kwestra5967
August 15, 2026 at 5:52 pm
we reconise order to disorder. Like ashes to dust. But before that it was more like dust to human beings and all. Looks more like disorder to order to me.
@stanleybarnes8756
August 15, 2026 at 6:02 pm
Interesting. A case for the existence of God?
@iurhviusdfavhi
August 15, 2026 at 6:52 pm
So it was just a perfect black hole alone and then it imploded and here we are
@cesarparra6025
August 15, 2026 at 7:32 pm
13:33 thanks for my second shower of the day
@PaulaRoederer
August 15, 2026 at 8:30 pm
Entropy could not be subject to the arrow of time, or there could be no galaxies or star systems, with order increasing in local areas, while entropy increases on the universal scale. I could be wrong, I’m definitely not smart enough to be a physicist, but these two occurrences (the creation of order in the form of galaxy, star, and star system formation in local areas, and the universe expanding and becoming more cold and empty in the larger scale) happening simultaneously seems contradictory.
@stevesangle
August 15, 2026 at 8:39 pm
This still does not tell me WHAT TIME ACTUALLY IS?
@snotchy2
August 15, 2026 at 8:53 pm
Or energy changes the structure of particles and this allows configurations to occur that seem like time and structure. So saying the big bang was structured or that time matters means nothing.
@TheoWerewolf
August 15, 2026 at 10:17 pm
Not time, clocks. Clocks run at different rates depending speed and acceleration. Clocks measure local time, they aren’t time.
That’s like calling a ruler (which also varies depending on speed and acceleration) “space”.
@JennyBrisk8
August 15, 2026 at 11:31 pm
Incorrect. Clocks dont measure time. There is nothing “time” over there (or around us) being measured — by a clock. Don’t insert something “time” into Nature, such that this thing “time” is getting measured. That’s the mistake. Simply, a clock measures how long it takes for an event (external to this clock) to arise. Eg, you play guitar song beside my Clock. I measure, with my clock, how many ticks of my clock it takes for you to reach a certain part of your song. What is measured, by my clock, is how many of THIS clock’s ticks correspond to your reaching that part of song. And this activity itself, of relating this clock’s events TO that guitar events = the activity “time keeping”. It is purely that relational activity. That APPROACH we have toward Nature, and our lives in general. In fact, we don’t NEED this thing here to be a “clock” in the sense that you think a “clock” is. It could be anything I use as a “clock”. It could be sand slowly falling through a funnel, changing how much sand remains UN fallen. So I can phrase it as “How much sand will fall before you reach that part of song?”. I don’t need a rotating clock thing (that is merely a convention we hang up on our walls). I could even use a man walking up a hill, slowly. So that he completes so and so fraction of the total length up the hill, before you reach that part of song. Anything relational like this, IS a clock. Just obviously we dont use men walking hills, or sand falling, because those are not very efficient. Eg, the man might change his speed further up, etc. Hence we have invented devices which are very uniform and efficient, and use THOSE as our clocks. But in Nature’s eyes, all of this stuff is a clock. In fact, so is your song. Eg, your song can be used to determine how many NOTES it takes for this clock to reach 5PM. This relational activity IS WHAT time is (time keeping). There is no other “time thing” out there. Hence no clock “measures time”. That is misleading. Now, as for time dilation, this is merely a name we’ve given to the (factual) circumstance, that “How many ticks are needed for you to reach that song part” can CHANGE of you accelerate while playing. Eg, it could be, although I have learned to expect you to be at that part of the song after 35 ticks by this clock (eg, we live off those 2 things being always in sync, always 35 lines up to your guitar part), it now happens in 95 ticks. Which is to say, my clock had effectively GAINED ticks somewhere somehow, or (another way to think), yours LOST ticks. There is no fact as to WHICH happened, but only the relation (being changed) is fact. Hence such notions “your clock is slower”. Another way this can happen is by me simply standing on your head as you stand on a planet. That TOO will cause your clock (your guitar progress) to end up