MigL

I was an 'all-rounder', and did many things, in my mid-teens also; none of them very well. Now, at 66 years of age, there is only one activity I really miss. Chasing girls, and not getting anywhere. So make sure you have some fun too, at your age, as that is what you'll miss most when you're old.

Hello. The privilege is ours for having someone share a new point of view with us. Looking forward to interesting discussions.

It is not 'competing spheres of influence'. It is aggressor and victim; and any 'spectator' that allows it, eventually becomes a victim also. Apparently it's even possible not to do it in secrecy, have everyone notice it, and nobody do anything about it for fear of nuclear weapons. But who cares; it's happening to someone else ( so far ). THAT, is appeasement.

The only 'influence' being challenged is that Russia wants to control/dominate their 'sphere', while Europe wants their 'sphere' to be equal members and free. It has established NATO as a DEFENSIVE treaty ( see article 5 ) precisely to safeguard against Russian aggression ( see the Ukraine invasion ). Unfortunately Europe spends too much time 'hand wringing' and not enough taking decisive action. Russia sent drones into Poland > Poland, with the backing of NATO should have the right, and the will, to retaliate. People believed appeasement would stop a repetition of a world war 85 years ago; history proved them wrong. Thinking such as yours will do it again. Only France has independent nuclear capabilities. Ukraine once did, but gave them upon condition of security guarantees from Russia and the US. That didn't work out too well, did it ?

Another one ???? In the last 6 months we've had more 'theories of everything' than I remember seeing in the last dozen years. Are people getting smarter, or does everyone think AI makes them a genius ?

I applaud your enthusiasm, but these are fairly advanced concepts that most of us here find challenging. Without a basic understanding of Physics and the Mathematical tools needed for such understanding, quite a few people go off on 'flights of fancy', and tend to get labelled 'cranks'. Maybe concentrate on Newtonian Dynamics, basic Quantum Mechanics, Special Relativity, Conservation Laws, and Calculus, before tackling subjects on the frontiers of modern Physics. The 'basics' will help bound the possibilities, and keep your 'flights' close to the ground.

Maybe White Holes are composed of SuperSymmetric Particles. Oh wait ... They're predicted by the models, but don't exist either.

We have members who are dyslexic. We just like to hear your thoughts and opinions, not those generated by a 'group-think' server. Look into the Wheeler- DeWitt Equation, and ask as many questions as you like. I'm sure the discussion will gain all of us a better understanding.

Of course BHs exist. But your statement was 'As white hole should act with positive radiation pressure, shouldn't black hole act with negative?' and since WHs don't exist, they don't act with positive radiation pressure, so BHs don't need to act with negative radiation pressure. Does that clarify my position ?

You have an idea; but it is an old one, and there is no need for AI. See here Wheeler–DeWitt equation - Wikipedia

Or, we can still believe in CPT symmetries, BUT, White Holes simply do not exist.

No. We won't call you at all.

Why ask us; ask your Priest or spiritual leader. Either you're weird, or have some other issue, which means you shouldn't be using social media to get a diagnosis, but a licensed professional.

If Russia used nukes in a war of aggression, they would lose the support of China, India, and the 'crazy' states. I would say, even now, some of his military commanders must be questioning Putin's choices, but are afraid of pushing back for fear of getting pushed out of windows. Once it becomes clear that Putin intends to sacrifice everyone if he can't get what he wants, they, and the population, will push back, and take him out. Remember B Yeltsin standing on top of a tank holding a Russian flag, and the Armed Forces backing down ? Not all Russians are crazy.

Just because the model we have imagined and used says something can happen, does not mean reality has to comply. White Holes would be a lot easier to find than Black Holes, in fact, they would be among the easiest things to spot possible. Wer have detected thousands of BHs, some in galaxies 10 Billion years distant/ago, and we have actual photos of closer ones. NO White Holes have ever been detected. So basing your premise on how White Holes should act is a non-starter.

