[[John Lighton Synge]] made progress in different fields of science, including mechanics and geometrical methods in general relativity. He had mathematician [[John Forbes Nash, Jr.|John Nash]] as one of his students. [[Kathleen Lonsdale]], born in Ireland and most known for her work with [[X-ray crystallography|crystallography]], became the first female president of the British Association for the Advancement of Science. Ireland has nine universities, seven in the Republic of Ireland and two in Northern Ireland, including [[Trinity College, Dublin]] and the [[University College Dublin]], as well as numerous third-level colleges and institutes and a branch of the Open University, the [[Open University in Ireland]]. [[Gaelic football]] is the most popular sport in Ireland in terms of match attendance and community involvement, with about 2,600 clubs on the island. In 2003 it represented 34% of total sports attendances at events in Ireland and abroad, followed by [[hurling]] at 23%, soccer at 16% and [[rugby football|rugby]] at 8%. The [[All-Ireland Football Final]] is the most watched event in the sporting calendar. Soccer is the most widely played team game on the island and the most popular in Northern Ireland. Other sporting activities with the highest levels of playing participation include swimming, golf, aerobics, cycling, and billiards/snooker. Many other sports are also played and followed, including [[boxing]], [[cricket]], [[fishing]], [[greyhound racing]], [[Gaelic handball|handball]], [[hockey]], horse racing, [[motor sport]], [[show jumping]] and [[tennis]]. The island fields a single international team in most sports. One notable exception to this is association football, although both associations continued to field international teams under the name "Ireland" until the 1950s. The sport is also the most notable exception where the [[Republic of Ireland national football team|Republic of Ireland]] and [[Northern Ireland national football team|Northern Ireland]] field separate international teams. Northern Ireland has produced two World Snooker Champions. [[File:Tyrone Blanket Defence.jpg|thumb|[[Tyrone GAA|Tyrone]] v [[Kerry GAA|Kerry]] in the [[2005 All-Ireland Senior Football Championship Final]]]] [[Gaelic football]], [[hurling]] and [[Gaelic handball|handball]] are the best-known of the Irish traditional sports, collectively known as [[Gaelic games]].