behind with respect to my clock. And yes, we understand exactly why these effects MUST arise (Einstein had a good picture of it, but he didn’t completely deeply understand what MANDATES this effect to arise. What mandates it is the same thing that mandates all phenomenon at the quantum scale). But yes we DO understand why this lost sync MUST arise (and there are more ways it arises, not just this accel+gravity). We know not just that this lostsync DOES arise, but we know why it HAS TO arise. Eg, why it would be absurd if Nature maintained sync regardless of said motion (or said altitude). I agree with your care as far as talking about CLOCK instead of TIME, but then you brought back the same kind of error by saying “Clocks measure time”. No they don’t. Nothing “time” is there being measured. What is measured, is how many ticks of this clock corresponds to the occurrence of an event in question. What is measured is ticks. Not time, but simply these spatial events. How many of these movements of this clock-hand Correspond to that other event (part of song being reached). Just like a ruler. How many of these lines on this ruler correspond to the END of the object (starting the ruler at the opposite end of it). In both cases it’s a SPATIAL inquiry (not even a temporal one, really). Think of the clock that was the man walking gradually up a hill. You could (and would) draw lines on that hill, so that you know which line he is at. THAT is a ruler. It’s a spatial inquiry (not temporal). “How many lines does it take (this man on that hill) FOR this part of song to be reached?”. Time is basically this abstracted way of measuring distance. Spatial. It is an abstracted form of spatial inquiry. Think of that hill as a vertical ruler. And the guitar song part as being ‘aligned to’ NOT a specific line on an actual ruler in your hand, but to a specific line on that hill ruler, where the LINE is determined by which one (of the man being at) aligns to the guitar part. Just like a “real” ruler, which line of the ruler aligns to the edge of the mass being measured. So it’s all the same thing. It is a SPATIAL inquiry. It is a relational inquiry which uses SPACE (not time) as the framework through which the relation occurs. SPACE. Not time. Just, in the hill case (or clock case), we are DOING this spatial relational activity in an abstracted way. That WAY being what Time is. Time is that WAY of measuring spatial extent.
@DiWerner
August 15, 2026 at 10:40 pm
13:33
@ultimatesoup
August 16, 2026 at 12:00 am
He explains complicated concepts in a whay that children cand understand. That is the mark of a true master.
@arzelzon1137
August 16, 2026 at 12:48 pm
modern Richard Feynman as of now.
@anniejk1591
August 16, 2026 at 1:23 am
Everytime I heard about entropy, my brain automatically thinks about the movie Tenet and I still have a hard time try to understand it
@o-CouragetheCowardlyDog-o
August 16, 2026 at 1:28 am
There is no such thing as time. Einstein’s theory of relativity proves this. The mere fact that “time slows down” at high speeds means that there is no such thing as time. What there is, is your perception of things that are happening around you. You, what slows down. Your perception slows down. Not “time”!
Enough of this bogus! You’re just milking this topic and making money off of it. Find something else to talk about.
@JennyBrisk8
August 16, 2026 at 11:48 am
Incorrect. Time does not slow down at higher speeds. First of all, there is NO time thing that is slowing. Second of all, to say “higher speeds” is to make reference to an operation distance divided by time. And so you bring back the very thing you try to reject. There IS time, we physicists DO believe there is time, but it’s NOT what you think it is. Nothing “time” is slowing. Or passing by. Or flowing. or anything. Time is simply Time Keeping. And Time Keeping is an activity we human organisms engage in, such that we relate the events of one system to another such that we ‘match them up’ as co-occurring. Time exists AS that relational activity. Not exists as some “outside” thing to it. Your general sense of Greene is correct — that he he misleading his audience for the sake of POP sensational science (media). But he does not matter — he is a mediocre physicist and is not a spokesperson for what we really think. This is POP science. If you don’t like POP science, don’t watch it. Instead, come and take a course. No point getting upset at Entertainment.
