MigL

Mathematics aside ( because we know GR is incomplete, and all its predictions are not consistant with scaling effects ), while I agree G cannot be variable locally, or wrt time dilation ( ? ), there is the possibility that G is a global variable, and in a Machian manner, could depend on the size, and/or energy distribution, of the universe. You would then, have G evolve with the evolution of the universe such that earlier eras of the universe would have differing values of G. Examining far-away ( and therefore, much earlier ) parts of the universe has yielded no variation in the value of G. And observational evidence, not pretty mathematics, is the final arbiter.

One could make the argument that a politician's most important job is to get elected, otherwise they are useless. re are many ways to get elected. Your dad, the bootlegger', and the 'mob' could buy your election. You could be vice-President when the President gets assassinated. You could wiretap your opponnts offices in the Watergate building complex. You could be vice-President when the President quits to avoid impeachment. You could tell 'folksy' tales to connect with common folks, even though you were a rich ex-Hollywood actor. You could promise "Read my lips, no new taxes", in order to get elected, then raise taxes You could argue about what the definition of 'sex' is, in order to get re-elected. You could take advantage of a dispicable terror attack, and call yourself a 'war President' in order to get re-elected. Etc.. Heck, you could even incite a bunch of idiots to attempt the overturning of an election that you lost ... You want me to do Canadian PMs next, Peterkin ?

Probably not the answer you're looking for, but why not cut a cga850 and a cga870 adaptor and have them welded by the machine shop. ( I don't think an adaptor is available commercially ) Any coupling disc you have made will more than likely leak, and will still need to be replaced every couple of fills. For filling hi-pressure, hi-purity Phosphine we only use coupling discs once at our plant. Then again, you don't really want 600-700 psi Phosphine leaking; Oxygen may be different.

I know what you mean Beecee, America's most beloved President, J F K, was a womanizer who had very little respect for his wife, and banged more women than Bill Clinton could ever dream of, or Donald Trump could ever hope to pay for. In my own country, our PM, while constantly preaching gender equality, is condescending towards women, and kicks them out of cabinet if they won't lie for him. The only female Canadian Prime Minister was a Conservative, not a Liberal. All the Presidents mentioned in the OP were 'right for their times', but also flawed in many ways. Same as some current Presidents. All are human, and have good and bad qualities; but there is never a right time for a D Trump.

IIRC, when there is enough angular momentum, the event horizon disappears, leaving a 'naked', ring singularity. " When {\displaystyle r_{s}/2<a} (i.e. {\displaystyle GM^{2}<Jc}), there are no (real valued) solutions to this equation, and there is no event horizon. With no event horizons to hide it from the rest of the universe, the black hole ceases to be a black hole and will instead be a naked singularity." From Kerr metric - Wikipedia AS for the OP, the 'rubber sheet with a bowling ball on it' is a visual model, and just like all models, even mathematical ones, it is not applicable in all situations, and some predictions are non-sensical. Just like GR, our best model, makes some non-sensical predictions, the visual rubber sheet model makes many non-sensical predictions. Such as the 'force' pulling the rubber sheet down. Or that the mass is not intrinsic to the spacetime, but sits above it. Or that there is an 'exterior' to space-time. Or that the warping of spatial dimensions is responsible/equivalent to gravity. Or many others where it ceases to be applicable.

Thanks for clearing that up, Phi and Swansont. I wasn't aware of the above cases; at least a few people have stopped 'throwing popcorn in our faces'. I did get something out of the discussion, such as knowledge is a 'justified true belief', which is still only a belief unless you ascribe one particular meaning to the word 'true', at least in my mind. Maybe Eise will elaborate, one day. And I hope Davy_Jones got some insights into Physics, and how it works, so that it wasn't a total wasteof time for all.

Sometimes the 'paradoxes' inherent in a model help determine its areas of applicability. GR allows for time travel, albeit using other theoretical constructs such as 'wormholes'. GR also allows for singularities, points of infinite density, which are obviously non-sensical, so we say that GR is not applicable in the realm of very small separations, and very high energies. By the same token, the grandfather paradox breaks causality, things happen before they are caused, which is also non-sensical. Therefore, although GR allows for time travel, any predictions are questionable, as the paradox shows GR is not applicable in that situation. Your question then boils down to "If I imagine something is possible, can I imagine something else is also possible ?" And there is no science in that question.

This is probably off topic in this thread Swansont, so please move or split off. This site purports to be a teaching/learning discussion site. Learning implies a modification/expansion of your thinking. So why assume, as the sock puppet rule does, that someone, who use to be a jackass, and got banned, has learned nothing from the interaction, and deserves to be automatically banned ( even while posting some interesting/thought-provoking and controversial questions ). I did agree to these rules on joining, so I'm not asking for a change of the rules; just an explanation of the thinking behind that particular rule.

Why does everyone assume one side or the other would have to give up their culture, customs and laws, in a union of the two countries ? Have any of you ever crossed the Ontario/Quebec border, in the country of Canada ? It's like instantly being on the other side of the world. I would say that even some current American States differ more in some respects than the UK would.

I thought he was too concise, to the point of being absurd. Ascribing only one specific meaning, to words the general population has different meanings for. And attempting this at length, over three threads ( is that the quantity part ? ). His fault was trying ( insisting actually ) to make us all think and communicate like Philosophers. ( sometimes, not always, that might not be a bad idea ) His posts had nothing to do with his getting banned. It was the 'sock-puppetry' rules, not posting style or content.

The UK ??? Not a chance. I give them 10 years before they're back with the EU; too many common interests and endeavors. Although parts of the US, specifically the North-East and the whole West coast, have expressed interest in becoming Canadian provinces.

