to be honest i heard i think everything he ever did. but when im on where im at i actualy test my self. i only pass my self with a 90% or better. then i pass me and move on. i wish school was like this. not just "oh you failed? to bad make it up on the next part you be shamed by your peers next year :'(
When I lost my mom. It was the hardest thing I'd ever experienced. And that was after losing my dad at the age of 8 yrs. And losing a brother to suicide.... but after the pain subsided, "it took awhile" I felt her every day, In the things I did. I and the way I went on to live my life.. the lessons she taught me as I grew up... and so I think she will live on for as long as I'm alive.and I never really lost her after all.
Very sorry to hear about your loss, cruel world. Just discovered this channel in recent months and it has been a wonderful resource that has helped me through these troubling times. Stay safe and thank you.
Sorry for your loss professor. Thankyou always for your effort for sharing your knowledge with us. We misses you professor glad your finally back. Watching your daily equation becomes part of my daily routine that's why so happy that your back ❤😍
We love you Brian! I'm so sorry about your mother. You're work is so important to so many. These videos play such a large role in quelling my overwhelming anxiety regarding what's going on these days. You are so deeply appreciated. Thank you 💓
Yeah , it really does make a difference I also listen to calm my mind and to control the negative thoughts , Brian always has a diplomatic view even abt the things he doesn’t fully believe in, always open minded... Never really radical..Love that about him...
You are still a good person and lecturer. I did not agree with you before and I still do not agree on most fundamental issues, but you deserve recognition. You are spreading your current knowledge and people are watching you because of your good presentation.
Professor, we would be happy to get our daily equation back. For me it was an important part of my life not because of what it teaches but because of the teacher who teachers.
Oh gosh Professor Greene i am very late in the day, only just found this video, but, i'd like to send my deepest sympathies for the loss of your dear mum, or mom even, so sorry for your loss, sending much love 😌❤🩹🙏 and also thank you so much for sharing you TIME 👌pun intended 🤭with us xx😎💙🖤🌍🌌🌠🪐☄🕰🚀🛰
Ots 2023 and such content I could watch hours and hours. Me Green is such a pleasure to listen/watch, it’s unbelievable what energy this man have. Me Green, much respect for brining science in that manner, Full of enthusiasm and passion; it’s unmatched. Greetings from Germany 🇩🇪
Dr. Greene, big fan here and I've watched every single episode of 'Your Daily Equation'....you did mention about your mother in one of the live sessions and the abrupt suspension of the series made me feel that you had to leave everything else aside and attend to her....as for now, I'm extremely disappointed at the passing of your mom and I hope you and your family have the strength to get through this irreplaceable loss. My heartfelt condolences are with you and your family. While the concept of heaven, hell, the human soul may all be a matter of conjecture for us, I certainly hope your mother is in a better place now, wherever that is in the Universe or beyond. Personally, I would love to see you continue the series, your insights into the intricate details, and just the feeling of one-to-one interaction is something that makes this series enjoyable.
Sorry to hear about your mom, Brian. We lost our mom last October and understand the feelings you must be going through. Keep up the good work as a legacy to the loved ones who aren't with us anymore.
Hey Mr Greene, I am in London England, I am half way through my Bachelors of Science, in Music Technology & Sound, having studied law before this, you are my fall asleep intelligence, and I love the delivery of your master classes, thank you so much for adding to my wealth of knowledge!!! Becks UK
I'm sorry to hear about your Mother, best wishes to you and your family. I love listening to your lectures and Q&A. you have made it possible for me to grasp many things that I had struggled with until your explanations, thank you so much Brian..
Dear professor, please accept our condolences for your loss. Thanks a million for coming back to help us learn new things from you. This is so valuable.🌹
This man is a Saint! His enthusiasm for science and wonder knows no bounds...to grace us with his presence after such personal tragedy so Thank You much kind Sir. And I’m so sorry our society failed your mom with our careless handling of the pandemic 😞
Only love transcends beyond reason. Many of us are feeling your sadness at the loss of your mother. You were always her true love and she will always be with you. In your heartbeat, in the dawn of your smile, in the light of your gaze when you give away the world your magic. Brian, we love you from any part of the world, because you are part of our lives.
So sorry about your Mom. You are a wonderful person , she did a good job. Thank you for making sure people like me understand whats going on in the Cosmos. Rest in peace Mrs Greene.
So sorry to hear about your mother, our hearts go out to all of your family, and of course you. Stay Strong! and Thank you for your Great work, and these awesome opportunities for regular folks like us to get to ask things :) Unfortunately I'm usually working in one way or another when I get the notification lol
Brian that's excellent, time doesn't begin when you're born time begins when you are conceived, also vocabulary is what moves time. Thank you for your knowledge
I heard your news in late,, professor. I am very sorry about your loss.. it must be indifinable emotion.. Thank for teaching joyful science bringhtly.. Keep your health professor Greene! Thanks a lot^^!
