What is Relativity? | Sean Carroll on Einstein's View of Time and Space

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According to Einstein's special theory of relativity, there is no such thing as a moment in time spread throughout the universe. Instead, time is one of four dimensions in spacetime. Learn how this "relative" view of time is usefully diagramed with light cones, representing the past and future.

From the series: Mysteries of Modern Physics: Time

0:00 Understanding Cosmology, Gravity, and Relativity
1:00 Taking a Four-Dimensional Viewpoint of Relativity
2:15 Moving Into a Space-Time View of Reality
3:40 Differences Between a Newtonian and Einsteinian View of the Universe
4:45 The Notion of Simultaneity
5:55 Einstein’s Clocks, Poincaré’s Maps by Peter Galison
6:05 Recurrence Theorem
8:00 Einstein's Clock Patents
8:45 Constructing the Present Moment
10:40 Why Space-Time Is Relative
14:00 What is a Muon?
15:00 Carl Anderson Discovers Muons
15:50 Why Do the Muons Reach Us Before Decaying?
18:30 Einstein's Notion of Time as Personal
20:30 What Are Light Cones?
24:20 Time Dilation and Length Contraction
27:00 How Einstein Conceptualizes Space-Time
28:00 Newtonian Rule for Time Travel
28:45 Implications of Relativity

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#physics #theoryofrelativity #Einstein

[Chukwu]

I like how Sean Carroll explains these complex ideas in a way that is well within reach of the minds of non-physicists. Well done sir.

[ahmedrafea]

It is always a joy to watch and listen to professor Carroll. Complicated concepts are clearly explained and visualized. Thanks for this very informative lecture.

[entrtnr]

I always thought Sean Carroll was one of the best science communicators. Great to see him in his element like this

[clydedurden]

i’ve been on this rabbit hole for months now.. this is the best explanation i’ve ever heard!! seems like others almost try to make it more confusing than it needs to be ? idk

[funkiskunki]

I now know that as much as science interests and amazes me especially astrophysics...astronomy...I will never fully grasp it, if I still mostly struggle even listening to Sean...still enjoyable..thanks for trying Sean Carrol...does anyone know anything that someone, who struggles like myself, could watch and maybe find easier to understand.

[poolbeasttv]

Amazing lecture
This man has a wonderful voice

[binuvarghese]

Really very helpful to understand time... his explanation is very precise and even a layman can also understand the concept and importance of relativity and time

[sujitkumardash]

That was really a great lecture to watch. I got my own CONE out of intuition. LOL. Joke aside, To grasp such an idea of spacetime isn't easy as you might think, but Mr. Carroll nailed it. Thank you sir.

[sagarg]

Awesome explanation! And the way speaks is so clear! Thoroghly enjoyed this lecture

[josephcollins]

I wish I had words to express how much I want to understand all of this. Why can't it be explained? You are the very best I have seen. I like the way you present (OMG, can I say that now?) and pace what you say. I am rather intelligent in everything else! WTF? Help!!!

[mareksamsel]

So many of these kind of. Vids yet this one, actually explains things in the most wonderful
way, I'm impressed and grateful

[unknownPLfan]

I don't really care for Great Courses. Just clicked for our boi younger Sean Carroll

[Nah_Bohdi]

He's one of the few people I disagree with in fundamental physics but still listen to for general discussion.

[jmanj]

Great job explaining complicated material!
I find it interesting that our modern model of (space-) time, with its forward and backward looking light cones, looks so similar to one of our oldest timekeeping devices, an hourglass

[zack_]

12:37 - they came back with 'different reading' of time is because they were affected by different forces by each going through different path/speed/trajectory, while the TIME remains the same everywhere which is an abstract thing that nothing can change it, i.e. it is absolute. So the Newtonian theory seems to make sense.

[STaSHZILLA]

Me: "Hey Sean, What time is it?"

Sean: " *Yes* ."

[apricotcomputers]

everything uploaded on this channel/topic I'm subscribing to 😂

[liveinfra]

Absolutely wonderful lecture, thankyou great courses plus for bringing these insightful sessions available to everyone 🙏 .

[dennisgalvin]

"There's no such thing as one moment spread through out the universe that everyone can agree on" [Sean Carrol] Interestingly the word moment despite being defined as "..a brief period of time" is in fact a brief period of an event because moment comes from momentum which is tantamount to events. Meaning that periods \ duration are of events not time. So events have duration that are measured by time as space has distance that's measured by the metric system or imperial units.

What we perceive as the passing of time is just the passing of events.

[guitart]

Highly recommend watching the full course