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Name: David
Status: educator
Grade: other
Country: Australia
Date: Fall 2011

One of my students showed me a paper which he found on your site

His question is that if a photon does accelerate when it comes into existence is its acceleration relative to a fixed point different if it is coming towards that point or away? Thus it is not at a constant speed to all observers which breaks a fundamental law?

David, A photon does not accelerate when it comes into existence. Things do not have to be still when it appears. Before the photon exists, you can neither say it is still nor moving. It is not even there. When it appears, it is already moving. Its speed is part of its existence.

Dr. Ken Mellendorf Physics Instructor Illinois Central College

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