I just wanted to say how important this series (and others) is. Usually scientists are like the proverbial people in the ivory tower. We "little people" read stuff and see them on TV, but are they "real"? Formats like this are so important to show that science is approachable, that you don't have to be some special person to get involved and be interested in it. I wish other branches of science would do more of this, like chemistry or biology. In my country there is almost no real scientist doing public work. So I am glad you Americans and Englishmen (and women) are out there explaining stuff. Our schools do very well to put people off science I fear. When I was younger, I was (still am) a big sci-fi fan and I wanted to know stuff. But what school had to offer was very limited and restricted. You need to know this and no more and this is how we do it. This was before the time of internet. So since then, the web (and TV formats) have been a godsent. This is what media is supposed to do, not the Kardashians or Big Brother season 2343.
Hi there! I first "met you" years ago when I bought one of your books through which I got introduced to String Theory. Over the years I've been listening to you every now and then but, lately, I've been focusing on the World of Science Festival sessions. Then "Daily Equation" happened but I've been struggling with finding the time to catch up. Finally, prompted by your curiosity about where/"when" we're following from, I thought I'd let you know how much I appreciate your effort answering all the really interesting questions. I'm watching from Portugal and, having learned about your loss, I'll leave a big hug. Please keep up with this awesome sessions if/when possible. Cheers!
I am sorry to hear abot your mom. My condolences. I love your videos and specially the way you explain Science, you make it easier to understand it. Regards from Spain. 🌸👍
May your mother rest in peace, there's probably a good chance she can see the wonder and curiosity you've helped permeate through the universe of human knowledge. She must be proud and she did a good job on this Earth.
Dr Greene, the revamped platform WSU is great. What you and dr Carroll are doing is historical. Politicians make promises, brag about themselves but usually they pursue their own interests and gains. You both are building democracy, and a better world, because culture and science are " a conditio sine qua non" to make the world a fairer, a better, a safer place. Many skilled people can't afford expensive experience of study. But you and dr Carroll really help, sharing for free your top-level knowledge in a systematic way. You both are great scientists and also great men. When I was a kid my family was a low income one, and scientific careers were expensive. So I had to change my plans. Sorry for your loss. From now on, as Saint Augustine wrote, your mum is no longer where she was, she is wherever you are.
I'm really sorry about your mom Brian. That really sucks. Thank you for coming back to keep teaching us about physics, a lot of us need the distraction these days
Hi Professor Greene, it's great to see you back again. Was very sorry to hear of your loss - I did send my condolences on your Facebook page. I have already registered with the re-vamped World Science U and am really looking forward to lots of interesting content, with some brilliant teachers. Since YDE stopped, us fans have just had the Sean Carroll videos to watch. They are also v good, but Dr. Carroll does like to torment his viewers with a lot of Maths. Best wishes from West Wales (UK).
Hi Paul figured i would find you in the comments, there was to much going on Friday so i could keep up. There's a moderator now and he blocked me, i have no clue why!? Didn't get a warning or explanation it just said the moderator has blocked u. It took the fun out of the chat completely for me. Wanted to let you know. Hope you're good and healthy maybe see you again this Friday. Wkr
I’m sorry for your loss Professor Greene. Thank you for your very informative videos. I remember in some older documentaries about time you mentioned that all time past future and present still exists and we just experience the “now” slice within that timeline. I hope one day we have the ability to slice anywhere within that timeline.
Im really sorry I missed this live. |Also very saddened to hear about your mom's passing and, particularly the circumstances of her passing. Condolences
At 7:51 I think you are wrong about the clock thing. It's not a clock in motion that moves slower it's a clock accelerating... Once steady velocity has been achieved (near instant in the example) time would indeed move at the same rate for both "clocks."
1:06:00, Regarding someone who seemed confused about the different types of gravitational "formats": As Dr. Greene said, Newtonian and Einsteinian gravity are described differently. So are the ideas of Galilean gravity. But the key concept being unseen here is that those three all deal with the macroscopic, give or take a few powers. As such, they are all three considered to be "Classical" gravity. This is a completely different animal from Quantum gravity, which deals with scales from molecules downward. This is, conveniently, referred to as quantum gravity, as compared to classical gravity. These are the two basic "groups", if you will. At least that's how I see it. I hope this helps, J
ad speed of light is constant: it is constant, but the constant varies in different space/time parts of the universe. It is observable from the Earth right now. It may be related to an average amount of mass/energy at that particular part. More mass somehow causes lower speed of light locally. It starts to be intuitive in this context. Thanks to Mr. Greene for speaking publicly this often. We love it!
