Sean is interested in what his guests have to say, and so am I, but I am just as interested, if not much more, in what Sean himself has to say, so the occasional solo episode is a real treat for curious minds. Thank you Sean and patrons!
@@mrloop1530 I had a two-part point and you just told me that you noticed the first part, and that's all. OK, understood. to reiterate, the second part is where I say that a Sean Carroll solo episode is a real treat, and I stand by it 😎
Dear Professor Carrol. I think this episode was brilliant. For me it was like catching up on the state of the art in theoretical physics. I have a PhD in applied physics and I was always left with the emptiness of not fully understanding the most basic (and hardest to learn) principles of physics. Thank you very much for your work on your podcast, I enjoy every episode while walking the dog.
Make sure you enjoy and appreciate every one of the walks with your dog. My best friend since 13 years left us a few weeks ago and words can not describe how much I miss him.
The way quantum field theory was described here allowed me to finally visualize it in my minds eye, I am very grateful for this. I think you did I great job providing a broad overview of the current state of physics and it was really helpful to an enthusiastic laymen. There is something about connection everything to one another that creates a solid chain of understanding that is difficult to find elsewhere. Thanks!
and yet his entire worldview is disproven by the tukdam event that occurred in taipei 2020 which was also the first time such a thing was fully monitored and tested by neuroscientists and others
Most people can't know how things work because they aren't capable of thinking beyond buttons that do everything for them. Especially liberals, who also tend to think that there is no objective truth whatsoever, only subjective truth based on your personal beliefs. i.e. - "I feel like the opposite gender or some random made up pronoun or some entirely different species therefore I am and that's what everyone will call me or I will have a mental breakdown"
@@user-np6tf8zx1u just search tukdam taipei 2020, you will get a few articles and reports. without going into heavy detail what is always externally observable of someone post clinical death undergoing tukdam is the body does not decompose for the duration of the meditation, even in taipei 38c summer weather, the body and skin remains supple and produces sweet fragrance, and heat is generated around the heart region for the duration. when tukdam ends and the subtlest level of mind moves to another object some blood will spill out of the bodys nostril indicating the tukdam has ended, and the body will begin regular decomposition. what was unique about this tukdam was the exceptional skill involved in being able to sustain it for over 30 days (3-5 days is typical, 2 weeks is rare, longer is very very rare). this extended duration also provided the opportunity for lazy western scientists to conduct monitoring and research for the first time on someone undergoing tukdam. they collected a large amount of data in addition to what i listed above, such as measuring spontaneous brain activity activation weeks post clinical death.
Sean had and has so much to contribute to the world of physics but he has even more to contribute as a philosopher and conveyor of scientific knowledge. In addition, its wonderful that he accepted the position at Hopkins. He belongs there in that position.
Challenge everything all the time. If you can't defend your theory it probably has weaknesses. The dialog is healthy. Don't attack the person, challenge the idea. Thanks Sean. Healthy dialog.
I was just kind of listening to this as background information until Sean Carroll started getting into the lattice that provides a discrete structure for complex quantum systems, serving as the foundation for quantum field theory. After he got into this stuff he had my full attention. Yes, Feynman diagrams do visualize these interactions, complicated by loop momentum and infinities from ultraviolet and infrared divergences. Wilson's effective field theory and renormalization technique set a limit to tackle these infinities. In this, the concept of running coupling emerges, showing interaction strength 'runs' with the energy scale, exemplified in quantum chromodynamics (QCD). Non-perturbative effects further deepen the understanding beyond perturbation theory, revealing phenomena like quark confinement in QCD. The lattice also facilitates studying these non-perturbative phenomena, illustrating the interconnectedness of quantum physics.
Would have been nice to hear a live chat as this was taking place, it has taken a long time, but today I would say that Sean is perhaps the best communicator of science we have in the english world, I've watched Brian Green, Brian Keating, Neil Degrass Tyson, Sabine Hossenfelder, who is very good as well, as is Neil Turok, and Carlo Rovelli, Lawrence Krauss. Thank you for sharing your time and work Sean, especially for those of us who are not formally educated in the sciences. Peace
I thought the crisis in physics was about how our standard candles to measure cosmological distances are leading to strange inconsistencies. I kept waiting for him to talk about that.
