Asteroids discovered by students and professors at Calvin College now bear the names of two Calvin retirees: former Calvin president Dr. William Spoelhof and former Calvin dean and physics department chair Roger Griffioen. Each asteroid is approximately the size of Calvin's entire Knollcrest campus. Asteroid Spoelhof (previously known as 2004 XU3) was discovered December 3, 2004 by Calvin professor of physics and astronomy Larry Molnar. Asteroid Griffioen (previously known as 2003 RA11) was discovered on September 5, 2003 by Calvin student Andrew Vanden Heuvel. When a new asteroid is discovered it is given a provisional name, but that it must be tracked for a number of years to fully establish its orbit before the discoverer is given the privilege of naming it.