Prof. Sarabhai has worked on the astrophysical implicatios of cosmic ray time variations. Work done by him in collaboration with his students at the research stations established at Ahmedabad, Gulmarg, Kodaikanal, Trivandrum and Chacaltaya in Bolivia (South America) has led to the discovery of new solar relationships of cosmic ray variations. He has demonstrated the significance of the study of anisotropy, within the solar system, of cosmic rays from the galaxy. This led him to an accurate experimental study of the variations of a few parts in a thousand which occur in the cosmic ray intensity arriving on the earth. He uses these cosmic ray variations to probe the electromagnetic state of the earth and thus to study the emission of a plasma wind from the sun and the configuration and movements of magnetic fields in the solar systems.