On Thursday, October 27, 2016 at 11:39:47 AM UTC+3, Pentcho Valev wrote:
> https://www.timeshighereducation.com/books/review-reality-is-not-what-it-seems-carlo-rovelli-allen-lane
> "If you think that you know what space and time are, be prepared for your intellectual foundations to be vaporised. Carlo Rovelli will melt your synapses with this exploration of physical reality and what the universe is formed of at the very deepest level. His story starts with the ideas of ancient Greeks and accelerates through the Newtonian revolution to the strange worlds of quantum physics and relativity, and their even weirder recent marriage in quantum gravity theory. Reality here is "a world which does not exist in space and does not develop in time"."
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> Bingo thinks he knows what his real name is but the Clown vaporizes his intellectual foundations:
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> https://www.youtube.com/watch?v=gX5ajyPr96M
> Bingo the Clowno
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> Joe Wolfe's students think they know what speed is but Joe Wolfe vaporizes their intellectual foundations:
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> http://www.phys.unsw.edu.au/einsteinlight/jw/module3_weird_logic.htm
> Joe Wolfe: "At this stage, many of my students say things like "The invariance of the speed of light among observers is impossible" or "I can't understand it". Well, it's not impossible. It's even more than possible, it is true. This is something that has been extensively measured, and many refinements to the Michelson and Morley experiment, and complementary experiments have confirmed this invariance to very great precision. As to understanding it, there isn't really much to understand. However surprising and weird it may be, it is the case. It's the law in our universe. The fact of the invariance of c doesn't take much understanding."
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> Steve Carlip helps Joe Wolfe in vaporizing students' intellectual foundations: The speed of light is constant by definition. Einstein said the speed of light is variable in a gravitational field - an interpretation which is perfectly valid and makes good physical sense - but after Einstein the speed of light in a gravitational field became constant and is going to remain so forever. So constant that "it does not even make any sense to say that it varies":
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> http://www.desy.de/user/projects/Physics/Relativity/SpeedOfLight/speed_of_light.html
> Steve Carlip: "Is c, the speed of light in vacuum, constant? At the 1983 Conference Generale des Poids et Mesures, the following SI (Systeme International) definition of the metre was adopted: The metre is the length of the path travelled by light in vacuum during a time interval of 1/299 792 458 of a second. This defines the speed of light in vacuum to be exactly 299,792,458 m/s. This provides a very short answer to the question "Is c constant": Yes, c is constant by definition! [...] Einstein went on to discover a more general theory of relativity which explained gravity in terms of curved spacetime, and he talked about the speed of light changing in this new theory. In the 1920 book "Relativity: the special and general theory" he wrote: "...according to the general theory of relativity, the law of the constancy of the velocity of light in vacuo, which constitutes one of the two fundamental assumptions in the special theory of relativity [...] cannot claim any unlimited validity. A curvature of rays of light can only take place when the velocity of propagation of light varies with position." Since Einstein talks of velocity (a vector quantity: speed with direction) rather than speed alone, it is not clear that he meant the speed will change, but the reference to special relativity suggests that he did mean so. This interpretation is perfectly valid and makes good physical sense, but a more modern interpretation is that the speed of light is constant in general relativity. [...] Finally, we come to the conclusion that the speed of light is not only observed to be constant; in the light of well tested theories of physics, it does not even make any sense to say that it varies."
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> Pentcho Valev