Strange

Here is a nice illustration of how you can view space as "falling" into a black hole (taking things with it). It reaches the speed of light at the event horizon, which is consistent with the description in the first post: https://jila.colorado.edu/~ajsh/insidebh/waterfall.html

Although it is often explained that way, that is not the reason you can't escape a black hole(*). After all, you can temporarily leave the surface of the Earth at less than the escape velocity. But you can't leave a black hole, even temporarily. It is better to think of it as being due to space time curvature: after you pass the even horizon, spacetime is so curved that there are no paths that lead away from the centre of the black hole. Whatever direction you go is towards the centre. Worse, spacetime is so curved that "towards the centre" is no longer a spatial direction but is your future. And there is no escaping the future (*) Actually, I suppose that in Guilstand-Painleve coordinates it is true.

! Moderator Note Amusing as some of the responses are, this is likely to be in violation of our rules in civility. (I'm not sure we have a defense of "provocation") so I am closing this thread. @Ken123456 Do NOT start another idiotic thread like this. We don't care about your beliefs.

! Moderator Note Similar threads merged

Odd that you don't tell us what you think the answer is, then. As with all these stupid puzzles, I guess one can make up a story to justify any answer, but in this case it seems reasonable to say (as your friend's list shows) that the answer is N * (N + 3) = 10. I don't understand what all the shouting about (or what your friend said vs what you said) or why you have posted everything twice. Is that part of the puzzle 🙂

You could stick around and get involved in other discussions. That might be interesting and it might help you clarify your ideas in you own head so that you are able to explain them to others.

It seems infinitely more likely that you just haven’t worked out how the trick is done. This should not be surprising: even professional magicians are not always able to work out how a trick was done. For example: https://en.wikipedia.org/wiki/Penn_%26_Teller:_Fool_Us - even when they are fooled, they have never said “well, I guess you must have really made it disappear”

As you are unable to explain this vague feeling to anyone else, in meaningful terms, it seems to be the most spectacularly useless idea ever. "My theory of everything is that things seem kind of right to me in a way I can't quite define"

! Moderator Note Please feel free to try again with an explanation of what you want to discuss.

! Moderator Note One is science and one isn't. You already have one thread that has rambled on incoherently for 11 pages. I don't think we need another one.

It doesn't strike me as a very useful analogy as you end with a croissant every time. (Half joking; half serious)

! Moderator Note What is the connection between data structures and interrupts? Stop posting nonsensical questions

Looks like someone beat you to it: https://www.quantamagazine.org/the-map-of-mathematics-20200213/

Without knowing more, it is impossible to say. But videos are notoriously bad sources of information (I have seen a video of aliens attacking Earth; pretty sure it wasn't real.)

I must have been away that day.

Is it bad that I have never heard of that before? Can I blame my teachers?

Pretty much everything in mathematics can be proved. There are a few well-known problems that have not been proved yet (some have substantial prizes associated with them). It took over 300 years before someone proved Fermat's Last Theorem. That is partly because it had to build on a huge amount of mathematics that was developed in the meantime. Some very simple looking problems can be very hard to solve. Some quite complex sounding problems, that people have struggled with for decades, might turn out to have a really simple proof. (Mathematics is one of the few files where outsiders can, and do, make breakthroughs.) There are lots of unknowns in mathematics (e.g the continuum hypothesis; that there is no infinity between the (infinite) set of integers and the (infinitely larger) set of reals) that have not yet been proved either way. And there are some problems for which it can be proved that there's no solution. But I don't think you can ever say that a particular problem is unprovable because of Gödel Incompleteness. Unless it is a problem specifically constructed to be unprovable for that reason (which is how Gödel proved the theorem; by constructing a mathematical statement that could not be proved in the rules of the system).

! Moderator Note I think we require something a little more rational and fact-based than this, even in the Philosophy section.

And I am just trying to give you an idea of the sort of massive scale you would need to be dealing with, even at close range, to produce something that can only just be detected by, perhaps, the most sensitive device on the planet. I'm not sure it would. And they would be swamped by the physical vibrations caused by the explosion.

No. They are purely about the "completeness" of formal systems. In other words, can a formal system (e.g. mathematics) prove that anything that can be written down using that formal system is either true of false. And the answer to that is no. You can write something using mathematics that you cannot use the same mathematics to prove or disprove. You can extend your formal system to make it more complete and allow you to prove that statement. But then there will be other statements that this extended system cannot prove. And so ad infinitum. Physics uses mathematics but it is not limited by that mathematics in the same way. (And some mathematicians complain that physicists are a bit "ad hoc" and don't really stick to absolutely formal derivations.)

Yes. Because the Lorentz transform is reversible (I'm sure there is a proper mathematical term; linear?) so the events get transformed from O to A and to B, then if you transform them back to O you end up where you started. So, they might not agree about the ordering of events in their frames, but they will agree about what is seen by an observer in O.

They can do it either way: they can transform their measurements to O (which could be one way of A and B comparing their own local measurements). O they can transfer O to A or B, respectively. Hang on. They won't agree on the time between events in O (as they measure it in A and B). They might not even agree on the relative ordering of events in O.

If we assume that things scale linearly (almost certainly not true) then, based on the first gravitational waves detected, you would need two masses of around 7kg total, spinning round each other at nearly the speed of light to generate an equivalent signal (i.e. causing movement of less then the size of a proton). So, not at all practical. I don't remember the exact figures, but I seem to remember that if those two merging black holes had been at the distance of the sun, the gravitational waves would have had almost no perceptible effect on earth. Even though they carried away several solar-mass equivalents of energy is a few milliseconds. Gravity is very, very weak.

If the LED was actually a laser (as in a laser pointer) then you might be seeing laser speckle. But that is only where it is reflected from a surface, not around the light itself.

Humans have about 25000 genes. So a change of 0.1 would require 2,500 mutations. Then again, the son only gets about half their genes from the father so the difference could be much larger than that