I have no problem with rats, snakes, snails, croccodiles, etc. It is only photographs of creepy-crawlies of the insect variety, that leave me feeling as if they are crawling all over me ... And yes, it is especially bad in fog, when you can't see the little bast*rds.

Never did like ouzo; I prefer sambuca 😀 . But the vistas, ancient sculptures/architecture and seafood on the islands are fantastic. I would submit that Italy , Spain and Portugal suffer from similar levels of fraud, hubris and incompetence. Their economies aren't in nearly as bad a shape as Greece. So what do you think is the real reason for Greece's economic meltdown ?

Such as? Greece .

During the 2008-9 deflaton, GDP dropped by about 5% ( biggest drop in the postwar era ). Government spending ( in effect, printing money ) increases inflation ( in the 4% range after 2008 -9 ), and while inflation is good for those who can manage to service their personal debt ( they owe the same amount, but their house has increased in value, ie. investment opportunity ), it is no consolation to the thousands who could not, and lost their homes. Are they not part of the economy ? How many small-industry towns became ghost towns after 2008-9 ? edit Not saying Government spending, or borrowing, is bad, but it has to be carefully weighed against what it could lead to. Exactly the same as personal debt.

Not sure if I would goall the way o free, if there is really 'free' anything. But certainly subsidized enough so that a student could work a summer job to earn enough for his/her tuition. Things you have to work for are always more valued/appreciated.

Yet we saw th case, in 2008, where house hold debt, brought world economies to their knees.

Given that rates are historically low and practically zero, they have literally nothing BUT opportunity to raise them, significantly or otherwise. How so? One of the 'controls' used to keep inflation at manageable levels is variance of lending rates. Once the citizenry has taken on too much personal debt, the ability to raise lending rates has to be used very carefully ( or not at all ) as it would lead to massive defaulting on debt, bank failures and recession. As in 2008. We realized, then, that unrealistic debt levels were a problem, and stricter controls over borrowing were solutions, yet in my area, home ownership has become impossible or young pople, due to house prices doubling in the past two years ( over 1/2 Million is entry level ). Scarcity of rental property ownership has resulted in skyrocketing rents, and increased homelessness Have we already forgotten ?

Isn't the bolded part exactly what Physics does ? Thereby making Markus' statements, about Physics, 'true'. ( or am I just Philosophising ? 😄 ) I also think Davy_Jones brought some interesting topics to the forum that got people participating again. I must say, I did enjoy his brief time here.

You choose from your available options; I'll choose from mine. And sometimes we make our own 'hell' by the options we choose. It's not always someone else's fault.

And if those entities are Philosophers, they may open several threads to convince the rest of us that theirs is the only 'true' meaning of reality ?

If by 'keep on going' you mean do things, like work, then it is energy that keeps it 'going'. Energy has some funny properties. If you have a box divided by a partition, where one side has a more energetic gas than the other side, the partition will be accelerated, and move. That is an example of doing work ( much like the pistons moving in your car's engine let you travel down the road ) When the gas on both sides of the partition has equal energy, obviously the partition will stop moving, and no more work can be done. Notice that the total gas still has energy, but it is the difference in energy that allows work, and processes to happen. So, we have useable energy, which can do work, and un-useable energy which cannot. We call this process, of converting useable energy into un-useable, entropy. Entropy can also be a measure of the 'order' of a system, which means that, although it can be reversed locally ( life is proof of that ), it must always increase globally. That is where the idea for the 'heat death' of the universe comes from. Once entropy of the universe is maximized, and there are no more energy differences, all work and processes will cease, and the universe will essentially be dead. This is a rather simple explanation, which is, hopefully, suitable for your level of understanding. If you should need elaboration, don't be afraid to ask.

Studiot's example considers the space-time interval ( actually a 2d interval in his example ), but you are right md65536, it doesn't illustrate the geodesic deviation ( I have to stop saying curvature because of the implications ).

That is NOT true, and could not have really happened! You are not 300 years old so you could not possibly have heard him say that. On the other hand, it is certainly true that he said that, Don't you see the variability of the word 'true' ? Atoms are now real ? Their effects and interactions can be observed and measured for sure ... Ask Mr Perrin if the mass of three quarks, which cannot be separated, that make up a proton/neutron in an atom, add up to the mass of said proton/neutron. Ask him to measure the diameter of one of those quarks, or an electron, that make up those atoms. Then ask him by what definition of reality do the masses of three dimensionless points add up to less than 2% of the mass of the particle they make up. Surely his definition of 'real' is not the same as yours. I am learning a little Philosophy from you, as I hope you are learning a little science from me, however I must admit, I am a little puzzled by this Philosophical technique you are using. What do you call it ? Beating your head against the wall, and insisting others use your definitions to describe their concepts, even after being repeatedly tol that your definition is not applicable ? Oh, and I fail to see why the opinions of the scientists you quote are any more relevant than the opinions of the scientists on this forum. If anything, they simply illustrate the variability of words like 'real' and 'true' to scientists, as opposed to the one-and-only definition, written on a gold bar and stored in a vault in France, that you Philosophers think everyone should use.

Wasn't that the point of your other thread, where you were told science describes effects and interactions, but does not so much care if things are 'real' ? You place too much emphasis on the word 'real'. He means real in the sense that the oserved effects are due to a grvitational interaction between massive particles, as opposed to an inadequacy of our gravitational model ( see MOND ) or a misunderstanding of the science. Real and true are not sacred words to scientists, although Philosophers seem to think so. Was that not the thrust of your second thread, the difference between Philosophy and Science ? We have different uses for those two words ( and probably others ), yet instead of being multicultural, and celebrating those differences, you want to make us conform to the Philosophical usage. ( I'm from Canada, we embrace multiculturalism here 😄 ) edit Frank Sinatra and poached eggs are both overrated. I prefer Dean Martin and over-easy.