When the European Physical Society (EPS) holds its general conference in London this month, there is likely to be much talk over coffee about the need for Europe to match the United States in a variety of activities. These will include journal publishing, the organization of conferences, funding and, maybe, even physics. The scientific communities in Europe and the US are of comparable sizes so why, delegates will ask, does Europe have nothing to rival the Physical Review? Why is the organization of conferences dominated by the US? Why has the European Union not pledged to double spending on science, as the US Senate recently did? And why has the US so thoroughly dominated the Nobel Prize for Physics in the 1990s? Of the 20 physics laureates decorated in the 1990s, 15 were born in the US.
Some of these questions are easy to answer. Physical Review Letters and its siblings are so prestigious because European physicists are just as keen to publish in them as their North American counterparts. American scientific societies are much larger than those in Europe, and this gives them an enormous advantage when it comes to organizing conferences. Promises to double funding for research over the next decade are fine in principle, but this will not happen in practice if the US Congress continues to cut R&D budgets.
The question about Nobel prizes is trickier. Roughly speaking, the US and Europe shared the honours in the 1980s. Moreover, four of the European laureates carried out their research at a lab owned by an American company (IBM), while three of the American laureates were actually born in Europe. Germany and Switzerland supplied most of the Nobelists in Europe, but there were also prizes for physicists from Italy, the Netherlands and Sweden. In the 1990s, however, only France has challenged the US’s domination of the prizes.
Of course counting Nobel prizes is not a very representative way of comparing the scientific excellence of nations, and various studies have shown that Europe is competitive with the US in many areas, including physics (Science 275 793). Not surprisingly US researchers publish more of the world’s scientific papers (35% of the total) than researchers from any other country, although Europe as a whole is not far behind. (Exactly how far behind depends on how you define Europe.)
Moreover, papers from the US receive 49% of the citations in the scientific literature, which places it at the top of the list when countries are ranked by “relative citation impact” (the number of citations for papers published by scientists from nation X, divided by the number of papers published by scientists from nation X). There is, however, a great deal of variation among different subjects, and in physics the top five nations ranked by the relative citation impact are: Switzerland, Denmark, US, Netherlands and Israel.
Apart from its sheer size, do any other factors explain why the US is such a dominant force in world science? A recent study by two American sociologists used a variety of measures, including election to the National Academy of Sciences and publication of highly cited papers and patents, to identify scientists who had made “exceptional contributions” to US science and engineering (Science 285 1213). The study found that a “disproportionate” number of these scientists were born and educated outside the US. The paper concludes that “the US has benefited from the educational investment made by other countries, presumably to their own detriment”. The authors do not discuss what attracts these exceptional scientists to the US, but the size of the US science community, and the facilities and funds available there, must surely be a factor.
But, as the EPS meeting in London will make clear, many areas of physics are thriving in Europe. The Large Hadron Collider at CERN will define the high-energy frontier in physics in the next decade, the neutron and synchrotron radiation sources in Grenoble are the envy of the US, and from Helsinki in the north to Catania in the Mediterranean, Europe has numerous excellent physics laboratories. Journals, conferences and prizes are important but, at the end of the day, the quality of the physics is what matters most.
