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Name: David B.
Status: student
Age: 30s
Location: N/A
Country: N/A
Date: 2001-2002


Question:
I just read Kenneth Salem's book, 2.8 angstroms.his theory claims that we, our galaxy is already traveling at, or near the speed of light,and is slowly accelerating at 2.8 angstroms. He also claims that this is reason why light propagates at a starting speed of 186,000 m/s, instead of a starting speed of zero. This slow acceleration of 2.8 angstroms is also the reason we feel or have gravity. He also says that the speed of light is not a universal constant as we have been told by Einstein's theory. Is any of this true?


Replies:
Sounds like science fiction to me for the following reasons: 1. Acceleration is the rate of change of speed (velocity) per second, so the dimensions of acceleration is (meters/sec)^2 which is not the dimensions of wavelength which is (meters).

Very recently there has been some conjecture that the speed of light in the early formation of he the universe may have been different than it is today. But that is very much speculation. The best measurements to date show no change in the speed of light. In fact, the length of the meter has been redefined in terms of the speed of light.

Third the speed of light is not a consequence of Einstein's theory or relativity, James Clerk Maxwell introduced this in his treatment of electromagnetic theory that pre-dated Einstein's work by a generation.

Finally, the nature of the gravitational force is not understood, to my knowledge. We know it exists. it appears to propagate at the speed of light. We know how to calculate its effects on stars, planets, and satellites very accurately -- but do we have an understanding of what it is, and why it is so much weaker that all the other forces of nature. I do not think so.

Do not let that stop you from reading science fiction, however. It is fun, we just have to suspend our sense of physical and chemical reality when we read it.

And occasionally, it turns out to be closer to subsequent reality than we first expect.

Vince Calder


David,

I do not know whether it is true or not. A person must understand an important property of physics: we do not know whether any of it is exactly true. It is a model, perhaps an approximation, for trying to understand and work with the physical world. For example, we know Isaac Newton's laws of force are not correct. However, we also know that in most situations they are an excellent approximation of what really happens. All theories are used so long as experiments and measurements support them. If a theory correctly predicts what will happen in many experiments, and if the theory is convenient enough to make it worthwhile, scientists will use it. I have not read the book to which you refer, but I do know some data indicates that the speed of light is changing VERY SLOWLY: an almost immeasurably small amount over billions of years. In most situations, it is reasonable to say that the speed of light is just about constant.

Dr. Ken Mellendorf
Illinois Central College



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