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| The mystery of "light"; head scratcher | |
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| Tweet Topic Started: Jul 26 2009, 07:18 AM (993 Views) | |
| Mike | Jul 26 2009, 07:18 AM Post #1 |
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http://www.nobeliefs.com/light.htm I started to read this, and then started to scratch my head. LOL. This is the perfect place to kick this around. |
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| Brewster | Jul 26 2009, 07:44 AM Post #2 |
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Applies to gravity as well... We have lots of formulas that describe and predict how it works/will work, but very little idea how it happens... Gives science something to do for the next few hundred years... |
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| ngc1514 | Jul 26 2009, 08:38 AM Post #3 |
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The problem is you are thinking there is some deep reality in quantum theory (the idea that light "exists" between events). The idea that the photon is a "real," something that can be described in non-mathematical terms, is the absolutely wrong way to approach quantum theory. Physics doesn't CARE if light exists between events. It's a meaningless question. The only way to can test whether it exists is by measuring it and measuring is an event. Quantum theory describes the universe not in terms of particles, but in terms of probability waves. Making a quantum measurement "collapses the wave function" and tells us something about the wave. If we measure to see if the photon is a particle, it will show the characteristics of a particle. If we measure to see if it's a wave, it will show the characteristics of a wave. It's how the universe works and we can predict the outcome of any quantum measurement perfectly. It's the only perfect theory man has ever devised. The author of the paper you linked said: "We know nothing at all about its physical mechanism." Physical mechanism implies some deep quantum reality behind the math. Nothing indicates such a reality exists. Simple? |
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| Mike | Jul 26 2009, 01:48 PM Post #4 |
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I don't think it's simple. Scientists cn only observe through measurements but can't define what they are measuring. One experiment I read about said particles jumped forward in time. A question for the scientists in the crowd. Where did the light come from that was being measured...and where did it just go off to after being measured? |
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| ngc1514 | Jul 26 2009, 11:22 PM Post #5 |
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You are making an assumption that the measurement is different than that which is measured. The question of "what they are measuring" is ANSWERED in the act of measurement. Look up the Copenhagen interpretation of quantum mechanics.
From the Wiki article on "Interpretations of Quantum Mechanics." As the article mentions, the question of "where was the particle before I measured its position" is a meaningless statement. Take it a little further and you'll see "what was the particle" is equally meaningless. The whole concept of particle is Newtonian. |
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| Mike | Jul 27 2009, 12:35 AM Post #6 |
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I don't doubt that the wave function is measured, but I reject the notion that in a thread discussing light, that where it came from or where it goes is meaningless. Probabilities are just that..something ill probably act a certain way. This is meaningless. Under differing conditions, light seems to curve around and is capable of being manipulated. And there is something behind light that keeps it at a ..well speed of light. Does it slow down when also affected by things around it? And if so, what causes it to speed up? |
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| ngc1514 | Jul 27 2009, 07:21 AM Post #7 |
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No one has said that where it comes from is meaningless. The process to create a photon - an electron dropping down an energy level releases a photon to conserve energy - is well understood. The concept of "where it goes" is meaningless. It is only through the act of measurement that the location of the photon can be determined and, during that act, the photon disappears as it is translated back into the energy required to move whatever meter is used for the measurement. Sorry Mike, but your declaration that the concept of a probability wave is meaningless is... meaningless. You continue to see some deep reality beneath the quantum measurement - a reality that physicists find no need. Photons travel at the speed of light from the moment of creation to the moment when they are absorbed and kick an electron into a higher, more energetic orbit. They can be slowed down and have actually been brought to a complete stop as photons are beamed into a Bose-Einstein condensate. Light slows down as it moves from a less dense to more dense medium (the basics behind refractive optics) and jumps back - without the input of any energy - to the speed of light when it gets into a vacuum. Asking "what causes it to speed up" is Newtonian thinking. Newtonian thinking will not help in quantum mechanics. The best non-technical introduction to all this is Nick Herbert's Quantum Reality. Edited by ngc1514, Jul 27 2009, 08:27 AM.
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| ngc1514 | Jul 28 2009, 11:05 PM Post #8 |
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Perhaps I scared you away, Mike. It's understandable why you declare the concept of a probability wave as "meaningless" if you don't understand what lead physics to this conclusion. This isn't something that was dreamed up by physics, but a result of experimental observations of how light works. The basic experiments into the nature of light are the single slit and double-slit experiment. The single slit experiment shows light can be thought of as little discrete particles while the double-slit shows light is a wave. The interference pattern can be perfectly explained by wave phenomena and the "interference" as the crest of one wave interferes with the valley of another and they cancel each other out. You can see the same phenomena if you throw two stones into a pond and watch how the waves interact. So far we are still in the world of Newtonian physics. We do not enter into the realm of "quantum strangeness" until the experimenter fires single photons or electrons at the double slit. Even now, the same interference pattern builds up as one electron after another is fired at the double slit. What can possibly interfering with a single electron? The answer is that the electron is actually going through BOTH slits at the same time and interfering with itself! Welcome to Quantum Strangeness! Here's a little video that might show the import of the double slit experiment in a more graphic format. |
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| ngc1514 | Jul 29 2009, 01:49 AM Post #9 |
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Just picked up a new book from the library entitled The Age of Entanglement:When Quantum Physics Was Reborn by Louisa Gilder. Got a good review in the NY Times Book Review section a couple weeks ago. I'll let you know if it's any good. |
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| BUCK | Aug 1 2009, 09:05 AM Post #10 |
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"One might still like to ask: 'How does it work? What is the machinery behind the law?' No one has found any machinery behind the law. . . We have no ideas about a more basic mechanism from which these results can be deduced." -Richard Feynman A friend of mine was a student of his at Cal Tech in 1955. We attended a lecture of his on orbiting bodies at Los Angeles City College. I had the pleasure of being introduced to him. His lecture was so enlightening that when he said, lets break for ten minutes so students can go their next class, no one in the audience moved, including most instructors. From all that I have heard about him, he was a real partytimer, and his students cried when he passed away a few years ago. |
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