http://www.eso.org/outreach/press-rel/pr-2004/pr-05-04.html [Broken] reports the work of a team of astronomers using the VLT in Chile. "To explain the Universe and to represent it mathematically, scientists rely on so-called fundamental constants or fixed numbers. The fundamental laws of physics, as we presently understand them, depend on about 25 such constants. Well-known examples are the gravitational constant, which defines the strength of the force acting between two bodies, such as the Earth and the Moon, and the speed of light. One of these constants is the so-called "fine structure constant", alpha = 1/137.03599958, a combination of electrical charge of the electron, the Planck constant and the speed of light. The fine structure constant describes how electromagnetic forces hold atoms together and the way light interacts with atoms." In summary, results from the ancient Oklo natural reactor show alpha is constant to within ~2 parts per 100 million over the past ~2 billion years; the VLT results ~0.6 parts per million over ~10 billion years.