Research universities increasingly function as a key hub institution of the knowledge economy - from Stanford University's role in Silicon Valley to MIT's role in greater Boston's Route 128 high-technology complex, from the University of Texas at Austin to the rise of the North Carolina Research Triangle, not to mention Carnegie Mellon's role in Pittsburgh's regeneration. But what are the world's leading centers for university research?

To get at this, my MPI team and I used the recently released Academic Ranking of World Universities (ARWU) to chart the locations of the world's leading 500 research universities by the city and metro region where they are located. The map below, by the MPI's Zara Matheson, shows the geography of academic research centers across the world.

The U.S. is home to four of the top five centers: Boston-Cambridge in first place, followed by Los Angeles, New York City, and San Francisco. Other leading U.S. research centers among the top 25 include: Chicago (6th), Durham-Chapel Hill (11th), Pittsburgh (13th), Trenton-Central New Jersey (14th), New Haven (17th), Ithaca (18th), San Diego (19th), Philadelphia (20th), Seattle (21st), Madison (22nd), and Baltimore (23rd).

But a number of foreign centers rank quite high. London (5th), Paris (7th), and Zurich (8th) all rank ahead of San Jose/Silicon Valley (9th). Cambridge, England is 10th, Munich 12th, Stockholm 15th, Oxford 16th, and Tokyo 24th. Toronto, where I teach, ranks 28th.

For the time being, the U.S. remains in the lead, but foreign centers appear to be gaining ground. And this trend may be accelerated by the mounting budget problems facing many states and research universities as well as cutbacks in research funding and growing anti-immigrant sentiment in some quarters of the United States. Great Resets like the current one have given rise to significant shifts in the locus of scientific research talent in the past. And this was a large part of the reason the United States eclipsed Europe on this front during the last Great Reset.

But what's even more striking about the map is the degree of geographic concentration on the East and West Coasts of North America, Western Europe, and just a few spots in Asia and Australia/New Zealand. The concentration of the knowledge and scientific assets in just three major mega-clusters -- the East Coast/Great Lakes, West Coast of North America, and in Europe - is astounding. And it is likely to reflect significant geographic advantages in research and knowledge-generation for them.

It's a given that scientific talent is highly mobile. But distance still plays a role. All other things equal, it is both easier for and more likely that leading scientists and researchers will move within these clusters - say between Boston and New York, or even Chicago and Toronto; much the same is true among, say, L.A., San Francisco, and Seattle. And collaboration within them is surely easier as well. This kind of proximity creates considerable short- and long-run advantages both for the universities and research centers within the cluster and the cluster as a whole.

This would seem to imply that ongoing efforts to upgrade research universities, attract top scientific talent, and build world-class research environments in China, India, the Middle East, and other parts of the world are likely to face significant uphill battles. And that established mega-clusters are likely to enjoy significant advantages into the foreseeable future.