Sunday, August 4, 2013

Monsters from Outer Space

Tentacled Alien Monster in Ames, IA (Aug 4, 2013)

The other night, when I was writing about the green monsters infestation in my garden, it came to my mind how common is our fascination with monsters. It is something that can be found in any culture, and at any time. It doesn't matter what we believe and what we know, there is always a corner of our mind where the shadow lurks, ready to conjure some supernatural being as an explanation to something we cannot explain otherwise. Many of these monsters have a base in reality, but become larger and more mysterious, magical, terrifying as their story gets repeated and recreated from mouth to ear to a new mouth. As strange and alien as they may seem, though, these monsters are nothing else than the projection of our minds. As such they retain the familiarity of our experience, fear, emotions. This familiarity makes them less alien, in the end. They are part of us.

I was thinking of this as I was watching the trailer of "The Europa Report", a science fiction movie that came out in the last few days. I still didn't see the movie, so don't worry, you won't find here any spoiler, just speculations. The movie tells the story of a mission to Europa, one of the four main moons of Jupiter. Europa is a world of ice and fire. It is close enough to Jupiter than its core is heated by tidal effects, but far enough that this internal heat is not sufficient to keep its surface above water's freezing temperature. The result is that Europa is covered by a thick crust of ice, under which it is believed to exist a vast ocean of liquid water, possibly rich of mineral and oxygen brought up by its underwater vulcanism powered by its tidal heat. The conditions on Europa may be, in fact, quite similar to the conditions that are found on Earth at the bottom of our oceans. These are conditions where life can exist, which is something that makes Europa the grand prize of planetary exploration, the best site where we can look for extraterrestrial life. Genuine alien monsters. Without having watched the movie, I don't know if the crew landing on that moon and penetrating the ice will find anything alive. I wish one day we could put together enough resources and technology to go and see for real. By judging at the resilience of life on every nook and cranny on Earth's surface, oceans and rocks, I am led to believe that the emergence of life is something as inevitable as sunset being followed by sunrise. But we really don't know, because we have only one example to refer to (Earth) and a statistics of one doesn't really count.

The question however remains: if we will find life outside our planet, will it be monsters ready to pounce on us, eat us, or use us as incubators for their larvae like the monsters in the Alien movie series? I seriously doubt that. The building blocks of all life on Earth are proteins, and proteins are made with smaller blocks called amino acids. All eukaryote cells (cells like the one in animals and plants) are mades with just 21 different amino acids. These 21 amino acids are however just a small portion of all possible known amino acids, In fact we know how to build about 500 different amino acids using the same basic arrangement of atoms of the 21 used by eukaryote life. Not only that, but each amino acid can exist in two symmetric forms (left- or right-handed): all eukaryote life uses the left-handed form of these 21 amino acids. This is not entirely surprising, as all life on Earth has evolved from a common ancestor, starting from the same building blocks. An effective ecosystem requires its members to be able to eat each other which has preserved the need of using the same set of chemicals through all different species. The end result is that life on Earth is remarkable homogeneous.

A bee in my garden!
This doesn't mean, however, that the same evolutionary solution must be found every time that life emerges. This is what worked and survived on Earth, with the specific challenges of Earth environment through the ages. Life on Europa, Mars on any other exoplanet of exomoon will likely find different challenges and different environments, so the evolutionary result may be quite different than our 21 left-handed amino acids. They may use any of the other 500 amino acids to make proteins. They may be right-handed. And if this is the case, I doubt that we will find monsters ready to devour us to satiate their infinite hunger for human flesh: our meat will likely be like poison for them, evolved to prey on different chemicals in a different ecological niche. That doesn't mean, of course, that the Europa Report movie, even if it manages to be scientifically correct (local aliens not really interested in eating us) will be a boring flick without monsters. Ghosts scare people to death even if they cannot touch them. Sharks sometime attack people even if human meat is not of a good taste for them: sharks usually bite people when they are provoked, or when they confuse swimmers for seals, and spit after biting (not that this is of much consolation for the person that is bitten). Alien monsters may provide the thrill for a successful sci-fi movie even if they cannot successfully eat us!

The alien-tentacled-monster above is just the stamen filaments of a flower in my garden: not very alien and not very monstrous. But monsters exists in our mind, so we can see them anywhere. Also, there is something else I found today in my garden: a bee! See photographic proof on the left. Not a run-of-the-mill western honey bee, but a bee nevertheless. There is still hope.

Jupiter, Europa, Ganymede and Callisto as photographed by my students last fall

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