One of the giant questions about the origin of life on the planet has always been, did it originate here, or was it delivered to Earth by another celestial object? Scientists have found most of the compounds for the major building blocks needed for the formation of life in meteorites, comets and interstellar dust. But one, sugar ribose, which is the backbone that forms RNA had not been detected in this manner.
A new study, cited in the Christian Science Monitor, is suggesting that even though it hasn’t been found, ribose can also form in comets, giving credence to the theory of comet colllisions being the beginnings of life on Earth, and also giving hope that these same comets may also have seeded other worlds.
RNA is much like DNA, but is a simpler, single-strand molecule, which many scientists believe may have been used by early life to pass along genetic information. Many viruses still today use RNA for that purpose.
Experiments in the study tried to replicate the conditions that formed not only comets, but also the planets in our solar system, by super cooling a mixture of water, methanol and ammonia, and heating it back up again, as a comet would be heated as it approached the sun.
The results show that a number of organic compounds were formed, including ribose and other sugar molecules. If a similar action transpired on the comets, any collision with Earth, or another world, could have delivered all of the basic building blocks of life to the planet.
Before we can make a definite assumption, researchers say they will have to see these results verified and observed in a real comet, and even then, it may not prove that the compounds that led to life as we know weren’t already here before the comets collided with the planet.
More intriguing is the thought that comets, passing through the outer reaches of the universe, may have carried these same compounds to other Earth-like planets, and life may have formed there as well. What kinds of life, and, if it exists, did it evolve similarly to ours, are questions that will keep the search for extra-terrestrial life alive.