Theoretical Physicist Brian Greene Explains Time in 5 Levels of Difficulty | WIRED

[@Attila_Beregi]

what i love about this is that it starts with mathematics with the kids but by the end it gradually turns into a philosophical discussion

[@neonblack211]

The problem with the internet and a lot of physics groups on the internet though is people seem to start as philiosophers and really don't even think twice about the logic and mathematics physics is built on... theres a reason why one comes before the other

[@angrymeowngi]

​@@neonblack211Yeah, I am more in favor of the mathematician's truth. In a way, this makes more sense considering that at the foundation of mathematics is logic. And really, philosophy also has its grounding in logic. And it is definitely a better guide for humanity not to skip mathematics and go directly to philosophy. Although yes, reality is that people don't even make use of logic before even going to philosophy. Mind you, this applies even to scientists and not just to regular people.

[@rsv298]

You have to first understand the mathematical model we have invented before you attempt to interpret its meaning.

[@freesk8]

The original Physicists were Philosophers. Aristotle. Democritus.

[@Nikkiflausch]

That's why I love cosmology so much. It's this beautiful intersection between physics and maths with philosophy and even theology, and it carries positive qualities of all of these fields.

[@TRex-fu7bt]

Love how he started with the child by asking how old they were. Just instantly relevant and on the child’s level.

[@B0nsai_444]

Just seems like a common introductory question for a kid but I also agree

[@justsomeguy8597]

@@Cvntslapper lil bro is so pressed calm down buddy

[@amooij]

I thought there was just one kid though. They were…?

[@TRex-fu7bt]

@@amooij I had forgotten whether the child was a boy or girl by the time I wrote the comment

[@rakshathapamagar2969]

They already prepared for it may be

[@kate_meara]

I’m constantly in awe of people like Massimo Porrati. Imagine being so intelligent you can communicate such high concept thoughts in your second language.

[@racooonito]

I had the same thought...

[@guaromiami]

And impeccably dressed in a double-breasted suit.

[@xendazzle7819]

I heard Massimo as a frequent guest on The Skeptics Guide to the Universe. He's great, thanks for reminding me.

[@caravicktitti97]

I was thinking the same thing! I can't understand nor explain these kinda of things in my language (that is his too), let alone in english 😮

[@СергейФедюков-н4ш]

Это эмир:"_(!) автономный Урод.. Baertyg k.. МУТАНТ.. ГЛАГОЛА.. ЗАГЛОЧЕНОГО ЯЗЫКА.. Тойсть... Ты помниш плохо.. Там жизнь Длица Пару секунд.. Потом, тибя бьют и пинают штоб ты Захлебнул яд'_этого мира.. Так ты паносиш мир.. Его темпом своего языка... Там Масса.. _-ее воруют.. И жрут скот потом.. Языком Шлют сибя В ад.

[@fernandamagalhaes867]

“How remarkable is it that we have this brief moment that allows us to think, feel, love, explore and illuminate. How wonderful is that.” Made me sob

[@cpryce6436]

Funny, it's a thought that plagues my episodes of bipolar depression. "Out, brief candle.."

[@sWooSH_wHooSH]

Bro this comment came up right at the moment kn the video.. this feels trippy af

[@lordhelmit1499]

No it didn't stfu

[@sushantsharma4854]

Well

[@johnsmith1474]

Emotions of tin.

[@LurkerPatrol5]

I'm a professional astronomer, have a bachelors in astrophysics and a masters in astronomy. He explained the derivation of the time difference between moving and stationary clocks better than any of my textbooks and professors have...

[@somerandomnon-importantper3219]

That exact derivation with the mirrors was shown to me in 11th grade, so I assumed that was the standard derivation

[@quandary23]

While I’ve seen the mirror derivation before, the way he explained it was much more succinct and engaging than my textbook.

[@veizour]

Good point!!

[@TavishHill]

Yeah in same boat with similar background. Greene is among the best in this area. His level of engagement with the kid was incredible too.

[@kevray]

I have a theoretical degree in physics

[@durpkied]

I was surprised how simple the conversation in the fifth level was. Super easy to follow.

[@hi12235]

At that point they r limited by humanity. How can we find truth in time while we r living inside of it

[@SoCloseToToast]

I felt like a kid watching this guy explain things. learned a lot in a short amount of "time" Well Done!

[@timbatimba]

Briane Greene is an incredible science educator!

[@hisokabeatbox9053]

We need D-Low to explain his inward bass in five levels of difficulty

[@15_subhajitghosh19]

ey our man

[@cid3384]

I don't think so Tim

[@frankdimeglio8216]

​@@timbatimba He's lying about physics.

[@asymptoticspatula]

"It might be a brief flicker on a single moat of dust floating in a cosmic eternity. But it's everything." Such a great way to put it.

[@Rajdev73]

Carl Sagan

[@virgilflowers9846]

⁠​⁠@@Rajdev73yes I think he was paraphrasing Sagan there. Carl had a special way with words, he is one of my favorite humans ever. The world misses him

[@HolyParsival]

I love how when he gets to the expert it becomes more of a conversation then a teaching

[@saimen1907]

It's interesting that he is not explaining any more but only asking questions. This kind of shows that on this level (or as a scientist in general) to be the expert means asking the right questions.

