Many ideas and many theories, but no firm conclusions, only uncertain and approximate conclusions. The clarity and humility with which this great scientist admits errors and/or the absence of certainties in almost every field Is truly admirable.  He doesn't introduce neither misterious ideas nor misterious concepts, but speaks of the need for new ideas and experimental confirmations. I deeply appreciate this "man" skill- and his intellectual honesty.

Prof. Sean C - forever making work on a Monday tolerable.

Piecing together cosmic puzzles is a lot easier with help from great educator Professor Sean Carroll.

I'm so glad you take the time to do these and share them publicly with the world.  I've loved learning about cosmology since I was little and seeing that there are hundreds of these in your channel makes me feel you really are doing a public service.  Thank you.

Thank you, Prof. Carroll 🫡🫡🫡

Well done. Those who genuinely seek to understand & also teach clearly are evident. Thank you for another excellent lecture. 👍

I wish I found your channel sooner.

Please keep posting never stop always a joy when u do

Preach. The injustice of a power imbalance in favor of companies,  owners of capital. We need consumer rights, not producer rights.

Amazing content as always!

What a great addition to my day

Excellent Dr. Carroll! Lots to think about, and of course I will be eagerly awaiting your next podcast when I assume you will shed some quantum of light on this matter – pun intended - I couldn't resist!  
It was 100 years ago in 1926 when Dr. Gilbert N. Lewis coined the term "photon" for the smallest unit of radiant energy!
I took two semesters of astronomy 47 years ago in college and got a 4.0 both semesters. My major was music education. I have listening to you on YouTube for around 10 years now.

Excellent, can't wait for a 3 part series

Awesome two-part series by Sean.
1:44:00 - The function $f(R) = R - \frac{1}{R}$ reminds me of Michael Jordan's philosophy of using failure as a metric for success.
Once I accumulate enough points, I'm buying Sean's two "Biggest Ideas" hardcover books.

Thanks for sharing this, learned a lot.

Thank you Professor! ^.^

Sean thanks so much for this podcast, this such a great avenue for learning more about modern physics. Could dark energy be entropic in origin? Sorta/kinda like Erik Verlinde's idea. Given your interest in entropy/complexity I am surprised I haven't heard you mention something like this before. I heard in a RI presentation that the expansion could equivalently be explained as the 'ruler' getting longer, so could it be the entropic 'cost' of observation is going up over time and we observe that as distant things receding? I believe it is due to things evolving into more special configurations over time, and observing a more 'special' configuration 'costs' more in some way entropically and we observe that as increased distance.

Looking forward to this !

On YouTube there was once a simulation of the birth of a black hole which showed material exhaust which I found interesting.😊

1:35:00 So, it's the speed of the in going space!