Recent content by Bosko

Space-time is a coordinate system. There are 4 numbers for each coordinate. Three for space and one for time. Some laconic answer would be that, like any coordinate system, it consists of points. In the theory of relativity, these points (four numbers) are called events. If you're looking for a...

Time and space as separate categories are a relic from the time before the theory of relativity. These are philosophical questions from 120 years ago. Now they don't make sense because space and time are not basic concepts. You should define more precisely what it means that something exists...

In my opinion two parameters are needed: p - the probability that the first (red) player wins on his serve q - for the other player (blue) to win on his serve Of course: 1-p and 1-q are the corresponding "loss" probabilities Here (tennis.svg) is a graph drawn in Inkscape (SVG format) if...

In general, if you have a system of differential equations with the property that space-time must be smooth everywhere, then a solution that is not smooth everywhere is suspicious. The only thing I found that has no proof in Schwarzschild's solution is: That a massive spherical object can be...

@PeterDonis, @Dale Thank you.

Look definition of the coordinate chart .

Is not with the Schwarzschild coordinates. If I understand you correctly, this would violate the very definition of the coordinate chart because of the diffeomorphism property .

Why is not ? Ok It should be smooth everywhere You are using a circular argument.

{Mentor’s note: split from https://www.physicsforums.com/threads/does-kerrs-argument-against-singularities-apply-to-all-black-holes.1061139 } However, a simple mathematical-logical problem remains: Einstein's field equations are a system of differential equations. Their solution should be...

The edge of a half sphere is not smooth. The spacetime should be smooth (Reimannian manifold) Does the speed of light remain the same then?

In that case, the gravitational flux would not be conserved.

In two consecutive serves ##p(1-p)## is the probability of the "win then lose" and ##(1-p)p## is the probability of the "lose then win" situation ##p(1-p)+(1-p)p=2p(1-p)## is the probability of winning one point each.

I read "Thirty Years that Shook Physics: The Story of Quantum Theory" by George Gamow. It is very catchy with a lot of personal impressions and anecdotes. Now I'm looking for a book with more details and formulas. Amazon > "Thirty Years that Shook Physics: The Story of Quantum Theory" by George...

Yes, and for me, the difference between OSI levels is not so clear. I consider as level 5 some simple protocols like Telnet, SSH, TFTP, maybe even FTP, SAMBA(SMB-windows file transfer) ... and mostly as level 6 some more complex like the HTTP/S because it needs, for example, to get index.php...

No. API is an interface. Check how the OSI model works. e.g. https://www.imperva.com/learn/application-security/osi-model/ HTTP and TCP are not at the same level of OSI HTTP have commands and messages for communication with the HTTP (web) server On API level you have a function like "give me"...