What is Sean carroll: Definition and 27 Discussions

Seán Carroll (20 January 1892 – 1 February 1954) was an Irish politician. He was first elected to Dáil Éireann as a Sinn Féin Teachta Dála (TD) for the Limerick constituency at the 1923 general election. He did not take his seat in the Dáil due to Sinn Féin's abstentionist policy.
He did not contest the June 1927 general election. He stood as a Clann na Poblachta candidate at the 1948 general election for the Limerick East constituency but was not elected.

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  1. S

    B Which science communicator do you find to maintain the most accuracy?

    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...
  2. George Keeling

    I How do a bunch of integrals make an n-simplex or an n-cube?

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

    I Uncovering a Decent Proof of E=mc^2

    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'...
  4. BillTre

    Sean Carroll podcast on Issues Related to Basketball Analytics

    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...
  5. George Keeling

    I Is Scale Factor a Scalar? Sean Carroll Invitation

    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...
  6. Pouramat

    Carroll chapter 2 questions 9 and 10 on Manifolds

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

    I Const Curvature Scalar & 3-Torus: Is It Maximally Symmetric?

    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...
  8. George Keeling

    I Solving Vanishing Tensor Eqn & Raising All Indices

    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...
  9. Quotidian

    What is the problem that the Many Worlds Interpretation aims to solve?

    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...
  10. George Keeling

    A Exploring Null Basis Vectors, Metric Signatures Near Kruskal

    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...
  11. A

    Math Courses to Understand General Relativity (by Sean Carroll)

    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
  12. George Keeling

    I What does comoving mean and how is it related to isotropy?

    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...
  13. George Keeling

    I Solving Geodesic Eq.: Mysterious Conservation Eq. (Sec. 5.4 Carroll)

    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 $$...
  14. George Keeling

    I Comparing Planck's Mass, Length, Time and Energy

    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...
  15. pinball1970

    I Sean Carroll podcast on many worlds interpretation

    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...
  16. George Keeling

    I Help with integration conventions in "Spacetime and Geometry" by Sean Carroll

    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?
  17. binbagsss

    A Schwarzschild Derivation: Sean Carroll Notes - Theorem Name?

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

    BBC Horizon S55E13: Sean Carroll at His Best

    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...
  19. Greg Bernhardt

    B Sean Carroll on Why Does Time Exist at All?

    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?
  20. Greg Bernhardt

    Insights Interview with a Physicist: Sean Carroll - Comments

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

    TOV Equation in (2+1)-dimensions for Perfect Fluids

    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...
  22. F

    Sean Carroll's Spacetime and Geometry Chapter 5. Questions 3

    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...
  23. Norman

    Sean Carroll and the immortality of the soul

    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...
  24. Simfish

    How did Sean Carroll manage to survive Villanova?

    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.
  25. robphy

    Uncovering the Mystery: The Disappearance of Sean Carroll

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

    What is Sean Carroll's Cosmology Primer?

    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...
  27. marcus

    News What are some quotes from Sean Carroll that Kerry should use in the debates?

    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...
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