Editor's note: This column originally published March 19, 2015
The first time I saw the solar system’s giant Jupiter was outside Pancheros. In Iowa City during my college years, midnight runs to get a fresh burrito, pop, chips and quesso were a common occurrence.
On the sidewalk corner near the downtown Mexican restaurant, a University of Iowa graduate student in astronomy sat on a five gallon bucket next to a tip jar and a small telescope pointed toward the heavens. Downtown Iowa City on a Friday night is a bright place, full of light pollution. But even the college town’s night life is no match for one of the brightest objects in the night’s sky.
It turns out the spirits-filled students of UI are perfect customers for a cosmic entrepreneur. The young astronomy student made solid tips that evening showing teens and twenty-somethings, filled with liquid joy, trippy out-of-this-world sights. When I peered through that telescope, I saw the famous red eye of Jupiter and its four largest moons. This began my long-time love affair with the planet and its four Galilean satellites.
Astronomers have become enamored with the largest moons of Jupiter and Saturn in the past two decades. Jupiter’s moon Europa is one of the largest bodies in the solar system with a possible subsurface ocean. Like Saturn’s moon Enceladus, Europa has a “young surface” shaped by geological activity. Scientists hypothesize the surface is recycled by ocean currents underneath, treating the ice sheets as tectonic plates here on Earth. Both moons also have geysers on their surface, shooting salty, water ice into the vacuum of space sometimes hundreds of miles above the ice crust.
NASA announced March 11 that another Galilean moon —Ganymede — also shows evidence of a subsurface ocean. The space agency announced plans earlier this year to send a “Clipper” probe to Europa with an expected launch in 2022. This will fly through the geysers’ water ice testing for organic compounds such as carbon or even for traces of microbial lifeforms.
The water is kept liquid on these moons due to tidal friction — the pulling and tugging on these planetary bodies’ crust and cores from the gravitational pull of their host gas giants. This repetitive action happens as the moons orbit the planets and generates heat.
Scientist believe the crust of the moons are made of silica-based material — aka rock. On earth, when salty water is churned against organic material in rock and paired with a heat source over millions/billions of years, life emerges. It’s the mantra of the scientific community: “Where there’s water, there’s life.”
The importance of exploring these icy moons can not be overstated. The effect on society of finding life on another planet would be profound, but finding life elsewhere in our own planetary backyard would suggest life is common throughout the universe.
This is the best time in human history to be a planetary science nerd. For the first time our species has the technology to find and prove whether life exists beyond our tiny blue dot. My love for burritos has brought more wonder to my life than I possibly could have imagined.