In 1995 I obtained my PhD from Leiden Observatory (Cum Laude). I have worked at the Johns Hopkins University and Harvard University before becoming a professor at the Kapteyn Astronomical Institute. In my theoretical research I focus on the formation of stars and planets, primordial and active galaxies, as well as space-time topology and particle physics.

Since 1995, I study the nature of space-time topology and its relation to general relativity and particle interactions. Specifically, in 1996 (see paper 1 below and its arXiv date stamp) I have proposed a lattice of three-tori in four dimensions as the topology of Planckian space-time. Such a lattice of three-tori allows for a natural implementation of the Heisenberg uncertainty principle, through the Feynman path integral, because it imposes different paths between space-time points. In fact, for any universe with a finite measuring accuracy, one must have a lattice of three-tori and therefore quantum mechanics. Furthermore, one may naturally attach wormholes to such a lattice of three-tori and thus include gravity. This leads (see paper 1) to a cosmological constant that is proportional to the number of black holes in the universe. In paper 2 below, section 9, a prediction was made in 2000 (see its arXiv date stamp) for the time travel behavior that the CERN neutrinos appear to exhibit, while locally preserving Einstein's special and general relativity.

Paper 1: read here how a lattice of three-tori extends general relativity.

Paper 2: read here how space-time topology determines particle physics.

A visual impression of travel by identification of distinct space-time locations. The red and blue ball are the same, their color simply indicates how the edges of the square are identified to form a closed tube (like the surface of a donut) in three dimensions. In four dimensions, one can do this with a solid cube to get a three-torus. A lattice is constructed by gluing many such three-tori together.