9513835 Bahcall This proposal has two main thrusts, string theory and neutrino astrophysics. String theory is an attempt to move beyond the quantum mechanical description of elementary particles as point like particles to a formulation of them as excitations of a microscopic string-like object. These excitations would include not only quarks, gluons, leptons etc., but also the graviton, the quantum excitation of gravity so that one would have a truly unified theory. The ultimate aim of this research is a better and deeper understanding of space-time and a quantum theory of gravity. The interior of the sun is cooled by the emission of neutrinos whose interactions are so weak that they can escape from the surface. By studying the detailed properties of these neutrinos, as seen in terrestrial detectors, one learns about neutrino properties and about the interior of the sun. ***
