- Question
- Do aliens exist?
- Position1 of 4›
- Yes, alien life does exist outside of Earth
The belief that humanity has accidentally contaminated other planets with life by sending rovers and landers to their surface that were not sufficiently decontaminated
The argument
On earth there are known organisms, often termed Extremophiles, that are capable of surviving conditions that until recently were thought to be completely inhospitable to life. One example of this is the tardigrade. The tardigrade has been shown to be able to survive incredibly unfavourable conditions, including being left in a vacuum, left without water for months as well as left under intense radiation. It has adapted abilities to survive all of these conditions for years. That particular combination is what makes it relevant here, because vacuum, desiccation and radiation are precisely the conditions an organism would meet outside a planet's atmosphere. An animal that endures all three for years is not merely hardy in a general sense; it is hardy in the specific way that survival of a journey between worlds would require. They've also been found all over the world, from hot springs to under layers of solid ice, all not simply surviving, but thriving. Resilience of this kind is therefore not a laboratory curiosity confined to one lineage in one place, but something life arrives at readily across very different environments. If organisms can endure those conditions, the remaining question is how they would travel — and here the mechanism is one humans have already supplied. In 2013, scientists discovered a new species of bacteria, Tersicoccus phoenicis, within the clean rooms that they use to decontaminate their spacecraft. A species found living in the very facility built to eliminate life is one that has survived the most rigorous sterilisation regime available, and it was found at the last point of contact before launch. It is likely that some of these bacteria will have made it onto some of the landers. Life may therefore already be spreading from Earth by accidental artificial panspermia — and if it can spread that way, it may have reached Earth the same way, which is one reason to think alien life exists beyond it.
Context
Humans have sent rovers and probes to the surface of 4 bodies in our Solar System. These are The Moon, Mars, Venus and Titan. Although before being sent they're thoroughly decontaminated and are again decontaminated while being exposed to the vacuum of space and solar radiation, it is believed that there is likely still life on the landers when they arrive on the surface of the planets. It is possible that any organism tough enough to survive these condition could reproduce and thrive on their new planets/moons
Premises
Counter-arguments
Though it is known that there were bacteria in the cleanroom, there is no evidence yet that any of it made it onto the landers leaving earth. There is little evidence showing that it can survive the harshness of space as well as the extreme heats of re-entry experienced by the landers. These conditions are considered harsher than those experienced in the cleanroom.
Rejecting the premises
It is not what we typically think of when we consider "Life Elsewhere in the Universe". Many people do not classify human contamination extra-terrestrial life. The conditions observed in space are far more extreme than those in a cleanroom, and there is a good chance these are sufficient to kill hitchhiking organisms