6 Bacteria can multiply inside a comet, which has a warm, liquid interior. Life with all its basic genetic information originated, not on Earth but on a grand cosmic scale. Bacterial cells are included in the clouds that collapse to form stars, comets and planets. Anaerobic bacteria replicate and increase their numbers vastly in the warm liquid interiors of comets. About 100 tons of cosmic debris arrive on Earth daily.
Cosmic microorganisms can change the evolution of Earth's species.
If, according to our view of astrobiology, we were indeed made up of space-bugs several important consequences would follow. The continued arrival of comet debris to Earth at the rate of some 100 tons per day must surely bring in new bugs. They interact with terrestrial life by adding to the genomes of plants and animal, and thus assist evolution. They could attack terrestrial lifeforms and lead to epidemics of disease. The new field of astrobiology searches for alien microbial life.