Dear Professor I unsubscribed from all UA-cam channels exept NASA . I passionate about becoming an Engineer, therefore I subscribed only to NASA channel b'cos it motivates me for learning. "World Science Festival" channel is great indeed. I learned from it. Thank you. 🌻
Sorry for you and your family's loss. Also, thank you for your contributions to education and to the curiosity of the general public. I have many questions, and I know that you can only answer so many on this forum. Can you possibly recommend a ccosmology/ astrophysics website or group where I might find some answers on a regular basis? Much appreciated.
Fantastic Video! Thank You so much for all you do to help people like me blundering in the dark. 01:06:31 shows why you are on the screen and we're not. Utter respect.
Prof. Greene, assuming that the fabric of space time is quantized into Planck length dimensional space time "cells" ,can we assume that between them there is a new fifth non local grid like dimension connecting them together? can it explain the quantum non local entanglement phenomena ? Thanks for sharing with us your knowledge . Eran Sinbar,Israel
while im thinking about it... i can tell by intuition when my kids are not well and why. i also can see who and what it bothering them!!!!!!!! spread that word for their well being of peace of mind for me plz
Dear Professor Greene, It's great to see you back on UA-cam, Sir! I missed this great Q&A at the time, but hope you see this anyway and can squeeze in a response next time, please! Forgive my questioning the logic of the Light Clock : 1; The photon needs to be detected each time it reflects off a mirror to register a tick or tock-- a photon must 'reflect' or be absorbed for detection-- it can not do both. A variant by having a photon emitter and sensor pair replacing each mirror may solve this , as I see it, but complicates the concept of reflection unsatifactorily imo. Anyway, we can ignore this for a thought experiment and imagine a demon registers the ticks and tocks instead, allowing the photon to 'reflect' up and down uninterrupted, but the demon can't help with my second point even in a thought experiment : 2; Suppose the light clock is placed with mirrors horizontally as in the video. With the clock at rest, the photon must bounce precisely vertically up and down. If it were at any angle, then it would zig-zag horizontally and eventually miss one of the mirrors. Thus the photon is always repeating the same vertical path, up and down, say at x=0 when the clock is at rest ( ie. the horizontal mirrors are centred at x=0 ) . It follows that if the clock begins to translate, say to the right on the x-axis, then the photon will continue to repeat bouncing up and down on precisely this same path x=0 ( why would it reflect at an angle different to the precise vertical since the mirror is still horizontal, and isn't 'sticky' ). Thus the mirror translates away from vertical path x=0 of the photon and the photon will miss the mirrors once the clock has moved such that the mirror is no longer under / above the original vertical photon path at x=0, and the photon escapes to infinity at x=0. Why would the photon would deflect to x0 just because the mirrors move ? In my mind, it is easy to see this if you make a very tall light clock, say, 10 light-seconds in height, which is one meter wide. The clock is just a frame with mirrors top and bottom so it has no solid walls, allowing the photon to escape if it misses a mirror. Start the clock by emitting the source photon at ground level. Now gently accelarate the clock to a walking speed of, say, one meter per second. After a second or so, depending on how fast you accelerate the clock, the photon will no longer be heading toward the top mirror as the mirror is no longer above the point of emission, and escapes to infinity. You could do this in deep space if wanting to avoid interference of gravity ( not relevant imo ). Could this be tested today, using LISA, perhaps ?
I can't believe I'm right ( implications ), but I can't understand why I'm wrong ! I am not questioning spacetime GR or SR of course, only the specific thought experiment of the light clock. Please help ! Sincerely, your pal Tom ( Cornwall, UK )
Tom, I may have this completely wrong, but I think the answer is all to do with perspective. Imagine the "moving clock" is on a train. There are two people observing the clock, one in the same carriage as the clock and one on the platform. The person standing on the platform will see the light in the light clock move in the "zig zag" motion you describe, going up and down whilst also travelling horizontally. However, someone sat on the train, moving with the light clock, would look at the clock and see the light bouncing only up and down (not a zig zag pattern) because relative to him, the clock is not moving. Does that help?
@@samanthaperks9142 thank you so much. As I see it, a physical object, say a bouncing ball, would appear to bounce vertically to the onboard train observer and zig-zag for the outside platform observer. As I understand it, this is due to the momentum of the ball, ie inertia. Yet a photon is not an object and has no inertia; it will travel vertically only compared to the point of emission. Thanks for taking the time to reply!
