In Discover Magazine, April 2003 (I know it's old, I just now heard about it) there is an article about Joao Magueijo. Aparrently, he came up with the theory that the speed of light hasn't stayed the same over time. It also says that energy can be created and destroyed spontaneously.
According to him, it would solve a few of the puzzles of cosmology. The first is how the universe (at the largest scale) appears the same (the galaxies are in a pattern). Because it is believed gravity travels at the speed of light, if the speed of light changed, it could "connect" the universe and let gravity move things into the pattern, except a lot faster.
The second is that cosmologists say that the universe is "flat", or poised between eternal expansion and imminent implosion. Less matter, and it expands rapidly until we can't see anything, and more matter would cause it to collapse. Because with this theory energy is created and destroyed, (and space-time bends because of mass and energy) it woul prevent the universe from expanding or shrinking catastrophically (when it gets too big, more energy, thus it slows down and regulates itself).
If the universe has too much matter, it's overabundance turns to energy, which simply vanishes. Voila, it's not too big!
Magueijo also notes that it only did this in the early universe.
To prove the theory, he looked at 68 quasars up to 12 billion light years away. During the light's journey to Earth, it passed through clouds of "intergalactic gas". In doing so, the light's spectra changed, depending on what was in the clouds. But in some clouds, the variation was smaller than expected by one in 100000. So 12 billion years ago the light was moving faster than it is now. Unfortunately for him, the clouds of gas may have had different compositions and densities. He has started an experiment on Earth that will be finished in about a year.
What do you think?