@jiraiya2000
August 16, 2026 at 2:21 am
Time is the same everywhere , time is different in certain places , and maybe it doesnt exist at all in other places .
@myco2408
August 16, 2026 at 2:23 am
I’ve always been saying this for the last few days
@adamjudsoncollins
August 16, 2026 at 2:34 am
where is place and how many different timely places are taking place at the same time with different time experiences?
@DobrinWorld
August 16, 2026 at 5:25 am
I’m sad to write this, but breaking an egg is not a vegan act! Brian Greene, who identifies as vegan, can break other things that don’t require the enslavement, exploitation, violence, and killing of animals.
@NickRoman
August 16, 2026 at 8:16 am
Time is a clock. Not a metaphor. If you don’t have a clock–something with regular movements that you believe to be regular that you can check other movements against, then you have no way to gauge time and if there is no gauge, then the concept is meaningless. If you have an empty universe and then one unique thing happens once, what is there to say about it? How long did it take to happen? 1 second or 1 trillion years? Seconds are measured against a clock, even if that clock is our animal body’s metabolism. Years are revolutions of the Earth around the Sun. If you don’t have a body, or the Earth and the Sun, what is there to say? The existence and use of a clock is what establishes the existence of time. We’ve always had regularities that we could use to compare things and declare an amount of time, even if it’s just day and night.
@JennyBrisk8
August 16, 2026 at 11:37 am
Most of what you said is aligned to how we Physicists think of Time, but your very first sentence is not correct. Time is not a clock.
@arzelzon1137
August 16, 2026 at 12:45 pm
that is a surface level of understanding of time, but there is more beyond and deep to grasp to understand, in quantum level
@ksdnsdkumar1375
August 16, 2026 at 10:24 am
Discussing time without referencing Stephen Hawking’s A Brief History of Time is a waste of time.
@arzelzon1137
August 16, 2026 at 12:42 pm
what about retrocausality? that the future affects the past? also i do think that the fundamental philosophical narrative of the existence of time is the existence of observer’s consciousness or “consciousness” which is until now is still mystery of its emergence, there is also a theory that reality fundamental is all about information, that it has its string or chains of connnection that was constant, same concept of entropy
@MartianCRT
August 16, 2026 at 1:43 pm
Two events take place simultaneously at point A and point B but it takes time for light (which indicates the event to an observer) to travel between the points. Time is the same. Light is just slow.
@KennethGangte
August 16, 2026 at 1:54 pm
Just admit theres a Higer Power in control of the universe
@Vladhin
August 16, 2026 at 2:48 pm
Why did it had to be egg 😩
@zhonlino
August 16, 2026 at 3:48 pm
Your room is so messy!
no, I simply create high entropy.
@condealexandervonhasslerra5527
August 16, 2026 at 4:51 pm
5:18 if you move towards the laser it will also hit you faster, this is a bad example
@2011Matz
August 16, 2026 at 4:58 pm
Just because things happen in sequence, does not mean time actually exists the way physicists talk about it, like a quantity or a quality. It is a mental construct. Remember Einstein sand, “You can prove anything with mathematics.”
@dragosvoda3445
August 16, 2026 at 5:35 pm
time is an invention of people to understand their surrounding
@kratomlover69
August 16, 2026 at 5:48 pm
Very cool video, he explained all perfectly for me to understand and I love how he is very passionate about it
@jas50w21
August 16, 2026 at 6:00 pm
“Time is an illusion, lunch doubly so” – Hitchhikers Guide to the Galaxy.
@bitOfEspresso
August 16, 2026 at 6:58 pm
Time is only a counter in the simulation 😂
@jasoncarter4343
August 16, 2026 at 7:08 pm
Time is everything happening all at once, all at the same time, dragged linearly so we can perceive past, present, and future.
@kimsahl8555
August 16, 2026 at 7:25 pm
About time – past exists, future doesn’t exist.