Sean carroll Definition and 27 Threads

Was watching a Sean Carroll video and his answers to some questions seemed to run counter to the norm. For example at 1:15:30 in the video, he seems to be saying that we'd see only a (hypothetical?) 'test particle' get stuck at the event horizon of a black hole. Also at 1:17:19 in the video...

This question arises from Carroll's Appendix I on the parallel propagator where he shows that, in matrix notation, it is given...

Sean Carroll says that in SR the time component of the 4-momentum of a particle is its energy. It is of course also ##mc^2dt/d\tau##. He uses that to prove that ##E=mc^2##. Which begs the question why does ##E=p^0##? Misner, Thorne, Wheeler do roughly the same thing. I find these 'proofs'...

Its is podcast #138, guest = Daryl Morey, analytics inclined GM of the Philly team. Apple Podcasts: https://podcasts.apple.com/us/podcast/sean-carrolls-mindscape-science-society-philosophy/id1406534739?i=1000513079530 It covers higher level issues like: how good's your data? Balance between...

Is the scale factor a scalar? I think that the answer is no but I want to check because god (or the universe) has been playing tricks on me... At Sean Carroll's invitation I wanted to check that the tensor$$ K_{\mu\nu}=a^2\left(g_{\mu\nu}+U_\mu U_\nu\right) $$was a Killing tensor...

Summary:: hodge Duality... Does anybody has idea for solving these 2 problems?

Spatial slices of the Robertson-Walker metrics are maximally symmetric so they must have a constant curvature. Is it true that in three Riemannian dimensions that a constant curvature scalar determines whether the volume is finite or infinite? Carroll seems to have given a counter-example for...

I have an equation $$ \chi_\nu\nabla_\mu\chi_\sigma+\chi_\sigma\nabla_\nu\chi_\mu+\chi_\mu\nabla_\sigma\chi_\nu=0 $$so we also have$$ g_{\nu\rho}g_{\mu\tau}g_{\sigma\lambda}\left(\chi^\rho\nabla^\tau\chi^\lambda+\chi^\lambda\nabla^\rho\chi^\tau+\chi^\tau\nabla^\lambda\chi^\rho\right)=0 $$Does...

Sean Carroll's most recent book is called Something Deeply Hidden, and is premissed on the idea that the Everett interpretation of the 'observer problem' in quantum physics is correct. Carroll, and several other prominent scientific popularisers including David Deutsche and Max Tegmark, are...

On the way to Kruskal coordinates, Carroll introduces coordinates ##\left(v^\prime,u^\prime,\theta,\phi\right)## with metric equation$$ {ds}^2=-\frac{2{R_s}^3}{r}e^{-r / R_s}\left(dv^\prime du^\prime+du^\prime dv^\prime\right)+r^2{d\Omega}^2 $$ ##R_s=2GM## and we're using a ##-+++## signature...

Hi. What are the math courses should I take in order to understand the mathematics involved in a book such as Sean Carroll in general relativity. Thanks

I come across the adjective 'comoving' quite often. I understand comoving coordinates for the Universe. They are coordinates which expand with the expansion of the Universe(?) but I'm confused about what it means in essence. Here are some examples: In Sean Carrol's book there is a question...

I'm still on section 5.4 of Carroll's book on Schwarzschild geodesics Carroll says "In addition, we always have another constant of the motion for geodesics: the geodesic equation (together with metric compatibility) implies that the quantity $$...

Sean Carroll gives the Planck's set of four dimensioned quantities: Planck's mass, length, time and energy. I wanted to compare them with actual things.\begin{align} m_p=\sqrt{\frac{\hbar c}{G}}&=2.18\times{10}^{-8}\rm{kg}&\rm{{10}^{7}\ E. coli}\phantom {100000000000000000000}&\phantom...

Interpretation of quantum mechanics is something that is discussed at length on pf so it would be interesting to get views of the quantum guys on this short (30 mins) podcast. Thanks...

I am reading Spacetime and Geometry by Sean Carroll. In section 1.10 on classical field theory, he uses this formula (1.132) The curly L is a Lagrange density. S is an action, Φ is a vector potential. Could the integral also be written as follows?

Hi, Page 166, theorem expressed as 7.2, does anybody know it's name? Many thanks

On this forum sometimes people moan about badly presented or just plain wrong media output about science. They should, though I thought this one was OK. http://www.watchseriesgo.to/link/vidto.me/6951511 If th link doesn't work anymore then it's BBC Horizon S55E13, Also Sean Carroll here at...

Interesting TedTalk from Sean Carroll last month. At the end he asks the question of whether the big bang was really the beginning. Is this simple multiverse talk? Thoughts?

Greg Bernhardt submitted a new PF Insights post Interview with a Physicist: Sean Carroll Continue reading the Original PF Insights Post.

Homework Statement Consider a perfect fluid in a static, circularly symmetric (2+1)-dimensional spacetime. Derive the analogue of the Tolman-Oppenheimer-Volkov (TOV) equation for (2+1)-dimensions Homework Equations Schwarzschild metric The Attempt at a Solution Okay. I'm trying to think...

Homework Statement I'm not in grad school but I've been trying to teach myself some GR and I asked a professor what problems he thought would be good to study. He mentioned this one. I'd ask him for help, but he's out of town this week. I've also attached a picture to this problem. (It seems...

Has anyone else read Sean Carroll's guest blog post at Scientific American on http://www.scientificamerican.com/blog/post.cfm?id=physics-and-the-immortality-of-the-2011-05-23 Please read the link above so that we are all talking about the same thing. If I understand his post well enough, he...

He's one of the most outspoken atheists on the Internet (far more hardcore than most atheists I know), and yet he graduated from a religious university. Hmm, this sounds interesting.

http://preposterousuniverse.blogspot.com/2005_05_01_preposterousuniverse_archive.html#111509098797695398 anyone know what happened?

Sean Carroll has posted a Cosmology Primer explaining contemporary cosmology for general audience It could be very handy for us to have at PF to refer to. Here, for example, is the FAQ http://pancake.uchicago.edu/~carroll/cfcp/primer/faq.html for other sections, go to the TOC and click on...

http://preposterousuniverse.blogspot.com/2004/10/come-lately.html Sean Carroll is a cosmologist, and also a pretty entertaining blogger http://preposterousuniverse.blogspot.com/ you get a mix of interesting science news, politics, personal events/comment, jazz, even lately some witty...