“Viruses arguably have coexisted with cellular life-forms since the earliest stages of life, may have been directly involved therein, and have profoundly influenced cellular evolution,” the researchers wrote in their paper, published in Astrobiology. “Viruses are the only entities on modern Earth to use either RNA or DNA in both single- and double-stranded forms for their genetic material and thus may provide a model for the putative RNA-protein world.”
As such, the team has proposed that astrobiologists seek out virions. This is the protein-encapsulated form that a virus takes when it isn't inside of a host. Although there may be debate as to whether or not viruses can be categorized as living beings, the researchers argued that viruses do indeed count. Their reproductive methods may not fit into the standard definition, but they come very close to what the National Aeronautics and Space Administration (NASA) has defined as life. (Related: Alien life could exist BELOW the surface of Mars, shocked scientists discover.)
Moreover, viruses are an essential part of life on Earth. Viruses have been evolving alongside cells since life first began, leading to an unprecedented diversification of life. Moreover, they can be found just about everywhere, and they play important roles in most of the planet's nutrient cycles. As lead study author and Portland State University biology professor, Kenneth Stedman, said: “Life on Earth would be very different if there were no viruses.”
It's these virions that would be the focus of “astrovirology”, wherein virus research and astrobiology would eventually come together to gain a better understanding of viruses in a cosmic environment.
Our technology isn't there quite yet, however. We don't have the tools to take virus research to an interstellar scale. Though we may in time. According to LiveScience.com, scientists are in the process of developing methods for identifying ancient Earth viruses through chemical signatures. Proven successful, then we could soon be looking out for viruses hidden in the deposits of Mars or Titan, Saturn's largest moon. From there, scientists could then be studying liquid samples taken from Enceladus and Europa, moons of Saturn and Jupiter, respectively.
And if we can identify viruses, then there's a good chance we may come across other forms of extraterrestrial life. “What is life? Are viruses alive? If we find viruses, is it indicative of life? And would this be life as we know it or life as we don't know it? We're hoping to get people thinking about these types of definitions,” said Stedman. “If we find viruses on other planets it is an indication of life, not something to be scared of.”
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