Primordial means they were formed in the hot, dense state shortly after the Big Bang event, not prior to it. Quantum fluctuations in the pre-inflationary universe would have led to regions of extremely high energy density, which would have gravitationally collapsed to BHs after inflation. The usual calculation involves upscaling from a quantum fluctuation with the inflation factor, and it predicts PBHs of fairly small size, prone to 'evaporation' by Hawking Radiation, and which may have evaporated by now. Hoever, the possibility exists that as these PBHs formed during the hot dense plasma stage, they grew very large through accretion, and formed the 'seeds' that became eventual galaxies. It is possible that some of the later formers, gobbled up their surrounding plasma too quickly, and were left 'bare', with no material to form galaxies around them, as the plasma, or eventual matter, had become much less dense. These would obviously be much larger than stellar BHs, and would probably only be found away from galaxy clusters ( voids maybe ? ), and through Gravitational lensing. Now, if you were to compress the ( observable ? ) universe back together, as suggested by "Big Bounce', everything would eventually be forced into a universal merged Black Hole, and we know of no mechanism which would allow for the 'bounce back' other than evaporation ( into where ? ), so I don't know how anything can 'survive' the collapse. I don't think Penrose's Cyclic Cosmology allows for full collapse into BH state

The AGM-114L is carried by helicopters ( L is for Longbow Apache ). and, due to its active mm-wave radar guidance, it can be used as a 'fire-and-forget' ordinance against other slow-moving aerial vehicles. But obviously, not jets.

What is 'real' ? Something that affects you in some way ? That you can see, smell, hear, touch, or detect with various equipment ? Because that star that went supernova a thousand years ago could not affect you in any way whatsoever a thousand years ago. But the image, which travels at the speed of light, along with any gravitational anomalies whose information travels at the speed of light, and any radiation, like neutrinos, which travel a little slower than the speed of light, are the effects that make it 'real'. By your definition, the Sun could be going nova as I type, yet it has no effect on me and I cannot detect it in any way for 8.5 min., so how is it 'real' ? Yet in 8.5 min. it will absolutely be real.

Thanks @studiot . looking forward to it.

Yeah. I think the 'anti-time' discussion ran its course awhile ago. But the tangential discussions have proved interesting.

Have a great time in Sicily; the cactus fruit, or 'prickly pears', are great.

Hellfire missiles don't bounce. Here is the detonation sequence for a Hellfire missile... "A Hellfire missile is launched, guided by laser or radar to its target, and upon impact, an M820 fuze activates the warhead's detonating mechanism. The fuze requires electrical power and significant forward acceleration (greater than 10 Gs) to arm itself. Once armed, it initiates the detonation sequence for the warhead, which can be a HEAT (High Explosive Anti-Tank) charge designed to penetrate armor or a thermobaric charge that disperses and rapidly burns. " And who, in their right mind, would fire a Hellfire missile at an unidentified object. Air forces, and armies, of all Hellfire operators have strict rules of engagement, requiring positive identification of targets. Could this have been simply testing of the guidance system of an unarmed Hellfire missile ?

Maybe I should add this to the 'Today I Learned' thread ...

I thought that was Syracuse in Sicily ( Southern Italy ). Maybe Ken can do another 'deep dive' and find out why ice levels seem to be disappearing at a faster rate in the Northern hemisphere as compared to the Southern. The slope of the ice loss graph seems much steeper for Greenland than Antartica; is the greater land mass just a larger heat sink or are other factors at play ?

Yeah. As TheVat mentions, in spherically symmetric systems, spherical polar co-ordinates can vastly simplify solutions. One example would be the solution of the Schrodinger equation for the Hydrogen atom. It is a partial differential equation in (radius, theta, phi) where we can use separation of variables, as the spherical symmetry allows the 'removal' of the angular co-ordinates (theta, phi) leaving a differential equation in one variable (radius), that even I can solve. I'm sure it could be done by someone ( else ) in cartesian co-ordinates, but it would be extremely messy.