Being a good heretic IS extremely hard work, and I've done it most my life. But as Sean says, it takes so much persistence, which is why I respect him the most. I can tell in his answers that they come from this point of view, and I appreciate his view... especially debunking most statements ... it is what I love. ☮
Props to you Sean for not striving to make the podcast “edgy!” Truth-seeking is a much more noble goal than just trying to conform to what the masses want to see/hear. We all appreciate it!
@@nPr26_50 in a scientific sense not per se. Sure Galileo was persecuted but it wasn't the case that Newton had to protest and fight for his right to do science. It was mostly a few states/rulers deciding it was "OK" to go ahead, these gettig a huge competitive advantage and thereby forcing other states to follow suit. Scientific freedom (STEM fields) and the freedom of (political) speech have been mostly separate developments, just look at current China.
My gut told me that was complete bullshit about the universe being twice as old. It’s disappointing to know that some of my favorite creators in the realm of astrophysics jumped on this. Your POV is always grounding and I’m super thankful for what you do.
@@daarom3472 Sean is by far my favorite science communicator. I like Fraser Cain for catching up on astronomy news. Lately I’ve been having fun watching Dr. Angela Collier. Hank Green because he’s a real life super hero. I’ll just name a few more, Dr. Matt O’Dowd on PBS Space Time and Joe Hanson Ph.D. on Be Smart. I could go on for days so I’ll just finish with Grady Hillhouse on Practical Engineering and also everyone featured on Numberphile esp Matt Parker.
@@daarom3472 In case you’re still interested I’ll just say Steve Mould, I did a thing, Boy Boy, Not Just Bikes, Climate Town, 3blue1brown, Undecided with Matt Ferrell, and Asianometry. Ok I think that is fairly comprehensive though I’m sure I’ve forgotten some.
@@codyramseur thanks for the recommendations! if you like Matt Ferrell also do check out "the engineering mindset" and "real engineering". Another gem I found (biology domain) is "real science".
@@daarom3472 oh ok and “lighthearted” stuff, I like Joe Scott and Simon Whistler. For politics, Brian Tyler Cohen. Then my guilty pleasure is H3 Podcast.
Really important podcast. Explains a lot of intermediate level stuff that clarifies a lot of what we hear about through the usual physics lectures and pop science stuff. Thanks for this - would love more!
Listened to many a blog. This one flows as a prize winning novel. Congratulations and thank you for enriching me again. It is a delightful train of thoughts woven in a comprehensive presentation.
I thought you might appreciate my sonnet, written when I heard about this latest "crisis" in physics. OUR GREAT GRAND COSMOS Turns out, the cosmos lied about its age and may be twice as old as we were told. The Big Bang may have only been a stage, and not her “birth,” so we’re not sure how old the universe we come from could be now, but we’ve glimpsed galaxies in her far past that were large even then, and can’t say how (that soon after atoms) they formed so fast. Maybe our red-shift measurements are wrong. Perhaps gravity was stronger back then. We’ve found black holes so huge they don’t belong around so early; we’re surprised again. To save our classical cosmology, we’ll need new origin mythology. ~ Jim (Bard Of Mars)
A tour de force. Sean's seemingly effortless romp across high level controversies in modern theoretical physics is always sensitive, positive, optimistic and humanistic. A needed antidote to so much anti-intellectualism and general negativism in our modern on-line world. Thank you.
Other sensational youtubers: make a 22 min video claiming that physics is in a crisis and physicists are stuck. Sean Carroll: makes a 4 hour 22 minutes video with the full history of physics of the 20th century, a summary of particle physics and cosmology detailed enough for us to understand that there is no physics crisis and encouraging the youth to join the ongoing epic endeavors of modern physics. This channel is honestly one of the best things that happened on RU-vid.
On the point made in this video's intro... One of my biggest takeaways from Neal Stephenson's "The Diamond Age" is on how subversion actually works. The book points out that if you want to subvert anything, you first have to completely master the existing system. The book was mostly referring to subverting political systems, but I think it's very broadly applicable.