[@brendawilliams8062]

I looked his videos up

[@owenl3929]

So lucky to have had Dr. Greene as my professor, such a great lecturer and educator. I recently asked him a question about relativity, and his answer was so well articulated despite being almost instant. I’m really glad to see him featured in this series!

[@gabcaves-ts7cy]

that is like, the coolest thing ever. good luck in school owen!!!! you're doing great!!

[@petrapinter349]

Love this guy. Very lucky to have had Greene as your professor 👍🥲

[@vikingthedude]

Oh sure and Richard Feynman was your high school physics teacher

[@Aashishkebab]

​@@vikingthedudeyou know he's actually a professor, right?

[@brusselseastside3546]

@@Aashishkebab People on the internet think things never happen it’s insane

[@Ash-xx5zd]

Dr Greene's body doesnt change in regards to who hes talking. A good teaching to every layman --check the ego and speak wholefully and earnestly no matter the external factors or people or pressures or even moods. Really inspiring conversation!

[@dannymartial7997]

This series gives me hope because I’m always surprised by how advanced the kids are. I expected him to give a Blues Clues style explanation but that was actually pretty advance 😂

[@khairm]

This ability to communicate on a single topic at all these levels is like watching art

[@carolchen5511]

As a student in Brian Greene’s Origins and Meanings of the Universe at Columbia, every lecture was existentialist like that - I sobbed in his last lecture

[@twalk2008]

Sobbed? Why?

[@Hyperbolic_G]

What could he say to make you sob?

[@ohohohitzmagic4536]

She had grown quite fond of Prof. Greene and this was the final lecture hence the sobbing

[@Sundar...]

​@@ohohohitzmagic4536 😂

[@mthedu]

@@Hyperbolic_G He did just tell a nine year old, "No, you'd be alive and we'd all be dead!" I'm joking of course, but ya know.

[@kevinm8865]

If I had a teacher like him, I believe I would have enjoyed the sciences more and pursued it further.

[@Scotty-vs4lf]

its easier when its 1 on 1 like this. being engaging with an entire class is more difficult since not everyone is gonna be at exactly the same pace and u cant just focus on one person

[@kevinm8865]

@@Scotty-vs4lf I agree. Seeing how he can explain this AND the excitement/passion we see as he does it leads me to believe his entire classroom presence would be more uplifting and inspire more imterest. No guarantees though. He seems like that one teacher everyone would love and remember.

[@DarwinRodriguez-e6f]

Its not too late! :)

[@rajabhattacharjee6982]

Absolutely Same here

[@kenscarpa2318]

Could they add a fetus level of explanation for me?

[@dennisgalvin2521]

Funniest comment yet, thanks for that.

[@GalacticGamerYT]

Yes Ken. Time is basically when you ate a cookie and now cookie is gone. You went forward in time eating cookie. We can not go back. Your cookie is gone.

[@nathanialhumphrey7137]

“Goo goo gaaa gaaa T I M E” -Brian Greene

[@samcr7minz73]

😂😂

[@ilirianbardhi7901]

😂

[@emeraldaly7646]

I was *totally* lost in the "teenager" explanation but bits and pieces with the adults made total sense to me

[@tonymorris4335]

@theeverlastingspiral This is literally as dumbed down as you can make time lol. Go read or study anything else on the topic and it will not even sound like English. Brian Greene by far brings this down to the most layman level you can get it to.

[@LouisKing995]

@@tonymorris4335I disagree. In terms of the pure information it was about a simple as you can get but he could have done much better about grading his language. Substituting certain verbose phrases for simpler ones etc. it’s something a scientist wouldn’t be very familiar with, but a language teacher would be. He wouldn’t need to “dumb down” any further when communicating with the first child, but simply making some vocabulary substitutions would have gone a long way, and I’m not even referring purely to the scientific terms.

[@AlexisgMorris]

There's zero chance that the teenager was able to follow along with the mathematical derivation. I don't think that it was appropriate, and was a bit disappointed that he didn't seem to realize how lost the teenager was.

[@blank6179]

​@@theeverlastingspiral9617he just started nerding out during that part, its something that happens when you try to explain something new(which you are fascinated about) to someone

[@360.Tapestry]

@@tonymorris4335 "the most layman level you can get it to"??? i don't think so. i don't have a background in this at all, but i can already easily tell that if i transcribed his explanation step by step, i'd be able to interpret and translate it in a much more digestible way (because that's what i would do in order to make sure i understood it for myself). not only was he hitting her with a lot all at once (jargon and concepts), but he wasn't communicating it in a way that a teenager would be able to grasp... aka "dumb down"... but it would actually smarten others up, not just show how far apart they are. his interaction with the kid had my alert up, but him running through the teen just made it hard to watch. it was more of a recitation than a conversation

[@rat.friend]

23:14 when the grad student said “it’s everything” I just started crying

[@tullytubbies314]

I love how both the experts have crazy socks on 😂

[@mocalida]

😂 that’s what I noticed as well 😅

[@cincinnatibrutality0201]

Einstein socks 😂

[@prongs4137]

Or... Awesome socks?

[@tullytubbies314]

@@prongs4137 I only called them crazy socks because in primary school we used to have a day called crazy sock day and we’d wear socks like those. So now whenever I see someone wearing them I think of crazy sock day 😅

[@citriosis]

The sign of a true physicist (probably)

[@seattlegolfer]

Brian Greene can explain the most sophisticated and complicated theories into the most basic simple terms, and that makes him the greatest gift to all fans of physics.

