"German satellite hurtling towards Earth"

ROSAT, a German satellite is indeed "hurtling towards Earth", as the Guardian and many other news outlets have been telling us in recent days. Well, "hurtling" isn't quite accurate, but it'll reach us sometime in the next few days as its orbit gradually decays (in fact, since I typed this it looks as though it's come down).

I was slightly surprised to learn it hadn't come down a long time ago. It was a pioneering X-ray astronomy space mission of the early 1990s. When the first X-ray detectors were thrown briefly up above the atmosphere on rockets, there were no great expectations. This was in 1962 and imaginations stretched only to a faint glow from the Sun's million-degree outer atmosphere, or possibly from the Moon's surface as energetic particles in the solar wind smashed into it. As the world knows, the results were much more exciting: bright, point sources of X-rays beyond the solar system, among the stars of the Milky Way; a cosmic "background", X-rays coming from all directions on the sky; X-radiation from the Crab Nebula. A new window had opened on the high-energy universe of black holes and neutron stars; nobody thought much about X-rays from the Moon for a long time.

ROSAT closed this particular historical circle by detecting, for the first time, X-rays from the Moon. The ROSAT image of the Moon, illuminated only on its sunward side, looks so familiar that you might need to look twice and think about it to realise just how amazing it is. It is lit up only on the sunward side because the Moon's surface is reflecting X-rays from the Sun (strictly, scattering those X-rays, and apparently also fluorescing).

ROSAT was used to make many important advances in X-ray astronomy; a brief list is here. I always had a soft spot for it because it closed the lunar loose end. None of this prevented its fiery doom, however, which no doubt is as it should be. None of us escapes his doom, watery, fiery or otherwise, no matter what sort of songs we've sung in the meantime.

None of the news reports let us forget it was a German space mission, rather than, say an "X-ray telescope", "orbiting X-ray laboratory" or some such border-less phrase. I wonder why? If it had actually fallen on somebody's head, would the German nation have been held to account? Would we have seen invoked the ghost of Wernher van Braun? I'm really not sure what's behind this.

One of the best Universities in the world

I wanted to black out the room for the sake of my powerpoint slides but the blind was broken. "And this is one of the top hundred universities in the world!" I joked. The students laughed. None of them corrected me although the latest Times World University Rankings had in fact just placed us at 102 in the world.

Are these league tables useful? I don't know. I'm sure there are people who consider them to be useful if they seem to support decisions already made. Maybe extremely affluent parents will look closely at them before deciding where in the globe to dispatch their glittering young things.

Every university manager in the country will be staring at their own position, asking themselves, "What can we do to move further up next year?" They'll be looking at the Universities they regard as close competitors. Cal Tech people must be really worried: the best they can do is stand still. Although we moved up 26 places I'm sure our leaders will be cross we didn't break the top 100 (we were a top 100 university two years ago, I think - or was that somebody else's list?).

The Times are very proud of their table. I'm sure they have thought in advance of possible criticisms, probably had to meet them in previous years. They make use of 13 separate prefomrance indctors (sorry, I can't type those words spasm-free) under five headline categories. Because they "recognise that different users have different priorities" the tables can be manipulated and customised (to some degree - haven't tried to play with them myself yet).

We can't do better than quote Einstein: "Not everything that can be counted counts, and not everything that counts can be counted." Numerical tables based on PI's inevitably focus on phenomena that can be counted. Inevitably these only capture part of the activity they're intended to describe. But they take on weight through the league tables so there will be good consequences for those who push them up and bad stuff is more likely to happen to those who don't - even if they contribute to their universities in ways that don't get caught in the PI's.

The choice of PI's and weightings represents a statement of values. Worst of all is the possibility that these values are formed by accident, rather than constituting the starting point for this exercise.

How should Principals and Vice-Chancellors respond? Well, they have presumably thought long and hard about what a University is, its function in society, and the means by which that function can be carried out. This should be their starting point and the extent to which the league tables support those values should be the starting point of their response. Anything less would devolve to the newspapers the job of leading the universities.