Recent content by Orodruin

  1. Orodruin

    Undergrad Curl of velocity vector in rotational motion

    No. It is a function of time as it changes with time, but it does not depend on spatial coordinates. If it did the object would necessarily change shape.
  2. Orodruin

    Undergrad Black hole questions

    That’s not starting from the singularity though 😉
  3. Orodruin

    Undergrad How does this configuration not create E field inside the conductor?

    It is exactly what they should look like.
  4. Orodruin

    Undergrad Curl of velocity vector in rotational motion

    By definition, ##\vec \omega## is constant is space - or you don’t have rotational motion. The curl does not contain derivatives wrt time so clearly letting ##\vec \omega## have a time dependence does not affect the result here.
  5. Orodruin

    Undergrad How can you model charge?

    The previous reply is excellent, so I will just add that the role of physics as an empirical science is to describe how things work, not to provide some underlying truth. You can always search for more detailed models, but physics will never describe what
  6. Orodruin

    How is x-vt a rightward moving wave?

    I’ll try to offer yet another perspective. The function ##f## describes the shape of the wave. We can consider a point on the wave with a particular constant value of ##f##, call it ##f_0##. Now consider how the point (or more generally, points) with this value are moving with time. We have...
  7. Orodruin

    Vector calculus: line element dr in cylindrical coordinates

    Because it was never there to start with. The position vector in cylinder coordinates is ##\vec r = \rho \hat \rho + z \hat k##, there is no ##\phi \hat \phi## term.
  8. Orodruin

    Praise 2025 PF Member Awards Ceremony

    Thank you everyone who voted for me and others! Not sure I deserved it this year considering how inactive I have been over the last 12 months, but still grateful. Almost instant mentorship and subsequent disqualification from member award polls? 😂
  9. Orodruin

    Undergrad Is this another "paradox" or a veritasium mistake?

    Yes, they would, but this would be attributed to the spaceship accelerating rather than the light following a curved path.
  10. Orodruin

    Undergrad What happens when two Neutrinos collide?

    If neutrinos collide they would undergo a regular weak interaction. This can either be elastic or inelastic depending on energy. An elastic scatter would not be very noticable. The cross section of interaction would increase manifold if the com energy approaches the weak scale.
  11. Orodruin

    Undergrad Where did the early photons go?

    … shortly put: if it is infinite today, it was infinite then. But with a smaller scale factor.
  12. Orodruin

    Schools How to Navigate Applying to HEPTH PhD Programs in Europe vs. the US?

    Not only is a Master’s degree helpful, it is often a prerequisite to be eligible for a European PhD program. (Local variations apply depending on country)
  13. Orodruin

    Undergrad How Is Intrinsic Curvature Measured in Higher Dimensions Like 4D Spacetime?

    Planes, I agree, but not with a single ball, which was my understanding from the discussion.
  14. Orodruin

    Undergrad How Is Intrinsic Curvature Measured in Higher Dimensions Like 4D Spacetime?

    I believe that is intrinsically applying the Levi-Civita connection as the geodesics of the Levi-Civita connection are the paths that extremise path lengths. More generally, for an arbitrary connection you could define the surface of the ball as the set of points reached from the center after...
  15. Orodruin

    Undergrad How Is Intrinsic Curvature Measured in Higher Dimensions Like 4D Spacetime?

    Not only why, but ”you cannot”. It is impossible to do it without parallel transport - or at least without parallel transport being defined - as curvature is a property of the affine connection that defines what parallel means. OP’s misunderstanding that parallel transport requires embedding is...