Leiden University astronomer Xander Tielens has been awarded a €2.5 million (about $3.1 million) Spinoza prize, the highest scientific prize in the Netherlands, the university announced. Tielens, a professor of the physics and chemistry of interstellar space, was recognized for his contributions to research on interstellar dust and ice and on the effect of gas in so-called photodissociation regions, a process in which molecules disintegrate when they absorb photons. This effect is the result of radiation from nearby stars. He discovered that a significant proportion of interstellar gas is found in those areas where molecules disintegrate as a result of the effect of stellar radiation. He is one of the first astronomers to understand the importance of large molecules such as interstellar dust and polycyclic aromatic hydrocarbons (PAHs), a group of hundreds of large organic molecules. In addition, Tielens is involved in the development and use of large apparatus and satellites, including the Sofia telescope for infrared astronomy and the European Herschel satellite, which is used to study the formation of galaxies and stars. Tielens is the third Leiden astronomer to win the Spinoza prize. Instituted in 1995, the Spinoza prize is awarded by the Netherlands Organisation for Scientific Research to a maximum of four scientists each year based on nominations from organizations such as the advisory councils of the KNAW (Royal Netherlands Academy of Arts and Sciences), the National Network of Female Professors and the Netherlands Academy of Technology and Innovation. It recognizes researchers who have carried out outstanding, pioneering and inspiring research. Presentation of the Spinoza statue will take place Sept. 7. For more information, visit: www.leiden.edu