The Biggest Ideas in the Universe | 5. Time

The Biggest Ideas in the Universe is a series of videos where I talk informally about some of the fundamental concepts that help us understand our natural world. Exceedingly casual, not overly polished, and meant for absolutely everybody.

This is Idea #5, "Time." We talk about what time is, whether it's "real," and about why it seems to move in just one direction. That gets us a bit into entropy, which is a teaser for a later video in the series.

#science #physics #ideas #universe #learning #cosmology #philosophy #math #time

[CoreyChambersLA]

Sean Carroll is among the greatest teachers of all time.

[FigmentHF]

Thank you for all your time and effort. I left school with no real education, but I find all this stuff fascinating. It always felt academically impenetrable to me, and while I do occasionally get a bit lost, I can actually follow along with most of it.

You’re a great communicator and teacher, you can convey complex ideas without being too esoteric, and yet you don’t tend to over simplify difficult concepts. It feels very genuine, honest and accessible.

Thanks again!

[pranaysheshak]

Watching this at 1.5x speed and thinking "I live life faster than 1 second/second"

[gkelly]

Wish I had a physics teacher like this at school. Fascinating stuff

[brankooffice]

For some reason, I find you the most eloquent professor while also being the most informative in the whole field of science popularization. I watch all of your videos and read all of your books for years now and you always seem to give the most understandable definitions for science readers while not making a lot of compromises and avoiding bad analogies. Sometimes I wonder if science popularization would benefit more if you gave talks to your colleagues about how to explain things and how to structure talks then just educating the public directly. But please don't stop :) These are great.

[James-fewd]

You sir have an incredible gift as an educator

[wagfinpis]

I can not get enough of Sean's awesome consideration's.

Great sense of humor, I love this guy every time I tune in!

Only way to keep the appreciation short is to not even begin to mention it.

[kostanchik]

Please, don’t stop these videos. This format is awesome!

[alexpotts]

48:30 that equation (written S = k log W) is written on Boltzmann's gravestone

[cambriolage]

Had to pause at 48:21 "the size of the macrostate is entropy" 𝖒𝖎𝖓𝖉 𝖇𝖑𝖔𝖜𝖓! A true moment of wow for me! Thank you, Sean for this work, it's a crucial part of my life!

[eel]

I use to watch you back in the day i think it was the Universe or some series. You have always been able to talk to me as the years go on. I have no background in physics/maths but after a few years of watching your lectures and the many others like you it starts to make sense. Anyhows I guess all I wanted to say was thank you for being here all these years. Cheers

[ASLUHLUHCE]

Wish you talked about time itself, and how it (& mass) are emergent properties of timeless & massless particles bumping around fields, resisting acceleration.

[richardofoz]

Your description of psychological time at around 39-40 minutes is fascinating.

Many years ago, when I was young and embarked on open-ended travel for the first time, I found that writing at intervals to my family at home was a weird experience for me. Reviewing my diary for news to send home, I found myself amazed that so much had happened in the previous week or fortnight. ("Was that just last week? It feels like 6 weeks ago!)

Somehow, time had been "stretched" to a significant degree, and it struck me how differently time is experienced while traveling than while working.

I attributed this to the fact that in a work routine, experiences are, to a high degree, predictable. Most people can anticipate reasonably well what they will be doing next Thursday morning or the Thursday morning after that. Consequently, little seems to happen. I frequently had the experience of talking to someone after a break of some weeks and finding I had no news to report to them. I think this is quite common. ("What's news?" "Oh, nothing.")

When travelling, however, the reverse was true. Upon waking each morning, we generally had no idea where we would spend the night or who we might have met and what we might have done during the day. So looking back on my recent experiences, I would be amazed at how "full" life had been. For a long time I attributed this richer experience to travel itself, and work itself. But of course, it's due not to travelling or working as such, but to the lack or abundance of new memories, which is how we experience time.

You have finally made clear to me - 50 years after the fact - what this experience of mine was all about.

[GodlessPhilosopher]

These lectures are incredible and Sean is a genius. Highly recommend his new book defending the many-worlds "interpretation" of QM.

[mgenthbjpafa]

Sean has become, over the last decade, my most admired personality in terms of pedagogy inspiration on top of his explicit expertise on QM, we feel the joy of acquiring knew skills, confronting the edge of Human Knowledge. This may be a truism, but it must be acknowledged...Congrats, once more.

[timgreenglass]

spice? thyme? time has always seemed (to me) to be connected to consciousness.

[cmacmenow]

Just like to give a huge thanks to Sean for putting together
these incredibly illuminating and engaging Y.T talks /presentations.
Green screen, apps and real time iPad usage works beautifully.

[AndrewCMumm-sfyo]

Sean, without knowing it, you kept me in the game when I was a grad student studying general relativity. I was lucky to come across the early .pdf notes of your general relativity book (you were offering them for free online) and it was such a relief to finally read a book that explained things clearly. I ended up writing my masters thesis on the Kerr metric and your book helped so much in that respect. You're an outstanding educator and I'm really enjoying some of you mindscape podcasts and youtube videos. If you ever come to Hong Kong (in a post-corona world), then please come give a talk to the awesome physics students at my school - we would even love to host you as a resident scholar for a short while if that could interest you. My school is an outstanding place that wants to push the boundaries of what's possible in high-school (we've hosted an AI researcher who spoke about entanglement, another Caltech quantum-professor who is an alumnus of our school, Jerry Coyne from Chicago U. on evolution - you would fit right in!). Take care.

[KamranRazvan]

You have a great course on "Great Courses" about the arrow of time. I "think" I finally grasped, in that course, what entropy is!

[stewarthayne]

I did a masters degree in physics 25 years ago and then became a lawyer. All forgotten until now. This is so amazing to watch. So well presented. Thank you!