Cosmic Panspermia hypothesis: According to Richter Adrenius and Prayer, spores of life came to earth from some distant planet, along with metiorites which keep on reaching the earth from time to time. According to this theory, a microscopic form of life accidentally reached the earth, with small bits of metiorites. This theory has been rejected, because the intense cold, extreme dryness and intense radiations of interplanetary space would not have allowed the spores of life to reach the earth, without damage. This theory only shifts the origin of life from earth, to some other planet, from where the spores of life fell on the earth.