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That isn't quite right Ten oz. The threat can be perceived or real, it doesn't matter, as long as another reasonable person also feels and acts the same way. That, unfortunately, is one of the reasons kids or teens playing with toy guns, sometimes get shot by police. It is not the officer's fault, do you expect him to calmly walk up and ask to inspect the gun to see if its a toy ? And its not the kid's fault, he's just playing, so who's fault is it ? Maybe instead of finding blame we should be looking for solutions. Like why aren't this kid's parents telling him not to play outside, after dark, with a toy gun ? I only use this example because of the recent shooting death of a kid with a toy gun

Thank you studiot, your last sentence was the most valid and important contribution made to this topic so far. And you thought it was a useless topic ( Ha ! ) And no, Willie, Fundamental Christians and American conservatives do not cut people's heads off, slaughter captured males and rape wives and daughters, nor do they impose Sharia law in formerly secular areas, stone women to death for sexual improprieties, force them to cover their faces, take away their right to vote, get an education and drive. Shall I go on ? Oh, and your prejudices are showing ! When are we going to stop apologizing for our way of life ? It may not be perfect and needs some work, but compared with other countries or areas of the world ? If I didn't think I lived in one of the best countries in the world, I would exercise my freedom to move to one that I thought was better. My parents did that in 1968 when they moved from Italy ( limited opportunities ) to Canada. Despite what ZVBXRPL says, I'd have no problem whatsoever living in the US, and I'd have no problem helping him pack if he could find a better country to live in.

But that's not what Robbitybob asked. is it xyzt ? Do you have trouble understanding this ? Because ,if you want, I can explain this to you just as condescendingly.

Quasars tend to develop in the early stages of galactic formation. As material and stars 'fall' together to form a galaxy, the central part, being most compressed and including the largest ( hottest burning and shortest lived ) stars invariably forms a black hole which quickly increases in size, eating everything falling into it. As the galaxy matures and stars settle into defined orbits, the infalling material feeding the black holr decreases and the BH becomes dormant like the one at the centre of our galaxy or Andromeda. The 'quasar' is the polar jets of plasma produced by an active galactic core BH, from the infalling material. Most quasars are found at great distance, implying long ago, when the universe was young and galaxies were first forming. If the Milky Way/Andromeda 'collision' upset enough orbits such that stars/material started infalling agai into either of the BHs, then sure, one or both could become active again. Do you know what the typical distance is between stars ? The closing rate is small enough for orbital motions to be established without too much disruption, and probably zero stellar collisions. And even if a quasar were to be re-activated, the fact that the destructive jets are polar means they would be directed perpendicular to the plane of our galaxy, and we would be safe.

Robbitybob asked.. "so doesn't that imply that light inside the frame is falling at the same rate as everything else in that frame?" To which you replied... "No it doesn't. I already explained that to you in the previous post" Then you go on to present the geodesic equation and the distinction between massive and massless paths. So one of us needs to pay more attention to what they type or read, and stop making things up. I leave it up to readers to decide who that someone is.

7- reduce or eliminate lobbyist and their influence from governments. Oh, this isn't a political/governmental wish list ? I vote in favor of the voting holiday anyway.

Not defending Wilson by any means Ten oz, but not being able to claim they were 'scared' ? Police and firefighters cannot refuse to do their job based on unsafe conditions, like everyone else who's aware of labour regulations can. In some parts of the country 16 yr old kids ( and I don't just mean black kids ) are better armed than the average police officer. But that's a topic for another discussion. American law says that if you fear for your life due to the perceived actions of another person you can use force, up to deadly, to defend yourself. Bot that's another topic also. And as iNow is fond of saying, "all police ?". ( and of course, "all black teens ?" )

No you're right iNow, I'm generalising. But some non-religious people also hold radical views, what then is their motivation. We are not discussing ALL Muslims just those that hold extremist views, and comparing to extremists from other religions. Islam extremists SEEM to be more radical. Or is that only a shared delusion ?

