It's tempting to look back, but there's so much more to come.
At Nature Physics, we often find ourselves thinking about the past. Anniversaries pop up regularly — 20 years (in 2006) since the discovery of high-temperature superconductivity, 50 years in space (2007), and, earlier this year, the anniversaries of C. P. Snow's 'Two cultures' lecture and of Darwin's On the Origin of Species (the latter celebrated in this journal as an intellectual achievement that still has a bearing on physicists' thinking). In this issue, in two short articles, we're ruminating on the history of quantum mechanics (page 383) and the centenary of a remarkable development in physics: Geiger and Marsden's α-scattering experiment that led to Rutherford's nuclear atom (page 380).
It's fascinating to look back. Physics has a rich history. Following the line of thought through which a concept has been devised and developed — which may span centuries — is often a good route to understanding. It's a history also rich in personality, as many biographies of physicists attest. But it is the past. So, with the twenty-first century touted as 'the century of biology', is it all over for physics?
Hardly. For all those centuries of achievement, there is still so much to do. And the breadth of enquiry is astounding, from the most intricate of studies on a lab bench, to profound questions about the nature of the Universe — answers to which could soon be beamed back from a satellite more than a million kilometres from Earth. ESA's Planck mission, and Herschel telescope (Planck, Herschel — again the backward glance, to honour Max Planck and eighteenth-century astronomer William Herschel), launched faultlessly on board an Ariane 5 rocket from French Guiana last month. Both will orbit the second Lagrangian point, from where Herschel will probe the evolution of stars and galaxies at infrared wavelengths and Planck will map the cosmic microwave background radiation in greater detail than ever before. Science operations begin in the next few months.
It's an over-worn phrase, but both missions are truly a 'new window' on the Universe, and on physics. And that's how it works — finding new windows through which to tackle the questions that have become so well formed through the efforts of physicists of preceding centuries. We seek new windows not only on the grand scale of the Universe, but on the scale of the atom, the electron, the electron spin. And we look forward to finding the answers. After all, every century is a century of physics.