One very basic question I want to ask. Why spacetime warp in order to keep light speed constant? What is the key source triggering the warping process? Is it just the mass of the object causing space time warp, if yes then how we can explain the phenomenon?
I love watching your visual explanations especially the one on time. Time slows when you watch the clock. It also slows watching your steak on the bbq but speeds up when you run to get a beer, proof is overdone steak🤣
I told my kids, no matter what else they study in college, that they should not consider themselves educated without understanding special relativity. At least that is what I felt in my college days. IMHO, this should be graduation requirement FOR EVERYONE. These days, you just gotta watch a youtube video. But you really don't understand how remarkable SR is unless you have struggled to work-out all of the nuances, twin paradox, Lorentz contraction, etc.
16:25, If we could add the velocity of the light to the velocity of wtvr emitted the light, then the light's inertia would have to increase. But inertia requires mass. Photons have no mass, therefore they can't change their inertia. So, it follows that the velocity of the light would necessarily remain unchanged. Or maybe not. Idk
Regarding the guy who asked what this has to do with age, I think I understand what he was trying to say. The person who has the clock slowing down doesn't experience any extension in years. They are inside a slower time bubble, so compared to the other person they are aging more slowly. It's relative.
We all need to grow our hair out again like it was the 70s, but on another note... at around 58:00 it is crazy how the world is just a projection of light coming in from every direction and since it is so fast it just makes sense... what a crazy system... before getting into physics you take so much of the real world for granted but never thought about the mechanics of stuff like light.
At 35:55 in the chapter "How do you know if an object is stationary". Theoretically, wouldn't it be possible to make an object completely stationary using the speed of light as a reference? For example, if I know that a photon is moving at the speed of light in this direction, then I subtract that speed in the opposite direction, and thus it would be completely stationary in the universe.
I'm so sorry to hear about your mother. My condolences to you and your family.
ps Brian. harry potter 2, i cant remember the name, wsa my faverate tho i love em all
@@Rockersoccerhockey He does not care about you. He will not respond to you. He is in his own world. Not yours.
This is a master class with Professor Greene coming back to grace our lives during the pandemic. Thank goodness!
U r right I accept it with u
@@localtitans4166 i been going thrugh them all in order, learning. i like him as a host on WSF my self tho
to be honest i heard i think everything he ever did. but when im on where im at i actualy test my self. i only pass my self with a 90% or better. then i pass me and move on. i wish school was like this. not just "oh you failed? to bad make it up on the next part you be shamed by your peers next year :'(
Ahahaha
Sorry about your mum , I lost mine about 5 years ago it gets easier but you never stop thinking about them❤️
Lost mine a year ago.. Sucks, but it's the way nature goes..
So right you are best to Dr Green
When I lost my mom. It was the hardest thing I'd ever experienced. And that was after losing my dad at the age of 8 yrs. And losing a brother to suicide.... but after the pain subsided, "it took awhile" I felt her every day, In the things I did. I and the way I went on to live my life.. the lessons she taught me as I grew up... and so I think she will live on for as long as I'm alive.and I never really lost her after all.
Very sorry to hear about your loss, cruel world. Just discovered this channel in recent months and it has been a wonderful resource that has helped me through these troubling times. Stay safe and thank you.
Brian, you rock
Seriously, you & Sean Carroll are like "candles in the dark"
Keep on keeping on
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999o9999o99o9999
99999999o999o9oo9o999999999o9999
99999o
9o99o
Physics is the field that is the cutting edge in science and Briane Green is a great spokesman.
Sorry for your loss professor. Thankyou always for your effort for sharing your knowledge with us. We misses you professor glad your finally back. Watching your daily equation becomes part of my daily routine that's why so happy that your back ❤😍
you're gorgeous :3
Your fuck*** stupid. He does not care about you nor your sympathy. He will NOT respond to you 😊
We love you Brian! I'm so sorry about your mother. You're work is so important to so many. These videos play such a large role in quelling my overwhelming anxiety regarding what's going on these days. You are so deeply appreciated. Thank you 💓
Yeah , it really does make a difference I also listen to calm my mind and to control the negative thoughts , Brian always has a diplomatic view even abt the things he doesn’t fully believe in, always open minded... Never really radical..Love that about him...
Thanks for coming back. You were missed. This series has been transformative for so many of us So saddened to hear of your mom's passing.
Deepest condolences to you and all your family Brian. Much love from Australia ♥️
He will NOT respond to you idiot.
So sad to hear that, Prof. Green. Stay strong! We all need you!!
You are still a good person and lecturer. I did not agree with you before and I still do not agree on most fundamental issues, but you deserve recognition. You are spreading your current knowledge and people are watching you because of your good presentation.
