For a species that is so often looking up to the stars thinking ‘are we alone?’, we tend to populate our fictional universes with less than benevolent compatriot species. Look at some of the more popular science fiction movies and stories to be released in the last century. War of the Worlds, Alien and even the recently released Life all approach the question of extraterrestrial life the same way: it’s out there, and it’s out to get us.
Since it is such a speculative field, there is virtually no consensus on how we might react upon first contact, simply because we don’t know what sort of aliens will turn up. The developing view is that, if there is other life in the universe it’s likely to be microbial in nature. If there is anything that the much-lauded tardigrades have taught us, it is that microbial life will find a way to survive. Therefore, most space-based programs are focused on the detection of this so called primitive life (Is it fair to call it primitive when they can do some pretty amazing things?).
Most missions have focussed on our closest sister, Mars, and its dry riverbeds that provide some tantalising bits of evidence that all might not be dead on the red planet. Methane is unusually high in the Martian atmosphere. As a gas that is highly reactive and therefore tends to disappear without regular top ups, this is indicative that something is replenishing it. Methane in our own atmosphere is typically produced from biotic sources; meaning that, from our experience, traces of methane might be indicative of life.
Of course, alternative theories exist for the presence of methane, including geological sources of the gas. But what if our rovers were to discover bacteria living on the surface of the red planet? What would we do with it? Well it wouldn’t be coming to our planet anytime soon – none of the rovers currently on the planet are equipped for that sort of mission. Even then, the samples would have to be tested and tested again to ensure that they aren’t just contaminants from Earth. They’re unlikely to alive by the time they reach Earth under strict contamination procedures. So, don’t worry, no Martian plague will be giving you the sniffles.
Image Credit: Max Pixel
Anywhere else we are currently scouting for life would face similar contamination issues. Europa for instance, one of Jupiter’s larger moons, is being targeted as our next life-seeking venture to the stars. With an ocean thought to be buried underneath its permanent ice-sheet casing, many scientists believe that ocean temperatures may just be warm enough to support the development of life, if again, simple in nature.
So that basically covers what’s known; in our solar system – at least there won’t be any tripods bursting out the ground anytime soon to exterminate us and Tom Cruise! But what about farther afield? Well, many radio telescopes are turned to the farthest reaches of our galaxies; and news publishers love a good story of astronomers finding ‘habitable’ exoplanets. If you pay attention to the Drake equation, there should be 1,000 to 100,000 intelligent civilizations in our galaxy. So why haven’t we heard from our cosmic neighbours.
There are many reasons that we might not have heard from them, and many reasons we should be thankful for that. If we’ve learnt anything from our own behaviour on Earth, the less technologically advanced society rarely survives first contact with a more advanced society. The most glaring example of this is the fate of the Native Americans in the wake of Europeans discovering the New World.
This is the cautionary tale that Stephen Hawking told in 2010 when questioned about our first meeting with E.T. On the other hand, many scientists question the validity of Hawking’s reasoning. As mentioned above, many are more worried about what the aliens bring with them accidentally rather than deliberately. As illustrated in H. G. Wells’ famous novel The War of the Worlds, contact with a previously unencountered pathogen can be devastating to any organism. Whether it was the Mayans and typhoid and influenza, to African swine fever in the American pork industry, foreign pathogens tend to wipe out whole communities before any resistance can develop. Just ask the abandoned Mayan cities of the Amazon.
Of course, other questions arise which are a bit harder to answer. What if the alien civilization is warlike? What if their ethics system is not comparable to ours? What if, and this has been considered, we are the ‘life, but not as we know it’ variety in the universe? Many astrobiologists have postulated that silicon based lifeforms may exist (we are carbon based), so what if we’re just too alien for them to visit?
An even sadder alternative is that we are truly alone, that alien life is non-existent, (considered highly unlikely) or that we are one of the first intelligent civilizations to evolve in the galaxy. Perhaps intelligent life is the exception rather than the rule. The Fermi paradox points to how extremely unlikely our own path to survival was. Maybe many creatures on that road seemly get snuffed out by Natural Selection before that point.
In any case, what keeps many scientists up at night is not thoughts of alien invasions, but thoughts of alien illnesses. Perhaps what we should be preparing for, and indeed looking for, is what makes little green men feel ill.