Today, the word ‘virus’, is automatically associated with illness and death. However, there may be something more to these organisms than their ability to infect living cells or bring diseases. According to PBS Space, “understanding viruses may be the key to understanding the origin of life.”
In line with the current virus circulating the planet Earth, scientific studies regarding viruses have also been developing. These complex microorganisms comprise a large majority of all living organisms in our world. But unfortunately, that’s also how far viral studies have gone and how much knowledge we have about them - limited to our world. With the ongoing search for other habitable planets, it is only fair to conduct investigations on the existence of viruses on worlds other than our own. The prevalence of viruses in our own planet and its possible role in how the first living cell came to be, is opening opportunities to discover its existence in other planets as well. In our search for alien life, discovering alien virus could be the breakthrough that we need to confirm it.
Astrovirology is a newly established branch of astrobiology that focuses on viral structure and activity as it relates to celestial and astronomical existence. It also deals with answering the question of whether or not viruses can travel to and from planets, or its capability to infect alien viruses.
The First Step
Detection of foreign viruses is a tricky job. The mere fact that viruses, as we know them, are unable to survive without a living host cell, makes the search difficult if we rely on just the foreign space material at our disposal. This implies that in order to manage finding traces of non-Earth viruses, the study must be conducted outside the Earth, or at least the specimen must be obtained from its home planet.
Mars is currently the only planet with ongoing studies being conducted on. The existence of microbes beyond the planet’s surface is a plausible claim, so it might be a good idea to start looking for traces there. Other candidates are the moons of Jupiter and Saturn, Europa and Enceladus, respectively. Just beneath their icy crusts, are oceans that are likely to contain microbial life, and quite possibly, viruses. To obtain planetary matter from these moons, space probes can be used to collect particles of ocean water that the geysers on their surfaces send out.
Interplanetary Space Travel
The main question remains: can alien viruses infect another? First, the possibility of survival in a space journey needs to be settled. Two transport mechanisms can be applied to that:
If viruses are successfully carried out into the planet’s atmosphere by means of small water droplets, then they can be transported into space via the radiation that a star emits or from the planet’s magnetic field. However, viruses are unlikely to be carried this way, because of the extreme radiation that it will be exposed to.
Also known as interstellar panspermia, this way of transport makes use of the solid matter that is driven out of a planet, and that matter carries biological signatures from one world to another. This is a possible mode of transport, since the solid matter can act as a barrier from external damaging factors.
Other Vital Factors
Despite of these transport mechanisms, it would be useless if the virus could not even survive exposure into the void of space, considering the absence of a host cell. Turns out, viruses have ways to do that too. They can either be modified to protect them for harmful environments, or they can break down and recreate themselves after. If all these were theoretically possible, the final point would be the biochemical compatibility of alien virus with one another. Knowing Earth-based viruses, there are only the RNA-based and DNA-based viruses that exist today. It may not be the case for alien viruses, as their genetic structure might be completely different from that of Earth’s and may not be programmed to invade an unknown cellular chemistry. To put it simply, it is only possible if alien viruses also follow the same RNA and DNA genetic composition that make it vulnerable to Earth-based viruses and vice versa. Unfortunately, there is no proof of that yet.
More studies have supported the integral role that viruses play in the process of cellular evolution. This draws a possibility that viruses may have even existed before cells. Though viruses may differ from living cells in their mode of survival, they do have one thing in common, and that is the ability to evolve. This is why there are a lot of different strains of the same parent virus that exist on Earth today.
It is safe to say though, that all of the viruses that plagued humanity in the previous years, are all Earth-based. It can be proven so by tracing the genetic origin of a virus, all of which lead back to Earth-based cells, and have only evolved through time.