My condolences on your loss and thanks for coming back....you make a difference.
Professor, we would be happy to get our daily equation back. For me it was an important part of my life not because of what it teaches but because of the teacher who teachers.
Right.
@@mokujin29 yup
Oh gosh Professor Greene i am very late in the day, only just found this video, but, i'd like to send my deepest sympathies for the loss of your dear mum, or mom even, so sorry for your loss, sending much love 😌❤🩹🙏 and also thank you so much for sharing you TIME 👌pun intended 🤭with us xx😎💙🖤🌍🌌🌠🪐☄🕰🚀🛰
My thoughts and a prayer for you and your mother, Brian. Glenn
From Singapore. Love your talks and lectures Prof. Greene. Sorry to hear about your mum. Just to let u know, all mums become angels among the stars.
Sorry for your loss of your mother. You will see her again.
Thanks for these sessions!
Lol😅. He will not respond to you idiot.
Ots 2023 and such content I could watch hours and hours. Me Green is such a pleasure to listen/watch, it’s unbelievable what energy this man have.
Me Green, much respect for brining science in that manner,
Full of enthusiasm and passion; it’s unmatched.
Greetings from Germany 🇩🇪
Condolences professor.Thanks for making cutting edge science so accessible and fascinating.Never stop please.
Dr. Greene, big fan here and I've watched every single episode of 'Your Daily Equation'....you did mention about your mother in one of the live sessions and the abrupt suspension of the series made me feel that you had to leave everything else aside and attend to her....as for now, I'm extremely disappointed at the passing of your mom and I hope you and your family have the strength to get through this irreplaceable loss. My heartfelt condolences are with you and your family. While the concept of heaven, hell, the human soul may all be a matter of conjecture for us, I certainly hope your mother is in a better place now, wherever that is in the Universe or beyond.
Personally, I would love to see you continue the series, your insights into the intricate details, and just the feeling of one-to-one interaction is something that makes this series enjoyable.
Brian, I am so sorry about your Mom. Comfort and condolences to you and your family. Moms are so important and are missed greatly!
You dumb ass. He will not see nor respond to you. Dumb ass
Sorry to hear about your mom, Brian. We lost our mom last October and understand the feelings you must be going through. Keep up the good work as a legacy to the loved ones who aren't with us anymore.
I can’t thank you enough prof Brian for doing these videos. Glad you’re feeling well, thank you very much
So sorry about your mom. I know how tough it is. Really appreciate these videos, thank you very much.
Lol😊. He will not see your comment nor care idiot
Hey Mr Greene, I am in London England, I am half way through my Bachelors of Science, in Music Technology & Sound, having studied law before this, you are my fall asleep intelligence, and I love the delivery of your master classes, thank you so much for adding to my wealth of knowledge!!! Becks UK
Regular listener from Australia. Enjoy these sessions very much. Thanks.
So sorry for your loss. My condolences to you and your family. But great to have you back, thank you!
I'm sorry to hear about your Mother, best wishes to you and your family. I love listening to your lectures and Q&A. you have made it possible for me to grasp many things that I had struggled with until your
explanations, thank you so much Brian..
Thanks for what you do Brian, listening to you is like a great of fresh air
Dear professor, please accept our condolences for your loss. Thanks a million for coming back to help us learn new things from you. This is so valuable.🌹
Sorry about your loss. You.are a gifted person.
This man is a Saint! His enthusiasm for science and wonder knows no bounds...to grace us with his presence after such personal tragedy so Thank You much kind Sir. And I’m so sorry our society failed your mom with our careless handling of the pandemic 😞
LOl😊. Saint but won’t respond to any comments from fans. You’re dumb as fuck.
Idiot
Your dumb as hell
Only love transcends beyond reason.
Many of us are feeling your sadness at the loss of your mother. You were always her true love and she will always be with you. In your heartbeat, in the dawn of your smile, in the light of your gaze when you give away the world your magic. Brian, we love you from any part of the world, because you are part of our lives.
So much appreciate you and your work. So sorry about your loss. Keep up your great work. I’ll be watching.
So sorry about your Mom. You are a wonderful person , she did a good job. Thank you for making sure people like me understand whats going on in the Cosmos. Rest in peace Mrs Greene.
He does not care about you dude.
So sorry to hear about your mother, our hearts go out to all of your family, and of course you. Stay Strong! and Thank you for your Great work, and these awesome opportunities for regular folks like us to get to ask things :) Unfortunately I'm usually working in one way or another when I get the notification lol
hear hear
Brian that's excellent, time doesn't begin when you're born time begins when you are conceived, also vocabulary is what moves time. Thank you for your knowledge
so sorry to hear about your mother, my sincere condolences
I am sorry for your loss, Professor. We are so hapopy to have you with us again!
