Orodruin's latest activity

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

<<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...

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

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

I believe that is intrinsically applying the Levi-Civita connection as the geodesics of the Levi-Civita connection are the paths that...

Not only why, but ”you cannot”. It is impossible to do it without parallel transport - or at least without parallel transport being...

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...

Free-streaming means that the (average) density of matter is so small that the mean-free path exceeds the size of the Universe. The...

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...

The FW transport in GR is the correct thing to use for gyroscopes precisely because we are talking about its frame describing spacelike...

I disagree. The definition of a geodesics as a curve that parallel transports its tangent vector makes no sense without parallel...

Compare to the density of the Sun's photosphere. The number density of hydrogen there is about ##10^{24}## per cubic meter. But of...

The entire point of FW transport is to keep a spacelike vector, such as a polarization vector, orthogonal to the timelike tangent of the...

The Levi-Civita connection is the unique metric compatible and torsion free connection on a Riemannian manifold (or pseudo-Riemannian)...

Parallel transport is perfectly well defined along non-geodesic curves. The manifold described in the video is a Riemannian manifold so...