…a great way to stay on top of the dynamic field of Opticianry and make some friends in the process.
…a great way to stay on top of the dynamic field of Opticianry and make some friends in the process.
December 2005 Scientific American has a cover story Scientific American: An ECHO of Black Holes [ PHYSICS ] “Sound waves in a fluid behave uncannily like light waves in space. Black holes even have acoustic counterparts. Could spacetime literally be a kind of fluid, like the ether of pre-Einsteinian physics??” by Theodore A. Jacobson and Renaud Parentani. In this article, the ether makes somewhat of a comeback. Perhaps a flashback is in order. Before Einstein, it was believed that time and space were both universal and absolute. One would take the position or time relative to the “ether.” It was also believed that vibrations of the ether is what constituted light. Einstein proposed that light was not a vibration of an ether, but packets of energy, called photons, that travelled through the vacuum without the need to be supported by any medium. One of the key ideas about the article states that “… the propogation of sound in an uneven fluid flow is closely analogous to the propogation of light in a curved spacetime.” As opticians, we hold to the wave theory of light as expounded by Christian Huygens. It’s interesting to see the notion of an ether being brought up again in physics. According to the article, thinking of spacetime as a fluid can solve a lot of conceptual problems related to Einstein’s theory of relativity. One such problem deals with Hawking radiation. Stephen Hawking wrote a very important paper about black holes that suggested to the physics world that black holes are not eternal and in fact do emit something. (Warning: the following may confuse the hell out of you. It did to me too, until a I reread the section a few times) The problem with Hawking radiation is that at the event horizon some virtual particles become real particles, if each pair of virtual particles seperate from each other (<-- This relies heavily on a phenomenon in quantum mechanics known as pair production). The crux of the problem is that a particle will infinitely blue shift as it goes away from the event horizon. I know that I may have lost a lot of readers with the previous statements and I’m trying to add as many links as possible to key vocabulary and ideas so that any of you that are confused at what I wrote can fill in any gaps I may have left. Overall, a very good copy of Scientific American.
Optician n. One who is extensively trained in the interpreting of ophthalmic prescriptions and applies that knowledge to obtain the optimum visual and safety performance for the patient in a pair of spectacles or contact lenses.
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Friend n. 1. A person whom one knows, likes, and trusts. 2. A person whom one knows; an acquaintance. 3. A person with whom one is allied in a struggle or cause; a comrade. 4. One who supports, sympathizes with, or patronizes a group, cause, or movement.
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