[@محمدبنقفوف-ص8ف]

No this person is diseptive?

[@robertolukas3minutos]

Just not in this video

[@phoby4584]

The majority of the public have 9 year old thinking on physics

[@anderandersson5229]

Great episode! 😊

[@terrylloyd9824]

He explains it exactly the same way as all the other media scientists because it's propaganda to sensationalize science to get people interested.

[@HearthHeathen]

Anyone else find this to be so calming? This was joyful to listen to really.

[@imrshn]

0:27 Child [Level 1: Kayla Martini] 4:05 Teen [Level 2: Maria Guseva] 10:09 College Student [Level 3: Zain Kamal] 16:16 Grad Student [Level 4: Alexander Novara] 23:56 Expert [Level 5: Massimo Porrati, PhD]

[@allenlee2149]

Time stamps are relative

[@chrisdali22]

You the man 😂

[@jimmydelosreyes1223]

​@@allenlee2149 vavaw,😂

[@masternobody1896]

bro time is just an invitible creature that moves. - islam

[@aucklandnewzealand2023]

Frame of reference, you used it wrong for Navara

[@Hahahahaaahaahaa]

I read The Elegant Universe as a kid. Watching Prof. Greene walk through this was nostalgia and pure adult nerd joy all in a short half-hour. Really appreciate his love and dedication to our existence.

[@TheSalaho1]

I'm impressed that you've read it as kid, it requires a really advanced level of mathematics and astrophysics!

[@mikemondano3624]

It was published in 1999. Your kidhood was yesterday.

[@elenazumika3752]

@@mikemondano3624 what does this even mean lol

[@russell_szabados]

You most likely read The Elegant Universe as a kid in the same way I read Gödel, Escher and Bach as a kid. You looked at the cool illustrations, read the first few paragraphs of a given chapter, said "huh?", then watched TV.

[@elenazumika3752]

@@russell_szabados What? I read several of greenes books through. been obsessed the universe and string theory etc since I was a kid lol not sure what u mean. ur experience is def not everyone’s some people actually enjoy reading and learning

[@Matt-wx9xd]

This is so sweet. Brian is such a brilliant observer in omniology. Very good at presenting difficult ideas. Not to mention very patient with his given audience. A very blessed human being. Mad respect.

[@Misteribel]

That nine yo girl is sooooo smart for her age!! Love her enthusiasm. Most adults won’t even get what the prof was telling her! ❤

[@ambition112]

0:48: 🕰 Time is a fundamental quality of the physical universe, and understanding it helps us understand reality. 4:27: ⏰ The concept of time is manmade, but it is still relevant in understanding the universe and its changes. 9:24: 🕒 The laws of physics do not distinguish between forward and backward in time, but our subjective experience does. 14:23: 🌌 The ultimate source of order is believed to be the Big Bang itself, and time behaves differently with speed and gravity. 18:38: 🔍 The laws of physics may prevent free will and time travel to the past, but there may be a preferred frame of reference in the universe. 24:30: 🕰 Time is a parameter measured by clocks that allows us to talk about change and causality. 28:08: 🕰 Time is a complex concept that exists as a continuum and is treated on an equal basis with space. Recap by Tammy AI

[@AS-fo3ew]

But "Preferred frame of reference" was still not a direct answer to the actual question the student asked and special relativity still remains a mystery especially if we keep thinking in terms of paradoxes and not taking into account the actual gravitational effects in context of the example the student asked. However, I still give benefit of doubt to the physicist because I know he would not have desired to bring much Mathematics into the scene preemptively. Sometimes, Physics is just not enough.

[@douglaswilkinson5700]

I've heard it called "the interwoven fabric of spacetime" and that everything moves through spacetime at the same velocity (a vector.)

[@adamwarlock1]

I like that the expert's "thing measured by clocks" explanation harken's back to the high schooler's question about time being manmade.

[@mamavswild]

4:27 Brian Greene corrected her…time is not a human concept but is connected to causality. They can NOT be separated and this is what he told her.

[@Lifes2short2hurry]

High quality video in general, but especially I notice it's beautifully lit and edited. Much sensitivity. Well done, gaffer/camera dept and editor.

[@jesperaung8592]

This dude is the teacher we all wish we had at each level.

[@fpeter01]

I always loved my psyhics teachers. They were the coolest people at the school/university.

[@TheBnzr]

Dr Greene is a great example of a scientist who also knows and understands how people learn science

[@daltonpoole0908]

the way he elevates the conversation through each person is brilliant my favorite living physicist and i hope i’ll meet him one day

[@kathyfrejoles775]

I'm a physics graduate. And the way we derive those formula that lead to the E=mc^2 took us a a whole 50 leaves ordinary notebook to completely finish it, well including the graphs and the like. It's just amazing that he simply illustrate it in a way that even ordinary viewers.can understand.

[@Bollibompa]

But, the Lorentz factor does not lead to E = mc^2? Assumptions about properties of photons do...

[@iPlayDotaReligiously]

​@@Bollibompaexactly

[@w花b]

Leaves? Like...Sheets of paper?

[@autohogar1016]

¿If time is the product of change, then is'nt it logical that time's positive arrow points forward in the direction of creation of change? ¿But is'nt change the product of positive time arrow movement? So a question arises ¿Can change exist in an anticlockwise negative time arrow direction? ¿Can change happens in an antichange state?...said differently can there be an antichange movement in the negative time arrow direction to cause a positive arrow change?

