Life's Essential Ingredient Ribose Can Be Found On Comets: Study

Does life on Earth have extraterrestrial origins? This is popular theory attempts to answer the question regarding beginnings of life on the planet. A new study now adds substance to this theory by demonstrating that a key ingredient of life can form on comets.

The scientific approach to test such theories often involves replication of primordial conditions on a young Earth in a lab and identifying circumstances that could trigger formation of life's building blocks. Such efforts in the past have led to creation of organic molecules, strengthening the theory that a comet or asteroid could have struck Earth, sowing it with life. However, the sugar ribose which is the backbone of nucleic acid RNA has proven elusive.

Now, researchers at Cornelia Meinert of the University have managed to show that the likelihood of ribose on comets is also high. In their experiment, they created conditions similar to a comet's icy surface when it is away from the Sun and subsequent melting of ice as it nears the parent star.

Using ammonia, cooled water and methanol, they were able to produce vacuumed ice as is known to exist on comets at temperatures of about - 195 degrees Celsius. As the comet nears its parent star like Sun, which during Earth's infancy would have been 4 billion years younger, the UV light would irradiate it. The experiment resulted in nearly 55 organic molecules including ribose, Gizmodo reported.

RNA is DNA's simpler single-stranded cousin which is known to hand down genetic material in less sophisticated forms of life. In complex multi-cellular organisms including humans, it is instrumental in transforming genetic information for protein synthesis, while it constitutes the genome of viruses.

"Our results suggest that the generation of numerous sugar molecules, including the aldopentose ribose, may be possible from photochemical and thermal treatment of cosmic ices in the late stages of the solar nebula," researchers wrote in the journal Science.

"Our detection of ribose provides plausible insights into the chemical processes that could lead to formation of biologically relevant molecules in suitable planetary environments."