Nidhal Guessoum M.Sc, P.hD. (born September 6, 1960) is an Algerian astrophysicist. He is a professor at the American University of Sharjah, United Arab Emirates.His research interests range from gamma-ray astrophysics, such as positron-electron annihilation, nuclear gamma-ray lines, and gamma-ray bursts, to Islamic astronomy, i.e. crescent visibility, Islamic calendar, and prayer times at high latitudes, problems that have yet to be fully resolved. He has published a number of technical works and lectured internationally at many renowned universities (Cambridge, Oxford, Cornell, Wisconsin, and others).In addition to his academic work, he writes about issues related to science, education, the Arab world, and Islam. Guessoum is also a columnist for Gulf News and The Huffington Post, and has made notable contributions to Nature Middle East. He has also appeared many times on international media outlets, including Al-Jazeera, BBC, NPR, France 2, Le Monde, and others.