The speed of light is defined, you c

E=mc².

Probably the most famous equation in the world, although perhaps

e^iπ + 1 = 0

is the most beautiful.

Anyway, I would recommend derivation of Einstein's equation from the Lorenz factor as a quick introduction as to how the famous equation was derived as a consequence of Special relativity.

Why mention this 101 year old equation now? Well I was interested in going back to first principles. If Einstein's equation is derived from the Lorenz factor, where does the Lorenz factor get it from? Even looking at the very interesting mechanics and special relativity paper from Harvard still begins from the principle that the speed of light is the same in any inertial frame without proving why the speed of light is the value that it is. Mathematical constants such as PI can not only be measured but their value can be derived and proven.

What then for the speed of light - can we do more than just measure it? Can we prove why it has to have the value that it does?

I asked this question over on Questionville and found that the speed of light can be expressed in terms of Planck time and Planck distance.

However that only resulted in unanswered questions over these values and what causes them to be the natural units of the universe.

New Scientist has a special treat this week, Stephen Hawking and Tim Berners Lee in the same edition. I've mentioned Tim indirectly in an earlier post on the semantic web and in the strange new universe that Stephen Hawking writes about, surely it is not so strange if all the building blocks in all the universes are the same size?

We recognise the universal building blocks
do we understand their dimensions yet?