Friday, September 2, 2016

astro picture for the day / quote for the day

Image Credit & Copyright: ESA/Herschel/PACS, SPIRE/Hi-GAL Project
Acknowledgment: G. Li Causi, IAPS/INAF

"Henceforth space by itself, and time by itself, are doomed to fade away into mere shadows, and only a kind of union of the two will preserve an independent reality." - Hermann Minkowski

Albert Einstein at first said, replying to the quote above, actually, "I can't recognize my own theory, after the mathematicians got their hands on it."  And so the legend that Albert Einstein was no mathematician grew.

Was he strictly a mathematician? No, he wasn't; he mostly just used mathematics already created to get his physics created.  It's known that David Hilbert helped him out on his General Relativity.  How much is unknown, as David Hilbert just gave all credit to Albert.  Fact is though, the mathematics and mathematicians had been leading towards Relativty theory for a long time. Bernard Riemann's work on "Riemann surfaces."  These can be thought of at a certain level as splitting a sphere into two sheets based on the positive/negative roots of a square root.  Then, there was Lorentze's and Poincare's work. Their work was in response to the Micheleson-Morley experiment disproving the existence of the Aether.  A substance that was suppose to carry the light waves through the cosmos.

- Some more mathematics, in relation to Jacob Bronowski's ideas. Jacob Bronowski points out that vague concepts are defined and expanded/generalized by creative analogy. In Einstein's General Relativity, Galileo's and Newton's for that matter, notion of inertia is generalized. Galileo's famous observation that different mass bodies fall at the same rate is explained by General Relativity. The inertial mass is equivalent to the gravitational mass.  Well, they weigh each other out. This is actually kind of analogous to Galileo's contraditons/thought experiment . . . that if you attach two bodies together, the logic says on the one hand, that the two bodies will accelerate faster because you have more mass.  On the other hand, the lighter mass will pull back on the heavier mass. Well, Einsten's equivalence shows that while the cannonball has more gravitational mass, it also has more inertia; so, they cancel out in a vacuum.  In a vacuum, the cannonball and the feather fall at the same rate.

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