Orodruin's latest activity
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Orodruin replied to the thread 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. -
Orodruin replied to the thread 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... -
Orodruin replied to the thread Undergrad Where did the early photons go?.… shortly put: if it is infinite today, it was infinite then. But with a smaller scale factor. -
Orodruin reacted to CrysPhys's post in the thread Schools How to Navigate Applying to HEPTH PhD Programs in Europe vs. the US? with
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<<Emphasis added.>> I don't see how the application process in the EU vs the US resembles each other here. There is a big advantage to... -
Orodruin replied to the thread 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... -
Orodruin replied to the thread 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. -
Orodruin replied to the thread 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... -
Orodruin replied to the thread 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... -
Orodruin reacted to Nugatory's post in the thread Undergrad How Is Intrinsic Curvature Measured in Higher Dimensions Like 4D Spacetime? with
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The tangent space at a point is not a plane in the 3D embedding space (although that is a natural way of visualizing it, continuing our... -
Orodruin replied to the thread High School Matter density right after the decoupling.Free-streaming means that the (average) density of matter is so small that the mean-free path exceeds the size of the Universe. The... -
Orodruin replied to the thread Undergrad Question about Parallel Transport.I mean, it is a two-dimensional gyroscope, i.e., one where the gyroscope is only free to rotate around one axis ... :wink: I'd like to... -
Orodruin replied to the thread Undergrad Question about Parallel Transport.The FW transport in GR is the correct thing to use for gyroscopes precisely because we are talking about its frame describing spacelike... -
Orodruin reacted to PAllen's post in the thread Undergrad Question about Parallel Transport with
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I disagree. The definition of a geodesics as a curve that parallel transports its tangent vector makes no sense without parallel... -
Orodruin replied to the thread High School Matter density right after the decoupling.Compare to the density of the Sun's photosphere. The number density of hydrogen there is about ##10^{24}## per cubic meter. But of... -
Orodruin replied to the thread Undergrad Question about Parallel Transport.The entire point of FW transport is to keep a spacelike vector, such as a polarization vector, orthogonal to the timelike tangent of the...