[@autohogar1016]

¿What is time? ¿What is cause? ¿Can cause exist without effect? ¿Can distance exist without space? ¿Can space exist without distance? ¿If time is the product of change, then can change exist without time? ¿Does time exist if conscience of its existente does not exist?

[@bdev1444]

I like how he explains to the nine year old: if you travel in a spaceship around the world and come back, everyone else will be dead. His intense look almost make it looks like a death threat.

[@kittiecandy747]

"I'd probably be dead" "Haha no, you'll be alive! Not everyone else." " 😧 "

[@barberhvac3438]

Brian is one of the best science educators out there. I remember watching a pbs special on string theory as a kid in the early nineties. I Had no way to really understand what he was talking about but he explained things with such wonder and zeal that it fostered my curiosity so much that I’m still watching his videos today. I’m no physicist and have only a high school level physics education, but to this day…I devour as much science content as I can. We were on the couch the other day, I had my iPad and my wife was watching something on TV. She leaned over and said…”No one cares about quantum tunneling but you, please go in the other room and watch that stuff” LOL. Appreciate Brian for sparking my interest all those years ago.

[@w花b]

High school math can take you quite far tbh. Even further depending on the country or the curriculum.

[@angrymeowngi]

The grad student could play Einstein in his younger years.

[@dewakbarr]

bruh i thought it just me to think of that

[@NM-zb6pd]

Came for this exact comment..

[@jbarnes4521]

or Ron Jeremy in his younger years

[@mil3761]

So true 😂

[@gregoryarutyunyan5361]

I came here to see if anyone else noticed it)))

[@ibnumachmud]

My professor told that those who have higher proficiency and comprehension in one thing, will likely simplify the explanation more easily. That's why I love this content. I can even understand physics even if I am a linguist.

[@pettiarchibald]

Any discussion that ends with calling upon the wisdom of Vonnegut is a great one.

[@mrtienphysics666]

omg, it is such a privilege to be taught theoretical physics by Dr Greeene

[@Mauricioantoniofranc]

These physicists sure have a great sense of style

[@cboers18]

The experts are like, "OK, I'll let you stylists dress me, but I'm going to pick the socks."

[@MariaTeodoraLonosa]

The higher the level, the more meaningful their conversations are (more philosophical/theoretical than experimental). After learning all the technicalities of our physical world, it is essential to understand the relevance of this knowledge. This is likewise to the purpose of higher learning... to find meaning.

[@SeppyDawg]

Wow I'm a mechanical engineer and I always love learning more about time dilation. His explanation of Einstein's equation was AMAZING

[@aliensarerealttsa6198]

It doesn't matter if something is moving or not. Only gravity matters. Although the Hafele and Keating experiment did confirm the gravitational time dilation effect on clocks predicted by Einstein, the velocity time dilation predictions of special relativity (1905) at low velocities would seem to have been proven wrong, since the Sagnac term was not accounted for. Time doesn't exist. It's an illusion. ScientificAmerican - Is the passage of time an illusion? PBS Space Time - What if space and time are not real?

[@pahandulanga1039]

Hi, I'm looking into studying mechanical engineering in a couple of years, do you by any chance learn the a lot of the advanced physics concepts in quantum and astro physics?

[@SeppyDawg]

@@pahandulanga1039 hi, no not all. If you want to learn those physics engineering is your only option

[@Engineeringuncovered]

@@pahandulanga1039no. You usually only learn up to special relativity and the very basics of quantum mechanics

[@pahandulanga1039]

@@Engineeringuncovered Thank you so much for the reply, I'm keen on learning anything I can about it. I assume special relativity is taught for the purpose of time synchronization while engineering anything that travels at high speeds? And what applications could engineers have for quantum mechanics?

[@wytemagic08]

Brian Green has always been so underrated. Everything he does is incredibly informative.

[@Nigelrudyardmusic]

Brian is so passionate about his subject, and communicates so well -- at all levels. I love reading his books for the same reason -- he's such a great writer as well as a great scientist.

[@jopo7996]

When he was doing the calculation with the second student, I was practicing my knowing thoughtful nod I like to do, when I don't understand anything a person is saying.

[@gaiagreen2690]

I really like you ❤ In time AND space!

[@lumen1715]

If you are in high school than that should concern you but if you are not in high school than its ok

[@tradingelk6914]

@@lumen1715 Good thing I graduated high school like 15 years ago!

[@thebuscio349]

​@@FirePandoraResident yes, he made a mistake and calculated the ratio Tm/Ts instead of Ts/Tm. So the conclusion of time dilation is right. By the way, the problem is symmetric meaning that if you were to tackle this problem in the reference of the moving system you would get the result that time for the stationary observer (who is now moving for you) is dilated. Just to add weirdness to this phenomenon.

[@griffinford528]

I think its crazy that the expert Mr. Greene spoke to had to learn all of these ideas and information in his native language and also how to explain and express these ideas in almost flawless English.

[@dreamdiction]

23:56 Level 5 expert, YES.

[@LuckyRowlands]

The last scientist (Massimo Porrati) is italian like me but strangely, despite being passionate about these topics, I had never heard of him.

