Checklist for Finding Utterly Bizarre Extraterrestrials
According to Christopher McKay, the director of NASA's Ames Research Center in California, the criteria that astronomers routinely check in order to decide whether or not a discovered exoplanet could be considered habitable are due for an update. McKay argues that newly discovered exoplanets are often disqualified from the quest for extraterrestrial life, simply because they don't meet certain conventional conditions for life, such as a certain distance from stars and a rocky surface.
According to McKay, these criteria are restrictive, outdated, and could prevent us from finding forms of life that are right in front of us. Based on some of the more obscure life forms thriving on our own planet, McKay proposes a new checklist of seemingly-other-worldly life forms that could thrive on exoplanets that don't meet all of the conventional criteria for habitability.
-Life on a planet with frozen or boiling temperatures
There are microorganisms on Earth that are able to metabolize in temperatures as low as -25 degrees Celsius (well below the freezing point), and as high as 122 degrees Celsius (well above the boiling point).
-Life on a planet with almost no water
According to McKay, a world with very little water could still host life. Earth's very own cyanobacteria live inside rocks in the nearly water-less Atacama Desert of Chile. "You don't need a Pacific Ocean [to host life]" argues McKay. "A planet like the fictional world in http://www.outerplaces.com/movies-decades/item/1763-dune">Dune would be habitable, though you may not have sand worms."
-Life on a planet with very little light
Photosynthesis can function with very little sunlight as seen by Earth's deep-sea red macro-algae that receive less than 1 percent of the sunlight that organisms on Earth's surface receive.
- Life on a planet bombarded with exposure to a Star
We humans are much more prone to the dangers of UV rays due to our thin exposed skin, but organisms such as Deinococcus radiodurans, the toughest bacterium in the world, could survive the conditions inside a nuclear reactor.
- Life on a planet with little to no oxygen
We always associate life with the consumption and production of oxygen, but unlike nitrogen, oxygen isn't always necessary for life to exist. Even some earthly creatures, like the Actinomyces genus function with very little to no oxygen, and are in fact allergic to it. Nitrogen, however, is the most essential building-block to the formation of DNA. According to McKay, "It's hard to imagine a kind of life that isn't going to need lots of nitrogen."
These atypical organisms might just become the aliens of the future. Maybe instead of monster movies about Godzilla-size creatures, there should be a wave of sci-fi creature features about the tiniest of bacteria. Not only would it, according to McKay, be more realistic, but it would open the door to a whole host of frightening possibilities: parasites, pandemics, mind control, and, of course, Alien-style body horror.