Sean, thank you for this masterpiece of interpretation on the "crisis" in physics today. It was so enlightening for me to hear how you layout our understanding and helped fill holes in my understanding. And I'm only at hour one! Thank you, Maxwell!!! What an age to be alive! 😊
1:33:25 -1:54:03 crystal clear explanation of dark matter's influence on galaxies and the CMB's power spectrum Dr. Carroll should get a nobel prize for education!!!
Favorite way I've heard a lot of these topics described. Will definitely share with friends. The philosophical influence is clear with the clarity and precision that otherwise nebulous terms are defined and explained.
Novel Dark Matter Hypothesis Dark Matter is simply unaccounted for gravity. GR states that gravity is the consequence of the curvature of spacetime. Is it possible that the structure of spacetime itself could be warped without the presence of matter? Spacetime has been shown to react like a fabric by warping, twisting, and propagating independently of mass, and all have been proven with observations from gravitational lensing, frame dragging, and now gravitational waves! Fabrics can also be stretched, pressured, and/or heated to the point of causing a deformation and losing its elastic nature. All of these conditions were extreme during inflation, so it is plausible that the “fabric” of spacetime analog could extend having its elastic property have hit a yield point leaving pockets of inelastic spacetime geodesic that cause gravity without the presence of matter? Therefore, if gravity is strictly the consequence of the warped of spacetime, and fabrics can be permanently overstretched, then those empty warped geodesics would create gravitational wells independent of mass. My hypothesis of DM is subatomic black hole imprints of the quantum fluctuations that popped in at the moment of inflation. The CMB shows where the hot dense regions were they created the galaxies. They would have been the initial cause and location of the warping. These imprints would be clouds of quantum sized floating fixed geodesics, so they couldn’t expand or evaporate. Perhaps nothing has been detected because there is nothing to detect. GR wouldn’t require modification because DM would just be an extension of how spacetime behaves at extreme conditions. No MOND, no WIMPs, and no parallel universes, just empty spacetime deformations that produce gravitational wells to help jump start galaxy accretion processes. Zwicky may have named is Missing Mass correctly since he detected some gravity without mass present to cause it…
Can’t thank you for taking the time to break in down for cosmos groupies who aren’t necessarily in the trenches but enthusiastic nonetheless! You’re a gentleman and a scholar! (In the truest, most literal sense!) P.S. I can definitely appreciate criticism but from me to you, don’t change anything. You and the podcast are absolutely perfect as presently constructed!
I’m not subscribed to your Patreon, but perhaps you can consider an inquiry. Could you possibly explain why neutrinos couldn’t possibly be a candidate for dark matter? Or perhaps even pure neutron matter?
I don't think Sean answers comments - you can google "why neutrinos are not dark matter" to find the answer. Part of which was "What rules neutrinos out of the running for dark matter is that in the Standard Model, they are considered “hot” particles, meaning they travel at speeds close to the speed of light. For a particle to constitute dark matter, it must be “cold,” or travel slowly compared to light."
I don't think Sean even looks at his comments. I never see any that he has even liked, much less responded to. But if you are considering neutrinos then you should look at hypothetical sterile neutrinos. They would interact with matter less than regular neutrinos. Sabine Hossenfelder did a video on them a year or so ago. I don't remember how much she got into them as a candidate for dark matter, but she explained what they are.
I understood exactly 6 and 1/2 words of this but I loved hearing it and imagining the concepts and processes that led to the discoveries. Ain't us humans grand?
great topic. ive loved all things cosmology and quantum physics since my teens in the nineties when you had to read books to learn anything about it. its terrific that now insights into the fields are so easily available for the average consumer but since JWST especially there is a lot of hooey on youtube and the like that completely confuses people or emboldens them, dunning kruger. thanks for how much you contribute, im working on Biggest Ideas space/time/motion. so grateful for your work making books for people like myself. keep living.
I have a question: If you take say the top 10 unsolved questions in fundamental physics, how many of them have a chance to be solved in the first half of 21 century?
If we only have a quarter century to go on that clock? 1 or 2 of 10 maybe? I've listened to a lot of this (fantastic) podcast, and I need to listen again, but at first blush: the semantic spectre of "crisis" may still linger, given that we can quibble about what that word entails. If we run out of feasible higher-energy experiments and are left to speculate and conjecture with paper and computer, many physicists do feel that we risk wandering astray, without the grounding bounds of data. I don't like to call that a crisis, but it feels like a concern to take seriously.