[@Nautilus1972]

Most people on the planet are Bilingual ….

[@jlack1985]

Well, he is a genius.

[@tonymorris4335]

@@Nautilus1972 Conversationally yes, but most aren't bilingual to a point of discussing complex theories of time lol.

[@JamieKitchens6]

I'm starting to regret those edibles.

[@marjanfatima5154]

I've just started learning Astrophysics and watched some of his lectures on different topics and I must say that no words would ever be enough to describe how elegantly and greatly he explains science! I fell in love with Astrophysics because of him and a couple of other great people like Neil degrasse Tyson, Michio kaku & Bill Nye!

[@marjanfatima5154]

​@@RustyDodd Thank you for your suggestion! I'll definitely check it out

[@bignamek]

Coincidentally, Brian Greens book is called "the Elegant Universe."

[@mastershooter64]

You should learn tensor calculus/differential geometry for GR and of course a bunch of electrodynamics because those two are used a lot in astrophysics

[@aishazafar7527]

He lost me after the 9 year old and I'm a college student:)

[@ezra9521]

what are you studying in college? :P

[@michaelz5633]

@@ezra9521 gender studies

[@_Saracen_]

yeah i got as far as the sign(?) of theta, then I zoned out until the math ended.

[@aishazafar7527]

​@@_Saracen_ ikrrr me too the whole general discussion part was understandable tho.

[@arseniix]

@Setanta it's sine, not sign, haha. It's just a function, i.e. it takes a number and spits a number out. It's originally defined for angles inside of right triangles as a ratio between opposite its sides. This is why it was used in the video. So sinθ is just a value for angle theta, but the thing is, we don't need really to know exactly angles or values here. Prof. used the equation of how sine and cosine are related to derive that time dilation factor

[@ChromaticPixels]

12:33 the phrase "and it's more likely for time to go forward than backward" popped into my head -- time going forward for us is identical to entropy tending to increase but it can always decrease sometimes so fractions of reversed time are constantly happening aaaaa i love the nature of reality

[@mamavswild]

That’s not how it works though- entropy only decreases when ENERGY is added and is targeted…in an enclosed system

[@adrianpochec5298]

It would be cool to see a philosopher explaining a concept episode!

[@sin9324]

I first saw Dr. Greene in JRE podcast. His way of explaining things that seems so complex is unmatched. I've been a fan of his interviews and podcasts ever since.

[@RandomPlayIist]

Why Mr. Greene went on that idiot's podcast I'll never know. Maybe he was trying to reach out to his moronic base.

[@abbieamavi]

I always think of the saying “the smartest people are teachers who can share their intelligence with all levels”. Something along those lines. I love these videos, especially the science/outer space ones.

[@heizoumain8132]

wired's finally feeding us with physics fr

[@VANTABL4CK]

frfr e deadass m straight legit c bussin squared fr no cap on god

[@heizoumain8132]

@@VANTABL4CK guys someone's having a stroke

[@natsbigworld]

​@@heizoumain8132 fr fr no cap havin a stroke 💯

[@YarondoPiano]

​@@VANTABL4CK you are a genius, the fact that you managed to put a E mc2 in sentence. big brain humor

[@stewartmoore5158]

I know we all get old, but Brian Greene is someone I wish could stay young forever. It's no exaggeration to say he's one of the best humans who have ever lived.

[@sophieb5440]

I SO wish he could have had a filmed discussion with Carl Sagan. What a beauty and brilliant conversation that could have been!

[@funnymomemts790]

One of my hero, I just love his flow and clarity. He literally lived the science festival. So calm and focussed.

[@Emma-eq8pm]

This makes me so excited! I’m a Sophomore in college just beginning my journey in science. I’ve chosen to do a major in physics and a minor in chemistry. The topic of time is so fascinating. I cannot wait until my job is to study all these fantastically interesting topics and questions. This guy is a legend and an inspiration!

[@ShailenKarur]

Good luck, it's fun stuff, and go for the unsolved mysteries in physics to challenge yourself, well worth it - there's a Wikipedia page on them, I believe

[@xants8512]

Loved the video, first of all. I didn't even finish high school, but according to the equations, time and distance are somehow measured together. What came to my attention is that if "time" is the basic unit of measure in general, than distance doesn't actually exist because "time" is the only measure. Without time, you can't calculate distance.....interesting IF and that's a big IF I'm on the right path

[@Iwanchek]

Absolutely brilliant! The emotions when explaining and how the “students” listen with “gimme me more” is incredible. I wish. I’ve had such Professor in my time. Professor Green is exceptional human being!

[@bradyblake6573]

I love Brian Greene. He is brilliant and is always keen to share his knowledge in such a clear and concise way. Thanks so much!! :)

[@enjoyinglifenatureandtrave9529]

im 29 yrs old so thanks for this video I know my level now in the first 5mins of the video

[@SmokerBuddy]

Brian Greene is one of those scientists who, like Sagan before him, do very well embracing the prosaic qualities of such weighted topics and I love it. That his peer Porrati mentioned Vonnegut just made the video even more wonderful.

[@amandinho03]

and of course, Proust as well ❤

[@VenturaPinkerton]

Right!? Greene, Parratti, & Vonnegut are all brilliant communicators of the complexities of Life. Hello, goodbye! 😂

[@Eztoez]

Brian is an amazing communicator and teacher. I loved this video. 30 minutes of nerdy joy.

