pa7x1

29 ms·

271.
by pa7x1 6y ago
If only those pesky physicist and mathematicians would name their variables correctly everything would become self-evident.
272.
by pa7x1 6y ago
There is two densities to care about when talking about energy sources. Energy density per volume unit and energy density per mass unit. Hydrogen has a very high energy density per mass unit (the highest of the chemical reaction energy sour
273.
by pa7x1 6y ago
I think we will look back into economic history to our times in surprising disbelief at how simplistic our central bank policy is. A bit like how we laugh at how doctors used leeches to treat various ailments. From 1929, central bankers lea
274.
by pa7x1 6y ago
Correct, to further explain the difference. The budget is drawn with a certain assumption of the price of oil, which nets them an expected profit per barrel with which they can balance income and expenses. If the price of oil is lower than
275.
by pa7x1 6y ago
As a physicist, I can confirm, they are absolutely top quality.
276.
by pa7x1 6y ago
You get new insights, that F is a curvature 2-form. Written in this way it's explicit that EM is also a geometric theory. This observation opens the door to Yang-Mills theories which are behind all the Standard Model.
277.
by pa7x1 6y ago
Geometric algebra is a bit awkward notationally. Physicist prefer to use an alternative notation based on exterior calculus that does provide a compact representation of Maxwell equations: d F=J dF=0 Geometric algebra produces two equation
278.
by pa7x1 6y ago
I think you are right on the source of confusion, I have tried to explain the relation between hyperbolic space and Lorentz transformations in my latest answer. See here: https://news.ycombinator.com/item?id=23549361
279.
by pa7x1 6y ago
> I am confused. Let me write down the definition I know, and let's error-correct to a point of agreement? Fixing the definitions is a good idea because they may vary slightly in the literature. > - A Lorentzian manifold is a pse
280.
by pa7x1 6y ago
There is a particle for gravity, it's the graviton (massless, spin-2). It is not observed experimentally because it's extremely far from our technological capabilities. In fact, mathematically, General Relativity can be understood
281.
by pa7x1 6y ago
They don't fall a gravity well, they follow straight lines in a curved spacetime. Not subject to the other forces everything follows the straightest line (geodesics) it possibly can in a curved spacetime. The field equations define the
282.
by pa7x1 6y ago
Some corrections to hopefully solve some misunderstandings. > A Lorentizian manifold looks locally hyperbolic, so we need to imagine a light cone. Now the curvature of this manifold tells us how we need to distort light cones at differen
283.
by pa7x1 6y ago
You seem to argue from an economic point of view, as if it was too "expensive" or "wasteful" to have all those universes. But MWI doesn't add any postulates to QM, in fact it is the simplest of the interpretations a
284.
by pa7x1 6y ago
This is indeed the case, this process is called decoherence. https://en.wikipedia.org/wiki/Quantum_decoherence
285.
by pa7x1 6y ago
This is historically not true. Einstein didn't work in complete isolation nor was he the first one to come with a geometric description of gravity. See for instance, [Nordström's theory of gravity]( https://en.wikipedia.