Large clusters of black martier or black stars also have gravity. 1) How does this affect Einstein's theory of spacetime and its possible curvature. 2) If there is curvature or gravity, then "ordinary matter" may have been attracted by it, which these processes may have provided, even if black matter and hydrogen influence each other directly, this form of a perhaps weaker space curve may well if this occurs on a gigantic scale and can create gigantic black holes?
Our hyperfine curiosity is divine and brings salvation and so much joy! Thank you, wonderful Sean Carroll, for your talent in transmitting your love for love/curiosity itself 🙌💓💞
@3:24:45 - Your comment reminds me of a quote attributed to Mahatma Gandhi (and I'm probably not remembering the exact phrasing here): "Everything we do is futile, but we must do it anyway"
In the video "Sean Carroll: The many worlds of quantum mechanics' it is said that if I make a decision it is not a quantum event, but a classical one. Given the molecules in my brain, I wonder why is it not a (series of) quantum event(s)
Nice! I enjoyed listening...I was able to comprehend about a quarter of what was said, which is a big improvement from when I started listening to this podcast (Ep. 1). Thanks Sean.
Honestly, listen to it again. I re-listen to dense podcasts all the time and find myself learning more on the 2nd and 3rd time, and with this one I think its worth it if you really want to further your understanding.
In support of what you are saying at 11:27 when you are dismissing the critique "yeah but we don't really UNDERSTAND gravity, what IS space time,....": It seems to me that the following two claims are true: 1. The naive picture that progress in science is about understanding one thing, then another thing, then the next thing, and thus ticking more and more boxes of things we have understood (while possibly raising even more open questions, like in the island metaphor), is wrong in the sense that even the seemingly simplest things, like, say, arithmetic, or free fall here on earth, there will always more to understand, in the sense that are always going to be connections and implications that were not aware of before, or deeper theories that explain the same phenomenon on a deeper level. Newton understood that Galileo's law of free fall is only true as an approximation (the acceleration is slightly different for different places on the surface of earth, and it will decrease the farther away from earth's center you drop something), Einstein understood that Newton's law of gravity is just an approximation that is strictly speaking nowhere correct; and most people assume that it is perfectly possibly and even likely, that Einstein's laws of gravity will prove to be just an approximation to a deeper theory, too. 2. While it is true that we can always understand something like evolution or gravity better, deeper - it is also true, that this is not going to upend the insight that the other animals "are our cousins", or that "the earth orbits around the sun (or the center of gravity of the solar system, which is inside the sun), or that even Newton's law of gravity allows to do pretty successful space travel.
Oh man, i really read that title wrong. I was like: "Good! I'm glad there's a crisis in psychics!" And i was about to comment: "I'm sure they've seen that coming..." But yeah, a crisis in physics is not so good.. (now i will listen to the remaining 4 hours and 21 minutes and 30 seconds)
I can hardly imagine over 4 hours of one person talking about particle physics, cosmology, and foundations of quantum mechanics being interesting, and yet, it is. Because putting the current state of Physics into perspective takes a lot of context that not many people have. I certainly didn't.
Finally found the time to listen to this fantastic podcast. I really appreciated the encapsulated history of the various theories. It provided a much needed context for the so-called crisis. The only part that confused me was your statement about the Standard Model requiring symmetry, and that broken symmetries, or anomolies, can't exist. But isn't it true that the Higgs mechanism and weak force bosons necessarily are consequences of broken symmetry?
I can agree to MOND in the way that Dark Matter(DM) does modifies gravity. In the meaning that all about electric engineering depends on DM and its modifications and in combination with gravity. DM is invisible and we know such an invisible substance can do it. Take matter out of a black hole with the mass of a proton. What happens to this gravity when it attracts DM? Exactly it becomes a proton and when it cools down it can attract more DM that gets pushed away in an orbital by that proton. That' s why Atoms expands if they get hot. That' s why atoms don' t collapse.