Thank you Brian for your humanity.
The more i listen to him, the more I feel his voice and Mathew macgaunagehy sound so similar
Sorry for your mom. 🖤 Thank you for your channel.
Brian, thank you from Orlando, Fl and New Hampshire. Best to all your cares
I heard your news in late,, professor. I am very sorry about your loss.. it must be indifinable emotion..
Thank for teaching joyful science bringhtly..
Keep your health professor Greene! Thanks a lot^^!
I just wanted to say how important this series (and others) is. Usually scientists are like the proverbial people in the ivory tower. We "little people" read stuff and see them on TV, but are they "real"? Formats like this are so important to show that science is approachable, that you don't have to be some special person to get involved and be interested in it. I wish other branches of science would do more of this, like chemistry or biology. In my country there is almost no real scientist doing public work. So I am glad you Americans and Englishmen (and women) are out there explaining stuff. Our schools do very well to put people off science I fear. When I was younger, I was (still am) a big sci-fi fan and I wanted to know stuff. But what school had to offer was very limited and restricted. You need to know this and no more and this is how we do it. This was before the time of internet. So since then, the web (and TV formats) have been a godsent. This is what media is supposed to do, not the Kardashians or Big Brother season 2343.
I am sorry to hear about your mom. Thank you for doing these videos.
Are you fucking stupid? He will not see your post nor does he care you dumb ass
Hi there!
I first "met you" years ago when I bought one of your books through which I got introduced to String Theory.
Over the years I've been listening to you every now and then but, lately, I've been focusing on the World of Science Festival sessions.
Then "Daily Equation" happened but I've been struggling with finding the time to catch up.
Finally, prompted by your curiosity about where/"when" we're following from, I thought I'd let you know how much I appreciate your effort answering all the really interesting questions.
I'm watching from Portugal and, having learned about your loss, I'll leave a big hug.
Please keep up with this awesome sessions if/when possible.
Cheers!
You are not alone ProfGreene, an attentive audience awaits WorldScience and I'm sorry for your loss w my condolences!
Lol😅
I am sorry to hear abot your mom. My condolences. I love your videos and specially the way you explain Science, you make it easier to understand it. Regards from Spain. 🌸👍
Thanks very much 😊🙏 . Extremely grateful for your help.
May your mother rest in peace, there's probably a good chance she can see the wonder and curiosity you've helped permeate through the universe of human knowledge. She must be proud and she did a good job on this Earth.
Very sorry to hear about your loss, Dr. Greene.
Hi Dr green , I’m so sorry to hear about your mother,which she became part of sky’s, safe journey for her.
You dumb ass. He will not read your comment nor does he care dumb ass
I am Connecting from Uruguay! Condolences about your mother…..
Dr Greene, the revamped platform WSU is great. What you and dr Carroll are doing is historical. Politicians make promises, brag about themselves but usually they pursue their own interests and gains. You both are building democracy, and a better world, because culture and science are " a conditio sine qua non" to make the world a fairer, a better, a safer place. Many skilled people can't afford expensive experience of study. But you and dr Carroll really help, sharing for free your top-level knowledge in a systematic way. You both are great scientists and also great men. When I was a kid my family was a low income one, and scientific careers were expensive. So I had to change my plans.
Sorry for your loss. From now on, as Saint Augustine wrote, your mum is no longer where she was, she is wherever you are.
Condolences to you on the passing of your mother. Take time to process. Hold fond memories close.
Professor Greene is an ocean of knowledge, thank you for sharing.Condolences about your loss
You idiot. He will NOT see your comment nor does he care idiot.
Sorry to hear about your mother, my condolences to you and your family.
I'm really sorry about your mom Brian. That really sucks. Thank you for coming back to keep teaching us about physics, a lot of us need the distraction these days
Thanks for another informative and entertaining lecture. I'll have to sign up for your course.
Hi Professor Greene, it's great to see you back again. Was very sorry to hear of your loss - I did send my condolences on your Facebook page. I have already registered with the re-vamped World Science U and am really looking forward to lots of interesting content, with some brilliant teachers. Since YDE stopped, us fans have just had the Sean Carroll videos to watch. They are also v good, but Dr. Carroll does like to torment his viewers with a lot of Maths. Best wishes from West Wales (UK).
Hi Paul figured i would find you in the comments, there was to much going on Friday so i could keep up. There's a moderator now and he blocked me, i have no clue why!? Didn't get a warning or explanation it just said the moderator has blocked u. It took the fun out of the chat completely for me. Wanted to let you know. Hope you're good and healthy maybe see you again this Friday. Wkr
My condolences to you and your family.
