Maybe E ≠ MC^2?
This is serious stuff. If E ≠ MC^2 then maybe ME ≠ MC^2 either. And then I would have to change my license plate. And slow down. Sammy can't drive 55 and I can barely keep it under 90 - in traffic. Dr Joao Magueijo is trying to sell a book, and to sell books you have to be controversial. So here is me whoring his book Faster than the Speed of Light - The Story of a Scientific Speculation so he can make a buck.
But let's take the argument on its merits. Dr. Joao says that time isn't actually a constant and that it is slowing down. The good thing about time is, science-fiction movies aside, it isn't really a dimension so we can get a handle on it pretty easily by using math. Time is just a change in position of an object in the three dimensions. To give you the 10-second primer on why time travel is impossible, look at it like this. The earth is spinning at just over 1000 miles per hour - that's the estimate of a 25,000 mile circumferance planet turning once in 24 hours. On top of that the earth is revolving around the sun at 67,000 miles per hour. And the sun is revolving around ... well, you get the idea. To travel back in time would mean you have to travel back to a place that is moving at an incredible rate of speed and has been doing so constantly since the universe began.
Could I do the math to calculate where I would have to be? Sure. In my head. But that doesn't mean I can create a device to actually do it. Because reaching that speed is impossible for a whole list of other reasons.
But anyway, back to this speed-of-light-as-a-constant thing. We can't go back in time but we can see back in time, because we can measure the distance of a far-away object and examine what we are viewing. If you look up at the stars tonight you're mostly seeing them as they were when Jesus was born. It just took 2000 years to get to your eyes.
What does it take to look all the way back to the beginning of time? A honkin' big telescope. One bigger than my ego, if you can imagine that. They didn't name it the Honkin' Big Telescope, though that would have been cool. They called it The Very Large Telescope and it is at the Paranal Observatory in northern Chile.
So right now they are looking at the biggest brightest quasar they can see, as close to the beginning of 'time' as we can go. And the results will tell us if Dr. Joao is a crackpot.
The good news is, even if he's right, light isn't slowing down by much. You still have billions of years to read my blog. But the E=MC^2 is a problem. If light isn't a constant then neither is energy and mass. And that's a blog for another time.