@2physics I hope, your country will have once nuclear weapons and also rockets. The so-named western civilization is going to a very bad direction; it seems without an external "threat" they can't get back
@2physics And don't worry that you can't pay on the net. Where it is possible, usually it only means that the whole country pays a lot to big u$ companies
@peterh maybe, but actually when you can't pay internationally on the internet, it means you also cant get money online :D . besides, here's third world, I don't expect much anymore
@2physics No, no, they aren't so dangerous. Our big brothers somehow doesn't fear from them, they have the second most on the World. It is tragic to see, how the whole EU is a whore of the U.S. political elite.
@2physics As the communism collapsed, we all loved the west, we were happy. But now what we can see, that the western world seems more and more like the communism.
@SirCumference : it forms from the inside out in finite proper time. Remember that Oppenheimer and Snyder found in 1939 that gravitational collapse in vacuum produces a "frozen star". Then use a hailstone for an analogy. You're a water molecule, you alight upon the surface, but you can't pass through it in finite time. However you can be surrounded and buried by other water molecules. So the surface can pass through you in finite time.
@peterh you know, although the government is closed tho China and Russia's govs, but people doesn't trust in russia's gov and also you may find it funny, you said we can find a way to deal with china or russia for our online payments. I have to say a general believe has formed here among the people that whatever you find the name of china on it to buy, is of low quality and doesn't worth it to pay for.
Hi guys! I need a suggestion. I am making the following plots. The first it's ok. I want now to apply an extremely important cut, imposing $x\geq 0 and y\geq 0$. I was thinking to "cut" the remaining area with diagonal lines like in the figure on the right (I made it with photoshop but I will do it with Mathematica) but I am not sure it's good… what do you think it's the best way (style) to stress the fact I am applying a cut?
@0celo7 : I don't have theories. They're Einstein's theories. And they aren't crackpot. If they sound crackpot to you, then it's probably because some other theories or interpretations that you've learned about are crackpot instead. For example you may have learned that light doesn't get out of a black hole because space is falling inwards. That's crackpot. A gravitational field alters the motion of light and matter through space. it doesn't make space fall down.
@0celo7 : ah, Kip Thorne, the man who believes in time travel. And Roger Penrose, the man who will tell you about the parallel antiverse. And Sean Carroll, the man who will tell you about the evil-twin universe where time runs backwards. Ho hum.
@JohnDuffield So I like the complex Penrose-diagrams... and it is so sad, that somehow tricky GR things excite the VtC reflexes of our most active reviewers.
@peterh : I dislike even the simplest Penrose diagram. Note that the precursors to the Penrose diagrams were Kruskal–Szekeres diagrams. I think they're misleading, because when your optical clock is stopped, you can't make it start ticking by putting a stopped observer in front of it. He doesn't see it ticking normally in his frame. He's stopped, and so is the clock. He doesn't see anything.
it's the list of undergrad, and grad studies courses and references in some universities over here*, but it's not standard , depends on teachers actually: phys.sharif.edu/…
@0celo7 There a very strange tradition to not teach this fact to people, and then define "separated" in algebraic geometry by a very similar property without saying it's a generalization of Hausdorff
Of course, you'll need certain characterizations of "closure" for that, and knowing your insistence to not use what you have not proved, I'm not going down that rabbit hole with you.
@0celo7 Defining the interior ot be the union of all open sets inside the set, and the closure to be all closed sets containing the set, this isn't hard to show. If you've been struggling with this for two years you never really tried it.
It's a classic "show carefully both sides are subsets of each other"
