Scientists Prove that a Comet Could Have Started Life on Earth
Astrobiologists have long theorized that life on Earth could have originated in outer space and then been brought to Earth by a comet. Now, researchers from the Central European Institute of Technology have proven that this theory physically could have occurred.
According to the panspermia hypothesis, life came to exist on Earth as a result of contamination from extraterrestrial structures such as comets, meteors, and asteroids. Evidence has been mounting for the theory of panspermia recently, especially considering that just a few weeks ago, the Philae lander found evidence of organic molecules on a comet.
But where most theories of panspermia involve life forms already existing on the comet and simply being brought down to Earth, the researchers hypothesized that molecules in the comet itself were split upon the tremendous pressure of the impact when the comet hit Earth, and then the split molecules became the building blocks of life. In order to test this theory, the researchers zapped formamide molecules, which have been found in comets, with an extremely powerful laser in order to imitate the extreme conditions of a comet impact. The heat and pressure produced all of the chemical bases of RNA, one of the building blocks of life.
From the paper: "These findings suggest that the emergence of terrestrial life is not the result of an accident but a direct consequence of the conditions on the primordial Earth and its surroundings."
"Suggest" is the operative word, as the study only proves that the scenario is possible, not that it actually happened. Furthermore, several experts downplayed the importance of the research, claiming that the amount of one of the RNA bases was small enough to be insignificant to their findings. However, other experts claimed that the study is, indeed, an important step towards understanding the origin of all life on Earth.
Lead author Dr. Svatopluk Civis said, "Our findings demonstrate that extraterrestrial impacts, which were one order of magnitude more abundant during the LHB period than before and after, could not only destroy the existing ancient life forms, but could also contribute to the creation of biogenic molecules."