Tuning in from New Zealand 👍
I’m sorry for your loss Professor Greene. Thank you for your very informative videos.
I remember in some older documentaries about time you mentioned that all time past future and present still exists and we just experience the “now” slice within that timeline. I hope one day we have the ability to slice anywhere within that timeline.
Im really sorry I missed this live. |Also very saddened to hear about your mom's passing and, particularly the circumstances of her passing. Condolences
At 7:51 I think you are wrong about the clock thing. It's not a clock in motion that moves slower it's a clock accelerating... Once steady velocity has been achieved (near instant in the example) time would indeed move at the same rate for both "clocks."
1:06:00, Regarding someone who seemed confused about the different types of gravitational "formats":
As Dr. Greene said, Newtonian and Einsteinian gravity are described differently. So are the ideas of Galilean gravity. But the key concept being unseen here is that those three all deal with the macroscopic, give or take a few powers. As such, they are all three considered to be "Classical" gravity. This is a completely different animal from Quantum gravity, which deals with scales from molecules downward. This is, conveniently, referred to as quantum gravity, as compared to classical gravity. These are the two basic "groups", if you will.
At least that's how I see it.
I hope this helps,
J
Prof Greene . i am so sorry to hear about your mother !
Lol😅
Dr brian greene , Iam inspired by you and want to become a great professor like you
Great video, well done. If you’re using OBS at all you could place the backgrounds in a box above your head.
Thank you for sharing!
ad speed of light is constant:
it is constant, but the constant varies in different space/time parts of the universe. It is observable from the Earth right now. It may be related to an average amount of mass/energy at that particular part. More mass somehow causes lower speed of light locally.
It starts to be intuitive in this context.
Thanks to Mr. Greene for speaking publicly this often. We love it!
Dear Professor I unsubscribed from all UA-cam channels exept NASA .
I passionate about becoming an Engineer, therefore I subscribed only to NASA channel b'cos it motivates me for learning.
"World Science Festival" channel is great indeed. I learned from it.
Thank you. 🌻
My condolences to Brian Greene and to the family and friends of Brian's mother. 🌸
Sorry for you and your family's loss.
Also, thank you for your contributions to education and to the curiosity of the general public.
I have many questions, and I know that you can only answer so many on this forum.
Can you possibly recommend a ccosmology/ astrophysics website or group where I might find some answers on a regular basis?
Much appreciated.
Lol😅lol😅
I am so sorry for your loss .. this virus took my mom as well ..
Thank you for all that you do. My sympathy with your mother’s loss🌅
I'm sorry for your loss professor 💔🙏😢..may she RIP. Much love to you and your family. Thank you for the times you've made my days interesting.
Your dumb as fuck. He will not see your post nor respond to it. You’re an idiot. Dumb fuck. 😅
I'm so sorry for your loss.
Sorry for your loss!!
Fantastic Video! Thank You so much for all you do to help people like me blundering in the dark. 01:06:31 shows why you are on the screen and we're not. Utter respect.
I'm sorry for your loss, Mr. Greene. Lost my father in april. Wasn't the virus tho, but cancer.
Loud and clear
Prof. Greene, assuming that the fabric of space time is quantized into Planck length dimensional space time "cells" ,can we assume that between them there is a new fifth non local grid like dimension connecting them together? can it explain the quantum non local entanglement phenomena ? Thanks for sharing with us your knowledge . Eran Sinbar,Israel
Great novel" Talking to myself here in Upstate New York".
Yes the bowler. And much sympathy for you and family about your mother.
Lol😅. Idiot. He will not see this post.
while im thinking about it... i can tell by intuition when my kids are not well and why. i also can see who and what it bothering them!!!!!!!! spread that word for their well being of peace of mind for me plz
Dear Professor Greene,
It's great to see you back on UA-cam, Sir!
I missed this great Q&A at the time, but hope you see this anyway and can squeeze in a response next time, please!
Forgive my questioning the logic of the Light Clock :
1; The photon needs to be detected each time it reflects off a mirror to register a tick or tock-- a photon must 'reflect' or be absorbed for detection-- it can not do both.
A variant by having a photon emitter and sensor pair replacing each mirror may solve this , as I see it, but complicates the concept of reflection unsatifactorily imo.
Anyway, we can ignore this for a thought experiment and imagine a demon registers the ticks and tocks instead, allowing the photon to 'reflect' up and down uninterrupted, but the demon can't help with my second point even in a thought experiment :
2; Suppose the light clock is placed with mirrors horizontally as in the video.
