The Search for Life on Europa

For as long as I can remember, Hollywood has often fantasized about the existence of extraterrestrial life in our solar system. Movies like Independence Day come to mind, where the alien race is super-intelligent, unforgivably evil, and morphologically terrifying. In reality, scientists and astrobiologists envision a different, more realistic picture of our friendly neighborhood ET: amino acid-based microorganisms, similar to chemosynthetic bacteria and archaea living near hydrothermal vents here on Earth.

We won't be finding him on Europa

Earlier this month, NASA announced that the Obama administration had proposed a $500 million increase for the space agency’s 2016 fiscal year. In total, the $18.5 billion budget aims to cover costs related to a variety of endeavors, such as continued Mars exploration and maintenance to the International Space Station. In early 2015, congress granted NASA $100 million to design a trip to Europa, Jupiter’s ice-covered moon that is an exciting prospect for extraterrestrial life. President Obama’s proposed budget will tack on $30 million to the project, giving NASA the go-ahead to begin development on the planned 2022 mission.

Europa in all its glory

Of the 67 confirmed moons of Jupiter, Europa cannot help but stand out from the rest. It is layered in thick ice, and geological activity related to tidal flexing leaves researchers believing that a liquid ocean exists under its icy crust. Water is a universal solvent – allowing life’s basic components (DNA, proteins, etc) to have a place in which they can exist and interact. In addition to water, Europa has an atmosphere composed primarily of oxygen, and some researchers have theorized that the ocean may have high enough oxygen levels to be considered capable of supporting macroscopic organisms similar to fish.

If life exists in the deep oceans of Europa, it would most likely resemble small, microbial organisms found living near deep-ocean hydrothermal vents. These organisms rely not on photosynthesis, but instead on chemosynthesis – which involves the conversion of carbon molecules into organic matter through the oxidation of inorganic compounds. Through chemosynthesis, life can prosper without sunlight as long as there is an energy gradient capable of synthesizing organic reactions. 

General mechanism of chemosynthesis

As our hunger for knowledge expands to the depths of our solar system, the search for alien life -- though different from science fiction portrayals – is as realistic as ever thanks to the newest NASA funding round. A mission to Europa could get us one step closer to recognizing biomarkers that suggest we are not alone in this universe. It is reassuring to recognize that our government is willing to allocate resources to the Europa space mission, and hopefully the exploration will grant us a better understanding of our solar system and of life itself.
 

Artist's rendition of Europa's icy surface

Posted by Michael Salhany (3C)