So it turns out the speed of light might not be constant after all

So, it seems the speed of light isn't quite constant after all. Two new studies published in the European Physical Journal D suggests that the speed of light in space isn't quite constant after all. The understanding is that space is not quite the perfect vacuum which it is often assumed to be.

LOS ANGELES, CA (Catholic Online) - The current laws of physics says that light travels approximately 186,000 miles per second in a vacuum. That's been a handy fact that has allowed scientists to calculate the distances to faraway objects and to conduct other research with great accuracy. However, that measurement assumes that space is a vacuum.

It isn't. Space is filled with tiny subatomic particles which although extremely diffuse, can theoretically slow down light just a tiny bit. How tiny? About 50 attoseconds per square meter of crossed vacuum. An attosecond is a one quintillionth (10^-18) of a second.

An attosecond is to a second what a real second of time is to 31.71 billion years. So that's not a lot of egg on the face of physics. Still, over very great distances light from distant objects could be slowed just slightly.

That slowing isn't enough to impact any currently accepted theories regarding physics, but it still suggests that even the most reliable of yardsticks may be variable after all. Very minor changes to currently accepted understandings may be required, but since the changes are so slight they might not be significant, and therefore unworthy of much modification.

The greatest change might be to textbooks, which will need to add a caveat that the speed of light is constant, only in a true vacuum-which space isn't.

The findings must still survive peer review before that happens.

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