Assuming there is a finite amount of scientific discoveries to make, we should expect scientific progress to slow. I'd imagine a bell curve distribution. With a quick ramp up to a height and then an equally drastic falloff. Our time may be better spent exploiting our current understandings. Maybe letting AI chug away at String Theory, while we advance the application of our knowledge.
As an older person it bothers me that modern physics has become an area where people seem to think out loud about the universe, without proof about what they are talking about. Some scientists have used the interest in finding answers to promote themselves. They have become rockstars. String theory anyone. .
Lol I’m very curious if literally anyone has ever commented saying you “rambled on too long” or that a certain tangent “could have been cut out” because you literally do not miss with making your roundabouts interesting and consistent with the topic. The cosmological constant talk was very engaging
Resembles the state of physics 120 years ago, when only some loose ends were thought to be required to add to the curriculum, and then all would have been done. I think stagnation and overestimation is worse than crisis.
Is there a limit to the concetration of matter inside a black hole's singularity? Can exceeding this limit cause a big bang? If we assume this singularity is spherical, at least conceptually, can Pi describe the splitting of this singularity once the maximum density is reached to cause a big bang?
I was a fantastic crank early on. Looking back, as brilliant as I thought my ideas were, I was a fucking idiot. Fortunately for me, I was wrong often enough that one day I decided I should actually try to learn this stuff before continuing on my apparent mission to make a fool of myself. I have plenty of other ways to do that. I really don't need to spread the wealth. I'm good. I am actually proud of my progress, although, it's taken way longer than it should have to get here, at least, I'm here.
Sean: at 24:52, you missed a crossfade in the audio. The end or beginning of two audio regions is "caught" in the crossfade function, so we slightly hear this "item" of audio that you didn't intend to be there... As a physicist, you should revel in the fact that programs allow you to choose linear or exponential curves for how the fade is done on either side of the crossfade. It's more work to delete/erase all the sound pre/post the edit point, but sometimes that's what is required. Try thinking how you can do the same function with two separate audio pieces on two separate tracks... and how you fade out one while overlapping the fade in of another and you will understand how the shortcut works on a single track (at the same time you will realize you don't have as much control with the single track short cut.)
According to Saurya Das and Rajat K. Bhaduri; if a dark matter Axion (or a massive Graviton) has a mass of about 1 eV or less then its critical temperature would exceed the temperature of the universe at all times, therefore it would have formed a Bose-Einstein condensate at very early epochs. The wavefunction of this condensate, via the quantum potential it produces, would give rise to a cosmological constant that could account for the *correct* dark energy content of the universe, and in the far future this condensate would be all that remains of the post heat-death universe "Dark matter and dark energy from Bose-Einstein condensate", Saurya Das and Rajat K. Bhaduri, arXiv:1411.0753v3
132 minutes, not a scientist, so forgive me ahead of time, it sounds like dark matter behaves like water, a wide open ocean without constraints beyond landmasses moves without interacting, however if it comes across an obstruction, the water builds and holds pressure at the obstruction while the water unaffected by the obstruction continues to move freely wherever it travels. In the case of dark matter a similar affect takes place where it interacts with dense gravitational fields created by different types of matter that exist at different levels of density. Sean's description of dark matter intensifying in the bounce as gravity intensifies but not interacting with the bounce back reminded me of water hitting a shoreline. Just guessing, but its fun all the same.150 minutes in, question, will agi be able to answer any of these questions Sean?
4:22:00 so close I like how you can deal with edginess, you are not scared to touch edgy topics, talk to edgy people if you think they have something to say. I feel like a lot of people get spooked way too easily and rather not talk about controversial topics and cede that ground to others who might not be as informed.
Geez. Now I’m questioning all my adorable foibles and wriggling. (Although I have solved for nothing, theoretically, just having difficulty with the field equation)
This stuff drives me nuts. At about 1h38m Sean mentions 2 clusters that interacted but the centers of gravity stayed with the galaxies and not with the hot interstellar gas ( which supposedly has most of the regular matter mass) But isn't that actually reverse of expectation? Wouldn't the far more massive dark matter slow even more because it is interacting far more strongly than regular matter? Or does Dark matter somehow not interact with itself?
