When is it okay to kill an alien life form?
In the movies, the answer is usually pretty straightforward: it’s fine in self-defense, especially if it inspires a rousing speech about human exceptionalism. But in the real world, the choice is neither simple nor abstract. Many missions to neighboring worlds might, accidentally or intentionally, disrupt alien life. Under what conditions would the loss of a few aliens (i.e., presumably microbes) be acceptable?
The range of viewpoints on this topic is diverse, fascinating, and essential to recognize as we seek to detect life on other planets. Current missions to Mars, as well as future missions to the outer solar moons, including Jupiter’s moon Europa and Saturn’s moon Titan, could find alien life forms. “It’s a question of what our priorities are, whether you’re an astrobiologist or a member of the general public,” says Jayme Johnson-Schwartz, a philosopher who has written extensively On the ethics of space exploration.
NASA’s Viking mission, which landed the first robots on Mars in 1976, had a clear answer: Yes, it’s OK to kill a few aliens, as long as there’s a scientific justification. The Viking probes conducted experiments on samples of Martian soil; some were bathed in nutrients and others were sterilized at scorching temperatures. The logic was that any hypothetical microbes that received the spa treatment might be reactivated, producing detectable activity, while microbes that were burned off would remain undisturbed, providing a control.
Let’s leave aside the fact that the Viking experiment apparently detected signs of life, a result That remains controversial. Nearly 50 years later. (The general consensus is that the experiment found interesting chemical activity, but one that can be explained without invoking life.) Imagine if alien beings came to Earth, gathered some people together, treated one group to a fancy meal, and vaporized another group just to make sure the first group was actually alive. It would be a strange introduction to a new species.
Of course, the thought experiment falls short, because microbes are typically considered expendable on an individual level, which is not the case for complex life forms such as humans, but it is still an interesting reflection of our values about first contact. In that sense, while we can’t help but kill a few microbes here and there (whether on Earth or possibly in space), entire ecosystems are another story.
The Committee on Space Research, an international non-governmental organization dedicated to collaboration in space exploration, Prohibits any activity This would pose a threat to the alien biosphere, or indeed to life on our own world. This principle of “planetary protection” is intended to prevent the transfer of terrestrial life to other worlds (forward contamination) or of alien life to Earth (backward contamination).
“With the Viking mission, great care was taken not to introduce any terrestrial organisms that could potentially disturb the existing Martian biosphere,” David Grinspoon, senior scientist for astrobiology strategy at NASA Headquarters, said in an emailed response that included input from Nick Benardini, NASA’s planetary protection officer.