With the clock at rest, the photon must bounce precisely vertically up and down. If it were at any angle, then it would zig-zag horizontally and eventually miss one of the mirrors. Thus the photon is always repeating the same vertical path, up and down, say at x=0 when the clock is at rest ( ie. the horizontal mirrors are centred at x=0 ) .
It follows that if the clock begins to translate, say to the right on the x-axis, then the photon will continue to repeat bouncing up and down on precisely this same path x=0 ( why would it reflect at an angle different to the precise vertical since the mirror is still horizontal, and isn't 'sticky' ).
Thus the mirror translates away from vertical path x=0 of the photon and the photon will miss the mirrors once the clock has moved such that the mirror is no longer under / above the original vertical photon path at x=0, and the photon escapes to infinity at x=0.
Why would the photon would deflect to x0 just because the mirrors move ?
In my mind, it is easy to see this if you make a very tall light clock, say, 10 light-seconds in height, which is one meter wide. The clock is just a frame with mirrors top and bottom so it has no solid walls, allowing the photon to escape if it misses a mirror.
Start the clock by emitting the source photon at ground level.
Now gently accelarate the clock to a walking speed of, say, one meter per second.
After a second or so, depending on how fast you accelerate the clock, the photon will no longer be heading toward the top mirror as the mirror is no longer above the point of emission, and escapes to infinity.
You could do this in deep space if wanting to avoid interference of gravity ( not relevant imo ).
Could this be tested today, using LISA, perhaps ?
I can't believe I'm right ( implications ), but I can't understand why I'm wrong !
I am not questioning spacetime GR or SR of course, only the specific thought experiment of the light clock.
Please help !
Sincerely, your pal Tom ( Cornwall, UK )
Tom, I may have this completely wrong, but I think the answer is all to do with perspective.
Imagine the "moving clock" is on a train. There are two people observing the clock, one in the same carriage as the clock and one on the platform.
The person standing on the platform will see the light in the light clock move in the "zig zag" motion you describe, going up and down whilst also travelling horizontally.
However, someone sat on the train, moving with the light clock, would look at the clock and see the light bouncing only up and down (not a zig zag pattern) because relative to him, the clock is not moving.
Does that help?
@@samanthaperks9142 thank you so much.
As I see it, a physical object, say a bouncing ball, would appear to bounce vertically to the onboard train observer and zig-zag for the outside platform observer.
As I understand it, this is due to the momentum of the ball, ie inertia.
Yet a photon is not an object and has no inertia; it will travel vertically only compared to the point of emission.
Thanks for taking the time to reply!
One very basic question I want to ask. Why spacetime warp in order to keep light speed constant? What is the key source triggering the warping process? Is it just the mass of the object causing space time warp, if yes then how we can explain the phenomenon?
I can see and hear you perfectly from Lima, Peru.
Many people misunderstand the Theory of Relativity. Brian Greene helps ensure we're not among them.
The video is cut, is there 2nd part? The last question he was responding to was quite interesting.
I love watching your visual explanations especially the one on time. Time slows when you watch the clock. It also slows watching your steak on the bbq but speeds up when you run to get a beer, proof is overdone steak🤣
I told my kids, no matter what else they study in college, that they should not consider themselves educated without understanding special relativity. At least that is what I felt in my college days. IMHO, this should be graduation requirement FOR EVERYONE. These days, you just gotta watch a youtube video. But you really don't understand how remarkable SR is unless you have struggled to work-out all of the nuances, twin paradox, Lorentz contraction, etc.
16:25, If we could add the velocity of the light to the velocity of wtvr emitted the light, then the light's inertia would have to increase. But inertia requires mass. Photons have no mass, therefore they can't change their inertia. So, it follows that the velocity of the light would necessarily remain unchanged. Or maybe not. Idk
Sorry for your loss.
❤ thank you
Regarding the guy who asked what this has to do with age, I think I understand what he was trying to say.
The person who has the clock slowing down doesn't experience any extension in years. They are inside a slower time bubble, so compared to the other person they are aging more slowly. It's relative.
We all need to grow our hair out again like it was the 70s, but on another note... at around 58:00 it is crazy how the world is just a projection of light coming in from every direction and since it is so fast it just makes sense... what a crazy system... before getting into physics you take so much of the real world for granted but never thought about the mechanics of stuff like light.
At 35:55 in the chapter "How do you know if an object is stationary". Theoretically, wouldn't it be possible to make an object completely stationary using the speed of light as a reference? For example, if I know that a photon is moving at the speed of light in this direction, then I subtract that speed in the opposite direction, and thus it would be completely stationary in the universe.