Motherboard -- There are probably only a few things about physics non-scientists know, but that the speed of light is constant is one hopefully of them. Itís what we all--again, hopefully--learned in grade school and high school textbooks. But new research is saying that that might not be the case. Some scientists are exploring the possibility that the speed of light actually changes due to the nature of the vacuum of space. It might go against what we think we know about the Universe, but thatís just what two papers published in the European Physical Journal D are arguing.
The speed of light, which beams along at about 670,616,629 miles per hour, is the backbone of many cosmological and astronomical theories. Itís the number astronomers use when measuring the size and age of the Universe, the distance between objects, and the qualities of the stuff that makes up everything around us. If the speed of light turns out not to be constant, it could mean that some pretty massive things, like the estimated size of the Universe, are different from what weíve long thought.
Using different means, the two papers try to derive a the speed of light from the quantum properties of space itself. The key in both papers is that the scientists treat space not as a vacuum, but full of particles.
One paper, led by Marcel Urban from the Universitť du Paris-Sud, focuses on the cosmic vacuum. According to laws of quantum physics, the science that governs all the tiny things in the Universe, space is full of particles that pop into existence, collide with their counterparts, and promptly pop out of existence. Itís what happens when matter and anti-matter particles collide: they annihilate each other.
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