While the Christian Bible is still the same Bible of the 11-1200s ( era of Crusades ), Christians have somewhat modified their thinking. While there is still a lot of intolerance towards differing ideologies and morals, no Christian group advocates the conquest andbeheading of others in the sake of religion. No matter what the bible says. Islam, on the other hand, still has the same barbaric views that Christians had almost 1000 yrs ago. That certainly can't be attributed to their holy book. Why have they not 'changed' with the times and also become more tolerant as the Christians have, no matter what their holy books say ? I would think there must be an alternate reason, as Vexen is suggesting. Oh, and studiot... By contributing to this thread, you are part of the problem. Just kidding. Looking forward to your scientific views on the matter.

You had better re-check that xyzt. In the frame of a falling observer, they are not accelerating. Otherwise you would have the curious case of seeing everything in a free-falling elevator become blurred, and horizontal light beams curving upwards.. Your equations and the resultant thinking are correct, but I don't think you're applying them correctly. Sorry, I don't do LaTex, but maybe Elfmotat can weigh in ?

For the case of a single extra compacted dimension, a simple looping line segment ( one dimensional ) at each point in space-time will do. The only guideline is that the loops be close to Planck length sized ( or else we'd 'see' them ). In the case of multiple extra compacted dimensions, such as in SString theory, the extra dimensions are subject to rules or constraints. I am nowhere near competent or confident enough to explain the fibre bundle concept, so I'll leave that to AJB. However, the idea that our 3d+t ( four dimensional ) reality is a projection of a higher ( 5d or more ) manifold is flawed. The idea is that you would take a 3D object like a pencil, and 'project' it into a 2D manifold, like a sheet of paper. The 2D 'Flatland' inhabitants of the paper would then 'see' a circle ( the circumference of the pencil ). In all models, the curvature has to be intrinsic, i.e. it doesn't curve in a higher dimension, there is no embedding. ( not sure about recent work in M-theory, can branes have curvature and even loop back on themselves ? maybe AJB can shed some light on that also )

We've had this discussion before AJB. While the EM field can be modeled on a flat background stage, and work perfectly well, the field equivalent in GR is space-time, with no background stage, and gravity ( or more exactly, curvature ) as a property of space-time. And while I suppose its just a 'point of view', I was implying that these are the commonly used models, and alternate models are possible, but may be more 'cumbersome' to use.

Just to be clear ( before Ten oz jumps all over me again ) we are not discussing the assignment of blame, That is for the courts to decide ( or not ). But if you are saying Brown had no choice in the way things went down you are wrong. He could have acted to defuse the situation, just as Wilson could have acted differently. They both made personal choices which, in retrospect, were extremely stupid, as one person lost his life, another's life is ruined and a whole community ( if not the country ) is suffering for those choices made that night. Now the only defense for Brown's actions ( we are not discussing Wilson at the moment ) that night, would be that the systematic mistreatment of black Americans throughout the country ( and certainly that area ), makes them distrust authority and more confrontational. But when I brought this up, many pages ago, in this thread, I was vilified by everyone as 'blaming the victim'. So again, as a community, how do we go about starting to change things. The ultimate goal is for all to have equal opportunity ( its not just a black thing ), but that could take years, decades ( its taken centuries to get this far ). How do we start building the trust between the black community and police to begin with, so that senseless deaths stop. Note that that trust has to go both ways. Police must 'trust' that not all blacks are criminals, and stop treating them as such. And black Americans must trust that police are there to 'serve and protect', not out to 'get them'.

I thought Blackberry security could already be incorporated into other platforms. Or is it just their 'secure' reputation that has people switching back. ( What do I know, I use a Win8.1 phone ) What about tensions in the Koreas, Ten oz, what's your predictions there ?