[@emmapasqule2432]

free bj for you Rico when you are next in town.

[@tahir-music]

I never had a good childhood in mathematics subject experience because of a very aggressive and abusive teacher but listening to the conversation here made me feel like I wish someone like Brian I had met in childhood. These kids are lucky to have had such an experience at this age; the future is wonderful for them and for humanity.

[@inannamystyrica3762]

This makes me think about the difference between the empirical measurement of time and the subjective measurement of time. When my children were young they would often get injured as young children do - by falling, tripping, all those simple things that children do. It wasn't uncommon for these incidents to happen in a room where both my husband and myself were with them, and often they were closer to my husband than me. When these accidents- incidents happened and the children would fall and cry, if they were closer to my husband I would wait for him to offer consolation to them. And so often, in my experience, he would let them sit there and cry and cry and not react. I would get so angry, until I would finally get up, walk across the room, and pick up one of our children and hold them and make sure that nothing was wrong. My husband would always say that I was overreacting, that he was about to help them. And, of course, I would think that he was making excuses for his inattention to these upset little humans in our care. Until the day a friend of ours was at the house when one of these events happened. Once again, one of our children fell, and they were closer to my husband thannto myself in a room where the three adults were talking. And again I waited, and waited, for my partner to check on our child. And again, he ignored them continuing on on his train of thought until I finally got up, crossed the room, and picked up our son. At this point, our friend commented that she had never seen me move so fast. In her experience, our son had fallen and before he had really started to cry, I was there picking him up. Yet, in my experience, you've been crying for quite some time. So, apparently, this may have been what was happening all along? My experience of time when one of our children was in distress was faster (or would you say slower?) than the people around me. I had all the time in the world to wait, get frustrated, then cross the room, and pick up our child while the other adults in the room had enough time to experience the child beginning to cry and me arriving almost concurrently. Which, to me, shows the real-life experience of the subjective nature of time as an experiential phenomenon in our physical universe. If our brains' ability to twist the experience of time so subjectively on a personal level, how can we trust anything empirically? All our our interactions with so-called reality are indeed relative to our personal observations of that 'reality.' Hence, how parenting - for me - made the theory of relativity make sense on an gut level.

[@tyroneallen7857]

Time is the fabric of the universe. For example, the theory of everything is time. Time is everything and everything is time. For example, time equals energy and energy equals mass times the speed of light squared, no space. Space is human imagination based on science fiction. we experience time through our star the sun. What is your age? No star no growth. What are you breathing? No star no oxygen. No oxygen, no consciousness. Our star the sun is conscious and producing consciousness. Time is consciousness.

[@mmgs1148]

what you describe is not a time relativity in a meaning of physics. The time relativity has obviously to do with the gravity or the motion on the simple level. But what happens to you is simply your brain concentrating on a source of discomfort. All of us have to pee, sometimes we are in situations we cant do it right now. But your bladder is full so the brain makes you concentrate on the bladder (not peeing has negative consequences for health), it constantly reminds yoh about itself and slowers your perception of time because you are focused on the trigger that is uncomfortable and you body and brain are impatient and want you to relieve yourself. The same with crying children - its a trigger, its a noise and you obviously care for them so their cry is longer for you because you are focusing on it and it is unpleasant AND TIME MATTERS - its also the same when you are waiting for something and time goes slowly for you. But look, 5 minutes passed for you and 5 minutes passed for your husband. And time relativity means that PHYSICALLY in one place 25 years passed and in the other place 1 minute passed or tousands of years passed. When you stand on top of a high building your time passes slower than on the ground, this is true time relativity. What you describe is simply brain trying to make you focus on an unpleasant trigger to make you deal with it faster, but 5 minutes is still 5 minutes and in the high building example very specific clock would note a real time difference. On the other hand when you are highly focused on a pleasant experience, you stop caring about time and your brain gets specific neurotransmiters that make you participate more and care less and less about time passing by. So the opposite.

[@melindam4841]

I value any and all conversations on how understandable and non esoteric they are at conclusion. I have to say that initially I got lost a few times but when it came down to the final conversation I had more comprehension. THANK YOU. This was very illuminating and also comforting to me. I was very very ill in the hospital a couple of years ago and came to terms with one of the concepts you discussed of being amazed that I existed in this time and space and given the life I had been given, upon being told when I went into surgery that I may not come out of it alive , I felt at peace and just fine with it in my own right, although not so for any stress and sadness my family would feel. Ultimately, I experienced a speed up and slow down of time in that very moment. I had only moments before I would be taken into emergency surgery and infinitum to value all I had had, been and connected to. I guess that sounds very hocus pocus and unscientific at best, but listening to this discussion made me realize it probably had more to do with science than I realized.

[@tonymorris4335]

Being spiritual isn't unscientific as long as you have the perspective to recognize it as emotion and experience rather than an objective view of reality. As a disabled USAF EOD (bomb squad) veteran I can understand your perspective on thinking you're likely to die soon but then not doing so. It can be both easier and more difficult to reconnect to daily life after this as you don't take little things as seriously but you struggle to find big purpose as well. Hope you're doing well now.

[@melindam4841]

@@tonymorris4335 What a thoughtful answer. Thank you. I hope you are doing well too.

[@lukewarmchilipepper21.12]

he is such an amazing teacher, when someone is on the wrong path he does not condescend he kindly explains! love him!

