@YuzurihaInori So there are people around who claim it is meaningless totalk about the inside of a black hole because (in our universe) that interior is physically inaccessible.
I don't know whether you would share that view or not ...
The observers outside have simply made a poor choice of coordinates. The interior exists but is accessibe only by falling into it, and as you say that causally disconnects you from the rest of the universe.
@YuzurihaInori what I'm getting at is that you should always study th maths whether or not you think it's physically relevant. The only way you will find out whether it's relevant or not is to study the maths. Do that first and worry later.
@YuzurihaInori lots of mathematicians become physiscists, and some (a smaller number) physicists become mathematicians. Choose the course you are going to enjoy most and let tomorrow take care of itself.
@JohnRennie I just read a paper that proved mathematically the existence of two retarded field, and a set of Maxwell like equations from one continuity equation.
The continuity equation had two parameters. If one identifies the parameters with the electric charge density and current density, the fields become the electric and magnetic fields, and the Maxwell like equations come out to be exactly Maxwell equations.
Now, as far as I know, the full set if Maxwell equations only listen to Lorentz transformations, not Galilean ones. So if, charge conservation gives Maxwell, then charge conservation is not a part of Galileo.
The continuity equation says that if charge is moving out of a differential volume (i.e. divergence of current density is positive) then the amount of charge within that volume is going to decrease, so the rate of change of charge density is negative. Therefore, the continuity equation amounts to a conservation of charge.
@YuzurihaInori Shrug. Theoreticians are endlessly inventive in finding new and interesting avenues to explore, but I don't recall that paper overturning our ideas about space and time.
The divergence of the stress-energy tensor is zero, and this is certainly very important in the construction of GR.
All bright guys down here, right at this moment, I have 2 options. 1. Take mathematics as a choice for future studies. 2. Take physics as a choice for future studies. To be honest, I love physics more than maths, And, the thing I want to do is get a thorough understanding of the universe and maybe later in life, work on the TOE.
" In the extreme, this association has led to the charge that invasion biology is rife with xenophobia and racism13 and is a lineal descendant of Nazism." lmao
We have these equivalences (1) $PD : H^1(M) \cong H_{n-1}(M)$ (2) $f : H^1(M) \cong Hom(H_1(M), \Bbb Z)$ coming from the billinear pairing $\frown: H^1(M) \times H_1(M) \to \Bbb Z$ given by cap product (3) $i : H^1(M) \cong [M, S^1]$ an abstract isomorphism, which I am going to describe
@0celo7 yeah forget about that. I should also mention (4) $[M, S^1] \to Hom(H_1(M), \Bbb Z)$ given by sending $g : M \to S^1$ to $g_* : H_1(M) \to H_1(S^1)$. This is also an isomorphism
@YuzurihaInori Yes, it doesn't mean what John thinks it means
Hey I'm the scheduled guest for the june 14th Physics AMA and I was told to maybe make a little presentation and asks for any questions for the AMA people might have, so here it is.
About me
So I am Samuel Lereah, got a Master degree in particle physics from the university of Nantes. My master ...
@0celo7 Ok, so, with the above equivalences, I think I can prove that given a class $\alpha \in H^1(M)$, $f(\alpha) : H_1(M) \to \Bbb Z$ being the corresponding map and $g : M \to S^1$ being the space level map, for any $c \in H_1(M)$, $f(\alpha)(c) = g^{-1}(p) \pitchfork c$ where $\pitchfork$ means the intersection number
Okay guys. Thanks a lot for all the information. I have an exam on Sunday, and need to study for them. Rather than sitting around with stuff that colleges don't teach till third or fourth year
In the site analytics, privileged users can monitor some things like the total traffic on the site. However, it seems to be broken at the moment, all figures are almost zero. This is how it looks for Meta Stack Exchange (other sites show similar pictures):
@0celo7 I'd say I'm about as far from a republican as can be, but I guess that'd put me in some sectors of the left that are rather... rabid and uncritical for my taste, I guess
@0celo7 You need to be careful about bush meat, especially with animals that spend their time rooting through the Earth. They have a tendency to be riddled with parasites. Admittedly many of these don't infect humans, but some do. And even with the parasites that don't infect humans, so you really enjoy eating roasted parasite?
@EmilioPisanty during my office hours yesterday for upper division E&M I had a guy who didn't know how to respond when I asked him how he'd compute the length of a vector
@NehalSamee given that there's multiple different written and mathematical statements of the second law, that's not (yet) a well-posed question as you've written it.
@EmilioPisanty Clausius said , " It is not possible to transfer heat by an automatic machine from lower to higher temperature body without the help of external energy
Claudius (; Latin: Tiberius Claudius Caesar Augustus Germanicus; 1 August 10 BC – 13 October 54 AD) was Roman emperor from 41 to 54. A member of the Julio-Claudian dynasty, he was the son of Drusus and Antonia Minor. He was born at Lugdunum in Gaul, the first (and until Trajan, the only) Roman Emperor to be born outside Italy. Because he was afflicted with a limp and slight deafness due to sickness at a young age, his family ostracized him and excluded him from public office until his consulship, shared with his nephew Caligula in 37.
Claudius' infirmity probably saved him from the fate of many...
@EmilioPisanty The text books I have don't include or compare entropy with the statements ...
@EmilioPisanty I know that entropy is said to be disorderliness and it's maximum value states that no exchange of energy is possible ( heat death ) ... I want to locate these in the statement ...
@0celo7 sounds like one of the other popular theories that the whole harry potter mythology are just delusions of a lonely kid locked in his cupboard by his abusive uncle and aunt