With Live 8 on in the background, I was able to get a bit of work done: colleagues from Imperial and 13 other UK institutions are putting together a “Letter of Intent” to the European Space Agency for the analysis of data from the LISA satellite. ESA, as expected of a multi-governmental agency guiding the spending of billions of euros, is vaster than empires, and more slow — with luck, it will be launched in 2014. But it’s a fantastic idea (in the real sense of “fantastic”): three spacecraft, millions of kilometers apart from one another, shooting lasers at each other in order to measure their separation to an accuracy of 10^-10 meters! This will let us observe the passage of gravitational radiation — ripples in space caused by the rapid movement of distant objects (such as black holes crashing into one another), one of the most exciting predictions of General Relativity, still to be directly observed. When we get it to work, it will be an extraordinary new way to look at the Universe — waves of spacetime rather than the waves of light upon which we have always relied.