Unweaving the Rainbow Makes it More Beautiful

Newton's unweaving of the rainbow led on to spectroscopy, which has proved the key to much of what we know today about the cosmos. And the heart of any poet worthy of the title Romantic could not fail to leap up if he beheld the universe of Einstein, Hubble and Hawking. We read its nature through Fraunhofer lines - 'Barcodes in the Stars' - and their shifts along the spectrum. The image of barcodes carries us on to the very different, but equally intriguing, realms of sound ('Barcodes on the ...

 Hawking's Equation

awking has written down an equation which looks rather like Planck's equation. Hawking's equation is S = kA, where S is the entropy of a black hole, A is the area of its surface, and k is a constant which I call Hawking's constant. Entropy means roughly the same thing as the heat capacity of an object. It is measured in units of calories per degree. A is measured in square centimeters. Hawking's equation says that entropy is really the same thing as area. The exchange rate between area and en...