Louis is a solid-state physicist from India. His hypotheses about the "red rain" phenomenon in Kerala have attracted controversy. In April 2008, he published a paper in which he hypothesised that samples of particles from the "blood-coloured" rain that fell in his state of Kerala, India in the summer of 2001 were the result of a comet disintegrating in the upper atmosphere which comprised mainly microbes from outer space. The paper drew much media interest. Other scientists disagreed early on with Louis' hypothesis regarding the red rain's origin. An earlier (2001) study by the Centre for Earth Science Studies, Kerala, India, reported that the red rain was the result of spores from local algae.