[@HugoDurou_EHTech]

Every one of the people he explains to seems waaaaay more wise and competent than what I recall of myself and the other students in my university 😮

[@xbabu142x]

That's the beauty of a phenomenal educator.

[@6classer]

I read The Elegant Universe shortly after it was published being interested in the subject way back then and had no knowledge of who Dr. Greene was. Since then I have sought out and enjoyed what he presents in all manner of media (TV, internet, books, etc) and this is another amazing example !

[@98f5]

I've been watching Brian most of his career and hes still one of my favorite science educators. Its a bit sad to see him getting older yet so am i. 😮

[@kellykillorin6230]

This guys explanation with the math proofing to the high schooler was so phenomenal. I live for this stuff!! To see it proven right in front of me to actually understand how it works is mind blowing and I wish there were more vids out there with that element

[@olivermathiasen3594]

There is everywhere u just need to learn where to look.

[@mcwho3]

I think Brian overestimates what highschoolers have learned.

[@danielvermeer3363]

Seems like he is catching on to her dialect and running with it. He might have not known how much she knows, but he seemed to understand quite quickly at what level she would answer the questions

[@FamilyKeepsakesVideo]

These videos are a fountain of humility and amazement. I am often tripped up with the teenager level (as I was here) but handle the others fine.

[@AneOnyme_]

I love this format so much! Great to learn things and at the same time how to explain them clearly and simply, which is often as difficult. Thanks!

[@userhFDR7PBw]

What smart kids though! I pulled it off but it was a challenge to really follow even at level 2 -that's how rusty the brain gets as you get older. Very endearing to see Mr Greene actively trying to understand someone else in the end, for a change. Wonderful video, than you!

[@Allahu_Akbar_the_one]

To be fair, no high schooler would’ve known how to manipulate identities like that. Most high schoolers would have a slight inkling about what’s going on,however, what he explained to high schooler is something called “relativity in 1-Dimension”-a topic that’s explored in college Physics 1 (Calculus required)

[@starfishsystems]

​@@Allahu_Akbar_the_one Based on my own experience, I'm obliged to disagree. When we studied trigonometric identities in Grade 12, we had already been exposed to basic trigonometry and algebra for two previous years. By then we'd also had complex numbers, polynomials, power series, limits and derivatives, but had not reached integrals. We'd had some basic exposure to derivations and proofs as well as introductory set theory and number theory, rational and irrational numbers, countable and uncountable infinity. This was all by the age of 17 at a perfectly ordinary Canadian high school. In particular, I recall deriving the various trig identities such as sin^2x cos^2x = 1 and visualizing them on the unit circle, so that equation was easily recognizable in the video today, some fifty years later. The rest of what we saw in the video was simple algebraic substitution, something that we routinely did throughout the last couple of years of high school. It all seemed completely straightforward and, I must say, also very satisfying. This, I gather, is the Lorentz transformation, or anyway part of it concerning the time dimension? I'd heard of it before, but never tried to make sense of it.

[@BartMesser-n1c]

I agree Dr Greene is an incredible teacher. I wish I had him when I was majoring in physics.

[@socaliguy81]

Kayla is adorably inquisitive. She reminds me of my daughter a little bit. PS I love when Doctor Brian is a guest on Star Talk!

[@rocketRobScott]

I learned something at the first level … how to visualize the speed of light in relatable terms. Specifically, visualizing going around Earth 7 times in 1 second. It’s crazy fast, but it’s understandably fast.

[@CommackMark]

Whats important to point out to people unfamiliar with this topic is that the perception of time passage never varies for an observer. If you travel near the speed of light while a second observer remains stationary relative to you...there will be time dilation ... time will pass more slowly and hence you will travel into the future of the second observer. But for you time on your wrist watch....on your speceship....always passes normally. Five seconds always feels like 5 seconds with a few heart beats. Its only in relative comparison does the rate of time reveal itself to have changed.

[@frogandspanner]

This demonstrates what I have known for a long time: kids are much, much brighter than we think, and it is parents who hammer the wit out of the best. I was lucky to have a dad who knew how to stretch rather than pummel.

[@gabrielgonzalez1993]

I love Brian Greene with an absolute passion. I know him as the brilliant science educator who has made immeasurable contributions to the accessibility of physics by people of all ages and walks of life. I imagine he has many hats; a colleague, a harsh grader, an awesome professor, and of course a father and husband to a lucky few.

[@SpencerTwiddy]

Nearly perfect comment! Just swap that semicolon for a colon and it’s a 100/100.

[@gabrielgonzalez1993]

@@SpencerTwiddy i wasn’t brave enough to use a colon :< … ironic isn’t it ;}

[@triplec8375]

I highly recommend Greene's "The Fabric of the Cosmos". His writing is very engaging and he has a tremendous amount of knowledge. Unless you already have a PhD in this area, you will learn surprising and interesting facts, particularly about entropy and it's role in delineating time. and controlling the "arrow of time". But, in the end, (spoiler) you will see that neither Greene nor anyone else completely understands time. While we can use math to describe time and model time and space, we don't really know what it is. For me, it was disappointing that, in trying to tie it all together, he resorted to speculation about what happened before the Big Bang. That implies that space with its quantum characteristics, existed before the Big Bang and it would, therefore, be infinite. We don't know that and we don't have any evidence of that.