I don't think you got my meaning Phi. The gruff, older gentleman, who 'doesn't suffer fools' would be a reference to Ophiolite. He would have told this 'new member', rightly or wrongly, but most certainly accurately, that he was 'ignorant of the facts'. He always called a spade, 'a spade', and maybe he wasn't well liked for this, but he was certainly respected. If, on the other hand, I misunderstood your post, please PM me. Sorry for the OT comments.

Well now that you mention it... GR is a geometric theory of gravity, and you're right, EM force isn't geometric. It does not warp space-time. And we have a perfectly valid field theory for EM which, by the way, can and has been quantized, unlike gravity. However, in the early 1920s, two gentlemen, Theodore Kaluza and Oscar Klein, decided to extend GR to five dimensions ( four plus time ), and to their amazement ( and Einstein's ), found that, when the field equations are worked out, Maxwell's equations appear along with the usual GR equations. In effect, if there was a use or a need, EM could certainly be modeled as a geometric theory. Again, I urge you not to confuse the model ( geometric, field or rubber sheet ) with reality. Models usually have a limited domain of applicability, and every good scientist should know those limits.

So Willie, if these cultural and psychological effects are so deeply ingrained that even leveling the playing field, and removing all discriminatory and racist factors, will not change things, what is the solution ?

The problem seems to be that you can't really discuss Religion ( politics is almost as bad ), because it is based upon beliefs or faith, rather than facts. No matter how many facts you present in your argument, you will not change someone else's beliefs. Religion and science are based on differing paradigms. I, myself, have stopped responding to a certain new member, because no good can come of it. Although I find it kind of refreshing that we've always had members trying to dissect Religion with Science, which isn't right, and now we have someone doing the opposite; dissecting Science with Religion, which obviously isn't right either. You know what we need ? Some gruff, opinionated, older guy, who 'doesn't suffer fools', to call this new member 'ignorant of the facts'. Anyone know someone like that ?

The 'rubber sheet' is atwo dimensional simplification of 4 dimensional space-time. It is presented to the layman as a simplified model for easier understanding. Do not confse the model for the reality. You know what they say about a 'little knowledge', don't you ? I would read an introductory text on Genaral Relativity, inform yourself, then, and only then, should you try and embarass yourself with a new model for GR. Which has worked extremely well and been teted extensively for 100 yrs.

Also, how do you convince people to actually get out and vote. Voter turnouts in Western Democracies have been in decline for years. Is it just a question of ' things seem pretty good, why bother ' ? Should it be seen, not just as a right, but a duty ? Here in Ontario, Canada, our former Premier introduced several laws which directly affect young people after one of his friend's kids died, while intoxicated, in a motor vehicle accident. Under 23 yrs of age, zero alcohol level in your blood, ( kids were getting vehicles impounded/fined for taking cough medication ). and no more than two youths in a vehicle after a certain time of night. Yet these same kids were being sent to Afghanistan at the age of 18. You would think they would have gotten out to vote in droves against these discriminatory laws. They didn't. People should realize that if you don't exercise your right to vote, you may end up losing it.

Thanks for your help against Imatfaal's cabal, Ten oz.

Yes, they would still 'see' the longitudinal pressure pulses we define as sound.

Number 5 hits the nail squarely on the head . We human beings need hope. When someone is diagnosed with cancer and given weeks to live, he has no hope left. Now you ( and science ) might say he should just accept the inevitable, but we are not wired like that, we need hope, and so we turn to religion, our last hope. Now I just used terminal cancer as an example, but it could be any stressful situation in a person's life. Some of us have a higher tolerance to this 'stress', while others need this 'crutch' simply to survive and deal with life.

But science already tells us that sound is an objective phenomenon, only the interpretation of that sound is observer dependent. Or else our world would have about 7 billion observer dependent realities.

You have never had to provide this information because you're already on the voter list. But how did you get on that list ? Could a tourist from another country walk into a polling station and vote ? Could a person on a work visa from another country walk in and vote ? Could a US citizen born in another country, walk in and vote ? AT some point in the above procession, that information has to be provided.