[@Bollibompa]

Why was it disappointing? The philosophy of intriguing ideas is important. How else will we ever think about or do anything different? You can't ever come anywhere in physics without first guessing, assuming and discussing.

[@triplec8375]

@@Bollibompa I have no problem at all with philosophical discourse or scientific speculation as long as it's presented as such and not as fact. I really did enjoy "The Fabric of the Cosmos". It was very interesting and thought provoking and I certainly learned a lot about entropy. But I found his ending speculative without admitting it. His solution hinged on there being something in existence before the Big Bang without anything substantive to back it up. One might as well speculate on a cyclical universe since that also requires something to exist before the Big Bang.

[@douglaswilkinson5700]

A bit more is known about time. It is interwoven with space giving the construct of *spacetime.* Also, everything moves through spacetime at the same velocity (a vector.)

[@andywalker8064]

Brian Greene is so cool. He's a brilliant physicist, of course, but a born teacher and communicator first and foremost. What a gifted human, and what a gift to the rest of us! Thanks , Brian!

[@Sohlarys]

Brian Greene, YOU made my high school science so easy , my teacher were confused as to why i was getting 100% everywhere and asking about Quantum Mecanic all credit goes to you and some fellow famous awesome super cool scientist ! :D much love 😁😁

[@shapowlow]

this video pushed me to the valley of despair after 6:00. taught me the difference between an interested layman, a real hobbyist, a serious student of the subject and a real expert.

[@kenversusryu]

I love Brian greene. He seems like such a humble guy. I can hear him talk for hours. Him and Janna Levin are amazing communicators of science with zero ego.

[@ChrisHovord]

Love this episode 😊 I could have listened to Massimo Porrati and Brian Greene talk all day about physics 😅

[@yehezkielpurba4149]

fr bruh thats the zizek of physics (aint belittle nobody, both are the GOATs)

[@professorchoy1009]

I am amazed by how well he did this, wow. Can I keep this video forever, KZbin, never delete this one.

[@Eris_Strife]

I know I would never be intelligent enough to be able to the one to prove or disprove these theories, but I am in terms of understanding the scope of them. It humbles me.

[@danieljakubik3428]

The children chosen are obviously above average students in science. As we progress to older students and established physicists, the discussion becomes more advanced and more fascinating.

[@HVBRSoF]

I think the child and teen levels of explanation were still one level above more difficult for average people and that if he tried to explain the concept to average people, he would need to dumb down the explanations more, especially to the level of a child. I think he started off brilliantly with asking how old the child was but then made the explanation more difficult by trying to explain time through the concept of space. the easier way to explain concepts to a child is through questioning. you just ask them leading questions and let them figure out the answer on their own. think for example a line of questioning that went like this: how old are you? so that means for you, x years have passed. what does that mean in terms of how we measure time? how do we measure a year? a month? a day? an hour? a minute? a second? if i asked you how much time have passed since you were born, could you tell me with accuracy that amount of time without using any unit of time? if you are walking, does time stop? if you still still, does time stop? what then, is time for you? how would you define time then based on what we have talked about?

[@Valuepak]

Well that's tye easiest way to explain it, time and space are inextricably linked. You cannot explain time without space, and vice versa. (At least in physics, which is what this video is going for.)

[@jordansiddock5152]

I thoroughly enjoy watching his videos and hearing his lectures. He explains things very well and is easy to follow!

[@Valuepak]

As a teen the explanation he gave to the teen was really interesting, and I learned a lot!

[@o2centre697]

I understood the graduate student conversation way better than the 16 year old conversation

[@unprofound]

My experience as well. 😅 I don't know if this is because of editing, or pace of the conversation. But a pretty involved concept is thrown at us pretty rapidly.

[@FirstOdin420]

I love how Dr. Greene can make science understandable for, literally, anyone. I was fortunate enough to see him in person and it was an amazing......time 😁.

[@szxnv]

wow. as a science student i get tons of nostalgia watching videos like this

[@angrymeowngi]

Lucky for you! Science and Math for me was introduced in a rather boring rote memorization subjects. I hope the new generations get an even more exciting introduction.

[@mxolisngiba807]

They would not correlate with yours

[@MosBaked]

Briane Greene is such a fantastic communicator, loved this episode

[@itsenergybob8917]

The way he described the idea with the billiard ball reminded me of how we can travel in time but we cannot have a physical manifestation within the time that is travelled to. It is only our consciousnesses that can travel in time.

[@chasescanlon6488]

Brian greene can put anything into words for the average person. Wonderful video

[@stdew07]

I envy the kids who got to meet Brian Greene. An inspiration

[@bradlevantis913]

OMG that high school explanation just blew my mind.

[@WARofROSES]

@22:55 That answer brought a tear to my eye. Beautiful 😭❤️

[@antonsil5719]

As a guy that never cries this sent a wave of emotions trough me. Glad to see I wasn't the only one

[@johnchessant3012]

He covers that same light clock derivation in his book The Elegant Universe! Blew my mind when I first read it. The key point which he glossed over kind of quickly here is the principle of relativity: there is no experiment you could possibly do to determine whether you're in the "moving" frame or the "stationary" frame. So this derivation isn't just some quirk of this weird light clock thing, the same time dilation factor must apply to our entire perception of time, because how our perception of time syncs with the light clock must be the same in both frames.